Decision Making in Emergency Medicine: Biases, Errors and Solutions [1st ed. 2021] 9789811601422, 9789811601439

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Decision Making in Emergency Medicine Biases, Errors and Solutions Manda Raz Pourya Pouryahya Editors

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Decision Making in Emergency Medicine

Manda Raz  •  Pourya Pouryahya Editors

Decision Making in Emergency Medicine Biases, Errors and Solutions

Editors Manda Raz Department of Emergency Medicine Monash Health Clayton Australia

Pourya Pouryahya Consultant Emergency Physician Director of Emergency Medicine Research (DEMR) Department of Emergency Medicine Casey Hospital, Monash Health Victoria Australia Adjunct Associate Professor School of Clinical Sciences Department of Medicine Monash University Victoria Australia

ISBN 978-981-16-0142-2    ISBN 978-981-16-0143-9 (eBook) https://doi.org/10.1007/978-981-16-0143-9 © Springer Nature Singapore Pte Ltd. 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Preface

Decision Making in Emergency Medicine is a unique publication that discusses a frequently overlooked aspect of emergency medicine which can impede the process of arriving at and justifying clinical decisions—cognitive biases. Unlike in other specialties, the emergency medicine work environment is especially prone to distractions and limitations, potentially compromising clinical judgement and problem-­ solving. The purpose of this book is to describe scenarios when errors, biases and systemic barriers prevail, discuss their impact, then offer solutions to mitigate their undesired outcomes. This is achieved through cases written by a team of emergency specialists and trainees who outline, in an engaging format, information pertinent to the practicing and teaching emergency doctor. Clayton, VIC, Australia Berwick, VIC, Australia 

Manda Raz Pourya Pouryahya

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Contents

1 We Can’t Escape Bias��������������������������������������������������������������������������������   1 Justin Morgenstern 2 Aggregate Bias��������������������������������������������������������������������������������������������   9 Khin Moe Sam 3 Ambiguity Bias ������������������������������������������������������������������������������������������  15 Elizabeth Sheffield 4 Anchoring Bias ������������������������������������������������������������������������������������������  21 Michail Kosmidis 5 Ascertainment Bias������������������������������������������������������������������������������������  29 Phillippa Wills 6 Attentional Bias������������������������������������������������������������������������������������������  35 Phillippa Wills 7 Authority Bias��������������������������������������������������������������������������������������������  41 Carly Silvester 8 Availability Bias������������������������������������������������������������������������������������������  47 Justin Morgenstern 9 Bandwagon Effect��������������������������������������������������������������������������������������  53 Carl Luckhoff 10 Base Rate Neglect��������������������������������������������������������������������������������������  59 Justin Morgenstern 11 Belief Bias ��������������������������������������������������������������������������������������������������  65 Elizabeth Sheffield 12 Blind Spot Bias ������������������������������������������������������������������������������������������  71 Charley Greentree 13 Commission Bias����������������������������������������������������������������������������������������  77 Anton Musiienko

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14 Confirmation Bias��������������������������������������������������������������������������������������  83 Michail Kosmidis 15 Congruence Bias����������������������������������������������������������������������������������������  89 Carl Luckhoff 16 Contrast Effect ������������������������������������������������������������������������������������������  97 Elizabeth Sheffield 17 Decision Fatigue Effect������������������������������������������������������������������������������ 103 Xiu Qing Lee 18 Deformation Professionnelle Bias������������������������������������������������������������ 111 Khin Moe Sam 19 Diagnostic Momentum Error�������������������������������������������������������������������� 117 William Ryan 20 Dunning-Kruger Effect ���������������������������������������������������������������������������� 123 Lisa TenEyck 21 Ego Bias������������������������������������������������������������������������������������������������������ 129 Myles Sri-Ganeshan 22 Expectation Bias���������������������������������������������������������������������������������������� 135 Elizabeth Sheffield 23 Feedback Sanction ������������������������������������������������������������������������������������ 141 Khin Moe Sam 24 Framing Effect ������������������������������������������������������������������������������������������ 147 Michail Kosmidis 25 Fundamental Attribution Error �������������������������������������������������������������� 153 Michail Kosmidis 26 Gambler’s Fallacy�������������������������������������������������������������������������������������� 159 Fiona Bowles 27 Gender Bias������������������������������������������������������������������������������������������������ 167 Kim Hansen 28 Hawthorne Effect �������������������������������������������������������������������������������������� 173 Kim Hansen 29 Hindsight Bias�������������������������������������������������������������������������������������������� 179 Khin Moe Sam 30 Illusory Correlation ���������������������������������������������������������������������������������� 185 Fiona Bowles 31 Information Bias���������������������������������������������������������������������������������������� 195 Lisa TenEyck

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32 Inter-Group Bias���������������������������������������������������������������������������������������� 201 Nicola Biggs 33 Mere Exposure Effect�������������������������������������������������������������������������������� 209 Phillippa Wills 34 Modality Effect������������������������������������������������������������������������������������������ 215 Myles Sri-Ganeshan 35 Multiple Alternatives Bias ������������������������������������������������������������������������ 221 Carl Luckhoff 36 Need for Closure Bias�������������������������������������������������������������������������������� 229 Carl Luckhoff 37 Negativity Bias�������������������������������������������������������������������������������������������� 237 Xiu Qing Lee 38 Neglect of Probability Bias������������������������������������������������������������������������ 245 Robyn Parker 39 Omission Bias �������������������������������������������������������������������������������������������� 251 Anton Musiienko 40 Order Bias�������������������������������������������������������������������������������������������������� 257 Lisa TenEyck 41 Outcome Bias���������������������������������������������������������������������������������������������� 263 Xiu Qing Lee 42 Overconfidence Bias���������������������������������������������������������������������������������� 271 Kim Hansen 43 Planning Fallacy���������������������������������������������������������������������������������������� 277 Carly Silvester 44 Playing the Odds Bias�������������������������������������������������������������������������������� 281 Khin Moe Sam 45 Posterior Probability Bias ������������������������������������������������������������������������ 287 Kim Hansen 46 Premature Closure ������������������������������������������������������������������������������������ 293 Charley Greentree 47 Psych-Out Error���������������������������������������������������������������������������������������� 301 Michelle Snape 48 Reactance Bias�������������������������������������������������������������������������������������������� 307 Nicola Biggs 49 Representativeness Restraint�������������������������������������������������������������������� 313 Phillippa Wills

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50 Reverse Ego Bias���������������������������������������������������������������������������������������� 319 Myles Sri-Ganeshan 51 Search Satisfaction������������������������������������������������������������������������������������ 325 Khin Moe Sam 52 Self-Serving Bias���������������������������������������������������������������������������������������� 331 Carl Luckhoff 53 Semmelweis Reflex������������������������������������������������������������������������������������ 339 Charley Greentree 54 Status Quo Effect �������������������������������������������������������������������������������������� 345 Robyn Parker 55 Sunk Cost Bias������������������������������������������������������������������������������������������� 351 Carly Silvester 56 Sutton’s Law and Sutton’s Slip���������������������������������������������������������������� 357 Phillippa Wills 57 Triage Cueing Error���������������������������������������������������������������������������������� 363 Michelle Snape 58 Unpacking Principle Error ���������������������������������������������������������������������� 371 Charley Greentree 59 Visceral Bias ���������������������������������������������������������������������������������������������� 377 Michelle Helen Snape 60 Yin Yang Out Error ���������������������������������������������������������������������������������� 383 Charley Greentree 61 Zebra Retreat �������������������������������������������������������������������������������������������� 389 Pourya Pouryahya

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We Can’t Escape Bias Justin Morgenstern

As this book clearly demonstrates, the human mind is imperfect. We all make mistakes. We are all susceptible to bias. Through learning about the various cognitive biases, and identifying some strategies to mitigate common errors, the hope is that readers will be able to avoid future mistakes. Unfortunately, there are limitations to the application of cognitive theory in medicine. Even armed with the wealth of knowledge provided by this book, we will still make mistakes. It is unlikely that we will ever completely eliminate medical error. The decisions we make are incredibly complex, and the human mind is inherently fallible. Integrating what we know about cognitive theory and psychology into medicine is a logical step forward, but there are significant limitations, both theoretical and practical, to the application of cognitive theory in medicine. This chapter explores some of those limitations.

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Theoretical Problems

An assumption that underlies much of this book is that, although the human mind is fallible, it also has the tools to self-correct. This is often explained in terms of dual process theory. Most of our thinking is rapid, unconscious, and intuitive—system 1 thinking. However, system 1 thinking is also prone to bias. Luckily, we are also capable of slower, more contemplative, analytical thought—system 2 thinking. Most proposed solutions for biased thinking involve recognizing faulty type 1 thinking, and shifting to the presumably more accurate type 2 thinking. However, this simple blueprint may be misleading. Type 1 thinking is not always bad and type 2 thinking is not always better. In fact, especially when it comes to experts like physicians, it isn’t clear that thinking is so easily dichotomized. The J. Morgenstern (*) University of Toronto, Toronto, ON, Canada e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_1

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clean distinction between type 1 and type 2 thinking is based largely on studies of undergraduate students, usually performing tasks in which they lack expertise, and so it isn’t clear that these results are applicable to expert medical decision making. The heuristics employed in type 1 thinking are efficient mental strategies that help us deal with uncertainty and ambiguity. Experts often use heuristics very effectively. In fact, in some scenarios, heuristics may lead to better decisions than analytical thinking [1–3]. Discussions about cognitive biases tend to overemphasize the harms of using heuristics, while ignoring their many benefits. In medical emergencies, the speed of (well trained) type 1 thinking is almost certainly more important than the accuracy of formal analytic thought. Although it occasionally fails, it is important to recognize that type 1 thinking is not inherently bad [4–6]. Similarly, although analytic thought results in more accurate decisions in some settings, it is by no means infallible. In fact, conscious reasoning can sometimes produce worse results, because type 2 thinking puts a heavy load on working memory, which has significant limitations [5]. Furthermore, many of the described cognitive biases also impair type 2 thinking. For example, premature closure and confirmation bias are both phenomena that arise during data gathering and synthesis, and are therefore more likely to be associated with type 2 thinking [5, 7]. A final and significant problem for dual process theory is the poorly defined interface between systems 1 and 2. How exactly is one supposed to effectively and consistently transition from type 1 to type 2 thinking? System 1 is generally described as always active, rapidly sorting through the avalanche of available data. Meanwhile, system 2 is described as monitoring system 1 and making corrections as necessary. However, it is not clear how that monitoring happens. What triggers the transition from system 1 to system 2? The act of monitoring would seem to require rapid analysis and pattern recognition to identify possible errors. Thus, the monitoring of system 1 sounds like a system 1 process, which presumably would also be prone to the same type of errors. If we want to correct errors, we need to be able to recognize those errors. Strategies to mitigate cognitive errors are based on the major assumption that we have active control over our decision making processes. They assume that, in the moment, we will be able to recognize that our thinking is biased and flip from non-­ analytical to analytical thinking. Unfortunately, there is little evidence that this process occurs reliably [2]. It seems like a simple task—we recognize errors in other people’s thinking all the time. However, the blind spot bias tells us that we have a much harder time identifying our own biases. In fact, a core paradox of cognitive theory is that you cannot know that you are wrong. While in the midst of making a mistake, being wrong feels exactly like being right [6]. Thus, although we can recognize past errors, there is actually no mechanism that alerts us that we are currently wrong. Much like understanding the concept of a visual blind spot does not eliminate the blindness, simply understanding the existence of cognitive biases does not prevent them from occurring. In fact, Daniel Kahneman (the Nobel Prize winning originator of dual process theory) says that after 30 years of study, although he can more readily recognize errors in others, he isn’t sure that he is any better at avoiding these biases himself [8].

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 iases Are Often More Complex than We Make B Them Seem

Individual biases are generally more complex than we initially realize. We tend to talk about biases as dichotomous. We either committed an error or we didn’t; our thinking was either biased or it wasn’t. However, much of the research describes behavior that falls into a grey area between those two extremes. For example, although the original research on base rate neglect involved participants completely ignoring the base rate, further research has made it clear that the base rate is often considered, and errors, when they occur, mostly arise from not fully adjusting for the base rate, rather than completely ignoring it. Furthermore, the extent of the error is significantly influenced by the specifics of the scenario, and many “biased” results can be explained by rational thinking that simply conflicts with researcher expectations [9, 10]. The majority of the research establishing cognitive biases was performed in carefully controlled laboratory settings, usually with college undergraduates as the subjects. This is important because there is evidence that experience can reduce or eliminate biased thinking. For example, athletes demonstrate much better statistical intuition when a problem is presented using a sporting example, as compared to when the same problem is presented in a less familiar context [11]. Similarly, a classic puzzle used to demonstrate confirmation bias involves asking participants to prove the rule “if a card has a vowel on one side, it has an odd number on the other side.” In this abstract, non-intuitive example, people frequently demonstrate confirmation bias. However, if you present people with the exact same problem using a real-world example (“prove that if a person is drinking beer, that person must be over 18 years of age”), participants perform almost perfectly [9]. Therefore, we should not automatically assume that the biases described in laboratory settings generalize to expert clinicians [7].

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Studies in Medicine Are (Thus Far) Underwhelming

The true incidence and impact of cognitive biases in medicine is unknown. The evidence is incomplete and imperfect. According to one meta-analysis, the majority of studies looking at cognitive bias in medicine did not take place in real clinical scenarios, but instead employed paper-based or simulated vignettes, often done by trainees, and therefore may not generalize well to clinical practice [12]. Studies that have attempted to examine bias in clinical settings have generally been retrospective and focused on known misdiagnoses rather than all clinical decisions. Therefore, the results will be skewed by significant hindsight bias and selection bias. Any attempt to classify medical bias retrospectively is fraught with problems. When assessing cases, experts frequently disagree about which biases might be present. When looking at the same case, experts are twice as likely to identify biases if they are told the clinician chose the wrong diagnosis, a clear indication of hindsight bias [13]. Similarly, whether or not physicians believe an error has occurred is heavily influenced by the patient outcome [14].

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There seems to be a general consensus in medicine that diagnostic errors are more likely to result from cognitive errors than knowledge deficits. However, the evidence for this claim is somewhat unconvincing. One of the most frequently cited studies, a 2005 survey by Graber et al., is a retrospective analysis of 100 cases of known diagnostic error. They state that knowledge deficits were only involved in four cases, whereas faulty synthesis of data (such as premature closure) was involved in the vast majority. However, it is almost impossible to distinguish premature closure from a scenario in which a diagnosis was not considered because it was unknown to the clinician, or because a known disease presented in an unknown way (in other words, from a knowledge deficit) [15]. In fact, knowledge deficits (whether medical or statistical) could explain a lot of decisions that appear to be affected by bias. Thus, knowledge deficits may be an underestimated cause of diagnostic error [5]. Furthermore, addressing knowledge is the best technique we currently have to improve medical decision making. That being said, considering the sheer number of decisions we make in medicine, and the large number of possible biases, it is likely that these biases play an important role in medical error. Assuming that our decisions are impacted by these biases, the more important questions are how and if we can prevent these errors. Unfortunately, the evidence that biases can be mitigated in medicine is mixed, with the bulk of the trials showing no benefit. There are a few trials that demonstrate improved diagnostic accuracy by trainees on paper-based vignettes when more time is taken for reflection [16, 17]. However, Sherbino et  al. (2012) actually demonstrated more errors occurred when trainees were instructed to slow down and be thorough [18]. Numerous other studies have demonstrated no difference in accuracy between clinicians instructed to work rapidly and those instructed to work slowly and thoroughly [19–22]. Three studies looked at educational interventions designed to improve diagnostic thinking by educating students about cognitive biases (meta-cognition). Another study attempted to use a cognitive debiasing checklist, with questions such as “did I consider the inherent flaws of heuristic thinking?” None of these interventions have resulted in improved accuracy [23–26]. Considering the potential extent of the problem, there has been relatively little research into potential solutions. The failures thus far are a sobering reminder of the complexity of human cognition. We should probably be skeptical of overly simplistic solutions. Our training as medical experts spans many years, and our training in critical thinking (whether formal or informal) started many years before that. It is doubtful that simple instructions to “think about our thinking” will be enough to change the momentum of our ingrained strategies. However, I don’t think these early failures should dissuade us. You wouldn’t decide that a child has no musical ability after only a month of piano lessons, but our early attempts at teaching cognitive debiasing look a lot more like that month than 10,000 h of deliberate practice. We need more research, and we need to find ways to train doctors to use their cognitive resources efficiently and effectively.

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Recognizing Potential Harms

Although improving medical decision making seems like a clear win, I think it is important to consider the potential harms of applying cognitive theory in medicine. The most obvious harm is opportunity cost. Thus far, there is no evidence that cognitive debiasing techniques improve decision making or patient outcomes. Time is a precious resource in medicine. If cognitive theory does not improve outcomes, the time and effort required to create curricula, teach, and learn this new material could be better used elsewhere. Likewise, in eschewing rapid heuristics and promoting slow analytic thought, debiasing techniques are likely to make the practice of medicine less efficient. This inefficiency would be worthwhile if it translates into better decisions. However, to date there is no evidence that these debiasing techniques are effective, so the inefficiency is just inefficient. In a worst case scenario, attempts to use slower analytic thinking in medical emergencies could result in delays to critical interventions and bad patient outcomes. Attempts to avoid cognitive biases could also result in substantial costs. Confirmation bias tells us to focus on ruling out alternatives, rather than searching for confirmatory evidence. However, there are always numerous potential alternative diagnoses. If the solution to confirmation bias is understood as requiring tests to rule out each of those alternatives, the result could be significant increases in testing, costs, and harms to our patients. A more subtle harm is the potential for attempts at debiasing to actually increase error. Many of the described biases exist at opposite ends of a spectrum. Avoiding one may cause us to necessarily commit the other. For example, the chapter on base rate neglect reminds us to consider the base rate whenever we make diagnostic decisions. Rare conditions are rare, and shouldn’t be pursued frequently. However, in avoiding the workup of rare conditions, we are falling into another cognitive bias: the zebra retreat. Rare conditions, although rare, do happen, so need to be worked up. The solution to one bias necessarily leads us towards another.

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Summary

Although there seems to be little doubt that cognitive biases play some role in medical error, the extent of their impact is not clear. Most importantly, it isn’t clear if these biases can be prevented, and if so, how. Thus far, attempts to mitigate cognitive biases through educational programs in medicine have mostly failed, although the research has been quite limited thus far. It is also important to acknowledge that many of the processes described as biases are really heuristics that are frequently used to efficiently and accurately arrive at a correct diagnosis. When attempting to improve our cognition, we need to be careful not to throw the baby out with the bathwater. How should the practicing clinician proceed? As we are used to with most scientific reviews, the conclusion is: more research is needed. I am reassured by evidence

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that more experienced physicians are less prone to bias than trainees [25, 27]. It is likely that we can teach ourselves to be more effective thinkers, but we are a long way from understanding the full impact of these biases on medical practice, and more importantly the techniques that may help prevent them. In the meantime, astute clinicians will endeavor to learn about these biases, attempt to identify specific areas of cognitive reasoning that might be improved, and, most of all, remain humble in their clinical reasoning.

References 1. Croskerry P. Diagnostic failure: a cognitive and affective approach. In: Henriksen K, Battles JB, Marks ES, Lewin DI, editors. Advances in patient safety: from research to implementation, vol. 2. Concepts and methodology. Rockville, MD: Agency for Healthcare Research and Quality (US); 2005. 2. Eva KW, Norman GR. Heuristics and biases—a biased perspective on clinical reasoning. Med Educ. 2005;39(9):870–2. 3. Monteiro SM, Norman G. Diagnostic reasoning: where we’ve been, where we’re going. Teach Learn Med. 2013;25(S1):S26–32. 4. Tversky A, Kahneman D.  Judgment under uncertainty: heuristics and biases. Science. 1974;185(4157):1124–31. 5. Norman GR, Eva KW. Diagnostic error and clinical reasoning. Med Educ. 2010;44(1):94–100. 6. Dhaliwal G. Premature closure? Not so fast. BMJ Qual Saf. 2017;26(2):87–9. 7. Norman GR, Monteiro SD, Sherbino J, Ilgen JS, Schmidt HG, Mamede S. The causes of errors in clinical reasoning. Acad Med. 2017;92(1):23–30. 8. Kahneman D. Thinking, fast and slow. New York: Farrar, Straus and Giroux; 2011. 9. Klayman J. Varieties of confirmation bias. Psychol Learn Motiv. 1995;32:385–418. 10. Koehler JJ.  The base rate fallacy reconsidered: descriptive, normative, and methodological challenges. Behav Brain Sci. 2010;19(1):1–17. 11. Nisbett RE, Krantz DH, Jepson C, Kunda Z. The use of statistics in everyday inductive reasoning. Psychol Rev. 1983;90:339–63. 12. Saposnik G, Redelmeier D, Ruff CC, Tobler PN.  Cognitive biases associated with medical decisions: a systematic review. BMC Med Inform Decis Mak. 2016;16(1):138. 13. Zwaan L, Monteiro S, Sherbino J, Ilgen J, Howey B, Norman G.  Is bias in the eye of the beholder? A vignette study to assess recognition of cognitive biases in clinical case workups. BMJ Qual Saf. 2017;26(2):104–10. 14. Caplan RA, Posner KL, Cheney FW. Effect of outcome on physicians’ judgments of appropriateness of care. JAMA. 1991;265:1957–60. 15. Graber ML. Diagnostic error in internal medicine. Arch Int Med. 2005;165:1493–9. 16. Mamede S, Schmidt HG, Rikers RM, Penaforte JC, Coelho-Filho JM. Influence of perceived difficulty of cases on physicians’ diagnostic reasoning. Acad Med. 2008;83:1210–6. 17. Hess BJ, Lipner RS, Thompson V, Holmboe ES, Graber ML. Blink or think: can further reflection improve initial diagnostic impressions? Acad Med. 2015;90:112–8. 18. Sherbino J, Dore KL, Wood TJ, Young ME. The relationship between response time and diagnostic accuracy. Acad Med. 2012;87:785–91. 19. Ilgen JS, Bowen JL, Yarris LM, Fu R, Lowe RA, Eva K. Adjusting our lens: can developmental differences in diagnostic reasoning be harnessed to improve health professional and trainee assessment? Acad Emerg Med. 2011;18(S2):S79–86. 20. Ilgen JS, Bowen JL, McIntyre LA, Banh KV, Barnes D, Coates WC, et al. Comparing diagnostic performance and the utility of clinical vignette-based assessment under testing conditions designed to encourage either automatic or analytic thought. Acad Med. 2013;88:1545–51.

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21. Norman G, Sherbino J, Dore K. The etiology of diagnostic errors: a controlled trial of system 1 versus system 2 reasoning. Acad Med. 2014;89:277–84. 22. Monteiro SD, Sherbino JD, Ilgen JS, Dore KL, Wood TJ, Young ME, et al. Disrupting diagnostic reasoning: do interruptions, instructions, and experience affect the diagnostic accuracy and response time of residents and emergency physicians? Acad Med. 2015;90:511–7. 23. Sherbino J, Yip S, Dore KL, Siu E, Norman GR. The effectiveness of cognitive forcing strategies to decrease diagnostic error: an exploratory study. Teach Learn Med. 2011;23:78–84. 24. Sherbino J, Kulasegaram K, Howey E, Norman G. Ineffectiveness of cognitive forcing strategies to reduce biases in diagnostic reasoning: a controlled trial. CJEM. 2014;16:34–40. 25. Shimizu T, Matsumoto K, Tokuda Y. Effects of the use of differential diagnosis checklist and general de-biasing checklist on diagnostic performance in comparison to intuitive diagnosis. Med Teach. 2013;35:e1218–29. 26. Smith BW, Slack MB. The effect of cognitive debiasing training among family medicine residents. Diagnosi. 2015;2:117–21. 27. Feltovich PJ, Johnson PE, Moller JH, Swanson DB. CS: the role and development of medical knowledge in diagnostic expertise. In: Clancey WJ, Shortliffe EH, editors. Readings in medical artificial intelligence: the first decade. Reading, MA: Addison Wesley; 1984. p. 275–319.

2

Aggregate Bias Khin Moe Sam

Have you ever prescribed a medication to a patient because of their repetitive request, despite there being no clear clinical indication? Have you ever ordered an unnecessary investigation because you felt that your patient was somehow different without any real grounds to believe so? Have you ever ordered a test because a patient or their relative insists you do so to exclude a condition even though such a diagnosis is implausible based on their presentation? These are all examples of ‘aggregate bias’ where a physician commits to unnecessary investigations or treatments based on the fallacy that statistical associations found between variables in a patient population do not apply to a particular individual. This is often due to a tendency for physicians to rely on anecdotal evidence from past experiences or treat their own patients as atypical. Physicians may use the aggregate bias to rationalise treating an individual patient differently from what has been deemed appropriate in the clinical guidelines for that group of patients. Furthermore, the clinician’s behaviour may be augmented by a patient’s demanding behaviour. In such situations, aggregate bias may be compounded by commission bias, where physicians have a tendency to avoid harm by active intervention or by ‘doing something’ for the patient [1]. Definition: The belief that aggregated data, such as that used to inform evidence-­ based practice, do not apply to the individual.

K. M. Sam (*) Emergency Department, Dandenong Hospital, Monash Health, Dandenong, VIC, Australia Faculty of Medicine, Nursing and Health Sciences, School of Clinical Sciences at Monash Health, Monash University, Melbourne, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_2

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Case 1

Sarah is a 24-year-old female at 8  weeks gestation. She has had one previous uncomplicated pregnancy. She has no significant past medical history and is a non-­ smoker. She has been receiving antenatal care from her GP and had an ultrasound earlier during the week which showed single intra-uterine live gestation. Her blood group is A positive. She presents to the Emergency Department (ED) at 9 pm after experiencing a vaginal bleeding for the past 3 h. The bleeding started as spotting and became slightly heavier which is comparable to a light period for her. It is associated with mild lower abdominal cramping. She reports no dizziness or urinary symptoms. You, a junior emergency registrar, assess Sarah, concerned that she may be having a miscarriage. You find her to be afebrile with a heart rate of 80/min and blood pressure of 115/70 mmHg. Her respiratory rate is 17/min and she is maintaining oxygen saturation of 98% on room air. Her abdominal examination is normal. You perform a speculum examination and find a closed cervical os with no abnormality. You order a range of blood tests and she is observed in ED while you wait for the test results to come back. Her bleeding settles while waiting for the blood test results. Her haemoglobin is 135 g/L (110–160) and serum beta-HCG is 65,000 IU/L which is appropriate for her gestation. Despite being reassured by her examination findings and test results, you make a plan to keep the patient overnight in the short stay unit for an obstetric ultrasound in the morning. A consultant present during the night shift handover does not agree with the plan and advises that Sarah can be discharged if there is no other outstanding issue. They suggest that Sarah could either return the next day for an ultrasound or have an ultrasound organised through the GP. A discussion is made between the patient and the senior doctor and Sarah agrees to go home and be followed up with her GP. A further discussion is made between you and the consultant to understand the reason why a plan was made to keep a low risk, asymptomatic patient overnight. You then revealed your past experience with a patient who had first trimester bleeding whom you discharged home only to have them return with worsening bleeding and cervical shock. The concern was acknowledged, nonetheless, the consultant recommends to risk-stratify patients on a case by case basis in accordance with the established guidelines, rather than based on a past anecdote.

2.2

Case 2

Julia,an 18-year-old female, presents to a tertiary ED with a rash. She presented to the ED 1 day earlier with a sore throat and was seen by a junior registrar. Upon reviewing the documentation, you, an emergency physician, note that Julia had a 2-day history of fever, sore throat, cough and myalgia. She was febrile at 38.2°C, but the rest of the vital signs were within normal limits. On examination of her throat, she had swollen and erythematous tonsils but no tonsillar exudate or no

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generalized cervical lymphadenopathy. No joint pain or tenderness was noted. She was prescribed amoxicillin by the treating doctor and discharged home. You revisit the history with Julia and find that it is consistent with the documentation from the previous presentation. Julia tells you that after the second dose of the amoxicillin she broke out in a rash. However, she reports no known allergies. You assess Julia and find that she has a temperature of 37.8°C, heart rate of 92/min, blood pressure of 100/65 mmHg, respiratory rate of 16/min and oxygen saturation of 98% on room air. She has a widespread non-blanching maculopapular rash which is more pronounced over the extremities. You send off a rapid monospot test which comes back positive. You make a diagnosis of amoxicillin-related rash. You explained to Julia that the antibiotic was unnecessary and is in fact responsible for her rash in this case. You apologise for the suboptimal care given earlier and tell her to stop taking the antibiotic and then discharge Julia home with supportive therapy. A review of records of patients seen by the doctor who prescribed the antibiotics liberally was done. It was noted that the doctor prescribed antibiotics to all patients presenting with a sore throat. A discussion with the treating doctor took place to get a better understanding of their rationale behind the prescription of antibiotics. The doctor revealed that they used to work in Central Australia and had past experiences with patients having bacterial tonsillitis complicated by glomerulonephritis or infective endocarditis. It had been their standard practice to prescribe antibiotics to all patients with tonsillitis. After appreciating the underlying reason, the epidemiology of sore throat in the local region and the standard of practice in the local hospital was explained to the junior registrar. Concept of antimicrobial stewardship, use of guidelines to risk-­ stratify for streptococcal sore throat, alongside with the use of clinical scores, such as Centor score [4] were explained to the junior registrar to mitigate the effect of the aggregate bias. The registrar understood the explanation and would now look into further literature and had set goals to improve their routine standard of care.

2.3

Case 3

Paul, a 40-year-old male, was brought into ED at 2 am by his friends after he got punched in the face. Paul tells you, a junior emergency registrar, that he was hanging out with his friends at a pub and got into an argument with a stranger. He then got punched once to the left side of the face. He had two glasses of beer prior to the incident. The event was witnessed by his friends. He and his friends report no head strike or loss of consciousness. Paul reports one episode of vomiting about 15 min after the incident. He has ongoing mild nausea, but no further vomiting. He has no headache, neck pain or limb paraesthesia. He is complaining of pain over the left maxillary region. Paul has no significant past medical history and is not on any regular medications. He has smoked about five cigarettes per day for the last 20 years and he has 2–3 standard drinks per night, three nights per week.

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On examination, you find Paul to have a temperature of 36.9°C, heart rate of 98/ min, blood pressure of 135/70 mmHg, respiratory rate of 19/min and oxygen saturation of 97% on room air. His GCS 2 h post injury is 15. His pupils are equal and reactive bilaterally. His cranial nerves examination is normal. Motor, sensory and cerebellar examinations are also normal. You note no retrograde amnesia. You find no scalp haematoma or depressed skull fracture on examination. There is a tender bruise over the left maxillary region without bony crepitus or subcutaneous emphysema. His mouth opening is normal without any trismus. No battle sign or racoon sign are noted. The cervical spine examination is normal. You order non-contrast CT scans of brain, facial bones and cervical spine and analgesia for Paul. You organize for Paul to be observed in the short stay unit while he awaits his scans. During morning handover, it is questioned why the patient needed a CT scan of his brain and cervical spine in addition to the facial bones. You let everyone know that previously you have dealt with similar patients who had attained spinal injuries after being king punched and hence, it had been your practice to organize both CT brain and cervical spine for those who had been punched in the head and neck region. The consultant explains about dangerous vs. non-­ dangerous mechanisms of injury and other factors to be considered when requesting an investigation with potential significant adverse effects, such as the increased risk of malignancy from extra radiation exposure in this case. They let you know about clinical decision rules such as NEXUS and Canadian criteria for cervical spine imaging and Canadian criteria for brain imaging. The CT scans are reported back as soft tissue injury of face without any underlying fracture or acute abnormality. Paul is discharged home with simple analgesia afterwards.

2.4

Case 4

You are a junior ED registrar reviewing Michelle, a 33-year-old female who presented with a headache. She has a past history of migraine since the age of 18 and also has a strong family history of migraine. She reports that this headache is similar to her usual migraine attack, but more severe and has not responded to her usual treatment regimen of paracetamol, ibuprofen and rest. Her headache started yesterday evening and she was not able to sleep well during the night because of it. Michelle reports being stressed recently at work and also having her period which has triggered her migraine in the past. She has associated nausea and was seeing flashing lights intermittently. She has not eaten anything since yesterday afternoon due to nausea. Michelle does not report any fever or recent travel. She had no other past medical history and is not on any regular medications. She is not a smoker. Her vital signs are:  temperature of 36.8  °C, heart rate  88/min, blood pressure 135/77 mmHg, respiratory rate15/min and oxygen saturation of 99% on room air. Her GCS is 15 and her pupils were equal and reactive without objective photophobia. Her neurological examination is normal. No neck stiffness or rash was present on examination and her systemic examination was normal.

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You make a provisional diagnosis of migraine. You approach an emergency consultant and have a discussion regarding the management of Michelle. You formulate a plan of IV cannulation, IV rehydration and analgesia which the consultant agrees with. In regard to analgesia you propose prescribing IV morphine. Your consultant highlights that this suggestion deviates from the clinical guidelines for the management of acute migraine and asks you why you thought IV morphine was appropriate in this instance. You state that you chose IV morphine as the first-line treatment since you thought IV opioids were the first line of analgesia in cases of severe pain. The consultant explains the guidelines for treatment of migraines and discusses the importance of the analgesic ladder and its application [2]. Together, you make a treatment plan of IV fluid rehydration, anti-emetics and high-dose aspirin with clinical review after 2 h to consider additional analgesia. You review Michelle after 2 h and she reports significant improvement in her symptoms and requests to go home. You discharge the patient home with aspirin and non-­ opioid analgesia after she tolerates oral intake in the ED. In this case, an aggregate bias was identified early and the effect was alleviated which benefited the patient by preventing the introduction of opioids and the potential risk of opioid dependence.

2.5

Conclusion

The inability to control the influx of patients to ED, combined with routine battles of access block and management of patient flow, ED clinicians are highly distracted and extremely vulnerable to all kinds of clinical prejudices. It is often more convenient to give in to the temptation of providing the patients and family members what they demand instead of what is the best for their clinical presentations. From the examples above, it is now obvious that the recognition of aggregate bias and mitigating its potential detrimental effects are crucial to best clinical practice. We will now discuss strategies to actively overcome the aggregate bias. Potential Solutions 1. Reflect on own thought processes; It is important to regularly self-analyse clinical decisions. By practising reflectively, clinicians may be able to detect possible cognitive biases or flaws in their reasoning and help detect errors [3]. 2. Utilise clinical decision rules and scoring systems to guide management plans; Strict implementation of these tools can help to improve the clinician’s decision making process and prevent over-investigation or over-treatment due to anecdotal experiences. 3. Seek help and advice from colleagues; By discussing patient cases and your proposed management plans with colleagues, physicians are able to get feedback on their thought processes and potential cognitive biases can be highlighted and mitigated. 4. Keep up to date with latest research, protocols and guidelines; This helps clinicians to stay on top of the most recent evidence-based practice as well as benchmark their current practice [3].

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References 1. Croskerry P. Achieving quality in clinical decision making: cognitive strategies and detection of bias. Acad Emerg Med. 2002;9:1184–204. https://doi.org/10.1197/aemj.9.11.1184. 2. Vargas-Schaffer G. Is the WHO analgesic ladder still valid? Twenty-four years of experience. Can Fam Physician. 2010;56(6):514–e205. 3. Graber M, Kissam S, Payne V, Meyer A, Sorensen A, Lenfestey N, et al. Cognitive interventions to reduce diagnostic error: a narrative review. BMJ Qual Saf. 2012;21:535–57. https://doi. org/10.1136/bmjqs-­2011-­000149. 4. Centor RM, Witherspoon JM, Dalton HP, Brody CE, Link K. The diagnosis of strep throat in adults in the emergency room. Med Decis Making. 1981;1(3):239–46.

3

Ambiguity Bias Elizabeth Sheffield

What would you say if you were offered: either 200 dollars now or a mystery sum of money which might be lower, higher, or the same value as the initial offer? Alternatively, imagine you were late for a meeting, you could take your standard route where you know the likely time of arrival or you could try a new course that may improve your travel time, but alternatively could make us even later? You would not be alone by choosing the first of these options—the ones for which a specific outcome is known. This tendency to choose a strategy or outcome where uncertainty is reduced is referred to as the ambiguity effect and it has an impact on everyday decisions ranging from which restaurant we choose to go to, what suburb we decide to live in and what banking strategies we use to prepare for retirement. In medicine, particularly emergency medicine, this ambiguity effect is especially pertinent. Many of our decisions are, by necessity, based on a variety of unknowns, and this tendency to try to choose options or differential diagnoses where this unknown quality is reduced and the potential outcome is more familiar can lead to inappropriate choices in the tests we order, the diagnoses we make and the treatments we commence [1]. Definition: The tendency for one to make a decision favouring the familiar, and thus avoidance of the ambiguous or uncertain, despite the lack of supporting evidence [2].

E. Sheffield (*) Emergency Department, Austin Health, Heidelberg, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_3

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E. Sheffield

Case 1

Lottie is an 8-year-old girl who attends late one evening with her parents. She has been complaining of lower abdominal pain for a week and a half, which occasionally is so intense that she is unable to stand up out of bed. She has no other associated symptoms and no fevers. She has been to see her general practitioner four times since the pain began and has had repeat urine samples and a set of bloods performed, which have revealed no obvious abnormalities. Her GP suspects abdominal migraines. Her parents have brought her in tonight because she has had another episode of severe abdominal pain just before dinner and they are uncertain what to do. You examine Lottie and find that she has a reassuringly soft abdomen, that she appears well hydrated, has normal observations, and is afebrile. Her parents report that she is immunised and has no significant past medical history, although she has suffered from milder “tummy aches” over the last year or two. Her mother has a history of migraines, but otherwise they are fit and well. You suspect that there will be no acute surgical cause for Lottie’s abdominal pain and concur that a diagnosis of abdominal migraines is likely. However, you feel unhappy sending an 8-year-old home without further evidence of no sinister pathology. Lottie’s parents warn you that she is quite scared of needles, so you apply a topical anaesthetic for bloods. When you go back to take bloods Lottie begins shaking and crying, and you have to pause several times before eventually getting two nurses to come in and help facilitate the procedure. It is nearly 1 a.m. and you advise Lottie’s parents that you need another urine sample. Lottie keeps falling asleep and you have to keep going in to wake her to encourage her to drink water, of which she reluctantly takes occasional sips. After her approximately 5 h in the department all of Lottie’s investigations including a urine dipstick come back normal. You ask Lottie’s parents to stay as you wish to obtain a senior review in the morning. You consider obtaining an abdominal x-ray, although you advise the parents that you suspect this would be normal. At this point Lottie is unable to stay awake and her pain has been well-controlled. Lottie’s parents also appear exhausted. They take your recommendation and stay until the morning. When the consultant arrives, she reviews the patient and discharges her. She advises the parents that although the diagnosis is unclear, she is reassured by the improving symptoms and lack of abnormal results on several occasions. She determines that the family lives 10 min away and advises them to return if any red flags which she counsels them on. She advises you that in the presence of reassuring signs and a child who lives nearby with responsible caregivers, it would be sometimes preferable to send the family home with appropriate safeguarding and plan for review in normal hours. In this case, your discomfort with the ambiguity of not having a concrete diagnosis has created a tiring and unnecessarily traumatising stay for Lottie and her parents. Although it is appropriate to keep a child or patient if you have ongoing concerns, it is also reasonable to send patients home with no clear diagnosis, in particular if they live nearby, can return readily and your examination had been reassuring at the time of assessment.

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3.2

17

Case 2

You are a second-year resident working with another resident on nights at a rural centre. You review Brian, a 49-year-old male who presents with worsening dyspnoea on the background of a 1-week history of general malaise, myalgias, fevers and cough. He has also lost 2 kg over the last week. His past medical history includes HIV, multiple previous admissions with opportunistic infections and low CD4 counts. On review, you find Brian sleeping and very lethargic on waking. He is appropriately orientated; however, he appears clinically dry. He is afebrile, his oxygen saturations are 92% on room air, with a respiratory rate of 20, and non-invasive blood pressure is 142/86 and HR of 100. His CURB-65 score is 0. You order a CXR which shows multilobar consolidation. You feel uneasy as you have not had much experience with patients who are immunocompromised or patients with HIV; however, you remember from medical school that patients with low CD4 counts are particularly susceptible to Pneumocystis pneumonia. Working with PJP as a presumptive diagnosis, you decide to commence him on IV sulfamethoxazole-trimethoprim. Brian continues to appear very flat, but his observations remain unchanged, so you ask the medical registrar if Brian can be admitted up to the ward for assessment there, to which he agrees. You find later that evening that a MET call has been activated on the ward for Brian, who became increasingly tachycardic and subsequently hypotensive and confused. He was admitted to intensive care. After following up the case, you learn that Brian did in fact have a low CD4 count; however, his cultures have grown Streptococcus pneumoniae, a typical pathogen for pneumonia in the community. You ask your clinical supervisor to debrief the case during which she tells you that although low CD4 counts will put patients at higher risk of opportunistic infections they will also be more susceptible to typical community acquired infections as well. The discomfort you have felt at having limited experience with patients with HIV has meant that you have inadvertently chosen to prematurely determine a diagnosis without adequately safeguarding treatment against other possible causes of your patient’s symptoms.

3.3

Case 3

Janet is a 56-year-old lady who has been brought in by ambulance with a 1-day history of severe lower back pain. She thinks she may have awoken that morning with the pain, but she reports that as she is moving house she has been lifting things more often than usual over the previous week. She tells you that she does suffer from low back pain normally and takes amitriptyline for chronic pain. She is a diabetic which has been poorly controlled. She also is wondering if the move and added stress has been causing her to be “run-down”, as she’s been feeling a bit tired as well as “fluey and feverish” over the last couple of days. On examination, Janet is afebrile with a heart rate of 84 and a blood pressure of 120/80. She was unable to walk with the ambulance, but you complete a

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neurological examination and are reassured that the power, tone, reflexes and sensation of her limbs remain intact. She also has preserved perianal sensation and anal tone. She has some midline pain to palpation in the L3/4 region, which does extend paravertebrally, and you diagnose a likely mild disc herniation and subsequent muscular spasm of the lower back. The systemic symptoms in the context of back pain make you slightly uneasy; however, you know that getting an MRI is difficult and you decide you favour a mechanical cause. You admit Janet to your short-stay unit for analgesia and review by your physiotherapy and extended care coordinator team. When you go to review her mid-shift, she tells you the pain is worsening and she is unable to get comfortable lying down, so you prescribe her a muscle relaxant as well as some further oral analgesia and decide to review her again later that evening. Another hour passes and Janet becomes febrile and hypotensive. Her pain has increased even further, and you get some bloods which show a raised WCC of 34 × 109/L. At this stage, you become seriously concerned as to a sinister cause to her lower back pain and order a CT which reveals a large multi-level epidural abscess. You arrange urgent transfer to the intensive care and refer to the neurosurgical team for urgent decompression. You realise that despite there being some symptoms in the context of back pain that were concerning, you failed to take bloods and investigate non-mechanical causes in part because you wanted to create a definite diagnosis and plan. You also wonder if the issue of imaging being difficult to attain has influenced your decision-­ making. You reflect that this has resulted in a delay to obtaining a correct diagnosis and delaying appropriate management of the patient.

3.4

Case 4

You are the Emergency Registrar in charge overnight at a small urban district hospital. Lakshmi is a 28-year-old woman who has been triaged as “throbbing right-­ sided abdominal pain”. Lakshmi tells you that she had felt well when she went to sleep but when she woke up to use the toilet, she realised she had right iliac fossa pain which began to increase in intensity when she was trying to fall back asleep. She had intermittent right-sided cramping over the last few days prior to this but had been working so had ignored it. Her brother had a complicated admission in hospital from “appendicitis which burst” so she asked her husband to drive her to hospital to “get checked out”. Lakshmi is normally fit and well and has no history of intrauterine devices or sexually transmitted diseases. She is currently mid-cycle and has regular periods. She has no history of abdominal surgeries. She takes no regular medications. You examine Lakshmi and find there to be mild guarding in her right iliac fossa. Her observations are normal though and she is afebrile. You prescribe her some intravenous morphine and oral analgesia for her pain and do some “basic bloods” and obtain a urine specimen and request a urinary b-HCG.

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Her pain improves with analgesia, and her bloods return “normal”. Her urine is clear, and her pregnancy test is negative. You suspect appendicitis but are also somewhat concerned about ovarian torsion. There is no O&G service at your hospital, but the surgical registrar is on-call 24-h and covers all referrals for abdominal pain. After an hour, the surgical registrar comes down and reviews the patient. Lakshmi is drowsy from the morphine and reports her pain has improved slightly with analgesia. The surgical registrar advises Lakshmi that she does not feel that this is likely appendicitis. She advises discharging Lakshmi with a presumptive diagnosis of a ruptured ovarian cyst. She further mentions that if this was during the day she might consider an ultrasound; however, ultrasound service is only available on-call for emergencies and she feels this is unlikely an acute abdomen. Despite your initial reservations, you decide to favour the opinion of the surgical registrar and acknowledge that ultrasound is not readily available. Early in the morning, Lakshmi returns with worsening abdominal pain and vomiting. Her pain has significantly increased, and she is writhing on the bed in pain. You obtain an emergency ultrasound which shows a torted right ovary and arrange for Lakshmi to be transferred to the nearest tertiary hospital for surgery. On reflection, you realise that you agreed with the surgical registrar not because of any convincing evidence to support her hypothesis but partly because it was felt more comfortable labelling Lakshmi as having a specific diagnosis. This combined with the lack of easy access to diagnostic imaging made you more likely to accept a common diagnosis despite a relatively less common and acute one actually being the cause of her symptoms.

3.5

Conclusions

No matter the stage of training, it can be difficult for clinicians to overcome ambiguity effect. There is comfort in anchoring on diagnoses or care plans that are familiar. It is worth noting that there will always be subjects around which knowledge gaps are present, and therapies in which fluency is lacking. Also, that there is an inevitability for encountering situations where no clear diagnoses are found [3]. Thus, we need to normalise and plan for ambiguity in our practice. In doing so, we can ensure that we seek assistance from our emergency and subspecialty colleagues when required. However, it is equally important to consider how one’s discomfort with ambiguity can lead to “over-investigation” which is not without consequences: e.g. if you refer a low-risk patient for an angiogram, this procedure has potential complications which can have serious consequences [4, 5]. Potential Solutions 1. Consider potential alternatives to your prospective diagnosis. Checklists and surgical sieves can force you to consider other differentials and help avoid premature closure with decision-making. Although initial instincts frequently prove correct, we are often wrong, and should approach each differential with this in mind.

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2. Foster and encourage a supportive workplace culture, so colleagues at every level will feel empowered to employ shared decision-making and seek counsel for the cases where they feel uncertain. 3. Continue prioritising lifelong medical education. In actively seeking to teach juniors, you can stay up to date on topics that have become less familiar or where goalposts of care may have changed. 4. Remember that mistakes are inevitable. Compassion to your colleagues as well as to yourself is an important part of ensuring a healthy mental model for your team, and also for future patients.

References 1. Croskerry P.  ED cognition: any decision by anyone at any time. CJEM. 2014;16(1):13–9. PMID: 24423996. 2. Han PK, Reeve BB, Moser RP, Klein WM. Aversion to ambiguity regarding medical tests and treatments: measurement, prevalence, and relationship to sociodemographic factors. J Health Commun. 2009;14(6):556–72. https://doi.org/10.1080/10810730903089630. 3. Howard J. Cognitive errors and diagnostic mistakes: a case-based guide to critical thinking in medicine. Cham: Springer; 2019. https://doi.org/10.1007/978-­3-­319-­93224-­8. 4. Inukai K, Takahashi T. Decision under ambiguity: effects of sign and magnitude. Int J Neurosci. 2009;119(8):1170–8. https://doi.org/10.1080/00207450802174472. 5. Osmont A, Cassotti M, Agogué M, Houdé O, Moutier S. Does ambiguity aversion influence the framing effect during decision making? Psychon Bull Rev. 2009;22(2):572–7. https://doi. org/10.3758/s13423-­014-­0688-­0.

4

Anchoring Bias Michail Kosmidis

Imagine walking into a used car dealership, where a car that you are interested in is priced at $800. Being a savvy consumer, you manage to haggle the price down to a more palatable $700 and happily drive off with your new car. If the same car was priced at $1600, however, you would happily shake hands at $1300, well above the price that you did not find acceptable in the first scenario. This phenomenon can be explained by the well-known tendency of the human brain to seek meaningful patterns, rather than make accurate and logical estimations, the latter often impossible in a world where countless stimuli are constantly competing for attention. In an attempt to make sense of a chaotic world, the brain desperately ‘anchors’ itself to the first available piece of meaningful information, such as the first price uttered during a negotiation, assessing all subsequent pieces of information by referring to the ‘anchor’, even if there is no real connection between them. In medicine, the ‘anchor’ can be the first of serial measurements of a particular vital sign, the first symptom mentioned when taking a history, or perhaps the first symptom that the physician considers important in the search for a diagnosis, meaning that subsequent findings are seen through the lens of this initial impression. The result is that any subsequent clinical or laboratory finding that discredits the initial impression is more likely to be ignored than to force a change in the working diagnosis [1]. Definition: The tendency to focus too heavily on the first available piece of information when making clinical decisions [2].

M. Kosmidis (*) Emergency Department, Armadale Health Service, Mount Nasura, WA, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_4

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M. Kosmidis

Case 1

Gerald is an 81-year-old man with a history of hypertension, hyperlipidaemia and a previous ischaemic stroke. He lives at home with his wife and is visited every few weeks by his daughter and son-in-law. He has become forgetful in the last few months and is presumed to be at the early stages of dementia. In the last few weeks he has developed a dry cough, and in the last few days he has not been eating very well, feels tired and has not been very active, only getting out of bed to go to the bathroom and back. You assess Gerald and start making a short list of differential diagnoses, with pneumonia featuring prominently on the list. You notice that his blood pressure is 92 systolic, with a heart rate of 80. His respiratory rate is mildly elevated and he requires two litres of oxygen per minute via nasal prongs to maintain saturations of above 95%. You arrange a cannula, bloods and an X-ray, which later confirms the diagnosis of right middle lobe pneumonia. He looks dry, but you don’t want to cause fluid overload in an 81-year-old with several comorbidities, so you prescribe 250 mL of crystalloid and antibiotics. In the meantime, you have a chat with the family. Gerald is a pleasant elderly gentleman who knows that he is in hospital, but he can’t get the month and the year right. His son isn’t too surprised, as he has noticed a gradual decline in his dad’s memory recently. His wife is a bit surprised, considering Gerald had remembered her birthday the week before. The blood pressure has now come up to 97 systolic so you prescribe another 250 mL bag of crystalloid. You have to attend to other patients, including an apparently sick neonate and an agitated methamphetamine user who needs sedation. You then phone the medical team to arrange admission, as Gerald needs oxygen and his urea is slightly elevated, allowing you to proudly bring up his CURB-65 score to convince the medics that he needs to be admitted, rather than observed in the short stay unit. After putting a bed slip in, you now return to Gerald to find out that his blood pressure is now 105 over 49, safely above ‘MET call’ criteria. You inform the nurse in charge that he is now ready for the ward. You return to your sick neonate that requires a septic screen and a lumbar puncture, which keeps you occupied for the next couple of hours, while you wait for your drug-affected patient to wake up. The next day you find out that Gerald had a MET call on the ward, as he had become hypotensive and agitated. He ended up in intensive care on vasopressors and needed intubation, as his agitation was interfering with treatment, causing him to be unable to lie still for the insertion of a central line. The medical consultant was not happy with the outcome, and the intensivist commented that the patient had been under-resuscitated in the ED. In retrospect, you realise that a blood pressure of 105 over 49 is indeed likely to be well below the baseline for an 81-year-old man with a history of hypertension and CVA, and the total of 500 mL crystalloid was probably not enough fluid resuscitation. The diastolic is quite low, suggesting a vasodilated state, consistent with sepsis, whereas the lack of tachycardia can be attributed to Gerald’s beta blockers.

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You regret not assessing his haemodynamic state with point-of-care ultrasound, which you would normally do. You also realise that you did not address his urine output and you dismissed his confusion as a likely manifestation of dementia, whereas he was probably underperfusing his brain all along. You were also distracted by the presence of your other two patients that needed attention, even though the neonate did not ultimately have sepsis, and the drug-affected patient woke up and went home after a few hours. You anchored yourself on the initial blood pressure of 92 systolic, which made the subsequent value of 105 appear much better. If the initial blood pressure had been 160 systolic, a subsequent drop to 105 would have raised alarm bells. You also fell prey to confirmation bias, as you dismissed Gerald’s confusion as being a result of his dementia, refusing to consider the possibility of delirium, since his numbers were momentarily improving.

4.2

Case 2

Maria is a 29-year-old woman with a history of migraines, for the prevention of which she takes regular propranolol. She has now had a headache with vomiting and photophobia for about 12 hours, similar to her previous migraines. You have met her before and have successfully treated her with fluids, prochlorperazine and sumatriptan on different occasions. You walk into her cubicle to find the lights turned off, while Maria is lying curled up in bed, holding a towel over her eyes. In a casual tone, you ask: ‘Are you having a migraine again?’ while preparing the IV trolley. She says: ‘I think so, but this feels worse’. You have seen loads of patients who describe their current migraine attack as the worst ever, so you are not overly worried. You also find out that she has had a runny nose for a few days, and she now has a temperature of 37.8 °C. She is mildly tachycardic at 110, and her blood pressure is 90 systolic, which you attribute to the dehydration, caused by vomiting. She is a small-framed lady whose baseline blood pressure is not much higher than this. Her neck does feel a little stiff, but, then again, she has been experiencing generalised myalgia, therefore her neck muscles are a bit stiff too. You prescribe a litre of fluids with prochlorperazine, as well as paracetamol and aspirin for her migraine, while waiting for the bloods. You do not want to bother her too much, as you are a migraine sufferer yourself and you know how annoying it is when people talk to you during an attack. Her white cell count is 18,000 with neutrophilia, which is not surprising in a vomiting patient, as stress often causes demargination of neutrophils, rather than a true rise in the white blood cell count. You see a few more patients and eventually return to Maria. The lights are still off in her cubicle, and you find out that the IV fluid has not gone through after more than an hour, as she has been sleeping with her elbow bent. You want to reassess her, but she is now difficult to rouse and feels hot to the touch. You turn the lights on to discover that she has a faint widespread rash. Alarm bells now start to ring, and you realise that Maria probably has

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meningococcal meningitis, and you have delayed investigation and treatment by more than an hour. Moreover, the 900  mg of aspirin that she received may now increase the chance of bleeding during her eventual lumbar puncture. You were falsely reassured by your familiarity with Maria’s past history of migraines and anchored yourself to the memory of your previous interactions with her, causing you to cut corners during her assessment and ignoring the signs of a serious diagnosis as they gradually emerged. Arguably, your threshold for suspecting meningitis would have been lower without this effect.

4.3

Case 3

You are seeing Greta, a 75-year-old lady who lives alone and has a past history of hypertension and osteoarthritis. She was brought in by ambulance after having had a fall at home. She was unable to get up at first, but she managed to press her alarm buzzer and was then able to slowly walk to the ambulance stretcher with assistance. She is complaining of a sore right shoulder but is otherwise well. According to the paramedics, Greta stated that she tripped on the carpet edge and found herself on the floor, which is what she also stated to you. Her two daughters and sons-in-law have now arrived and are by her side, showing their concern. She appears a bit overwhelmed by the attention. You examine her and suspect a soft tissue injury of the right shoulder, which you decide to X-ray anyway, in order to rule out a fracture. Her vital signs are normal, apart from a borderline tachycardia of 100, which you attribute to her slight anxiety about being in an unfamiliar environment, and her examination is otherwise unremarkable. You are happy with her cervical spine, which you clear clinically, and she does not appear to have any other injuries. You ask for an ECG, which is normal. You prescribe paracetamol and an NSAID for her pain. Greta is on regular NSAIDs for her arthritis, so you are not too worried about prescribing her another dose. You even do some ‘basic bloods’, showing a slight deterioration of her renal function, which retrospectively makes you feel a twinge of regret for prescribing a NSAID, but surely this can be followed up by her primary care physician. You ask the Allied Health team to assess her ability to manage her activities of daily living at home after the fall, now that her X-ray has not revealed a fracture. A couple of hours pass. You are preoccupied with other patients, while waiting for Greta’s Allied Health review. It is still daytime, so you are hoping to send Greta home, perhaps with a family member staying with her overnight. Suddenly, the emergency buzzer sounds and you discover that Greta has collapsed in the toilet, with black liquid covering the floor and her clothes. She is conscious but pale, and she is also bleeding from a deep laceration in her scalp. You expertly resuscitate her with two large-bore IV cannulas, blood, an immediate referral to the gastroenterology service for an endoscopy and a proton pump inhibitor infusion, while you repair her laceration. At this time, you realise that you clearly missed the diagnosis of upper GI bleed when you first assessed her. You ask

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her again about the fall, and it turns out that she cannot actually recall tripping on the carpet. She had only assumed that this had been the case, as the carpet edge was a bit raised next to where she fell, and she has tripped on that carpet before. Greta, it also turns out, does not like to be a ‘burden’ on her daughters and often downplays her symptoms, as she feels guilty about being the centre of attention. In this case, you anchored yourself to the initial history of an apparently ‘mechanical’ fall and thus underestimated the significance of the slight tachycardia and worsening of renal function. In all likelihood, the history of a ‘non-mechanical’ fall, caused by an upper GI bleed, would have been elicited, and promptly confirmed with a digital rectal exam, if you had paid more attention to the details. When declaring a fall to be ‘mechanical’, the full ‘mechanism’ of the fall should be clear and explainable.

4.4

Case 4

Caleb is a 3-year-old boy brought into the ED by his mum, with a history of 36 hours of vomiting and diarrhoea. He does not have any other symptoms. Mum is concerned that Caleb is not eating and drinking much, which worries her, because he is already an underweight little boy, as a result of multiple food allergies. You walk into the cubicle and see Caleb lying next to his mum on the bed, looking unhappy. His abdomen is vaguely tender and the rest of his examination is non-­ specific. He is mildly tachycardic at 130, has a temperature of 37.8  °C, and his capillary refill is about two seconds. He does not want to smile for you and does not co-operate with your exam. Mum says that Caleb has had a few skin prick tests for his allergies, and therefore tends to associate doctors with needles and itchiness. You try to cheer him up with an impression of a cartoon character from your own childhood, but he only seems to find some comfort in mum’s phone. You begin a rehydration regime for gastroenteritis. You prescribe paracetamol and enlist mum’s help in the form of the administration of oral rehydration solution with a syringe every few minutes. You are hoping to avoid having to insert an IV cannula in this already unhappy child. An hour later, you discover that he has had about half of what he was meant to have according to the protocol. You decide that it is worth trying for another hour, in order to avoid more invasive methods of rehydration. Another hour passes and Caleb has been drinking a little better. He has had about 75% of the prescribed amount, he is afebrile and his capillary refill is under 2 seconds. He still does not want to interact with you, but one of the nurses states that he was smiling to his mum earlier, when a doctor was not around. Mum is becoming somewhat impatient, as it is getting late and Caleb is becoming more tired, now that it is well past his bedtime. She asks if she can just take him home, since he is not having a drip anyway and she ‘could have been doing this at home’. You are not too happy with this, as he is not quite back to his baseline and is still a bit dehydrated. His abdomen is still vaguely tender. You attempt to establish rapport with him again, and your attempts finally result in a smile and a high five.

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Meanwhile, the department is getting busy, and you are strongly tempted to free up Caleb’s bed. Mum seems reasonable, so you finally agree to send them home, as long as they get reviewed by their primary care physician the next day. You come back for your afternoon shift the next day, only to find out that Caleb presented again in the morning with worsening abdominal pain and vomiting, and was promptly transferred to the tertiary paediatric hospital, where he underwent laparotomy for a ruptured appendix. Looking back on the case, you realise that you anchored yourself to the presence of diarrhoea, which is more consistent with gastroenteritis than appendicitis. This caused you to ignore features that should have prompted you to further investigate, such as the persistent abdominal tenderness and the suboptimal hydration in a child that is significantly less active than expected for a 3-year-old. Framing effect might have also contributed, as mum’s main concern appeared to be the dehydration in an already underweight child.

4.5

Conclusions

The sheer amount of information that exists in a clinician’s knowledge base cannot realistically be interrogated at every clinical encounter. Anchoring is the brain’s way of taking a shortcut in order to arrive at a ‘good enough’ solution to a problem that has been presented. The obvious danger is that reasonable alternative diagnoses may not be considered, not due to lack of knowledge but, ironically, as a result of the brain’s attempt to function more efficiently. The cognitive flaw may be glaringly obvious through a ‘retrospectroscope’, even to the clinician who made the mistake, when the case is later reviewed in a setting where time pressures and distractions are not present [3–5]. Potential Solutions 1. Enlist other people’s perspectives. It is useful to have regular meetings on the floor where all patients’ plans are discussed and alternative opinions can be heard. A formal handover meeting at the end of each shift, free from interruptions if possible, is an example. 2. Question others’ clinical plans, in the same way that you would question any piece of information presented as fact in any other discipline of life. This will prompt your colleagues to identify instances of anchoring in their own thinking. Speaking out when you do not agree is particularly important in resuscitation scenarios. 3. Frequently take mental snapshots of your current list of patients. This may help disconnect each patient from their initial presentation and focus on the present moment.

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4. Resist the urge to make decisions in a hurry. The quicker the decision, the greater the reliance on that initial ‘anchor’. This is difficult in an environment where rapid disposition plans are valued, and is, of course, impossible in some clinical scenarios. 5. Having a set of obligatory triggers, such as the automatic implementation of a sepsis pathway in patients meeting certain criteria, may help avoid overreliance on subjective impressions to some extent.

References 1. Furnham A, Boo HC.  A literature review of the anchoring effect. J Socio-Econ. 2011;40(1):35–42. 2. Mussweiler T, Strack F, Pfeiffer T.  Overcoming the inevitable anchoring effect: considering the opposite compensates for selective accessibility. Personal Soc Psychol Bull. 2000;26(9):1142–50. 3. Simonson I, Drolet A. Anchoring effects on consumers’ willingness-to-pay and willingness-to-­ accept. J Consum Res. 2004;31(3):681–90. 4. Riva P, Rusconi P, Montali L, Cherubini P. The influence of anchoring on pain judgment. J Pain Symptom Manag. 2011;42(2):265–77. 5. Englich M, Mussweiler T.  Anchoring effect. Cognitive illusions: intriguing phenomena in judgement, thinking and memory. 2016;22:223.

5

Ascertainment Bias Phillippa Wills

Ascertainment bias is probably something that we all have to some degree, but don’t like to admit to. It is otherwise known as stereotyping, but also includes what may be more bluntly called racism (racial bias), sexism (gender bias) or other “isms” based on a patient characteristic. It may be overt or covert. We may use it overtly to help us get to the answer more quickly in our busy emergency departments. You may have “ascertained” the cause for something based on something you already know about the patient, such as their race, gender, or illicit drug history. It’s worked for you before, so now you “just know” because of that prior experience that “this presentation” in “these people” will be due to this certain cause. When your thinking is shaped by prior expectations, you see what you expect to see. However, this may not be the actual reality, and it can lead to trouble for both us and the patient. It may also be covert. That muttered comment at handover which subtly directs you to not bother investigating further, but ultimately leads to poorer care. In Emergency Medicine we treat all comers and aim for the higher goal of treating them without judgement. Unfortunately, we often fail as studies show inequalities in care by race, gender and other factors, even in emergency departments [1–3].

5.1

Case 1

Bob is a frail, thin elderly man with wispy grey hair who was dozing off on the hospital trolley despite the chaos in the department. He had been brought into ED by his family. You can’t really get much of a history from him as he is too drowsy, so you start asking his family. They tell you that he had been “unwell” for a few days and “taken to his bed”. He was not eating or drinking much, but it was only

P. Wills (*) Emergency Department, Northern Health, Epping, VIC, Australia © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_5

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today they had noticed he had been so “weak”. He had no febrile or infective symptoms that they were aware of, and had not seemed to be in pain at any stage. There had been no urinary symptoms until today when he was incontinent, but he also hadn’t been able to get out of bed to go to the toilet. He had a past history of hypertension, high cholesterol and type 2 diabetes. His medications included perindopril, rosuvastatin, aspirin, metformin and lantus insulin. While not eating or drinking much, they proudly tell you that he had been “good” and had been taking all his medications. You assess Bob and find that vital signs are all normal; his blood pressure is 120/65, heart rate is 82, oxygen saturations are 96% on room air and respiratory rate of 16 breaths per minute. However he has marked right-sided weakness in his arm and leg, less so in his face. You shake him awake and find that his words are very slurred and you can’t understand what he is saying. He seems to understand mostly what you are saying to him though, and can follow commands enough for the neurological examination. The family hadn’t really noticed that the right side was weaker than the left as he had been in bed, so they were not sure how long the right-­sided weakness had been there. However, they now remembered that he had had a stroke before. Unfortunately, they couldn’t remember when, what sort of stroke, or how it had affected him, except that usually he had no residual neurology. You organise bloods, a CT brain and chest X-ray. You advise the nurse and family that Bob should be kept fasted for now and order some gentle IV hydration. You then contact the neurology registrar to refer the patient for admission. About 10 min later Dave, the bedside nurse, comes up to you. “You’re looking after the bloke in cubicle 5?” “Yeah? The stroke?” you respond. “Ah, yeah. I just got some blood from him”. Dave says with some urgency. “I’ve done you a form” you say irritably. “Nah, it’s not that. His glucose is 1.1”. Oh. “D” stands for neurological Disability AND Don’t forget the glucose. After IV dextrose, Bob’s “stroke” miraculously resolved. The family thought you were amazing. You felt like an awful fraud. You had missed a basic premise of medicine due to ascertainment bias. You had expected that the elderly patient with a previous stroke was having a stroke, despite having diabetes and decreased intake, so a significant risk of hypoglycaemia. You apologise to Dave, for your appalling dismissive behaviour as well as the neuro team, for the false referral then reflect on the biases at play.

5.2

Case 2

Simon is a 23-year-old man, recently returned from holidays. He had started to become unwell with fevers, runny nose, slight cough, and generalised aches and pains about a week ago, but he was on holiday for a mate’s bucks party so continued to party with the boys. They were out drinking and partying every night. He was taking cold and flu medication regularly and possibly a little MDMA was taken when out clubbing, but not for at least 4 days prior to presentation, and he stated that

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he wasn’t a regular drug user. He had developed a cough with shortness of breath over the past 2 days but there wasn’t much sputum, and the cold and flu medication wasn’t helping much. He still had aches and pains in his head, chest, limbs—pretty much everywhere. For the past 2 days he had pretty much taken to his bed as he had felt so unwell. Hadn’t eaten much and had drunk minimal fluids. Certainly, he hadn’t had any alcohol for the past 2 days. On arrival in ED, his heart is 140, temperature is 37.4  °C, blood pressure is 105/65, respiratory rate is 24 breaths per minute and oxygen saturations are 96% in the room. You assess the patient, and find him looking pretty sorry for himself lying in the ED bed. Barely opening his eyes as his girlfriend fussed over him, patting his hand and fluffing his pillow. Really? Man flu, and self-induced dehydration from excess alcohol, drugs and minimal intake is your less-than-empathetic provisional diagnosis. You reluctantly chart an antiemetic, 1  L of stat IV fluids, and paracetamol, fully expecting everything to resolve. An hour later, he was still just as tachycardic, and the BP hadn’t changed much, so you chart more fluids, over 4 h this time. Luckily, you start to question your initial diagnosis and think that you should probably check some bloods, and a chest X-ray, you know, just in case. You also review his ECG. For a young bloke, apart from the sinus tachycardia, those complexes were a bit small. Good thing I did. An elevated troponin and “globular heart with mild interstitial oedema” on a chest X-ray later and the “pathetic bloke with man flu” was now “the interesting young man with myopericarditis and heart failure” for cardiology.

5.3

Case 3

Sally is a 43-year-old woman with left iliac fossa pain since earlier in the day. It is sharp and severe. Her last period was 3 weeks ago and she has a history of ovarian cysts. Her abdomen is soft and minimally tender with normal bowel sounds and normal vital signs. It is 7 pm and a junior ED doctor calls you to refer Sally for short stay as they had already given her morphine and ibuprofen but the pain was ongoing. The junior doctor tells you that it was “probably just another ovarian cyst” and “can you have her in short stay waiting for the bloods and if the pain doesn’t settle then we can order a pelvic USS”. You point out that normally this would be a reasonable plan except there’s no way we’ll be getting an USS overnight at this hospital. You asked if she was the woman in cubicle nine. They confirmed that she was. About an hour earlier, you had walked past that cubicle and seen Sally pacing around and rocking in pain. You ask if they had any results yet. He stated that the bedside urine test showed “a negative pregnancy test and no sign of infection”. When you asked specifically if there was any blood in the urine he said, “Uh, just a minute”. You listen to the rustle of the chart as they flick through the nursing notes to the documentation. “Uh, one plus of blood”. “Mmmm”, you say “Can you tell me any more about her pain?” “She said it was sharp and very severe”.

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“Yes. But was it constant, or did it come and go? Did it radiate anywhere else? Has she got any urinary symptoms associated with it?” you do not want to sound like you are interrogating them but they really do not seem to be getting your hints. “No UTI symptoms. I don’t think it’s a UTI. The dipstick was negative”. “I agree. Doesn’t sound like a UTI. But she has severe left groin pain with blood in the urine and a soft abdomen. What else do you think it could be?” “Renal colic?” they ask. “Maybe” you agree. “And at this time of night, given an USS is unlikely to happen, what other test could we organise?” “A CT KUB?” “Yes!” you almost applaud. “So how about we transfer her to short stay under the renal colic pathway, if you can put in a request for the CT KUB?” “That would be great. Thanks”. A 3 mm calculus at the left vesico-ureteric junction proved that women too can have renal colic.

5.4

Case 4

Patricia had presented to ED with erratic sugars. She was admitted and discharged a few days later on the same medication. She represented less than a week later, again with erratic sugars. You see her for her second presentation. She is an older indigenous woman with very poor eyesight. You are impressed by the respect her large family showed to her and say to one of them how lucky she was to have them. He corrected me. They was lucky to have her. She was a well-respected elder, a retired teacher of many years, one of the first in their community to get a tertiary qualification. She was mother and aunty of many other key community members. She was a keeper of many cultural traditions and still taught language, especially to the children. You walk into the ED cubicle, and a path cleared through the family for you to see her. She is sitting upright in the bed as if she was holding a command performance. She was alert, orientated and very quickly it became apparent to me that she wasn’t very impressed with being back. Her observations were normal except for a bedside glucose of 24. You ask her about her insulin and she was very clear about the medication she was taking. This seemed at odds with the discharge letter from the last admission which stated “indigenous woman with poor medication compliance” as the cause of her admission. Luckily, she had brought her medication in with her, so you get her to show you exactly what she took. She uses a moderate dose of short acting insulin three times a day and a small dose of long acting insulin at night. She had been on the same regimen for the past 2 years and all had been good until recently. She went travelling a month ago and her sugars seemed to have been upset since then. But she had now been home for the past few weeks and her sugars were still unstable. This was in the days before insulin pens so she would draw up the dose of insulin out of the bottle to inject. The syringes had been marked so she could identify how

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much to use even with her poor eyesight. She identified which one to use by the colour of the box that the bottle was in. I opened the box to look at the bottle inside. Problem solved. Somehow, the bottles had been switched. She was using the long acting insulin three times a day and the short acting one at night. If the initial team had thought past the stereotype of “elderly indigenous woman”, and wondered why an intelligent educated woman, with few previous acute diabetes related presentations, who checked her sugars regularly, was suddenly presenting with out of control diabetes, maybe a second presentation could have been prevented. And her poor eyesight? Macular degeneration, not diabetic retinopathy. You note that you will need to give feedback to the doctor who saw her the first time.

5.5

Conclusions

It is very easy in the busy ED to rely on the quick thinking afforded by stereotyping our patients. Unfortunately, pre-judgement of patients can also lead to harm and may result in incomplete assessment. Emergency physicians need to be alert to their own stereotype biases, and alert for the potentially discriminatory comments of others. Potential Solutions 1. Do not allow triage notes to overly influence your thought process. While the information on triage notes can be beneficial to help direct your initial assessment, it is important to be wary of triage notes that outline textbook presentations and suggest a particular diagnosis. If you are rapidly looking at the triage screen and coming to a quick diagnosis just stop, think, is this a stereotype or could there be something else going on? Am I missing something? 2. Avoid discriminatory or judgemental comments in your documentation or clinical handovers. Provide feedback to others when you notice overtly discriminatory comments [4]. 3. Acknowledge your own emotions and biases. Recognising when you might have positive or negative feelings towards a patient can be a red flag to thinking about such bias and may help mitigate against ascertainment bias [5]. 4. Frequently take time to pause and reflect on your decision-making. This can provide the opportunity to stop and try to make sense when things aren’t progressing as expected. Stop and ask—is there any other reason why this may be happening?

References 1. Chen EH, Shofer FS, Dean AJ, Hollander JE, Baxt WG, Robey JL, et al. Gender disparity in analgesic treatment of emergency department patients with acute abdominal pain. Acad Emerg Med. 2008;15(5):414–8. 2. Khan E, Brieger D, Amerena J, Atherton JJ, Chew DP, Farshid A, et al. Differences in management and outcomes for men and women with ST-elevation myocardial infarction. Med J Aust. 2018;209(3):118–23.

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3. Talmet J, de Crespigny C, Cusack L, Athanasos P. Turning a blind eye: denying people their right to treatment for acute alcohol, drug and mental health conditions–an act of discrimination. Ment Health Subst Use Dual Diagn. 2009;2(3):247–54. 4. Harris R, Tobias M, Jeffreys M, Waldegrave K, Karlsen S, Nazroo J. Effects of self-reported racial discrimination and deprivation on Mâori health and inequalities in New Zealand: cross-­ sectional study. Lancet. 2006;367:2005–9. 5. Croskerry P. Achieving quality in clinical decision making: cognitive strategies and detection of bias. Acad Emerg Med. 2002;9(11):1184–204.

6

Attentional Bias Phillippa Wills

Attentional bias is believing there is a relationship between two variables when instances are found of both being present. More attention is paid to this condition than when either variable is absent from the other. So, if A and B are present we immediately think the diagnosis must be C, perhaps to the exclusion of other possibilities. But if we only see A or B we may forget to think of the C diagnosis. We often think of diagnostic decision making as considering the compilation of risk factors, symptoms, and signs. In many instances, this is indeed the case. But sometimes, a sole symptom or sign may be present which alone can lead us to the correct diagnosis. Not everyone has to have every “thing”. Likewise, just because two symptoms are together does not always mean that the diagnosis is certain.

6.1

Case 1

A 74-year-old previously fit and well man presented to our ED having recently become homeless due to his behaviour. He had been increasingly aggressive with his family and on examination appeared to have some psychotic features. His family was unfortunately not present and unable to be contacted initially. I had worked him up fully for new onset psychosis in the older patient with CT and bloods as, of course, an organic cause was most likely in this age group. His observations were normal except for a mild tachycardia which I thought may be due to some anxiety around the psychosis. I was about to refer him to the physicians for admission when the son finally called. I took the call and explained what I was concerned about. The son said, “Do you think its got anything to do with the drugs?” “What drugs?” I asked. As far as I knew he was on no medications. “No, the drugs. The ice?”

P. Wills (*) Emergency Department, Northern Health, Epping, VIC, Australia © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_6

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I hadn’t even considered illicit drug use in this older man. The other 5 aggressive, psychotic patients I had had that shift were all young and of course I had asked about illicit drug use with them. In my mind young person plus psychosis equalled likely drug use. Unfortunately this is all too true in my community. I had failed to do so in this case because of my attentional bias—to me “old man plus new psychosis equals organic cause”. In this I had neglected to ask an important variable which turned out to be critical to the diagnosis. “Tell me more.” I asked. The son proceeded to tell me that his dad had become addicted to methamphetamine. He had previously been a truck driver and used a little bit of speed at times to cope with the long hours. It had never impacted on his family life and he had been happily married until a couple of years ago. On his retirement he had few interests and had been introduced to ice from one of his previous contacts. He found he enjoyed the buzz and felt more energetic, so he continued to take it. Despite the family telling him numerous times about the dangers, and asking him repeatedly to stop, it had unfortunately descended into a full blown addiction. He had spent most of his life savings on buying the drug. This, and the resulting poor behaviours, had ruined his family life and relationships. His wife had kicked him out after he became violent, and his kids wanted nothing to do with him as he was belligerent and physically aggressive towards them at times too. He had become homeless and the ED presentation had been sparked by a member of the public calling the police about an old man acting inappropriately near her house. I reassured the son that his call had been most helpful and that we were admitting Dad to hospital where we would not only look into the physical and psychological issues, but hopefully be able to access the drug and alcohol service too.

6.2

Case 2

The junior doctor sat down next to me. “Can I discuss this one with you?” “Sure.” I replied. “She was here a few days ago with UTI symptoms but has come back with increasing pelvic pain. But the urine we sent didn’t grow anything despite having white cells. Do I need to send another MSU?” I took a quick look at the previous notes then asked, “Was it just sent for MC&S?” “Yes.” He looked perplexed. I could see his attentional bias at play. UTI symptoms and white cells in urine is surely a UTI. “So what exactly are her UTI symptoms?” I asked. “Ahh, she has pain on passing urine? And pelvic pain?” He looked at me as if to say, why are you asking such dumb questions? “Does she have a vaginal discharge?” I continued. He hesitated now. “She didn’t say so?” “But did you ask?” I pushed. He looked a little abashed. “Not specifically.” I continued, “Did we ask for PCR for chlamydia and gonococcus on that urine?” “I didn’t think of that. She’s 60, and married?” He shrugged his shoulders.

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Oh dear. Poor innocent young thing. “So? She has pelvic pain, and pain on urination. Is it dysuria or is it worsening pelvic pain when she urinates?” I asked. He looked at me blankly. “How about you go back and check about a discharge.” I continued. He came back some time later with an embarrassed smile. Sure enough, she had noted a recent discharge but had thought it was maybe thrush and had not considered that it may be related to the sexual “incident” that had occurred a few weeks ago. The junior doctor had enquired further and was pretty confident that it wasn’t thrush but another STI. He had organised some swabs and added on the tests to the urine sample she had done for us. He then counselled her about safe sex (“That was weird. I would have thought she’d have known that by now.” he said), and arranged treatment and follow-up. So, the junior discovered that UTI symptoms plus white cells in urine may be a UTI, or it may be something else, maybe an STI. Lesson learned.

6.3

Case 3

Gita was a 40-year-old woman who presented to my emergency department with abdominal pain and fever. At triage she had a heart rate of 100, temperature 38.6, oxygen saturation 95%, and respiratory rate 20. She said she had had the pain for a few days now and it had been getting worse. When asked where the pain was she pointed to her right upper abdomen. I immediately thought right upper quadrant pain plus fever equals cholecystitis, and continued my questioning. Yes, she had some nausea, was off her food, no vomiting, no diarrhoea, no change in stool or skin colour that she had noted. She hadn’t eaten much in the past few days as she felt so unwell, so she wasn’t sure if food made any difference to the pain. The only other thing that made the pain worse was if she took a big breath in, but, as I said to her, “If your gallbladder is infected that will make it hard to take a big breath.” That would also explain the slightly low oxygen level in a non-smoker. She had never previously had any problems with her gallbladder that she was aware of, and had no past medical history of note. She was on no medications. On examination she was a little tender in the right upper quadrant when I palpated and it was difficult to hear the air entry at her lung bases as she wasn’t good at taking a big breath in. Plus, the screaming baby in the bed next door made listening to anything difficult. I organised some blood tests, wrote her up for biliary appropriate antibiotics, put in the form for the ultrasound (which I was assured would be done—“maybe sometime later”), and called the surgical registrar about my woman with suspected cholecystitis. As usual there were no beds and several hours later the bloods confirmed an infection, but there were surprisingly normal liver function tests. Then the ultrasound finally came through—no cholecystitis. The surgical registrar had, of course, leapt on that with a gruff—“Not surgical then.” I had to rethink my assumptions. Right upper quadrant pain and fever. If it’s not biliary, what else could it be? Some weird diverticulitis or appendicitis maybe? Did I need to get a CT? I spoke to my ED senior. As I went over my notes with her I came to “pain on deep inspiration”

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and had an epiphany. Could it be a pneumonia? My consultant smiled. “Maybe a chest X-ray before the CT?” she suggested. “But at least you’ve given good antibiotic cover.” I could she was trying to make me feel better. Sure enough, the chest X-ray showed right lower zone consolidation. At least it made an easy medical referral now.

6.4

Case 4

“I’ve got a patient for the observation ward.” the junior doctor said to me. “He’s 24 years old with gastro and I think he needs a bit of fluid cause he’s a bit dry.” “Really?” I replied, “Can’t he just go home and try some orals there. Tell him it’s more comfortable in a place with your own toilet.” I suggested. “Oh, he doesn’t have diarrhoea.” she responded. “No?” I was now a little more interested. This sounded like a teaching opportunity about to present itself. “So why do you think its gastro?” She told me the story. The patient had woken that morning feeling sick with a fever and aching everywhere. He had tried to have some food but started vomiting. He’d been able to keep down a bit of fluid but not much and had rapidly felt more unwell in the next few hours. There was some headache and mild abdominal discomfort, but he had not yet passed a bowel motion. He worked in retail so wasn’t sure of potential gastro contacts, but denied having any bad food. The junior finally got to the observations. His temperature was 38.8, heart rate 120 with blood pressure 100/70 (“That’s why I think he’s a bit dry.”), respiratory rate 22, and oxygen saturation 99%. I stood up grabbing a drug chart. “How about we go and see him together.” In the room was a young man lying with his eyes closed looking flushed and unwell. I quickly looked at the monitor which confirmed the observations hadn’t improved. He reluctantly opened his eyes and squinted against the light. Some directed questioning revealed no obvious ENT, respiratory or urinary symptoms, but definitely a headache and he would prefer the light to be off. I quickly examined him for a rash and showed the junior what early petechial spots looked like. Ceftriaxone and fluids were quickly ordered and a full septic workup commenced. At the end of the shift I was walking upstairs with the junior. “So, how was the shift?” I asked. She looked guiltily away. “Yeah, sorry about that septic man.” “Nothing to be sorry about. You learned something.” “Sure did.” she agreed. “It’s called attentional bias.” I explained. “You’re so busy looking at the vomiting and fever, thinking it’s a gastro, that you forget to look for other causes. It’s a reminder to keep your mind open. Think what else could it be. Most of us learn it the hard way.” “But he could have died.” The junior replied. “Yeah. He could have. But he didn’t.” I knew the young doctor had learned her lesson.

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Conclusion

We often look for quick heuristics to assist with our decision making. Unfortunately, we sometime focus too much on one or two main factors which jump out at us, particularly if together they lead to a particular conclusion. This may cause us to forget all the other risk factors, symptoms, or signs which may have led us to consider other possibilities. We may also consider these two factors so inextricably linked that if we don’t see them together we don’t consider a possible result. So how can we overcome our attention being distracted in this way? Some of the techniques are described above. If you find yourself leaping to a conclusion just stop and consider, could it be something else? What would the consequences be if it were? If you find yourself saying “It can’t be that because there’s only the one part of it.” Just check. Can it occur without the other part? What else would you need to look for? This intervention to improve attentional bias is called reflective reasoning [1–3]. It helps to develop an awareness through experience, such as more senior doctors have learned [1, 4]. If the junior doctor is uncertain, they can augment their own cognitive ability by obtaining advice from a more experienced colleague (w 2012). Senior doctors also have a role to play in educating juniors about clinical bias [5] as I tried to do in case 4.

References 1. Croskerry P. The importance of cognitive errors in diagnosis and strategies to minimize them. Acad Med. 2003;78:775–80. 2. Norman GR, Monteiro SD, Sherbino J, et al. The causes of errors in clinical reasoning: cognitive biases, knowledge deficits, and dual process thinking. Acad Med. 2017;92(1):23–30. 3. O’Sullivan ED, Schofield SJ. Cognitive bias in clinical medicine. JR Coll Physicians Edinb. 2018;48(3):225–32. 4. Graber ML, Kissam S, Payne VL, et al. Cognitive interventions to reduce diagnostic error: a narrative review. BMJ Qual Saf. 2012;21(7):535–57. 5. Croskerry P, Norman G.  Overconfidence in clinical decision making. Am J Med. 2008;121(5):S24–9.

7

Authority Bias Carly Silvester

Consider an advertisement you recently watched on television, perhaps for a breakfast cereal. There was likely an elite athlete touting the nutritional benefits and importance of this particular cereal in starting their day right! Advertising executives are experts in cognitive bias and appealing to authority. Celebrity endorsements are used to appeal to your inclination to elevate a high status individual’s opinion even if there is poor data to back it up. Much of modern society is built on normative deference to authority. Examples within our education systems, family structure and workplaces are easily brought to mind with compliance rewarded and rebellion punished [1]. Authority bias occurs when the opinions and instruction of an authority figure are accepted and followed unquestioningly [2, 3]. The Milgram obedience experiment is the most widely known example of authority bias and how it influences behaviour. This study involved participants delivering electric shocks to another person under the instruction of an authority figure. Despite many feeling it was wrong and expressing the desire to stop, many participants continued to follow orders to deliver further painful shocks [4]. Medicine is filled with authority figures and hierarchy. It can be seen in the doctor–patient relationship, within the medical and nursing teams and within all levels of medical training programmes. Doctors with higher status often control how healthcare is provided, determining timelines, attributing importance to particular symptoms and weighting investigations, usually gleaned from prior experience. The challenges of identifying and negating unwarranted authority bias both as leader and follower can be very difficult and need to be actively considered within healthcare structures. Definition: The tendency to attribute greater weighting to the opinion of an authority figure and be more influenced by that opinion.

C. Silvester (*) Department of Emergency Medicine, Noosa Hospital, Noosaville, QLD, Australia © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_7

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Case 1

You are the night registrar working at a large tertiary facility taking handover for your short stay area from the evening consultant. One of the patients in short stay is Glenda, a 74-year-old woman, brought in by ambulance following a fall at her home earlier in the day. She reported right groin pain and had not been able to mobilise since her fall. She has a past medical history of atrial fibrillation, hypertension, COPD, osteoporosis and GORD. During handover the consultant states that Glenda is a sprightly woman who feels well other than some persistent pain in her right groin region. She is not confused, and can recall all the events of her fall, but somewhat sheepishly admits that she should have used her walker to get to the bathroom. Her GCS is 15, with no focal neurology, and no other evidence of trauma including an absence of haematomas or bruises. Glenda underwent a CT brain, C-spine and chest X-ray which were normal. An X-ray of her right hip/pelvis showed a minimally displaced, right inferior pubic rami fracture. An eFAST showed no evidence of intra-abdominal bleeding. You review her bloods which included an FBC with Hb 105, WCC 7, plt 254, eGFR 77 (her baseline) and normal electrolytes. The consultant tells you that the plan for Glenda is to remain in short stay overnight with a mobility assessment and physiotherapy in the morning and discharge back to her nursing home with ongoing analgesia. During this handover a nurse reports that Glenda has been a little drowsy since arrival to the short stay unit and her BP is a little low. Your colleague reports he thinks he may have been a little over-enthusiastic with her analgesia regimen—he notes she has been administered a total of 100mcg of fentanyl as well as 15 mg of oxycodone in the past 4 h. He advises he will review her but to organise a small fluid bolus and a dose of naloxone. You enquire whether any CT scans of her abdomen/ pelvis have been done and are informed it’s not necessary as her pain is very localised to her region of injury in her pubic rami. He also pulls up her previous records and shows that her baseline BP during her previous admissions have been generally recording a systolic of 100 mmHg. Your consultant returns and confirms a trial of naloxone has shown an improvement in her cognitive state and her BP. You feel somewhat reassured and continue on your other patient assessments. You are called to review Glenda an hour later for a further deterioration in her BP with a reading of 88/55. She is awake and reporting further pain in her groin region. She is oriented to person, place and time with a soft abdomen. You feel conflicted over managing her pain and managing her hypotension so call the consultant and advise them of the changes. You are advised again to start some slow fluids and give her a dose of oral Targin and refer the patient to the medical inpatient team as he can foresee that she won’t be able to be discharged in the morning. The following morning you overhear the nurse’s handover for, the now medical inpatient, Glenda. It seems she has had a difficult night. After review, the medical registrar organised a CT of her pelvis/abdomen which showed no other bony injury but a large retroperitoneal haematoma. She has received three units of blood and is awaiting review by interventional radiology.

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You realise the mistakes you made in missing this injury and the false reassurance you had felt after she had been reviewed by a consultant. You wonder why this opinion outweighed your immediate thoughts of whether further imaging or investigation was warranted given the clinical changes. You reflect that you felt hesitant in challenging a more experienced clinician than yourself.

7.2

Case 2

Theo is a 19-month-old boy brought by his father to Emergency in the late evening. He has been unwell with abdominal pain and vomiting for the past few hours. His father noted his appetite was reduced today and seemed more lethargic than usual. Theo had good wet nappies and at times during the day was happy and settled. His father tells you he has had one dirty nappy today which was looser than normal but he did not notice any blood or mucus. You note Theo is an otherwise healthy child, with no other medical conditions. He is immunised and attends daycare with his brothers. You examine Theo and he has a soft abdomen without any palpable masses and squirms away only on deep palpation in his umbilical region. He has moist mucous membranes and normal vital signs. Theo is very settled with you; his father reports that this is the best he has been this evening and he was worried about how much pain he was in before arriving here. You present your case to the senior registrar and suggest you want to undertake investigations including an abdominal X-ray, bloods and observation for a few hours, concerned about the severity of abdominal pain. The registrar is surprised and states she has already eyeballed Theo and he looked very comfortable. She is reassured by his normal vital signs, soft abdomen and combination of both vomiting and diarrhoea. You are told by the registrar that a pain-free child does not need radiation, to start a trial of fluids and move Theo and his father back to the waiting room. Accepting her advice, you advise Theo’s father of the plan and reassure him your team feels it is likely gastroenteritis. You are seeing another patient when you are flagged down by Theo’s nurse who informs you he is unsettled and vomiting and he has not progressed at all with his trial of fluids. Your registrar overhears and quickly charts a dose of ondansetron and asks you to check a BSL and ketones—which are both normal. When you go to see Theo again, he appears quite irritable and unsettled. You hope the antiemetics work quickly. Later, on a brief ward round you update the team about his progress and events of the evening. They comment on how comfortable he now looks and suggest that he can be discharged home as soon as he passes a trial of fluids. You feel obliged to rapidly follow through and negate your own concerns by writing an exhaustive safety net of signs and symptoms that Theo’s father should consider returning for further review. Theo is back in the department a few hours later. He is pale, distressed and inconsolable. Your team rapidly gains IV access, starts rehydration and analgesia. An abdominal USS is organised and confirms a diagnosis of intussusception. You feel

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an immense sense of failure as the surgical team take-over care and counsel his father about the diagnosis and management plan. Theo’s nurse approaches you and diplomatically suggests you need to trust your own judgement more. She wisely counsels you that the senior registrar had their own biases at play and missed the diagnosis. Your vulnerability lay not in your assessment, but in feeling obliged to follow a plan defined by an authority figure, even when you had concerns the diagnosis and management plan were wrong.

7.3

Case 3

You have just referred a patient to your surgical colleague when you hear a collective groan arise from the nearby desk. The surgical registrar states ‘not again’ and your emergency consultant agrees. They relay to you from the triage screen that Johnny Parsons is back. Johnny is a well-known alcoholic with chronic pancreatitis who frequently presents with abdominal pain requesting opiate analgesia. You are quickly brought up to speed and told that Johnny does not get any analgesia until it is shown he has acute pathology, and he will often self-discharge once he gets sick of hanging around. ‘Just don’t give him any opiates’ is the mantra and you quickly agree. When you see Johnny he is very agitated and squirming on the bed. You note he is tachypnoeic and tachycardic, but afebrile with a blood pressure of 145/88. Johnny asks what you think is wrong and requests more analgesia as this doesn’t feel like the usual pain to him. You remain calm and reply that you will need to examine him and undertake some further tests to determine this. You step out to delay further confrontation and analgesia requests. You soon hear a large noise and shouting as you realise Johnny has left his cubicle. You feel a little relieved that he has left of his own accord and tell the nurses not to worry about him. An hour later Johnny reappears in your acute section. He was found collapsed near the hospital groaning and diaphoretic. He appears to be in septic shock and continues to moan with abdominal pain. The bloods you sent earlier have returned and show evidence of acute liver failure, renal failure and pancreatitis. You manage this efficiently with fluid resuscitation, organise an urgent CT scan which shows necrotising pancreatitis and admit Johnny to ICU with surgical input. You consider your earlier approach to Johnny and wonder why you were so easily influenced to minimise your contact and withhold certain treatment based on others’ experiences with this patient. You accept that both the emergency consultant and the surgical registrar were authority figures in this interaction and their advice outweighed the initial abnormal vital signs and your patients voiced concerns. Because of their seniority, you continued to follow the course dictated by the authority figures rather than comprehensively assessing the patient in front of you.

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Case 4

Rose is an 83-year-old female who presents to your regional emergency department one morning. The ambulance service has handed over confirming she was found in the bathroom following another fall overnight. She has normal vital signs and is in no apparent pain, and ECG shows sinus rhythm. Rose is of a Vietnamese background and speaks little English. Her daughter translates much of your conversation. You learn Rose has fallen at home multiple times over the past month without explanation. This is her second presentation to the hospital in 48 h and her family are very concerned about her continuing falls, weight loss and declining condition. She lives independently after her husband died 6 years ago, with no formal services in place but has extensive family close by providing support. You peruse the notes from yesterday evening and learn that Rose had an unwitnessed fall at home whilst gardening. There is insufficient documentation to suggest whether this was mechanical, syncope related or another precipitant cause. The brief notes state her vital signs were normal, she had two small skin tears on her lower legs that were patched up, urine dipstick and a CT of her brain was normal. There is documentation from the nurse that Rose seemed pleasantly confused, but no reference to her baseline. The discharge instructions included advice to see her GP for a thorough assessment next week. Whilst you acknowledge the shortcoming of the assessment of a geriatric fall presentation you wonder why Rose’s family felt obliged to take her home. In your brief time with them you can see they are very fearful and not sure of how to protect and look after Rose. After gently enquiring about their understanding, Rose’s family hesitantly reply that they felt the doctor knew best and wanted to follow the medical team’s advice. Rose didn’t want to be a burden to anyone and didn’t want to be seen as a complainer. They felt reassured that no injuries had been found and didn’t want to continue to bother the busy doctor with questions about their elderly mother. They were not aware of any services that could be arranged for Rose and this was not discussed. You provide a thorough assessment of Rose considering the cause for her falls including orthostatic blood pressure, gait and balance evaluation, functionality, infectious cause, general cognition, medications and nutrition. Ultimately you determine she needs admission for likely dementia, microcytic anaemia and home safety support arrangements. This interaction is a reminder to you of the powerful societal position a doctor holds. Patients are disadvantaged by a complicated structure and trust that doctors make their decisions altruistically, using their experience and system familiarity to obtain the best outcomes for a patient [5]. As an authority figure it is important to remember that patients may not feel able to speak up about their concerns or question doctors’ decisions. Safe spaces must be made in order to allow this to happen.

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Conclusions

Authority bias predisposes people towards believing and obeying authority figures. Within medical culture it can be difficult to determine the line between learning and taking guidance from an experienced practitioner versus blindly following a senior figure’s instruction. Potential Solutions 1. Take the time to think logically and independently. Consider what you might do if the cognitive short-cut of following your senior colleague’s instructions was not available to you. 2. Make questioning part of your day. Ask your colleagues why they are making particular decisions and how they have come to their conclusions. 3. Create a distance between yourself and the authority figure (time or physical) to mitigate their influence on your own thoughts and decisions [1]. 4. In the role of an authority figure, give others opportunity to express ideas before your own to allow discussion and independent assessment and thought.

References 1. Shatz I. Effectiviology. Authority bias: lessons from the Milgram obedience experiment [internet]. [Cited 5 Jul 2020]. https://effectiviology.com/authority-­bias-­the-­milgram-­obedience-­experiment/. 2. Campbell SG, Croskerry P, Petrie DA.  Cognitive bias in health leaders. Healthc Manage Forum. 2017;30(5):257–61. 3. Howard J. Cognitive errors and diagnostic mistakes: a case-based guide to critical thinking in medicine. Cham: Springer; 2009. p. 21–56. 4. Milgram S. Behavioral study of obedience. J Abnorm Soc Psychol. 1963;67(4):371–8. 5. Greenhalgh T, Snow R, Ryan S, Rees S, Salisbury H.  Six ‘biases’ against patients and carers in evidence-based medicine. BMC Med. 2015;13:200. https://doi.org/10.1186/ s12916-­015-­0437-­x.

8

Availability Bias Justin Morgenstern

In an ideal world, each diagnosis would follow an algorithm that starts with a pretest probability and then applies the likelihood ratios of each feature of the patient’s history, physical exam, and required tests, to arrive at the most likely final diagnosis. However, that is simply not how the human mind works. There are many ways that this algorithm can fail. Clearly, a clinician cannot make a diagnosis that they have never heard of. Even when they know the diagnosis, it has to come to mind while they are assessing the patient. The diagnosis will always be, by definition, one that came to mind. Furthermore, the clinician must understand how important each feature of the presentation is, know the likelihood ratios, and accurately adjust their pretest probability based on the gathered information. There is some evidence that medical errors are more often the result of cognitive failure than knowledge deficits [1]. In other words, the correct diagnosis is likely to come to mind, but we fail to choose it from the menu of available options. One possible reason for such errors is that we do not arrive at a diagnosis by following a mathematical algorithm using likelihood ratios, but instead match the patient in front of us to examples of various diseases we have developed in our minds. We use heuristics to rapidly match the patient in front of us to the many disease patterns we learned throughout our training. However, the process can go awry when examples of some diseases come to mind easier than others, causing us to overestimate or underestimate the likelihood of the diagnosis. This can occur because the diagnosis is seen frequently, a rare diagnosis was seen recently, or a specific case had a significant emotional impact, making it easier to recall [2, 3]. Definition: The tendency to judge the likelihood of a diagnosis based on how easily similar examples come to mind. J. Morgenstern (*) University of Toronto, Toronto, ON, Canada e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_8

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J. Morgenstern

Case 1

You are a consultant about to start a shift in a metropolitan emergency department. Despite expecting it to be busy as it is a Sunday afternoon in the middle of flu season, you came in energized and ready to work. Unfortunately, the first words out of your colleague’s mouth upon your arrival were, “do you remember that patient?” Yesterday, you had seen a young woman with pleuritic chest pain that seemed to be muscular. She had no risk factors, a normal physical exam, and was PERC negative, so you sent her home with some ibuprofen and follow-up with her GP. Unfortunately, she was brought back to the emergency department by ambulance this morning in significant distress and a CT scan revealed large bilateral pulmonary emboli (PE). It has been a long day. As you near the end of your shift, the registrar presents a case. “This one should be easy. It is a young female who has some right sided pleuritic chest pain that started after a big coughing spell. She has no prior history of PE or DVT, no leg symptoms, and no risk factors. Her vital signs are normal. The only finding on exam is tenderness to palpation of her right chest that exactly reproduces the pain that brought her in. Her ECG and chest x-ray are normal. She is low risk by the Well’s score and PERC negative, so I don’t think she needs any further testing. I am just going to treat her pain, give her good return precautions, and have her follow-up with her GP later this week.” An image of yesterday’s patient immediately forms in your mind. The registrar seems surprised by your tirade on the shortcomings of the PERC score, but agrees to add bloodwork and a CT scan “just to be safe.” You hand the patient over to the oncoming consultant, and head home feeling good that you did not make the same mistake twice. When you check the results 5 days later, you find that the CT was negative, but notice that the patient is still admitted to the hospital. It turns out that there was an incidental mass found on the CT. The surgeons performed a biopsy, which was thankfully negative, but the patient developed pneumonia after the procedure. The workup of PE is somewhat algorithmic, with clinical decision aids that help us determine a pretest probability, and then a limited number of tests can be added to rule in or rule out the diagnosis. Usually, a negative PERC score in a low-risk patient ends the workup for PE. However, in this case, despite being low risk, the patient presented by the registrar closely matched a patient seen the day before by the consultant in whom PE was missed. This missed diagnosis was already on the consultant’s mind throughout the day, and so when a similar patient was presented, PE was moved to the top of the differential diagnosis. Despite using the PERC score to correctly rule out PE in hundreds of patients previously, the recent misdiagnosis is the only patient that came to mind. This resulted in an overestimation of the patient’s risk of PE, an unnecessary test, and downstream complications. Recent presentations, and presentations with a strong emotional component (such as missed diagnoses), are more likely to come to mind, resulting in a misperception of the likelihood of that diagnosis.

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Case 2

A child presents with a fever, runny nose, and a rash. The history and physical exam are not concerning. She is acting normally according to her parents. There is no history of vomiting. She is previously healthy and fully vaccinated. There is no travel history or sick exposures. The vital signs are normal, and the child appears well aside from the general features of a URTI: coryza, mild conjunctivitis, and some lymphadenopathy. There are no meningeal signs. The rash is a nonspecific, erythematous, blanchable, maculopapular rash that looks like a viral exanthem. Your instincts are that this is just another viral illness, but you are a little nervous. Three children were recently diagnosed with meningococcal disease in a different area of the country, and meningitis has been all over the news. This was reinforced by an email from public health that you read at the beginning of your shift discussing the possibility of meningitis in children with fever and a rash. It seems very unlikely that this child has meningitis, but it is hard to ignore those dreadful news reports. As you debate the best course of action, a different child pops into your head. During residency, you saw another well appearing child with a rash who rapidly deteriorated in front of you, and ultimately died of meningococcemia. The details were different, that child had not been immunized and had a nonblanchable rash, but you cannot afford to make the same mistake. After explaining the risk of meningitis to the parents, they agree to a lumbar puncture (they have also been watching the news). The first attempt fails, and you have to use procedural sedation for the second try. Thankfully, the sample obtained is completely normal. Two days later the child returns to the emergency department and is diagnosed with Kawasaki disease. In retrospect, she had all the symptoms on your initial assessment, but you were so concerned about meningitis that Kawasaki disease never crossed your mind. As is illustrated by this case, misdiagnosis is frequently the result of multiple cognitive biases; one study demonstrated an average of six cognitive or systematic errors per incorrect diagnosis, and many cognitive biases are closely related [1]. In this case, the widespread media coverage of meningitis made the diagnosis seem more likely, and made the clinician lose track of the incredible low pretest probability of meningitis in a well appearing, fully vaccinated child with no travel history. Once meningitis was considered, it was the main focus of the workup, and the negative workup resulted in false reassurance and premature closure of the decision-­ making process.

8.3

Case 3

You have no idea what is going on with this patient. He is a 28-year-old man with no major medical problems. He is on bupropion for smoking cessation, but does not take any other medications. When he is able to speak, he denies using drugs. The

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triage nurse originally placed him in the psychiatric assessment area, because he was rapidly pacing back and forth, not making a lot of sense. Every 15 s or so, he grimaces and appears to be in a lot of pain. Occasionally his legs seem to spasm and he will fall to the floor, but he never loses consciousness, and will quickly resume pacing again. It is difficult to get any vital signs recorded, and he is not cooperative with any aspect of the physical exam. The patient was given an antipsychotic to settle the agitation, but, if anything, the symptoms got worse. Looking at the repetitive grimaces, you wonder if the patient is having seizures. You move him to the resuscitation room, and give multiple doses of intravenous midazolam, but his symptoms remain unchanged 20 min later. The patient is clearly sick, but you are not sure how to proceed. You ask a colleague for help, and she immediately says, “this is extrapyramidal symptoms caused by the bupropion. I had a patient who presented almost exactly like this 2  years ago.” You give the patient a dose of benztropine, and 10 min later he is sitting comfortably on the stretcher, talking quietly with the nurse about his attempts to quit smoking. Unlike the prior examples, the availability of a previous similar patient rapidly led to the correct diagnosis in this case. It is important to remember that considering similar cases does not always lead to errors. More generally, we call this type of reasoning the availability heuristic, and it is often quite useful [2]. It only becomes the availability bias when the limitations of such reasoning are not accounted for. In reality, we often only label it a bias when it results in the wrong answer. Unfortunately, without the benefit of hindsight, it is often impossible to distinguish appropriate uses of the availability heuristic from potentially dangerous uses of the availability bias. To be effective, clinicians need to embrace the diagnostic benefits of comparing current patients to prior examples, while remaining wary of the potential errors that can result from overreliance on such non-analytic thinking.

8.4

Case 4

Midnight shifts on the weekend are always hard, but homecoming weekend has doubled the number of patients. Not surprisingly, the majority of the influx is directly related to alcohol abuse, and you are starting to get a little fed up. The nurse hands you another chart. “We’ve got another one who is going to need to sleep it off until morning.” There is still a very long list of patients waiting to be seen. You quickly enter the room, are hit by a strong aroma of alcohol, and see a young man snoring on the stretcher. He only responds with a moan when you touch him, but he is maintaining his airway. His vital signs are unremarkable, and his pupils are normal. You do not see any evidence that he has taken anything other than alcohol, and you do not see any obvious signs of trauma. You decide to leave him to sober up, like the ten other students clogging the department, and ask the nurse to tell you when he is awake so you can talk to him. Six hours later, the end of the shift is finally in sight. You have dispositioned most of the drunk patients, and just need to finish a few charts while you wait for your

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relief to arrive. One of the nurses approaches. “Hey doc. Have you had a chance to recheck the kid in room 9? He still isn’t waking up at all. He must have had a ton to drink, or do you think maybe he was on something else?” Your heart starts to race. How many times have you heard the lecture cautioning against missing trauma in a patient presumed to be drunk? You can clearly picture the horrible CTs from the most recent grand rounds. You quickly order a CT scan of his head. Unfortunately, because of the overnight backlog, there is a delay, but an hour later you breathe a sigh of relief as the images pop up and are completely normal. But he still isn’t waking up. As the stretcher rolls passed on the way back from radiology, you notice something on his wrist: a medic alert bracelet. He is an insulin-­ dependent diabetic. Eight hours into his ED visit, you finally check his glucose level and it is undetectably low. In this case, availability bias struck twice. First, the diagnosis of intoxication was made because of the huge number of drunk patients already seen that night. Second, when the possibility of a missed diagnosis was considered, the first thing that came to mind was trauma, based on similar cases presented at grand rounds. In both cases, the availability of a believable diagnosis prevented the clinician from identifying hypoglycemia as the true cause of the patient’s altered mental status.

8.5

Conclusion

Availability bias occurs when we overestimate the likelihood of a diagnosis because similar examples are readily available in our memory. Consequently, we will also mistakenly underestimate the probability of diseases that do not come easily to mind. The use of availability is not inherently bad; it can rapidly lead us to the correct diagnosis. Furthermore, common conditions are likely to come to mind more easily, which is a natural way to ensure that we are considering the base rate of disease. However, there are numerous ways that the availability heuristic can lead to biased thinking. Recent cases can weigh more heavily in our thinking, but the diagnosis of a patient is generally completely independent of other recently seen patients. Cases with high emotional impact, such as those with a bad outcome, missed diagnosis, or resulting in a lawsuit, can result in individual doctors overpursuing a certain diagnosis, to the detriment of their patients. Conversely, availability bias can result in a rarely seen disease being too easily dismissed. Potential Solutions 1. Routinely consider alternatives. Get in the habit of routinely asking: what else could this be? Physically writing out a differential diagnosis can make gaps more obvious. 2. Limit reliance on memory. Using cognitive aids for the differential diagnosis limits the chance that you will miss an important diagnosis just because it does not come easily to mind. 3. Meta-cognition: Take time to ask yourself, why do I think this? Might my thinking be overly influenced by cognitive biases?

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References 1. Graber ML, Franklin N, Gordon R. Diagnostic error in internal medicine. Arch Intern Med. 2005;165(13):1493–9. 2. Tversky A, Kahneman D.  Judgment under uncertainty: heuristics and biases. Science. 1974;185(4157):1124–31. 3. Eva KW, Norman GR. Heuristics and biases—a biased perspective on clinical reasoning. Med Educ. 2005;39(9):870–2.

9

Bandwagon Effect Carl Luckhoff

The bandwagon effect within medical practice is one that can easily be misunderstood for updated practice and the implementation of new evidence in the delivery of healthcare. Notwithstanding this, the bandwagon effect, in the right circumstance and with the correct understanding, can have very positive effects on healthcare provision as new evidence becomes incorporated into practice. Traditional definition refers to the bandwagon effect as a movement that occurs without sound reasoning or judgement, and this is where the risk of a bandwagon effect exposes patients to harm [1]. In our modern-day society of social platforms communications and readily available information, these platforms further increase the risk of being caught up in such a movement as opinions are presented without thought and/or reasoning. It is in this fashion important to recognise that specific groups of clinicians may be at risk of this effect, namely those very groups that attempt to stay on trend with modern-day thinking and practice. On the other side of the coin lies perhaps a less engaged clinician group, who do not adapt their practices in line with newer medical evidence and research. In the following few examples, the focus is directed towards identifying practices that highlight decision-making that are part of a bandwagon effect, but may not actually be recognised as such, and in that lies its greatest risk.

9.1

Case 1

A 44-year-old male presents to the emergency department of a small rural hospital following an accident whilst running up a flight of stairs. His foot slipped and slid off the corner of the step, causing a large wound on the sole of his foot. Immediately C. Luckhoff (*) Emergency Department, Alfred Health, Melbourne, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_9

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following the accident the patient and his family applied a bandage to the area and this managed to stop what they had perceived as a large amount of bleeding. They presented with the foot elevated and in bandages. The nurse at the front desk saw him soon after his arrival and when she opened the wound it again started to bleed. She quickly put the patient on a bed, elevated his foot and re-applied a pressure dressing. This seemed to control the bleeding until the patient could be seen by a doctor. The emergency doctor was quick to act and after taking a brief, but focused history, he explained the process of exploring, potentially numbing and closing the wound. The patient was told that if the wound was too deep or large, he would require closure of the wound in an operating theatre, but this could only be assessed after taking the bandage off. Following a review of the wound the doctor felt that this wound should be closed in theatre. However, surgeon availability was limited. Whilst exploring how to facilitate this planned care, the doctor was promptly informed that processes at this hospital were different to those in other hospitals and that they would often close wounds such as this in the emergency department. This was a practice that was locally well accepted. The first doctor felt uncomfortable with this advice and asked a second doctor to review the wound. Following his review he was happy to proceed with wound closure. However, given the size of the wound the second doctor was concerned about infection and it was agreed that the patient would come back to hospital for intravenous antibiotics for the next 5 days, again in line with local practice, but without evidence to support this practice. The second doctor noted that he initially did not practise in the above fashion, but over time he became used to local challenges and practice, and adapted his care accordingly. Despite the lack of guidelines and/or evidence for such practice, he and other staff became used to this process and thus started to incorporate this as a standard of care, without exploring more appropriate solutions. Rather than attempting to find a solution for a problem they considered outside of their ability to fix, they had decided to adapt their practice and follow what other clinicians were doing.

9.2

Case 2

A 73-year-old courier driver presents to a metropolitan emergency department with a history of atypical chest pain. Soon after arriving to the emergency department an ECG was performed and this was presented to one of the doctors on duty. The doctor that saw this ECG did not think there were any concerning abnormalities and the patient was observed until a clinician became available. Unfortunately there were lengthy waiting times, but the patient was pain free at the time of his presentation and his vital signs were normal. You now see this patient approximately 2  hours later following evening staff handover. The patient had again developed minor chest discomfort, but clinical examination was normal. However, you feel that the second ECG is not normal, and that there are potentially ischaemic abnormalities in the chest leads. When you look

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at the first ECG you feel these were already present then, but without interim dynamic changes. The patient was given Aspirin and analgesia, and you repeat the ECG. This does not show progression or change in the abnormality. An initial high sensitivity troponin test is mildly raised, which in the setting of the ECG abnormality and atypical chest pain you discuss with the Cardiology team. They advise for a repeat troponin to be done, and serial ECGs to be completed. You are uncertain about this advice and decide to discuss this with a colleague, and she tells you that the Cardiology team would in general not admit these patients, but rather referred to these clinical scenarios as that of a “troponin leak”. You had heard of the term, but never really understood when it was applicable. However, you don’t want to come across as not knowing and the doctor you spoke to had been working there a while and told you it was standard practice. Besides, it sounded appropriate. You have a discussion with the patient and reassure him that there were no signs of an acute event or life threat. It is late at night and the patient was reluctant to wake his wife to go home, so you agree that he would stay in the emergency short stay unit until the morning, at which time he could go home. You hand over to the day team a few hours later. Following their review they discuss the case with the Cardiology team and a plan for admission and further testing is made given the ECG changes and troponin result. The testing reveals reversible ischaemia requiring further intervention. Upon hearing this outcome you realise that you had followed this movement of calling minor positive Troponin results a “Troponin leak”, without understanding what this meant or when this term was appropriate, and in that you to missed a potentially significant diagnosis.

9.3

Case 3

A 28-year-old female presents to the hospital with a history of scraping her arm against a piece of broken plastic. She sustained a superficial wound to the outside of her forearm, approximately 5 cm in length. Three days later she noticed that it had become quite red around the wound, but she thought this could be normal and that perhaps this was a local reaction to the plastic. She felt well and made a mental note to herself that she should keep an eye on the wound. She dressed the wound and only reviewed it 2 days later, at which time she noticed that her forearm had become swollen and red. Following a medical review blood samples were sent off and the doctor decided to start intravenous antibiotics, with a plan to continue this for 5 days. An ultrasound was also completed on that day and the patient was asked to return daily for intravenous antibiotic administration. All the tests supported an uncomplicated infection, but the doctor followed local practice at this hospital. Three days later the patient started to complain of diarrhoea, but she was told that she would need to complete the intravenous antibiotic plan and then continue on

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oral medication. She became increasingly unwell and in the end needed to take time off work as she felt too weak and unwell to attend to her usual occupation. A discussion with her own GP resulted in a review of local practices at the hospital and it became clear that there was an increased trend to use intravenous antibiotics for various community acquired infections. An in-depth review of local practices, guidelines and behaviour highlighted that staff had noticed this trend to increased intravenous antibiotic use, but as this practice developed there was no review or questioning of this behaviour. Nursing staff also noted an increase in patient presentations for intravenous antibiotic administration, but had assumed that this was a more recent trend in wound infection management, and therefore also adopted this pattern of care without further questioning or review. The potential adverse impact this could have on patient care is evident from the above case, but patterns such as this also have large impacts on nursing staff and patient care at large.

9.4

Case 4

A young doctor has recently started work at a metropolitan hospital emergency department. She was hard-working and diligent, but found the emergency rotation daunting and challenging, mainly due to risk of missing a significant diagnosis. As in most hospitals there were many urban legends about missed diagnoses and adverse events following emergency department presentations, and it was especially young doctors that were very aware of these reported cases in the various hospitals. One particular story within the hospital was that of a patient where the bedside pregnancy test was negative, and the patient ended up having a large haemoperitoneum secondary to a ruptured ectopic pregnancy. As the emergency rotation was only her second rotation she also liked to discuss cases with her colleagues regularly, and felt reassured by their advice and also by the fact that they displayed similar fears about missing underlying disease or making mistakes. The management of female patients presenting with abdominal pain is a presentation that many doctors are apprehensive to manage. There are many stories of missed ovarian torsion, urinary tract infection with missed underlying renal calculi, and of ectopic pregnancies where it was missed that the patient was pregnant. On the day that this doctor managed a young female with lower abdominal pain she made sure that she thought of all of the above scenarios. The patient was a young female and a bedside urine pregnancy test was performed as part of the initial bedside investigations. The doctor also collected blood for a quantitative B-HCG to be sure that she wasn’t going to be caught out by the above-mentioned scenario. It seemed a bit superfluous, but following a discussion with colleagues she was reassured that this was standard practice amongst her peers. At the same time as the above event the laboratory of this particular hospital was looking at orders received and decision-making behind blood requests, both from a patient care, and cost and workload perspective. They had noticed a four-fold

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increase in B-HCG ordering, but this could not be explained by patient presentation numbers nor patient population. Bedside urine pregnancy test use did not display this same trend in use. Upon exploration it was evident that quantitative B-HCG testing had increased as a result of this urban legend within the hospital. New doctors, and especially younger doctors, are often victim to these legends as they establish the safe boundaries of their own practices and risk management. Caution should be taken when ordering and interpreting test results and it is important to understand the use and limitation of tests so as to ensure that you don’t get caught up in this bandwagon effect of over-testing for indications poorly understood.

9.5

Case 5

A 48-year-old male presents with right flank pain since the early morning hours. He is usually very fit and healthy and exercises at least four times per week. Yesterday he became aware of a dull ache in his right flank whilst he was exercising, but he thought that it was a muscular spasm, given the intensity of the exercise he was doing. He tried to rest that evening and also took paracetamol and ibuprofen at home, thinking that he would feel better in the morning. The pain woke him from sleep and after pacing around and trying some stretch exercises he took more pain killers. This had very little effect and by 08:30 the pain became unbearable. His initial plan was to see his own doctor in the morning, but he could not wait any longer and went to the emergency department. The emergency team on duty that morning had just finished their morning review of overnight patients at the time that this gentleman arrived. It was a medium sized emergency department in a large rural town, suffering from long-term staffing challenges. Medical cover was therefore often reliant upon locum doctors who would complete small blocks of shifts. The doctor in charge of the shift on this day was a locum emergency physician, and although he had worked in this department on a few occasions in the past he was still getting to know local processes and culture. Following a review in the triage area a nursing staff member approached him asking for paracetamol and oxycodone for a patient who had presented with likely renal colic. The locum Emergency Physician wasn’t quite sure why the request had been so specific, and knew that this approach to suspected renal colic may not be the best course of action for pain relief in this scenario, but he also did not want to offend the nurse by flatly refusing. He decided to enquire why the nurse specifically wanted the mentioned combination of pain relief and was told that this was in line with local practice and it was “what they always gave patients with pain”. Given that it was not too busy, the doctor offered to quickly review the patient and following a rapid assessment a more appropriate analgesic management plan was derived. The doctor was curious to explore the triage nurse’s initial request and when the opportunity arose later that day he had a quick chat with the nurse. In an attempt to provide at least some initial care to patients when they presented, triage nurses would often ask one of the doctors to prescribe pain relief. The nurse

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recalls that this used to be restricted to paracetamol and non-steroidal anti-inflammatory medications, but in recent months a trend had developed whereby most doctors would prescribe paracetamol and oxycodone. He was unsure of how or where this had started. In an attempt to provide better patient care, staff had started to adopt practices that seemed to be in line with medical evidence and research, but in truth a trend to increased non-evidence based opioid analgesic strategies were being incorporated into daily practice without oversight and/or support mechanisms focusing on optimal patient care. Although seemingly innocent, these types of bandwagon effects tend to gain a momentum of their own and can lead to increased risk behaviour without understanding the origin and recognising when such forces are at play.

9.6

Conclusion

It would be unfair to assume that the bandwagon effect has only negative impacts on patient care. Perhaps the bandwagon effect could be seen as two sides of a coin. On the one hand it may be the very stimulus that enhances patient care to improve health outcomes, and on the other hand it may facilitate at risk practice and thus medical error. For the clinician it is the awareness of this effect that likely provides the best solution to not falling victim to this flawed decision-making process. Self-reflection and staying current with scientific evidence, rather than practising in accordance with what seems to be trend, is a good way to ensure appropriate application of an effect that is sure to have lasting impacts on medical practice and care [2, 3]. It is also worth noting that the bandwagon effect can have earlier and larger impacts on smaller facilities that do not necessarily have the resources available to maintain academic programmes to ensure practice in accordance with the medical evidence available. Within these non-academic programmes an oversight of guidelines and local practices may help to mitigate a bandwagon effect, especially for seemingly less acute scenarios. At the end of the day vigilant oversight and review of practice probably provides the best opportunity for identification of a bandwagon effect within a department or hospital.

References 1. Cook J. Jumping on bandwagons: taking the right clinical message from research. Br J Sports Med. 2009;42(11):863. https://doi.org/10.1136/bjsm.2008.048629. 2. O’Connor N, Clark S.  Beware bandwagons! The bandwagon phenomenon in medicine, psychiatry and management. Australas Psychiatry. 2019;27(6):603–6. https://doi. org/10.1177/1039856219848829. 3. Francisco RA.  Varied dynamics of bandwagon mobilization. In: Dynamics of conflict. New York: Springer; 2009. p. 51–2.

Base Rate Neglect

10

Justin Morgenstern

The likelihood of a diagnosis in a patient is directly related to the likelihood of that diagnosis in the general population. Rare diagnoses occur rarely and common diagnoses occur commonly. This is why every medical student has heard the saying, “when you hear hoofbeats, think horses not zebras.” This sage advice (albeit not applicable in Africa) reminds students to consider the pretest probability or base rate of a disease. However, zebras do exist, so ignoring them completely is also a faulty strategy. The question is when should we seriously consider a rare diagnosis? The formal approach to this problem involves Bayes’ theorem, in which the pretest probability is adjusted by the likelihood ratios of the clinical features and test results. Unfortunately, test results are often interpreted without consideration of the pretest probability, resulting in misinterpretation and misdiagnosis. Similarly, the benefits of medical treatments are often discussed using relative risks, without any mention of the baseline or absolute risk, leading to skewed understandings of the benefits of medical interventions. Definition: Failure to sufficiently consider probabilities in clinical decision-­ making, such as the disregard or undervaluation of the incidence of a disease, resulting in the over-pursuit of rare or exotic diagnoses [1].

10.1 Case 1 Diane is a very anxious 35-year-old woman who arrives at the emergency department after being told by her family doctor that she has breast cancer. She has an appointment with the breast clinic in 3 days, but she does not think she can wait that long. J. Morgenstern (*) University of Toronto, Toronto, ON, Canada e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_10

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It turns out that Diane was diagnosed using a new screening test that your hospital recently purchased. It is a (hypothetical) form of CT mammography, and based on the grand rounds talk last week, you remember that the machine is very accurate: it has a sensitivity of 99% and a specificity of 97%. It sounds like the diagnosis is pretty certain. Considering that this could be a devastating diagnosis in a young mother, you ask the surgeon on call for a consult. The surgeon, who happens to have a degree in epidemiology, pulls you aside after reassuring the patient. She reminds you about a fundamental principle of screening tests: the base rate matters. Diane is only 35 years old. Despite being the most common type of cancer in young women, the incidence of breast cancer in 35-year-olds is only about 1  in 1500 [2]. If we think about 1500 asymptomatic women undergoing a screening CT scan, only 1 of them is likely to have cancer. Because the CT is 99% sensitive, that cancer will almost certainly be caught. However, even though the specificity is excellent, a 97% specificity means that the CT will result in 3 false positive tests for every 100 women scanned. For our population of 1500 women, that means there will be 45 false positive scans. In total, there will be 46 positive scans, but only 1 of them will be a true positive. Therefore, Diane’s actual chance of having cancer is only 1 in 46 or about 2%. As this case demonstrates, the pretest probability or base rate is essential whenever interpreting test results. The tests we order feel objective. We often take the CT interpretation and transcribe it as our final diagnosis. However, when imperfect tests (which all tests are) are ordered in low risk populations, you should expect many more false positives than true positives.

10.2 Case 2 Your hospital recently instituted a new policy on the assessment of febrile children in the emergency department. Last year, there was a bad outcome. A 6-month-old girl presented to the emergency department 2 days in a row with fever and an apparent viral illness. On the second day, although she looked well, pediatrics was consulted. The pediatrician agreed that the child appeared well, and discharged her home with a diagnosis of “probable viral illness.” Unfortunately, the child became unresponsive in the car on the way home and returned to the ED in cardiac arrest. She was revived and transferred to the pediatric intensive care unit, where it was determined that she had myocarditis. After reviewing the case at morbidity and mortality rounds, and a large number of subsequent meetings, persistent tachycardia despite fever management was identified as a major risk factor for myocarditis. A new policy was enacted to encourage the admission of all children with tachycardia after treatment, in an attempt to prevent a future miss. It is now the middle of flu season and the new rule means that you have been consulting the pediatrics team several times each shift. Tonight, you are caring for Samantha, a 3-month-old who is hypoxic and has a clear pneumonia on her chest x-ray. You speak to the pediatrics consultant, but because of the new policy, all of their beds are full. The pediatrician agrees that the child needs admission, but there will be a delay because of the bed block. In this hospital, the pediatrics nurses

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usually place pediatric IVs. Unbeknownst to you, the emergency nurse has struggled with IV access, and the antibiotics you ordered were never given. You are called to the bedside 2 h later because the child is lethargic and hypotensive. Base rate neglect is (partially) to blame for this case. The new hospital policy did not account for the very low prevalence of myocarditis, nor the very high prevalence of tachycardia in otherwise well children with viral illnesses. Although the goal of preventing another case of missed myocarditis is laudable, the hospital quickly (and predictably) became overwhelmed with false positives.

10.3 Case 3 You are seeing Wallace, a 75-year-old man with bilateral red and swollen legs, as well as diarrhea. On reviewing his chart, you noticed that he was referred to the emergency department 2 days ago by his primary care physician for assessment of cellulitis. He has a long history of bilateral leg swelling, but over the last few weeks his legs became more red and inflamed. They are also somewhat itchy. He is otherwise well. He has not had a fever. He had already been on oral antibiotics for 5 days when your colleague assessed him, so intravenous antibiotics were started. On returning to the ED today, his legs still have not improved, but he has now developed diarrhea. Your examination today reveals a well appearing patient with a chronic appearing, itchy rash on his medial legs bilaterally. The redness improves significantly when the legs are raised. He has varicose veins and signs of chronic skin changes including hyperpigmentation. You reassure the patient that he does not have cellulitis. You stop the antibiotics. You prescribe topical steroids, elevation, and compression stockings for his venous stasis rash. Unfortunately, you also have to tell him that his stool culture is positive for Clostridium difficile. In this case, the initial treating physicians ignored two different base rates when diagnosing the patient with cellulitis. Bilateral cellulitis—or cellulitis spontaneously arising in both legs at the same time—is very rare. On the other hand, venous insufficiency is very common, with stasis dermatitis estimated to have a prevalence of more than 5% in patients over 50 years of age. It turns out that the original treating physician had considered venous stasis dermatitis; however, he had been taught to consider “worst first,” and thought it was more important to treat cellulitis, as it was the more dangerous condition. Base rate neglect occurs anytime the prevalence of disease is not considered. It frequently occurs when pursuing a rare disease, but it can also occur, as it did in this case, when a very common condition like stasis dermatitis is discounted.

10.4 Case 4 Unfortunately, there are many real examples of base rate neglect from the history of medicine. In the mid-1990s, the United Kingdom Committee on Safety of Medicine issued a warning that third-generation oral contraceptive pills (OCP) containing

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gestodene or desogestrel were associated with a doubling or 100% increase in the rate of blood clots. This warning was sent to over 190,000 general practitioners and pharmacists, as well as to various media outlets. The result has been described as the “pill scare” or “pill panic,” as many women either immediately stopped taking their OCP or switched to alternative options [3]. Over the next year, conception rates rose by 3–5% and abortion rates also increased. Across England and Wales, there were 26,000 more conceptions in 1996 than 1995, and 13,600 more therapeutic abortions [3]. Despite all these women stopping the “more dangerous” contraceptive pill, there was no difference in the rate of venous thromboembolism [4]. How is it possible that thousands of women stopped a medication that was doubling their rate of blood clots, but the rate of blood clots was completely unchanged? The answer lies with base rate neglect. It is true that these newer contraceptive pills double the rate of blood clots, but the important question is: what is the base rate? It turns out that the actual yearly risk for women taking the third-generation contraceptive pill was only increased from about 15 in 100,000 to 30 in 100,000. In other words, it barely changed at all. Lost in the message was the fact that the risk of venous thromboembolism is even higher in pregnancy (although at 60 in 10,000 it is still overall low risk in terms of absolute numbers). The women who stopped the pill because they were afraid of clots may have actually been putting themselves at higher risk if they stopped using contraception altogether or switched to a less effective birth control method. Thus, base rate neglect impacts not just our diagnostic decisions, but many aspects of medicine. We need to consider the base rate when assessing the benefits and harms of our interventions. We also have to be careful to clearly state the base rate, or use absolute numbers, when communicating with our patients.

10.5 Conclusion The problem of base rate neglect is particularly relevant in emergency medicine, where hundreds of unique presentations are seen every week, each with a different differential diagnosis. It is nearly impossible for an emergency physician to know the prevalence of every condition they include in their differential diagnoses, but without considering the prevalence, we are bound to make statistical errors. Imperfect tests applied to low risk populations will result in false positives and cause harm through overtreatment. Conversely, applying imperfect tests to high risk populations will result in false negatives, and cause us to withhold important treatments from patients who need them. Considering the significant impact that base rate can have on both diagnostic and therapeutic decisions, it is important to get in the habit of looking up base rates and considering their impact on our decisionmaking. Validated decision tools, such as the Canadian CT Head rule or the PERC rule, can be an excellent source of evidence-based pretest probabilities in welldefined populations.

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Potential Solutions 1. Review Bayes’ theorem. Ensure Bayes’ theorem is adequately covered in medical school curriculums. Appropriately accounting for pretest probability relies on a solid understanding of Bayesian reasoning. 2. Get in the habit of thinking about the pretest probability before ordering any test. Do not order tests in populations with extremely low or extremely high pretest probabilities of disease, because the results are more likely to be wrong than right. 3. Use validated tools whenever possible, and follow the recommendations for most patients. When you ignore a negative PERC score, or a negative D-Dimer, the positive CT result is more likely to be a false positive than a true positive. 4. In an ideal world, our electronic health systems would include cognitive forcing strategies. For example, if every time you ordered a CT pulmonary angiogram, you were forced to put in a pretest probability, the computer could present you with a post-test probability, rather than just a dichotomous positive or negative result. 5. Systematically improve science literacy and communication. Our medical journals need to emphasize the importance of base rates, rather than just presenting potentially confusing statistics like relative risks, sensitivities, and specificities.

References 1. Norman GR, Eva KW. Diagnostic error and clinical reasoning. Med Educ. 2010;44(1):94–100. 2. Anders CK, Johnson R, Litton J, Phillips M, Bleyer A.  Breast cancer before age 40 years. Semin Oncol. 2009;36(3):237–49. 3. Furedi A.  The public health implications of the 1995 ‘pill scare’. Hum Reprod Update. 1999;5(6):621–6. 4. Farmer RD, Williams TJ, Simpson EL, Nightingale AL.  Effect of 1995 pill scare on rates of venous thromboembolism among women taking combined oral contraceptives: analysis of general practice research database. BMJ. 2000;321(7259):477–9.

Belief Bias

11

Elizabeth Sheffield

Imagine you have two female patients attending the emergency department. They are seen on the same day, by the same doctor, and given the same standard of care. Both women are in the throes of a threatened early miscarriage. The first lady is highly religious and after discussion with her doctor goes home and prays for a happy outcome. The second is an atheist, and after discussion with the clinician believes there is nothing that she can do to affect the course of her condition, and as such goes home and waits. Subsequently, both of these women go on to have successful pregnancies and healthy infants. The first lady believes this outcome has been positively affected by her prayers. The second instead attributes her result to chance. This tendency for people to arrive at conclusions which align with their personal belief system can create an unconscious bias. For example, conclusions arrived at while watching members of opposing political parties are often coloured by preconceived notions of the organisation’s political agenda. Similarly, opinions on medical treatments such as efficacy of vaccines or potential harms are all subject to intervariability in perception based on our pre-existing belief systems and world view. In medicine, “belief bias” can result in favouring evidence that is aligned with your previously held personal, religious, or moral value systems, and may make you reject evidence which supports the contrary. Additionally, there may be an emotional component, thus reducing your ability to objectively synthesise information. Definition: The tendency to judge the validity of a conclusion based on pre-­ existing beliefs rather than the objective evidence at hand.

E. Sheffield (*) Emergency Department, Austin Health, Heidelberg, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_11

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11.1 Case 1 Amanda is a 45-year-old woman who has presented to the emergency department with vomiting and a headache. You observe an alert on her electronic record which advises that Amanda frequently attends nearby emergency departments in the context of asking for pain medication. Her past medical history includes current IVDU, hepatitis C and heavy alcohol use as well as a myriad of pain presentations, occasionally with headaches, and several “did not waits”. When you arrive in her cubicle she is vomiting copiously into a plastic bag. She is unkempt and dishevelled and looks like she hasn’t showered in a number of days. She reports she has been unable to keep anything solid down since waking this morning, and when you ask her about her headache she begins to vomit again. You manage to ascertain that she has a bilateral parietal headache and that she had a heavy session of binge-drinking and cannabis use the night before. She says the headache is “bad”, but denies it being sudden onset, and when asked if her headache is different from her usual headaches she begins vomiting and says she is unsure. You prescribe an anti-emetic and commence some fluids. You find no focal neurological deficits on examination. However, you decide on balance that as she has been to the ED multiple times before, and since you have seen many patients with heavy THC use attend with cyclical vomiting, that rehydration will probably help her headache, but if not, you would prefer her to be in a safe place to further evaluate her. You decide to refer her to your short stay unit. Later that evening, on attending short stay your colleague informs you that Amanda self-discharged. You ask the reason why and are told “I don’t know why, but you know patients like that probably just want to get more drugs—I saw people like this all the time growing up”. They reasoned that because she wasn’t getting what she wanted in the emergency department she went elsewhere to look for it. You find her discharge against medical advice form and review her notes. It seems as though there was little discussion with Amanda with regard to convincing her to stay or with regards to alternative treatment options for her. The next morning when you arrive, there is a patient being intubated by the night team. When you walk in to take handover at the resus cubicle, you find that the patient being intubated is Amanda. She had reattended early in the morning with a worsening headache. She had a CT scan which revealed a large subdural haematoma with significant midline shift. On questioning her why she left yesterday, she told the night staff that the doctors in the short stay unit could not guarantee that she would be able to stay the night and she wanted to leave in time to get into a shelter so she could stay indoors that night. While waiting for theatre, she dropped her GCS and thus was intubated for airway protection. You realised that your colleague perhaps displayed a belief bias that intravenous drug abusers are always presenting with secondary gain aims. As a result of this belief they assumed what was why Amanda was trying to leave and as such there was little attempt to explore her reasons and offer an alternative for her.

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11.2 Case 2 You are a Director of Emergency Medicine Training at an urban district centre, who is seeking feedback for the registrars in your cohort at the end of term. You send out a form for a 360° non-blinded survey to your fellow consultants, the nursing staff, and the other junior doctors. On receiving the data from your survey, you note that three of the registrars who, by all accounts when you have been on the floor, frequently receive commendation for making well-thought-out, careful plans and considered decisions about patients, have all received negative feedback from one particular member of your consultant colleagues. Furthermore, this feedback generally rates the three trainees as being “below expected standard”, which is out of keeping with the rest of the feedback that has been submitted and could have a significant impact on their progress for the current term. You note that the negative feedback for all of the trainees centre around taking too much time with patients and a lack of efficiency. You decide that the correct way to evaluate the situation is first to make time to discuss the submitted comments with the relevant consultant. You meet with her the following day and, on further discussion, she reiterates and describes her feelings that trainees were taking too long with patients. You ask her to cite specific examples, and she advises she will email some patient identification numbers for you if she can look at the lists from when they were on together. After reviewing the patient notes and time to disposition, whilst carefully considering your colleague’s perspective, you conclude that in all examples you would personally consider all patients managed appropriately and cannot find fault with any of the trainee decisions. On further discussion with your colleague and gaining insight into how she would have managed the specific situations, you find her methods and practice values very different to your own with more of a focus on a shift and sort philosophy to her clinical practice. You realise that you and your colleague have different approaches to the practice of emergency medicine with each of you holding different ideas about what is more important. Your colleague would consider efficiency and managing the department’s workload-as-a-whole to be her number one priority. Whereas while you might consider this important your focus seems more geared towards the individual patient–doctor interaction. You each have your own biases with regard to assessment of trainees, and each have your own idea of what is important for trainees to display: in this instance the values seem to be at odds with each other. In the case of your colleague, no evidence that the trainees are functioning above standard otherwise will solidify them in her mind as being an adequate trainee as her belief is biased in favour of a very specific paradigm of an emergency doctor. Alternatively, if a trainee demonstrated more of the characteristics she prioritises at the risk of ignoring other aspects of clinical practice, you might mark that trainee down in a way that she would find strange. Each of your value systems predisposes you to bias when evaluating your staff.

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11.3 Case 3 Fatima is a 66-year-old lady who attends ED feeling light-headed. On further history, you find she has had presyncopal symptoms and palpitations off-and-on for several days. Fatima has a background of ischaemic heart disease and asthma. She has been feeling that her asthma is slightly worse than usual so has been increasingly using her salbutamol inhaler. In the last few days, she has generally been feeling well with no infective or other notable symptoms. Fatima denies any chest pain and although she reports feeling slightly short-of-­ breath she is speaking full sentences with ease and reports her current breathlessness is not worse than how she has been over the last few days. You perform a cardiorespiratory examination and find her pulse to be irregular and find soft crepitations in her lung fields but no wheeze. She is afebrile. You ask the nursing staff to perform an ECG which reveals atrial fibrillation which is new at a heart rate of 150. Her blood pressure is 130 systolic. Fatima is placed on telemetry and a portable CXR is obtained which shows some alveolar opacification and diversion of the pulmonary vasculature suggesting heart failure and no infective changes. You are awaiting the bloods and decide to commence her on 20  mmol of IV magnesium. You are aware that there has been a shift amongst many clinicians to only administer IV magnesium in specific cases, e.g. if a patient is noted to have low magnesium. However, your father is a critical care doctor also and he has always lauded IV magnesium as one of mainstays of treatment for fast AF, and you yourself have seen magnesium seemingly revert patients in your clinical practice. Moreover, you feel it is unlikely to be detrimental and is what you have used most of your clinical life. Fatima’s bloods return and you find that she has an eGFR of 20 where it had been >75 the year before. Her magnesium level also returns high at 1.47 mmol/L. On further history taking you find that earlier this month she has had her regular diuretic dose reduced by her GP. Her most recent echocardiogram is also faxed over from her GP which shows recent EF of 25%. You realise that Fatima has likely become clinically fluid overloaded due at least in part to the reduction of her medication, and you subsequently administer her IV furosemide. The IV magnesium was not only not indicated but of potential harm, and without clear clinical evidence to support its use. However, having known the controversy you believe, based partly on family advice, that it would be of benefit to your patient. At the end of this patient encounter, you are still prone to value the use of IV magnesium in AF and feel that Fatima is an unusual anomaly. Despite evidence to the contrary, you will continue to administer it in your usual care of the patient in fast AF because you believe it works even in patients who are not hypomagnesaemic.

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11.4 Case 4 The ambulance drops off a patient to your rural emergency department, a 70-year-­ old man named Phillip who has had a witnessed collapse with his wife when out to lunch. The paramedics let you know that he was having nonsustained runs of ventricular tachycardia en route to hospital. You obtain a 12-lead ECG in the emergency department which shows widespread ST elevation and a sinus rhythm. Your team begins preparing the patient for transfer to the cardiac cath lab when Phillip arrests and a code blue is called. As the senior on shift you begin to team lead, CPR is commenced and the patient is attached to the defibrillator. Phillip has a short thyromental distance and a history of cervical spondylosis; however, your resident is ventilating Phillip adequately with good technique of the bag valve mask. A few minutes into the advanced life support, the on-call anaesthetic trainee arrives and takes over the airway, as is the procedure in your hospital. The anaesthetist advises he would like to proceed with intubation. You explain that the bag valve mask is currently effective and suggest continuing or inserting an LMA especially as you suspect a difficult airway. However, the anaesthetist states that if there is a hypoxic cause for the patient’s arrest it is better to proceed with intubation as the patient will do better. You are not convinced however the anaesthetist is adamant and thus you proceed with intubation. However, he has difficulty placing the endotracheal tube, and has subsequent failed attempts. The result is that the patient receives prolonged interruption to compressions, during which time the patient is also not being ventilated. You decide to debrief with the anaesthetist post transfer of the patient, as it is your belief that the decision to intubate and not proceed to an LMA or return to using the bag valve mask has likely resulted in a worse overall outcome for your patient. When asked about his decision, he advises you that he believes that intubation provides the superior outcome for patients. You cite a randomised control trial which showed that there is little difference in the outcome between groups treated with endotracheal intubation and BVM with regard to 28-day survival and 28-day survival with favourable neurological outcome [1]. He counters this by saying that he hasn’t read that study and says that the airway providers were likely not appropriately skilled and probably didn’t intubate every day likely he did. He says the evidence base doesn’t apply to managing the airway as it comes down to the individual provider and that you can’t convince him with any data that what he did was incorrect. You believe that the anaesthetist’s belief in the finite superiority of intubation has potentially led Phillip to a worse outcome from persistent attempt to secure the endotracheal tube, despite no evidence against clinical equipoise between adequately placed bag valve mask, placement of LMA, or ETT.

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11.5 Conclusions In emergency medicine, belief bias can be extremely difficult to overcome; for one thing it is frequently implicit and for another, it is often associated with an emotional component [2, 3]. Because of this, it is often challenging to disassemble the ways in which diagnosis or management plans have been influenced by these prior belief systems. This task becomes even more tough as emergency medicine is a varied and constantly evolving field meaning there is often less time than other areas of life to adequately reflect on how you came to a specific conclusion. As such, we need to try to practise examining how we arrive at interpretations rather than just synthesising data. This added reflective step is necessary to understand how we are processing new information and ensure we advocate for and protect our patients and colleagues to the best of our availability. Potential Solutions 1. Practise analytical questioning of your decision-making. If you feel that there is an emotional component with your assessment of a patient or colleague, ask yourself why, and be prepared to challenge your assessment [4]. 2. Question yourself: “when and how did I arrive at this belief” and consider the possibility that you could be incorrect? Seek out facts that both support and contradict your view and be prepared to objectively evaluate evidence that does not uphold your previous conclusion [5]. 3. Seek out the perspective of others and brainstorm with colleagues to help you weigh up the various evidence as to what the most appropriate conclusion from the scenario or information at hand [6]. 4. Engage in modules or education with regard to cultural competencies, to challenge your own perceptions.

References 1. Jabre P, Penaloza A, Pinero D, Duchateau FX, Borron SW, Javaudin F, et al. Effect of bag-­ mask ventilation vs endotracheal intubation during cardiopulmonary resuscitation on neurological outcome after out-of-hospital cardiorespiratory arrest: a randomized clinical trial. JAMA. 2018;319:779–87. https://doi.org/10.1001/jama.2018.0156. 2. Croskerry P. Achieving quality in clinical decision making: cognitive strategies and detection of bias. Acad Emerg Med. 2002;9(11):1184–204. https://doi.org/10.1197/aemj.9.11.1184. 3. Howard J. Cognitive errors and diagnostic mistakes: a case-based guide to critical thinking in medicine. Cham: Springer; 2019. https://doi.org/10.1007/978-­3-­319-­93224-­8. 4. Caravona L, Macchi L, Poli F, Vezzoli M, Franchella M, Bagassi M. How to get rid of the belief bias: boosting analytical thinking via pragmatics. Eur J Psychol. 2019;15(3):595–613. https:// doi.org/10.5964/ejop.v15i3.1794. 5. Marcelin JR, Siraj DS, Victor R, Kotadia S, Maldonado YA. The impact of unconscious bias in healthcare: how to recognize and mitigate it. J Infect Dis. 2019;220(220):73. https://doi. org/10.1093/infdis/jiz214. 6. Trippas D, Kellen D, Singmann H, Pennycook G, Koehler DJ, Fugelsang JA, et al. Characterizing belief bias in syllogistic reasoning: a hierarchical Bayesian meta-analysis of ROC data. Psychon Bull Rev. 2018;25(6):2141–74. https://doi.org/10.3758/s13423-­018-­1460-­7.

Blind Spot Bias

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Charley Greentree

The bias blind spot is interesting and unavoidably ubiquitous. It is described as the ability of noting the effects of biases on the perceptions and reasoning of other clinicians while not recognizing the effects of biases from multiple sources on our own personal judgement [1]. Most biases are predominantly unconscious in origin, although it is possible to have deliberate and conscious prejudice in clinical reasoning, and life. Blind spot bias is a deeply unconscious bias held by all but the extreme minority of the population [2]. To understand this bias better, let’s consider it through the concept of a metamodel which explores “how” this phenomenon occurs to better understand what it is [1]. We all have an internal representation (map) of every sensory experience we have and we then have a linguistic representation of this map. There are three elements within this model—deletion, distortion, and generalization. Deletion is where segments of the sensory map are overlooked in the verbal expression. This is neither good nor bad, but necessary to protect against overwhelming amounts of data, can connect logical structures with less cognitive steps and allow impressive concentration. Distortion is the effect of interpreting or changing our experience through many means that can contribute to creativity, original thinking, and conclusion jumping, otherwise known as premature closure. Generalization is the use of one or a limited number of sensory experiences to represent a whole group. We often use this element as a basis of learning but must remain aware and cautious about which experience or experiences we use for generalizing to remain flexible and look for the exceptions. How do you know this exists? With time you may become aware of something that you systematically, repeatedly overlook—a “miss.” Usually, this is entirely an unconscious process and unintentional. For most of us practicing and training in emergency medicine, this will be pointed out by a colleague in some format, or less

C. Greentree (*) Emergency Centre, St Vincent’s Hospital, Toowoomba, Australia © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_12

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often, we may become aware of our predilections on our own. This bias itself may “protect” itself from this feedback as we perceive that our own cognitive integrity means we are less susceptible to any bias compared to those around us [2]. The challenge of the bias blind spot is understanding that it is a fact of existence. If we contextualize it as a fault, then it makes sense that it is much easier to see a fault in others than yourself. This context is not entirely accurate however and if a less judgmental paradigm is applied to understanding this bias, we are more likely to recognize it in ourselves, recognize the potential error traps it creates, and explore mitigation strategies. The difficulty of the bias blind spot however is that thos with a strong bias blind spot are prone to ignore advice from others and less likely to show positive change from training focussed on bias deprogramming [3]. This bias is a second order bias, that is, it can be caused by other biases and (unbalanced) cognitive strategies. Interestingly, blind spot bias is not related to decision-­making ability, is independent of measures of intelligence and independent of self-esteem [3]. Definition: The tendency to recognize the biases or cognitive errors of other but overlook our own.

12.1 Case 1 It is an incredibly busy day in your emergency department. Your colleague asks if you could also examine their patient who is a 2-year-old boy named Brian who is here with his mother, Karen. He is a representation from 2 days earlier with persistent nasal discharge, now purulent. Brian has a past medical history of Trisomy 21 and an atrial septal defect that has not required operative intervention. His mother reiterates that she suspects there is a piece of Lego in Brian’s nose. This had not been visible on examination 2 days earlier and a decision was made to observe and return if needed. Brian is in an acute care cubicle with his mum, there is the hint of a yellow head amongst the green discharge coming from his left nostril. Your colleague leaves the cubicle to arrange time and space in the procedure room and possible procedural sedation for Brian. You think it’s a shame for Brian to undergo such rigmarole when you could simply extract the foreign body and use the cubicle suction catheter to attempt to remove it while Mum holds on to him. Brian becomes distressed and cries vigorously. He develops stridor and you can no longer see the yellow object in his nares. You race him into a resuscitation bay to further evaluate and re-establish his airway integrity. At the end of your shift you are debriefing with your colleague. During the conversation you talk about your intent and ability to remove nasal foreign bodies and how well the rescue of Brian’s airway integrity had proceeded. Your colleague is uncomfortable, but professionally enquires about your blindspot with respect to airway management in the cubicle and your perception of their perceived lack of effectiveness in approaching the airway differently.

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12.2 Case 2 On an evening shift in ED, you and the team receive a call from your ambulance service pre-notifying their arrival with four patients between 16 and 25 years old in the next 20 min. The group has been found unconscious in a residence with evidence of illicit drugs on scene. Two of the patients are needing airway support and assist ventilation en route. Ambulance officers suspect use of gamma hydroxybutyrate (GHB) amongst other substances. You are part of the team responding and are allocated the role of airway management for the second patient to arrive who is being ventilated via a laryngeal mask with the ambulance. You and your team prepare the resuscitation environment to receive the patient. As the pre-hospital team arrives, you are appropriately concerned as there is evidence of vomitus around the laryngeal mask and mouth although the ambulance officer appears to be effectively ventilating the patient. As they are transferred onto the trolley, you comment to your airway nurse that the LMA was a wrong decision and you will need to emergently intubate the patient who does not currently have a protected airway. You proceed with emergent rapid sequence induction before the ambulance handover is completed to find you have a paralyzed patient with a soiled airway and a grade 3 view of the cords due to an anterior larynx. You intubate the esophagus on the first pass of the endotracheal tube and urgently recruit help and ask for the difficult airway equipment to be opened. The patient is desaturating. Following your training for approach to difficult intubation, you try to establish ventilation and successfully reposition a size 4 laryngeal mask and ventilate the patient while planning your next attempt for a definitive airway with more consideration. Your perception of your prehospital colleague’s airway management is that it is suboptimal. You are unprepared for your own team’s constructive feedback about optimizing your own approach to airway management.

12.3 Case 3 You are sitting at home at the end of your day, waiting for your meal to cook and reflecting on your work. You shake your head as you think back to your patient this afternoon with a moderately severe asthma attack. Josh, a 24-year-old medical student became acutely short of breath during their final OSCE exams for their medical term. So much so, that they had to abandon the exam and attend ED.  Unable to speak effectively and give history for the first hour, they (and you) were relieved that they improved enough to avoid ICU. Your asthma management met standards of care, but you were surprised when the admitting respiratory registrar sought you out to share the history you had not obtained. The patient had a history of performance anxiety, particularly with OSCE format exams. They had self-medicated with propranolol (despite a known history of asthma) in preparation for their exam today. You reflect on their choices despite their implied intelligence and expected knowledge and how they had self-induced a potentially life threatening illness. You decide that your next lecture with the medical students will include some material on self-care and resilience. You sit back and decide to pour the last of the bottle of

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wine into your glass as you hope it will help you get off to sleep a bit easier tonight before another busy shift tomorrow.

12.4 Case 4 You find the quiet space in the write-up area of ED to take a moment and document notes for your last patient who was Crystal, a previously well, 52-year-old woman who presented with a non-survivable intracranial bleed. The management decision, in collaboration with the neurosurgeons, has been to withdraw support and palliate in ED/on the ward. You have just had a 30 min conversation with her grief stricken family explaining the diagnosis, prognosis, and plan. You take pride in being able to hold these difficult conversations and support patients and their families through these confronting situations. You are documenting clearly and in detail about extubation and comfort measures, when you hear two of your nursing colleagues talking about the case, out of sight from where you sit. The first of your colleagues is asking about the family and how it is going. The second colleague who had been in the family discussion with you states that they are still mopping up the carnage from the family discussion. They go on further to describe your communication skills in this case as lacking empathy and care and although realistic in describing the outcomes, the language and tone used may have added to the trauma of the events for their loved one. You are affronted at this negative criticism of your communication skills as your intent is to provide clinically excellent care and you have frequently used the same language and approach in your work without any negative feedback from patients, family, or staff.

12.5 Conclusions Blind spot bias is independent from intellect, skill, and decision-making. However, it can have a profound effect on our professional performance. Blind spot bias exists because we have the self-view that our perceptions and judgements are rational and accurate and we are less biased than our colleagues. It appears to be a stable cognitive reality and can persist even if we examine our own metacognition (how we think what we do and why we think that way). Therefore tackling blind spot bias can be hard and need continuous review. Dishearteningly, current research into this bias has shown de-biasing training has not been effective at reducing its impact. There is likely to be different experiences in different cultural contexts however. The blind spot bias occurs irrespective of our locus of control (internally vs externally referencing). This is important to acknowledge before exploring different strategies and approaches to mitigate or solve blind spot bias. Potential Solutions 1. Reflect on your medical practice on a daily basis. Think analytically about medical decisions made that day with the intention of gaining insight (overcoming blind spots) and using the lessons learned to maintain good practice or make

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improvements where possible [4, 5]. Doing so, can help foster increased self-awareness. 2. Utilize specific tools for developing self awareness. Several of these are available e.g., the Johari window [6]. This tool uses self and others as perspective and explicitly attends to “blind areas” (known to others, not known to self). Using a strength-­based approach to learning and training on identified blind areas does not ignore challenges, and is likely to enhance necessary change, and retention of change in practice. 3. Once aware of particular blind spots, develop cognitive aids to prompt illumination of these blind spots. Rehearsal and repetition of integrating these cognitive aids into practice is necessary. 4. Practicing mindfulness in clinical duties. Having awareness of your emotional and intellectual state and approaching situations with a deliberately curious paradigm (I wonder how/why/what if/what else) rather than the more natural righteous paradigm (my way is best) may also be helpful. The skill of using Type 2 thinking which is deliberate, conscious and calculating imbues resilience to bias, but requires sustained attention for expert execution. 5. Discuss decision-making and performance with mentors. External assessment and input from the coach or mentor can consolidate cognitive aids by reflecting and paraphrasing thinking statements and cognitive strategies back to the clinician and use explicit questioning techniques to provide a structured approach using questions like: What does the way I approach this make me prone to miss? What would some different points of view be? What data are we not seeing/hearing/aware of? What would “x” do?

References 1. Bandler R, Grinder J.  The structure of magic, vol. 1. Palo Alto: Science and Behavior Books; 1975. 2. Morgenstern J.  Cognitive errors in medicine: the common errors. First10EM blog. 2015. https://first10em.com/cognitive-­errors/. 3. Scopelliti I, Morewedge CK, McCormick E, Min LH, Lebrecht S, Kassam KS, Karim S. Bias blind spot: structure, measurement, and consequences. Manag Sci. 2015;61(10):2468–86. https://doi.org/10.1287/mnsc.32014.2096. 4. Academy of Medical Royal Colleges, UK conference of Postgraduate Medical Deans, General Medical Council, Medical Schools Council. The reflective practitioner—guidance for doctors and medical students. https://www.gmc-­uk.org/-­/media/documents/dc11703-­pol-­w-­the-­ reflective-­practioner-­guidance_pdf-­78479611.pdf. 5. Academy of Medical Royal Colleges, UK conference of Postgraduate Medical Deans. The reflective practice toolkit. 2018. http://www.aomrc.org.uk/wp-­content/uploads/2018/08/ Reflective_Practice_Toolkit_AoMRC_CoPMED_0818.pdf. 6. Pronin E, Lin DY, Ross L. The bias blind spot: perceptions of bias in self versus others. Personal Soc Psychol Bull. 2002;28(3):369–81. https://doi.org/10.1177/0146167202286008.

Commission Bias

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Anton Musiienko

Imagine you are seeing your first patient for the day. You are buzzing on a morning coffee and a nutritious breakfast. It is a 35-year-old fit office worker, presenting with a headache, cough and runny nose. They have a fever, but no signs of otitis media, bacterial pharyngitis or pneumonia—in short, they have a non-specific URTI. You spend 10 min explaining to them that the antibiotics are not indicated. Eventually, they leave, slightly anxious but empowered to join you in your fight against over-­ prescribing, antibiotic resistance and possible complications. Fast forward 4 h: you are seeing a nearly identical patient. You give them your spiel about simple analgesia, plenty of hydration and rest. “But aren’t we gonna hit it hard, doctor?”, they ask. Your phone rings to tell you that you are needed to insert a difficult cannula. It is clear that this patient will require a lot more convincing. You are hungry, tired and torn between tasks. Embarrassed but unable to find the will to argue, you succumb to the patient’s request and discharge them on a short script of antibiotics. If this has happened to you, you are not alone. In a study of over 20,000 acute respiratory presentations to ED, the likelihood of inappropriate prescription of antibiotics was found to increase towards the end of the shift [1]. As the decision fatigue rises, our willingness to resist “doing something” drops, and we fall prey to commission bias. An obligation to act is often driven by the public perception that the more tests or treatment doctors do, the better the care. It is often driven by an attempt to avoid feeling regret about a missed diagnostic or treatment opportunity, even when its effectiveness is minimal and the associated risk is substantial [2]. Definition: The tendency towards action, even in a situation where not performing an action results in the same, or even better outcome.

A. Musiienko (*) Emergency Department, Monash Health, Clayton, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_13

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13.1 Case 1 David is a 30-year-old gentleman with no past medical history, other than being a smoker. He presented with a sudden onset of shortness of breath and chest pain; the chest X-ray demonstrated a moderate-to-large size pneumothorax. Richard denies any preceding trauma. On presentation, his heart rate was 100 beats per minute, and the oxygen saturation has at one point dropped to 92% on room air. When you assess him, you find him comfortable on 2 L of oxygen via nasal prongs, with stable observations. Pain is now reasonably well controlled with paracetamol and a NSAID. You review the case with an intern and teach her how to estimate the size of the pneumothorax from a chest X-ray. In this case, it amounts to ~40% according to the Collins method. It is Saturday night, and you do not want to hand over a patient who may need an intervention and thereby putting more work on your colleagues’ shoulders. You and the intern scrub up, and you guide her through putting in her first pigtail chest tube. The procedure goes well, and the repeat CXR confirms lung re-expansion. Three months later, you recognise Richard’s last name in the list of patients in ED. Turns out, he represented with another spontaneous pneumothorax. You look at his records, and learn that the first time he had stayed in hospital for 6 days. He also developed a skin infection around the insertion site requiring a short course of antibiotics. You talk to your consultant about this case, and she points you towards a recently published trial which challenges the necessity to intervene even with pneumothoraces of a large size, and suggests a lower recurrence rate in the group who did not receive an intervention [3]. This challenges your instinct “to do something and intervene”. You realise that you did not want to appear lazy and hand over a potential intervention. You were not aware of that trial at the time, but you realise that even if you did you would find it difficult “to do nothing” in such a case. However, you learn that sometimes watchful waiting is associated with less complications and optimal management of the patient.

13.2 Case 2 Prudence is an 80-year-little-old lady. She has a history of type 2 diabetes, hypertension, AF (for which she is on a direct-acting anticoagulant), hysterectomy and knee replacement, but is otherwise quite well. She presented today with epigastric pain. It has started after a meal, was associated with some nausea, and, after lasting for a couple of hours, now is seemingly getting better with some paracetamol. She recalls similar episodes in the past, but she has never got to the bottom of their cause. She denies any other symptoms, her abdomen is soft, with no palpation tenderness, and her observations are within normal limits. You ask the nurses to collect the “standard abdominal bloods” and a urine dipstick. The bloods return completely normal; on the urine dipstick you notice 2+ of blood and 2+ of white blood cells. You return to reassess Prudence, and she tells you

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that she is feeling “much better”. You tell her that you think her pain might have been caused by gallstones, and that you also incidentally have picked up a possible urine infection. She is slightly surprised, as she cannot recall having any urinary discomfort whatsoever, but you explain that those are quite common in the elderly, especially with diabetes. You give her a script for cephalexin, an appointment for an outpatient gallbladder ultrasound, and discharge her home. Two weeks later you see Prudence again. She has now presented with more abdominal pain and severe diarrhoea. You learn that her GP has given her a second course of antibiotics, because on the repeat dipstick, her urine was again positive for leukocytes and red blood cells. You see that the urine that you had sent off earlier has not grown a microorganism. You are now very concerned that Prudence has developed C. diff colitis. You realise that you have fallen prey to a very common tendency of ordering a standard battery of tests (in this case for “abdominal pain”), before you had an opportunity to assess the patient—in statistical terms, to determine the “pre-test probability” of the test result. You then felt obliged to treat your finding (in this case, an asymptomatic pyuria, with microscopic haematuria that could easily be attributed to the patient’s anticoagulant medication). The GP then fell prey to the status quo bias and repeated your actions. As a result, a serious complication was caused by ordering an unnecessary test and then treating its result, instead of critically evaluating the risks and benefits.

13.3 Case 3 Timothy is an 89-year-old man from a high level care nursing home. He is brought in by the ambulance after the staff had noticed him being considerably more drowsy than usual. He was found on the floor of his room this morning, possibly after suffering a fall, incontinent of urine. When you assess him, he is in the presence of his very upset daughter. You go over Timothy’s medical file. He suffers from advanced dementia, as well as a long list of other comorbidities. This is the third admission to your hospital in the past 12 months. You notice that his goals of care were previously limited at “no CPR, no intubation, no surgery, no ICU admission”. You assess the patient with that in mind. On your assessment, the observations are within normal limits, except for GCS which is about 12: Tim only opens his eyes to painful stimuli, and is only saying single words. He seems to not recognise his daughter, which is unusual for him and is very upsetting for her. On examination, there are no signs of trauma and no focal neurological deficits. You and the daughter have a chat and she is hopeful that there is something you can do. She is his next of kin. She understands and agrees with the limitations of treatment and you document those, similarly to the previous admissions. She tells you that a few months ago, a similar presentation turned out to be from a urinary infection and her dad had improved with a course of antibiotics. You agree that it is not unreasonable to try those, and start him on ceftriaxone. You also order a chest

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X-ray and a CT brain, as per daughter’s tearful pleas “to do everything you can do”. You explain that should the CT reveal a bleed it is unlikely that an intervention would be possible, but it might be useful “just to know what is going on”, and the daughter is very thankful for it. Few hours pass by and you hear a code blue from the radiology corridor. You quickly remember that your patient was there waiting for his turn at your hospital’s overcrowded CT scanner, pushed back by a trauma and a code stroke. When you arrive, you see a junior nurse performing CPR, which you stop, and shortly after the patient is pronounced dead. You return to the cubicle to tell the sad news to the daughter. Looking back at this, and many similar cases in your practice, you reflect on the amount of futile tests that we order. You realise that you felt the pressure from the family “to intervene”, and that imaging had no role to play in the management of this patient. Indeed, ordering it only contributed to the workload of the department, and regardless of the findings, the management would have arguably remained the same. It would have been more prudent to focus on addressing the family expectations, and to make the patient’s comfort and dignity the primary goals of your care.

13.4 Case 4 Peter is a 60-year-old, overweight gentleman presenting with a lower back pain. It has intermittently troubled him for many months, gradually became worse, and now it stops him from moving around as much as he used to. There is no history of trauma, no fevers or night sweats, no history of malignancy, and if anything he had put on weight over the last few years. There is no bladder or bowel symptoms, and no weakness or sensory changes in the legs. He finds that paracetamol helps, but he does not use it very often as he believes he needs a “full workup and strong medications” to address the problem. On examination, there is no midline tenderness. The lower limb neurological examination is normal, and there is no saddle anaesthesia. The aorta appears normal on the bedside ultrasound. The pain is now better after a dose of paracetamol, NSAID and 5 mg of oxycodone at triage. You explain to Peter that you are not concerned this is a sinister pathology, and he is OK to go home, continue on simple analgesia, and see his GP in a few weeks time to monitor the progress. Turns out, Peter does not get along with his GP and he insists you start him on “something stronger”. After a lengthy discussion about the downsides of chronic opiate use, you reluctantly give him a script for pregabalin instead; you also agree to arrange for an outpatient MRI, as Peter wants to be “certain this is not a cancer or a nerve compression”. Few weeks later, you see Peter again. Since starting on pregabalin, his mood has decreased to the point of having suicidal thoughts. Unsurprisingly, the MRI only revealed chronic degenerative changes in his back, with no other pathology. You arrange for a mental health consultation and write a weaning plan for the pregabalin. You manage to convince Peter to have a trial of regular paracetamol, NSAID and physiotherapy.

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You reflect that you allowed the patient to coax you into ordering an unnecessary test and prescribing a strong medication with potential side effects, before the appropriate first-line therapy had been trialled. The patient’s perception that ordering more tests or using stronger medications equates to better care should have been countered by the physician’s understanding of the objective evidence.

13.5 Conclusions An obligation to act is ingrained in our training as clinicians. There are many reasons for this. Patients and their families commonly believe that the more tests and interventions we do, the better the care they receive. Clinicians themselves often order investigations or perform procedures in order to avoid feeling regret at a later stage on the off-chance they have missed something (omission regret), even though this may benefit only a few of their patients [4]. This is especially pronounced at the life-or-death situations where it is compounded by the perception of death as a treatment failure, resulting in ultimately futile interventions. Fear of blame and litigation also pushes clinicians towards the commission bias. Research has shown that clinicians are less likely to be personally blamed for the harms of an unnecessary intervention, especially if the said harms are delayed (e.g. antibiotic resistance) or are at a system level (e.g. the rising number of futile diagnostic tests), than they are for “missing a diagnosis”, or “not being thorough with treatment” [5]. Finally, profitdriven promotions of medications and procedures from the industry can influence physician decision-making. Potential Solutions 1. Slow down and question your interventions. Ask yourself: what am I trying to find out and why? What would happen if I do not do it? Are there safer or cheaper alternatives, and how do they compare in terms of the patient benefit? 2. Be familiar with the most recent evidence and keep an open mind about the need to intervene. Beware that this may change as the new research emerges, and “common sense” is not always backed by the evidence. 3. Regularly check the resources specifically designed to reduce the amount of unnecessary interventions, such as Choosing Wisely®. 4. Question whether you are treating the patient, or unconsciously protecting yourself from a possible litigation. And if the latter, at what cost does it come to the patient and the healthcare system? Remember that most lawsuits arise from poor communication and interpersonal failures, and not from the omitted tests or interventions [6]. 5. Death is not always a treatment failure. Appreciate that alleviation of suffering and preservation of dignity are sometimes more important than preservation of life. Your role as a clinician is then to guide the patients and families through the end-of-life situations, rather than to focus excessively and exclusively on the diagnosis and treatment.

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References 1. Linder JA, Doctor JN, Friedberg MW. Time of day and the decision to prescribe antibiotics. JAMA Intern Med. 2014;174:2029–31. 2. Dobler CC, Morrow AS, Kamath CC. Clinicians’ cognitive biases: a potential barrier to implementation of evidence-based clinical practice. BMJ Evid Based Med. 2019;24:137–40. 3. Brown SGA, Ball EL, Perrin K, Asha SE.  Conservative versus interventional treatment for spontaneous pneumothorax. N Engl J Med. 2020;382:405–15. 4. Scott IA, Soon J, Elshaug AG, Lindner R. Countering cognitive biases in minimising low value care. Med J Aust. 2017;206:407–11. 5. Kanzaria HK, Hoffman JR, Probst MA, Caloyeras JP, Berry SH, Brook RH. Emergency physician perceptions of medically unnecessary advanced diagnostic imaging. Acad Emerg Med. 2015;22:390–8. 6. Vincent C, Young M, Phillips A. Why do people sue doctors? A study of patients and relatives taking legal action. Lancet. 1994;343:1609–13.

Confirmation Bias

14

Michail Kosmidis

A week after you donated some money to charity, you win the lottery! What better proof do you need that you have been rewarded for being such a good person? Your newly friendly neighbour, however, reasoning that, statistically, someone has to win the lottery without supernatural involvement, fails to see how the fact that you won the lottery is any proof that you are a better person than him, although he may not necessarily tell you so in this case. In another scenario, a politician that you dislike becomes the head of state and, a few months later, your country is affected by a financial crisis. In your mind, this is proof of that politician’s disastrous economic policies. Your annoying friend, however, who enthusiastically voted for that politician, is more inclined to believe that the financial crisis was caused by a slump in the global markets. In other words, we tend to see what we believe. In a medical context, we may be inclined to favour a certain diagnosis over others, for reasons that are not clinically based. Commonly, we may be worried about the implications that a particular diagnosis will have for our patient. In another example, when the influx of patients already exceeds available resources, we may be reluctant to consider a diagnosis that would further increase our workload, as when a time-consuming procedure will be required as a result of making that diagnosis. In addition, confirmation bias is the main reason why researchers are, ideally, ‘blinded’ in a research trial [1]. Definition: The tendency to look for, and favour, evidence that supports our prior beliefs and to discredit evidence that refutes them.

M. Kosmidis (*) Emergency Department, Armadale Health Service, Mount Nasura, WA, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_14

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14.1 Case 1 Helen is 24 weeks pregnant and presents with a one-day history of sudden onset right sided chest pain, worse on breathing and movement. She can remember that the pain began suddenly as she was sitting on the sofa, and she believes that it might have been caused by her turning to the right to pick up a drink from the side table. She is also feeling short of breath, which she thinks began in the last 24 hours as well. You assess Helen and find her to be somewhat tachycardic, at 110 per minute, and slightly tachypnoeic at 22 per minute. She does not appear breathless at rest, but does have to stop after 2 minutes of walking to catch her breath, although at no point does she become hypoxic. Pulmonary embolism certainly crosses your mind, but you are painfully aware of the trouble that it would take to rule it out in this case. Your hospital does not have a clear policy for ruling out pulmonary embolism in pregnancy, other than a guideline stating that a D-dimer should not be used. You dread the prospect of having to tell a pregnant woman that she needs to be irradiated to rule out a lifethreatening condition. The logistics are also complicated; even though you could simply order a CT pulmonary angiogram, your Diagnostic Imaging department has a policy that only ventilation-perfusion scans, which, in your hospital, are only available within office hours, may be used to rule out PE from 20 weeks of pregnancy onwards. It is now after hours, so Helen would need to be admitted for a V/Q scan the next day. To make matters worse, your hospital is currently experiencing severe access block. Faced with the possibility of exacerbating your hospital’s access block and inconveniencing Helen with a likely overnight stay in the Emergency Department, you go back to reassess her after analgesia. Her heart rate is now 105 and her respiratory rate 20. You poke hard at her right lower chest wall and ask her if this is tender, to which she answers ‘a little’. Suddenly the prospect of discharging her home with a diagnosis of muscular strain seems more realistic. Her pain ‘might’ have been caused by her turning to the right while sitting, and it now appears to be reproducible on palpation. Her tachycardia and tachypnoea are somewhat consistent with the physiologic changes of pregnancy. You suggest to her that the pain is likely to be a muscular strain, and she accepts the possibility. You eventually discharge her with simple analgesia. Sure enough, you find out 3 days later that Helen returned the next day with worsening symptoms, and was eventually diagnosed with a submassive PE. Helen’s pain could certainly have been muscular, but, looking back on the case, you acknowledge that the probability of a PE was not low enough for it to be ruled out on clinical grounds. Factors outside Helen’s best interest, such as your hospital’s access block, influenced your decision, causing you to downplay the real possibility of this diagnosis. You also augmented the importance of equivocal findings in the history and examination, such as the slight tenderness on forceful palpation of the chest wall, in order to confirm your preferred diagnosis.

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14.2 Case 2 Your next patient is Edward, a 72-year-old man with a history of ischaemic heart disease and hypertension, presenting to the Emergency Department because he has been feeling vaguely unwell and lightheaded for a few hours. He has been given a triage category 2 because he is hypotensive, at 85 systolic, and bradycardic, at 35 beats per minute. You quickly assess Edward, who looks pale but is conscious and alert. He has no chest pain but he is feeling nauseated. His ECG shows sinus bradycardia with a heart rate of 35 and no acute ischaemic changes. He is not on beta blockers or any other rate-controlling medication. You insert an intravenous cannula and sent blood for electrolytes and a troponin, as a silent myocardial infarct is a possibility. You ask the nurse to prepare 600 μg of atropine. A few seconds after administration of the medication, Edward becomes unresponsive. He exhibits some seizure-like activity and stops breathing. He appears to be pulseless. You push the ‘assist’ button and take over the airway while compressions take place and until help arrives. You notice that the rhythm on the monitor is still sinus bradycardia, so you ask for more atropine and begin external pacing, resulting in a faint pulse. Edward remains unresponsive so you decide to intubate. His blood pressure is stabilised with an adrenaline infusion initially, while preparations are made for transfer to the cardiac catheterisation laboratory. After you debrief your team and congratulate everyone on a job well done, a nurse asks you whether you used suxamethonium as a muscle relaxant for intubation. You reply that no drugs were used for intubation, as the patient was in cardiac arrest. The nurse seems puzzled, as there is one opened vial of suxamethonium among all the medications used. You then both realise that it was accidentally administered, instead of atropine, right before Edward became unresponsive. Retracing your steps, you can recall the details of the moment that you administered what you thought was atropine, down to checking the name of the medication on the side of the vial, as you always do. Clearly, you saw what you believed was written on the vial, which was not helped by the fact that the vials are quite similar in appearance. Confirmation bias is responsible for a large number of instances where the wrong medication was administered, or where the wrong part of the body was operated on, or even where the wrong surgery was performed on the wrong patient. This has led to the development of rigorous processes and checklists, generally requiring that more than one person needs to confirm the identity of a critical medication, or of a patient, or the nature of a procedure that is about to be performed.

14.3 Case 3 You are approaching the end of a very busy shift. You have just picked up a new patient, a 71-year-old woman called Elsie, who, according to the triage note, has presented following a fall and is complaining of left sided chest pain since then. As

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you are about to enter her cubicle, you are asked to review another one of your patients, presenting with urosepsis, who has now become hypotensive despite administration of two litres of crystalloid. You prescribe some analgesia for Elsie and go back to your patient with urosepsis. You decide that he now requires vasopressors and admission to the High Dependency Unit. You supervise your registrar during the insertion of a central venous catheter and arterial line, which took a bit longer than expected, as this was his first central venous line insertion. By the time you return to Elsie, your shift has finished but you do not wish to hand over the care of a patient with no clear plan. You find out that Elsie slipped on some spilled water at home and fell onto the coffee table, landing on the left side of her chest. She complains of pain in the left side of the chest, laterally and posteriorly, worse on breathing and movement. She otherwise feels well and the analgesia that you prescribed earlier is working. On examination, she has tenderness on palpation of the left lower ribs posteriorly and slightly reduced air entry in the left base. On palpation of the left upper quadrant, she experiences some pain in the posterior lower thoracic area, and there is no involuntary guarding  in the abdomen. You believe that this is caused by pressure on the painful rib from within the abdomen. The rest of her examination is normal, as are the vital signs. A urinalysis only shows trace of haematuria, which you are not too concerned about. The reduced air entry in the left base causes you to order an X-ray, looking for atelectasis or a small haemothorax. You finally hand over to the night registrar to check the X-ray, stating that Elsie possibly has a broken rib. As it turns out, the night shift is very busy and it takes more than two hours for the night registrar to review Elsie. He also palpates her left upper quadrant and notes that there is now significant tenderness. A cannula is inserted and a CT scan with intravenous contrast is obtained, which confirms the presence of a subcapsular haematoma of the spleen. As your hospital is not a trauma centre, Elsie needs to be transferred to a tertiary hospital. When you find out about this the next day, you realise that you did in fact think about splenic injury, but convinced yourself that the absence of guarding and of significant haematuria were reassuring and that the tenderness could be attributed to pressure on the presumed broken rib from within the abdomen. You were tired and had to catch up with your notes, and, therefore, you were not thrilled by the prospect of having to request more investigations, which would require further work, such as the insertion of an intravenous cannula for the CT scan. It seemed much more preferable, given the circumstances, to simply avoid considering the possibility of an intra-abdominal injury.

14.4 Case 4 Jessica is a 25-year-old woman who presents with exacerbation of her chronic abdominal pain. She has had multiple similar presentations over several years. She has had a full workup, including ultrasound, CT scan, gastroscopy and colonoscopy, all negative so far, and her last CT was about 3 months ago. She has even had an appendicectomy, and several laparoscopies, which did not result in improvement of her symptoms. She also has a history of anxiety, depression and self-harm.

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You walk into the cubicle, where Jessica is lying in the foetal position with a hot water bottle in her lower abdomen. Her mum is by her side, holding her hand and looking very worried. You have already formed the impression that this is going to be a difficult consultation and that Jessica’s symptoms are probably not of organic origin, but you are also mindful of the danger of preconceived views and of the need to approach every patient with an open mind. Your examination reveals generalised abdominal tenderness, but no guarding, while her vital signs are normal. You have seen Jessica before and her abdomen today does not feel any different. During several of her previous presentations, Jessica has been advised to follow up with her primary care physician with a view to being referred to a chronic pain clinic, but she has not done this, nor has she recently seen her psychiatrist. At the end of your examination, you state your opinion that Jessica’s pain is unlikely to have a cause that will be identifiable with the limited means of an Emergency Department. You suggest some simple analgesia and possibly a low dose of a benzodiazepine, at which point Jessica’s mum states in an annoyed tone that her pain needs to be ‘sorted out’ and that ‘it could be something different this time’. You eventually agree to perform blood and urine tests. After some simple analgesia and a bit of time, Jessica looks more comfortable and is seen chatting on the phone on a few occasions. When you come back to announce that the blood tests come back normal, she states that her pain is ‘still very bad’. Her mum dismisses the suggestion of a non-organic cause and states that they are not going to leave without another CT scan, ‘just in case’. You try to explain that Jessica’s pain is longstanding and that it is unlikely that a repetition of the same tests, and more ionising radiation, is going to be productive. Jessica’s mum becomes angry and threatens to complain about the hospital to the media. Your shift is nearly finished, and you are nowhere near convincing Jessica and her mum that she can be discharged. Exasperated, you re-examine her abdomen and you are now convinced that she has developed guarding in the left iliac fossa and periumbilically. As a result, you order a CT scan and hand over to a colleague. The next day, you follow up on the case. The CT was normal. Jessica’s mum had to leave the Department, as she had to look after her other daughter. Apparently, Jessica stated that her pain was nearly gone when your colleague went to see her with the results of the CT, and she was subsequently discharged. You then realise that your desire to avoid conflict and formulate a disposition plan for Jessica led you to perceive the clinical need for a CT scan where there was none, resulting in unnecessary cost and radiation risk.

14.5 Conclusions Confirmation bias can manifest in different ways in Emergency Medicine. By definition, the cause is always the presence of a false belief, generated by either wishful thinking or lack of awareness [2, 3]. The latter can be addressed by the development of policies and protocols that reduce the possibility of error by introducing multiple safety checks. The elimination of wishful thinking, on the other hand, is not

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straightforward. In general, learning to suppress wishful thinking is a lifelong process that involves training of the imagination to view situations from different perspectives without preconceptions [4, 5]. Potential Solutions 1. Encourage rigorous adherence to checklists and protocols where the potential for serious error exists, as in the case of medication administration and procedures. Read out the name and dose of the medication that you are about to administer, or describe out loud the procedure that you are about to perform. Always ensure that you know who you are talking to. Use a standardised tool for handing over, such as ISBAR. 2. Always imagine yourself in your patient’s position. What diagnosis would you be mostly worried about? What risks would you consider unacceptable? Involve the patient in decision-making. 3. As with all of your personal beliefs, practise addressing issues from several different perspectives. Think about how the evidence could fit alternative diagnoses. 4. Try to obtain perspectives from others whenever possible. Ask your colleagues what they think about your patient, without worrying that they will think less of you for asking. Ask what the nurse thinks is wrong with your patient, and what the patient believes is the cause of his or her illness. 5. Look after your physical and mental wellbeing. You are less likely to have the energy to face the prospect of a difficult decision if you are physically or emotionally drained.

References 1. Pines JM.  Profiles in patient safety: confirmation bias in emergency medicine. Acad Emerg Med. 2006;13(1):90–4. 2. Nickerson RS. Confirmation bias: a ubiquitous phenomenon in many guises. Rev Gen Psychol. 1998;2(2):175–220. 3. Ask K, Granhag PA. Motivational sources of confirmation bias in criminal investigations: the need for cognitive closure. J Investig Psychol Offender Profiling. 2005;2(1):43–63. 4. Mendel R, Traut-Mattausch E, Jonas E, Leucht S, Kane JM, Maino K, Kissling W, Hamann J. Confirmation bias: why psychiatrists stick to wrong preliminary diagnoses. Psychol Med. 2011;41(12):2651–9. 5. Tschan F, Semmer NK, Gurtner A, Bizzari L, Spychiger M, Breuer M, Marsch SU. Explicit reasoning, confirmation bias, and illusory transactive memory: a simulation study of group medical decision making. Small Group Res. 2009;40(3):271–300.

Congruence Bias

15

Carl Luckhoff

Congruence bias refers to the over-reliance on direct testing of a given hypothesis, and a neglect of indirect testing, leading to an inability to consider alternative hypotheses. In medical practice, it can be hard to identify this specific bias as we as clinicians rely upon the exploration of a given hypothesis, and differential diagnosis, to guide investigation and decision-making. However, when we place specific and direct focus only on a single sign or symptom we risk excluding multiple other causes for an event, and therefore risk not considering potential sequelae. In considering a differential diagnosis it is important to also look at indirect testing of a theory, facilitating the exclusion of other causes and/or options, and therefore supporting the habit of initial inclusion of a broad spectrum of disease patterns and presentations. The below cases aim to highlight examples of common mistakes that clinicians make when reviewing patients and not necessarily considering indirect testing to support a given hypothesis.

15.1 Case 1 A 48-year-old female is brought into a small district hospital by her family. She has a longstanding history of alcohol abuse and the last few weeks have been particularly challenging as the patient has gone missing for days, returning with a history of excessive alcohol consumption and little recollection of other events. Her family managed to find her this evening after only hearing from her once over the past week, and they were desperately seeking help. On initial examination she appeared dishevelled but cooperative, and she was able to coherently have a conversation. She was not clinically intoxicated, but her C. Luckhoff (*) Emergency Department, Alfred Health, Melbourne, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_15

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breath and blood alcohol levels were moderately elevated. A decision was made to admit her to the general medical ward, where an alcohol withdrawal scale could be started and IV fluid rehydration commenced. The following day on the ward saw some periods of mild confusion, but these were thought to be related to alcohol withdrawal and no formal assessment was made to explore these periods in more detail. That night proved particularly challenging for staff as the patient became restless, disruptive and at times very confused. Blood tests and clinical review were completed the following morning and it was decided that her clinical picture was that of acute alcohol withdrawal. However, it was a Saturday morning and the night staff expressed concerns around their own and other patients’ safety. This small district hospital also had no trained security staff members on site, and this added to staff members’ concerns. A decision was made to transfer the patient to a larger hospital with both security and overnight medical staff cover. The patient was discussed with the receiving unit and handover completed. In an attempt to expedite transfer an ambulance was booked to take the patient to the emergency department of the larger hospital. A quick courtesy phone call and brief history were provided to medical staff in the emergency department. Upon the patient’s arrival to the larger hospital she was behaving normal and could communicate all her wishes and questions accurately. There were no signs of confusion and clinical examination was normal. Almost immediately after arrival to the larger hospital she expressed a desire to go home. A doctor reviewed the patient and subsequently met with family members present at the time. Clinical findings and current state were communicated and it was explained that there was at the time no clear rationale or avenue for restraining the patient against her will. She was thus allowed to discharge herself against medical advice as she seemed coherent and she had capacity to make such a decision. Soon after leaving the department a bystander brought the patient back into the department. She now seemed slightly drowsy and confused. Examination upon return to the ED revealed a patient with a clinical syndrome synonymous with alcohol intoxication and in the absence of seizure activity and no signs of trauma it was decided to observe her. A breath alcohol level was attempted on a few occasions, but an accurate sample could not be obtained and staff assumed that this was due to alcohol intoxication. A review of previous medical records noted a couple of occasions where the patient was discharged and soon afterwards found to be intoxicated. Medical staff thought they were dealing with a similar scenario and continued to look for and document signs of clinical alcohol intoxication. The patient remained confused and difficult to manage, but did not display concerning signs, and staff continued to treat her for an acute intoxication syndrome, continuing with sedation assessments and other parameters aimed at the management of an acute alcohol intoxication. After a few hours the patient became more sedated and was found to have unequal pupils. A CT brain revealed a large extra-dural haemorrhage with mass effect. Urgent referral for neurosurgical decompression was arranged. The treating medical team assumed that the second presentation was related to alcohol and/or other intoxication, and continued to elicit signs supporting their

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suspicion, rather than considering the differential diagnosis from a more objective viewpoint and considering other scenarios as possible causes for the presentation. Recent hospitalisation and normal investigations, without a clear history of any new events, falsely reassured them and they continued to focus on the direct testing of signs that supported their suspicion, rather than considering broader differential diagnoses and approaching the patient from that perspective.

15.2 Case 2 A 27-year-old female presents to the emergency department after recently giving birth to a healthy boy. She was 39 weeks pregnant at the time of the delivery and her baby was delivered through vaginal delivery after 17 hours of labour. He was breastfed and growing well, with the family suffering from the usual disruptive sleep patterns associated with a newborn. The mother now presents to the emergency department 5  weeks post partum, complaining of chest discomfort. Her partner had recently been unwell with a viral illness and she was concerned that she was developing a similar infection, although, apart from a documented fever she did not report any sore throat or other symptoms associated with an upper respiratory tract infection. Instead, her symptoms were more related to severe fatigue and chest pain. Over the past 3 days she had also developed some shortness of breath, and she was concerned about the fact that these symptoms were not improving. The doctor that reviewed this patient in the ED noted the above history. He felt that she presented with non-specific chest pain and shortness of breath on the background of family contact with a viral illness, and he thought that her symptoms most likely represented a viral lower respiratory tract infection. He prescribed intravenous fluids and symptomatic relief agents. The patient was mildly tachycardic, but his thoughts were that this was to be expected in the setting of a viral illness. Given her chest discomfort, an ECG was done. This ECG displayed T-wave abnormalities in the limb leads and upon review the treating physician considered a pulmonary embolism (PE) as a possible cause for these T-wave abnormalities. This diagnosis did not quite fit the clinical picture, but the physician felt compelled to rule out this possibility. A chest X-ray was completed and this was normal. Blood tests were also sent and a second documented clinical review noted predisposing factors and risk factors for a pulmonary embolism. Given the recent pregnancy, a decision was made to complete a CT pulmonary angiogram (CTPA). The doctor also completed an arterial blood gas analysis with calculated A-a gradient, which was normal. The CT pulmonary angiogram was reported as being normal. A few hours had now passed and the patient felt much better. The treating doctor, initially concerned about a possible PE, now felt reassured by largely normal blood tests and a normal CTPA, and given that the patient felt better he planned for a discharge home. The ECG changes were not dynamic and given the absence of significant clinical signs and exclusion of a PE, the patient was discharged.

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However, the patient’s symptoms continued and she saw her own GP a few days later. Her GP noted the recent hospital review and observation, but with the abnormal ECG it seemed that the doctor became focused on exclusion of a pulmonary embolism alone, and examination and investigations were determined by this consideration, with no further exploration of the abnormal ECG or other causes for the patient’s presentation. The GP referred her for an urgent cardiology opinion at which time she was diagnosed with a cardiomyopathy. The emergency doctor caring for this patient initially suspected a viral infection, but with the abnormal ECG also considered a pulmonary embolism and in that felt that the considered differential diagnoses were broad enough. The focus on a pulmonary embolism became the main focus of care, rather than looking at the clinical problem(s) at hand and addressing and exploring these systematically.

15.3 Case 3 An 86-year-old woman is referred to the emergency department with new onset shortness of breath, which has been present for 4 days. She lives independently at home, but has a complex background history of amongst other conditions, recurrent lymphoma. Following chemotherapy approximately 8 months ago she was cleared from having lesions and her oncologist was very happy with her response to therapy. Unfortunately she developed a saddle pulmonary embolism 6 months ago and was started on a novel anticoagulant. Soon after starting this medication she developed knee haemarthroses twice, and in a meeting with her haematologist, oncologist, respiratory physician and general physician it was decided to keep her on high dose aspirin and fish oil, and cease the novel anticoagulant. Up to 4 days ago she felt well. Following a discussion with the doctor in the emergency department it was decided to do some blood tests and a CT scan, looking for a recurrent pulmonary embolism (PE). The patient’s clinical examination was normal and the doctor felt that a recurrent PE was very likely the cause for her presentation. Given her previous history the only other consideration in the doctor’s opinion was that of a recurrent mass secondary to her lymphoma, although previous lesions were intra-abdominal. At this time the case is handed over to you, pending results of the CT scan. The CT scan shows a segmental pulmonary embolism and large pleural effusion, and you contact the physician to whom the patient is known to arrange a transfer to the ward. The case seemed quite straightforward and you do not think about the case again until you see the patient’s treating physician a week later. He tells you that the patient was transferred to the ward and started on anticoagulation as discussed. However, the patient became more breathless overnight and was reviewed on the ward. A repeat chest X-ray overnight demonstrated significant enlargement of the pleural effusion and an urgent pleural tap was arranged. This tap suggested a secondary haemorrhage into the chest cavity, and anticoagulation was again ceased.

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In retrospect, when comparing previous CT scans with the one completed the night of admission, it is apparent that the reported segmental pulmonary embolism was part of the previous pulmonary clot burden, and not a new finding. The benefit and risks of anticoagulation could therefore have been considered more carefully prior to starting this therapy. You realise that when you received the report about a PE that you did not consider any other causes and/or sequelae, but given the patient’s symptoms and signs you simply started anticoagulation. Careful and indirect testing of the given hypothesis around the pulmonary embolism causing this patient’s symptoms may have in fact identified that it was more likely that the pleural effusion had led to the symptoms, rather than the suspected pulmonary embolism.

15.4 Case 4 A 5-year-old boy is brought to hospital by his mother at 05:00 in the morning. They are visiting family from interstate and since arriving 2 days earlier the boy’s mother has noted that her son has had a runny nose with a persistent dry cough. The patient’s mother describes a history of mild fevers over the past 2 days and her son had also complained of a mild sore throat. She took her son to a local GP a day prior to her current presentation and the GP told her that her son had a viral upper respiratory tract infection. He advised her to buy some cough syrup from the local chemist and to trial this that evening. The cough syrup made no marked difference to the patient’s condition, and in fact, the boy’s mum felt that his cough had worsened in the preceding few hours. The patient was a fully immunised, generally healthy and very active boy. He had not had any previous presentations to hospital. The triage nurse thought that she could hear an audible wheeze on auscultation. The doctor reviewing the child noted the above history from the triage notes. The child had a history of mild flexoral eczema as a baby and his father had a history of mild asthma, but he had never been diagnosed with a wheeze or any features of hyper-reactive airways disease. Nonetheless, the doctor felt that his suspicion for a viral-induced wheeze was confirmed when he heard a few mild wheezes scattered throughout the lung fields. He did not feel the need for any extensive further history and/or investigations and proceeded to prescribe a bronchodilator. The child was reviewed after the bronchodilator doses were completed, and again an hour later. The child was now comfortable and it was thought that his cough had improved. The doctor saw this as a reassuring and confirming feature and discharged the patient home with advice for ongoing bronchodilator therapy as required. An asthma management plan was provided, but the treating doctor did not feel a need for steroid therapy. The child re-presented later that evening with severe respiratory distress and was found to have life-threatening croup. Following initial intervention a discussion with the boy’s mother suggested a history of a barking cough for 2 days, and the presentation earlier that day was noted. The patient’s mother noted that it was this

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very cough that prompted her to present earlier that day, but after the finding of a wheeze the wheeze became the main focus of questioning and intervention. The doctor entered the consultation knowing that the nurse had heard an audible wheeze, and when he found this same finding he continued to look for information to support his clinical diagnosis directly, rather than exploring other components of the cough and presentation. The lack of further history and examination limited the ability for considering alternative diagnoses, therefore potentially preventing the subsequent event and presentation.

15.5 Case 5 Substance abuse and its sequelae are unfortunately a common cause for presentation to emergency services. A healthy 71-year-old female with a long history of alcohol abuse presents late one evening. She has gone through home detoxification programmes a few times and up to 4 months ago she managed to not drink any alcohol for several months. Over the past months her abuse pattern had been deteriorating slowly, despite her trying to manage this at home. She feels ashamed that she has ended up in this position again, but in part she also feels that her current intake is not as bad as it had been at times in the past. She was recently seen at her local hospital following a fall and was determined to stop drinking after that event, but a few family occasions and other events made this challenging. A major sports event over the weekend meant that she had consumed more alcohol than she had wanted to over the past 2 days, and she was now feeling unwell and seeking medical review. The doctor on duty that day had recently seen this patient following a fall. When he saw her present to the emergency department he suspected that her presentation may be related to alcohol abuse and given his previous knowledge of her background he reviewed her. However, on this occasion the patient’s complaints were vague and she mentioned feeling generally unwell, in conjunction with a higher than usual alcohol intake over the preceding days. She stated having “felt hot at times”, but there were no other specific features pointing to a cause for her current symptoms. She did not recall any falls, and apart from a sore left arm she did not display any stigmata of trauma. She was alert and orientated, not intoxicated, and did not display any features of acute alcohol withdrawal or encephalopathy. The only clinical finding was that of a sore left arm, which the patient stated was an old rotator cuff injury that had been causing pain over the past couple of days. The patient declined moving her shoulder as this worsened her pain. At that stage the treating clinician had a wide differential diagnosis, but strongly suspected that the patient’s presentation was related to her excessive alcohol intake. He proceeded with taking blood tests and in light of her symptoms he also requested for X-rays to be done. Initial management focused on symptomatic relief. The

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doctor felt that his suspicion for an alcohol-related cause was confirmed when the patient’s liver function tests were severely deranged, in keeping with an acute hepatitis, and given the strong history of alcohol abuse the abnormal blood tests were in keeping with alcohol-related pathology. The patient was admitted under a Gastroenterology Unit for further care. The inpatient team thought that these deranged liver function tests were in excess of what they would have expected for alcohol-induced pathology and considered further and broader hypotheses. They also looked at the patient’s sore arm in more detail and as part of these investigations a CK level was performed, and in conjunction with the clinical findings a compartment syndrome of the left arm was diagnosed. The first doctor failed to consider other causes for the patient’s presentation and remained focused on the history of alcohol abuse. Once the abnormal LFTs were identified, no further consideration was paid to these results and a diagnosis of alcohol-­related pathology was made, only to miss another significant condition. Although not directly related, this secondary diagnosis allowed the team to review the likely cause for the acute hepatitis, rather than remain focused on a single theory of aetiology.

15.6 Conclusion The advent of time-based targets necessitates rapid investigation and decision plans [1]. However, it is important to recognise the effect that these time pressures potentially have on decision-making processes and consideration of causes and responses to therapy, and clinicians need to be weary of diagnoses where there is an absolute focus on one hypothesis only. Having a structure whereby consideration of broad differential diagnoses is considered, thereby allowing for indirect testing of a given hypothesis, will help the clinician to negate the effects that congruence bias may have on their practice. One suggestion would be to encourage actual documentation of considered options, thereby almost forcing the clinician to explore both direct and indirect testing of the various considerations. It is important to also test whether the final hypotheses test negative to specific questions, thereby not only focusing on proving the clinician’s diagnosis, but also on disproving other potential causes. This is equally important when obtaining a history from the patient as question phrasing can have pertinent effects on response. Another potential solution is to have established patterns for follow-up of patients and in-hospital feedback. The emergency setting is particularly prone to consideration of short-term care alone, therefore limiting the ability of the clinician to explore different hypotheses. Through an active and conscious feedback system both inpatient and emergency staff would be able to identify likely scenarios where this form of bias affects decision-making and patient care most significantly.

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Whether the solutions need to be explored through training of junior staff, or perhaps through electronic recording systems, remains to be seen.

Reference 1. Martire K, Dahlman C.  The effect of ambiguous question wording on jurors’ presumption of innocence. Psychol Crime Law. 2019;26(5):419–37. https://doi.org/10.108 0/1068316X.2019.1669598.

Contrast Effect

16

Elizabeth Sheffield

It is nearly midnight and you are heading home after a late shift at work. You turn the corner onto your street and find yourself dazed by the flashing lights from several police cars stationed outside your family’s home. Your mind races and you begin to feel physically ill from the fear that some terrible harm has befallen your wife and son. On arrival into your house, you see your wife and son sitting on the sofa, perfectly well and seemingly in the midst of giving statements to the police. As it turns out, the house had been burgled while they went out for a night at the movies. You are flooded with a deep sense of relief and gratitude that no one has been seriously injured or worse. In contrast, if you had all arrived home together, you would have been dismayed at finding your belongings missing and your home trashed. However, your perception of the current situation is altered in comparison to the one of much graver consequence that you conjured in your mind [1, 2]. When interpretation of one stimulus is altered by comparison to another, this is called “contrast effect.” In emergency medicine, this can be seen across the entire spectrum of the patient experience, beginning with triage (for example, a patient who is driven in by her family with chest pain might be interpreted less acute than the one who is brought in by ambulance and flanked by paramedics) to disposition (as will be later discussed). Definition: The variation in how information is received, either being enhanced or diminished in relation to occurring before or after a more or less significant event.

E. Sheffield (*) Emergency Department, Austin Health, Heidelberg, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_16

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16.1 Case 1 An ambulance arrives with a patient involved in a multi-car trauma on the expressway. A truck crashed through a divider resulting in a huge pile-up in a 100 kph zone. Jadon is the 18-year-old driver of a car that diverted into a tree, and whom the fire brigade had to extricate from his vehicle. He is complaining of abdominal pain and shortness of breath. A trauma call is made. On review, his saturations are 86% on 15 L of oxygen through a non-rebreather bag. His heart rate is 130 and his blood pressure is 90/60. He has a C-spine collar on and a pelvic binder that were placed at the scene. He has two large-bore IV lines already inserted and the nursing staff immediately get a full panel of trauma bloods and you perform an eFAST scan and identify a pneumothorax on the right side of his chest and free fluid in Morrison’s pouch. You perform a finger thoracostomy as your resident prepares and inserts a formal intercostal catheter. A portable pelvis x-ray is performed as you are arranging for urgent transfer to the operating theatre and commencing blood products and TXA, and you find a lateral compression fracture. He is urgently transferred to theatre and is found to have, in addition to the pelvis fracture, a grade IV splenic laceration, multiple left- and right-sided rib fractures and widespread pulmonary contusions. Soon afterwards, a nurse asks you to see Giovanni, who has also been in a pedestrian-­versus-car accident. He is an 88-year-old man who was struck by a car that was in the process of stopping as he was crossing the road. According to witnesses at the scene the impact was slight but had caused him to fall forwards onto both hands. He did not sustain a head injury and walked independently with the paramedics. He is extremely tearful and complaining of pain in both wrists. His past medical history includes ischaemic heart disease and diabetes. He lives alone independently. When you assess Giovanni you find him to be GCS 15 with completely normal observations. You obtain a full primary and secondary survey and a number of radiographs. You find he has bilateral Colles fractures but no other injuries. Giovanni tells you he wants to go home. You explain to him that he will need to come into hospital and that he will not be safe at home at the moment. Giovanni insists that he wants to go home and so you comply, going through a discharge against medical advice form and assisting him in getting a taxi to take him home. Two days later, Giovanni’s daughter brings him in and is very angry that he had been allowed to leave. He has been unable to cope at home alone and has taken his casts off in frustration overnight. You see him again and realise that, with his social situation and frail premorbid state, he has sustained a very debilitating injury and that he will require a prolonged stay in hospital plus rehab until he is safe to go home. In comparing his case to Jadon, you glossed over the serious impact that Giovanni’s apparently minor injuries would have on his life and thus did not take the appropriate time to counsel him and ensure a holistic approach to his care.

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16.2 Case 2 Andrew is a 48-year-old male who presents with “nail versus hand.” He tells you that while working in construction he was using a nail gun which accidentally slipped, and the nail has gone through the back of his right hand. He tells you some of his fellow workers pulled the nail out and then washed his hand in cold water for 10 min while preparing to bring him in. You examine him and find no active bleeding, some numbness over his fourth and fifth fingers with associated rotational deformity. X-rays reveal fractures of both the fourth and fifth metacarpals. He has been given analgesia at triage and his pain is well managed. After administration of a tetanus vaccination and IV antibiotics, you phone the plastics registrar and explain that Andrew has a compound fracture of his dominant hand and you would like him to be brought in for a formal washout. The plastics registrar agrees and the patient is placed in a backslab and admitted to hospital. Later that same day, Jamal, a 28-year-old, attends with flexion of his DIPJ of the index finger of his right (and nondominant) hand. He reports that while playing football with his son he sustained a direct blow to his finger and has since been unable to fully extend. You evaluate him and diagnose a mallet finger. You obtain x-rays and find no underlying fracture or indication for acute surgical referral. You believe conservative management will potentially give the best outcome. In comparison to Andrew, you feel this is a relatively minor injury and that it can be managed as an outpatient. You immobilise the finger with a finger splint, then advise the patient to take NSAIDs for pain and follow-up with their GP. After a few weeks, your supervisor asks to see you to discuss a patient you had seen. Jamal has put in a complaint with regard to the care he has received in the ED. As it turns out, Jamal is a concert pianist. He has spoken with his cousin who is a plastic surgeon and advised him to see an occupational therapist the following morning, and he has since been put under the care of a hand surgeon to ensure he receives the “proper follow-up” and decide if any surgery will be required down the track to ensure full functional outcome. Because you had seen Andrew just before, your assessment of Jamal was affected, and you evaluated his injury as more minor. Had you seen him first you might have obtained a social history and realised how much the injury would affect his livelihood, and thus been more thorough in your discharge advice, and perhaps referred him to your own plastics outpatients and OT given his occupation.

16.3 Case 3 It is 1 AM on a Saturday night and the department is busy, even for a weekend. You are the in-charge seeing Joseph, 50-year-old male, who has been brought in by ambulance after a suicide attempt. He was found at home by his ex-wife, in the

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garage with the car running, having taken several diazepam and half a bottle of spirits. Joseph has never been to hospital and has no previous psychiatric history. According to his ex-wife he’s recently lost his job and is estranged from their daughter, which she believes has contributed to his presentation. When you had arrived on shift 3 h earlier, Joseph had been sleeping and had been medically cleared of any emergent medical issues. However, he had just woken up an hour ago, and you only just manage to attend him now. You find him to be withdrawn, but compliant with initial questioning as you begin your further risk assessment of events leading to his self-harm. Outside the cubicle, a 21-year-old patient who is being monitored following a GHB overdose has just woken up and begins angrily screaming and throwing medical equipment from the resus bay into the corridor. You excuse yourself hurriedly and go to attempt to verbally de-escalate the other patient; however he starts swinging at staff and trying to punch them. Security is called and they assist by restraining the patient physically as you administer a dose of droperidol. After 15 min of ongoing screaming, the patient has settled and you are able to go back to Joseph. On your return you find Joseph withdrawn and unwilling to engage in a conversation with you. He denies any suicidal thoughts and tells you he “just wants to go home.” You are confused and tell Joseph you are just waiting for a psychiatric assessment but that if he feels like he might want to discuss anything further to let you know. There is a delay of 6 h as there is a large queue of patients waiting for psychiatric evaluation. During this time there are multiple other patients who present intoxicated and agitated. Early the next morning the psychiatric liaison finds you and advises that he will admit Joseph but that Joseph is extremely distressed and terrified about coming into hospital. He reports that Joseph has disclosed to him that he was horrified by the sounds of the patient next door being physically restrained, and that he is concerned that he will have a similar experience whilst in care. On reflection, you realise that the events of the previous evening are ones that you have experienced multiple times before and as such normalise. For Joseph, however, who has never experienced a similar situation, what he has just witnessed was extremely fear-provoking. Had you taken the time to explain things to him, or perhaps found him a quiet place to stay overnight where he would be less affected, you could have lessened his anxiety and reduced his distress over coming into hospital.

16.4 Case 4 It is another night shift and you are again in-charge. Marie is a 40-year-old female who has been triaged with general lethargy and myalgias. There is no past medical history highlighted in her electronic record, and the nurses have not yet been in to take a history. However, her observations from triage are within normal parameters.

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As you are about to go see her the buzzer goes off and a 60-year-old patient who had presented with chest pain suddenly arrests. The team immediately commences CPR and you go to lead the team in the resuscitation. After a prolonged effort, it is determined the patient is unlikely to recover and the team decides to withdraw resuscitation. The patient’s family has been in the room and you need to go debrief with them and refer the patient to the coroner. As you are about to go into the family room, the nurse looking after Marie reports that she is upset as she has been here for 3 h without seeing a doctor and she wishes to self-discharge so she can go home and get some sleep. The nurse has told Marie that it won’t be much longer but Marie still wants to leave. You are a bit annoyed by Marie considering you have just had a patient pass away and feel this takes precedence—you advise the nurse to try once more to convince Marie to stay and ensure she understands that you are unable to evaluate her risk should she leave and that she should return if there are any concerns. Should she still wish to, she can then self-discharge. After the family meeting, you find that Marie has left. The following night Marie returns via ambulance, unable to mobilise. It turns out that she has recently moved to the city to be near her family as she has metastatic breast cancer to the lung, bones and liver and is being treated palliatively and had just been referred to the local service. The previous night she had come in with worsening pain, nausea and had been increasingly unable to feed herself and get to and from the toilet. Since going home she had further deteriorated. The scene the night before had grossly upset her as she felt confronted with her own mortality. Even though she hadn’t eaten well in weeks she felt psychologically unable to stay. On a different evening, you would have prioritised seeing Marie and ensuring she was safe at home and counselled her more fully prior to self-discharging. However, because her initial visit had presented almost concomitantly with an acute resuscitation, it meant that you had not adequately triaged Marie’s risk appropriately, which led to a delay in her being safeguarded in hospital.

16.5 Conclusion In life it is difficult to synthesise information as if it exists in isolation. Just as a Great Dane might appear excessively large next to a chihuahua but quite small compared to an elephant, it is a normal part of human cognition that our evaluation and processing of a stimulus is in comparison to the rest of the world around it. In medicine, this can create a bias with regard to how we interpret information, and also devise management [3, 4]. This contrast effect is especially pertinent for emergency physicians, whose work relentlessly presents them with a diverse group of patients: spanning from the very old to the very young, the sickest to those who might be managed in the community, those with different cultures, as well as opposite ends of the socioeconomic spectrum. It is particularly important not to accidentally diminutise a patient’s experience, because in doing so patients may fail to engage in their treatment, and the doctor-patient relationship can be wounded [5, 6].

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Potential Solutions 1. After seeing each patient try to evaluate them as an individual and not in comparison to other patients. 2. Engage in multidisciplinary thinking. Ensure that you take a full history and ensure you give the patient opportunity to discuss their concerns and to objectively evaluate the patient holistically. 3. Practice metacognition and try to reflect on how you arrive at certain decision points—consider what the patient is actually trying to achieve, try and reflect on your thought process that led you to your conclusions, what knowledge you could gain to improve next time? 4. Ensure that you allow for adequate time in evaluating patients, as well as sufficient time in between patients. Take regular breaks to refocus on how you structure your assessment and focus on your patient.

References 1. Beck AT. Cognitive therapy of depression. New York: Guilford Press; 1979. 2. Croskerry P.  The cognitive imperative thinking about how we think. Acad Emerg Med. 2000;7(11):1223–31. https://doi.org/10.1111/j.1553-­2712.2000.tb00467.x. 3. Howard J. Cognitive errors and diagnostic mistakes: a case-based guide to critical thinking in medicine. Cham: Springer; 2019. https://doi.org/10.1007/978-­3-­319-­93224-­8. 4. Laskey AL.  Cognitive errors. Pediatr Clin N Am. 2014;61(5):997–1005. https://doi. org/10.1016/j.pcl.2014.06.012. 5. Medina MS, Castleberry AN, Persky AM.  Strategies for improving learner metacognition in health professional education. Am J Pharm Educ. 2017;81(4):78. https://doi.org/10.5688/ ajpe81478. 6. Patel VL, Kaufman DR, Cohen T.  Cognitive informatics in health and biomedicine: case studies on critical care, complexity and errors. London: Springer; 2014. https://doi. org/10.1007/978-­1-­4471-­5490-­7.

Decision Fatigue Effect

17

Xiu Qing Lee

Imagine the motor on your current refrigerator has just burnt out. You pop into an appliance store to buy a new one and the salesperson tells you about the assortment of options: top mount, bottom mount, side by side, French door, integrated ice maker, wireless connectivity. They explain the different capacities and energy efficiencies, from different brands, in different colours. They show you new release models, ones on sale and ones that are on special clearance. After you have walked around the displays multiple times and opened far too many tabs on your mobile phone browser to try to compare consumer reviews and check prices at other stores, you manage to narrow it down to just one. After confirming your choice, the salesperson asks if you want to purchase an extended store warranty on the refrigerator, which they offer for durations of 1, 2, or 3 years. As you look at the pamphlet to work out what the store warranty includes, the salesperson asks if you want to join their loyalty program. It does cost extra, but you get 12 month servicing coverage for this purchase (which is not the same as the extended warranty), as well as a discount on the delivery charge, and special offers on your birthday. As you process this new information, the salesperson asks if you want your old refrigerator removed as well when they deliver the new one, which will be an additional cost—but not covered by the loyalty program discount. Inundated by the options, when all you want is the last 2 hours of your life back and a working refrigerator in your house, you pay to sign up for the loyalty program, as well as a 2-year extended warranty, delivery of the refrigerator, and removal of the old refrigerator. When you get home and peruse the fine print of what you have signed up for and work out the overall costs, you realise that your purchase choices were clouded by decision fatigue. X. Q. Lee (*) Emergency Department, Mater Hospital, South Brisbane, QLD, Australia University of Queensland, St Lucia, QLD, Australia University of Melbourne, Parkville, VIC, Australia © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_17

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Making decisions requires comparing options. The more decisions you have to make, the greater the cognitive demand, and this is further exacerbated if multiple decisions have to be made in a short time. The consequence is that your subsequent decisions are not as good or as well thought through as your earlier ones [1]. Emergency Medicine is a setting that is particularly conducive to decision fatigue, as clinicians are usually faced with multiple simultaneous demands, and there are high-stakes decisions to make in a limited timeframe [2]. Definition: The deteriorating ability to make good quality decisions after a long or intense period of decision making.

17.1 Case 1 You are in the middle of seeing a patient in the acute area when you are called to the resuscitation room. Bob is a 78-year-old man who has been brought in by ambulance with worsening shortness of breath over the last few days. He is sitting up in the trolley, tachypnoeic and diaphoretic. When monitoring is applied, it shows him to be tachycardic with a rate of 130–140. He is also hypoxic, saturating at 85% on room air. His blood pressure is 95/50. Oxygen is applied, and his saturations improve to 90% on 6 L oxygen per minute via a facemask. A cannula is placed, and bloods drawn. You plan in your head what blood tests you will request. An ECG is attempted, and is marred by plenty of artefact due to his tachypnoea, sweatiness, and his reluctance to stay still for long enough for a complete trace. You can make out that he seems to be in atrial fibrillation, however. You make a mental note to add a coagulation profile to his blood tests. You auscultate his chest, and hear widespread crackles. You organise a mobile chest X-ray as you add to his problem and differential list. Bob has a limited ability to relate a history to you, but his wife, Anne, and his daughter, Kate, followed the ambulance and have arrived in the Emergency Department. They tell you he doesn’t go to the doctor much, but has high blood pressure and cholesterol. Bob was in hospital a couple of years ago with a ministroke, but seemed to have recovered fine from it. He is on a few medications, but they are unsure what. In the rush to come to hospital, they forgot to bring the packets with them. They have not heard the term “atrial fibrillation” before. Bob does not have an advanced health directive. As you begin to consider management options for Bob’s new rapid atrial fibrillation and likely pulmonary oedema, his venous blood gas result is placed in your hand. The results that catch your attention are his potassium of 6.5 and his creatinine of 160. You suspect acute renal impairment rather than haemolysis to be the cause of the raised potassium. You decide to initiate management of this, rather than wait for the formal blood results. You prescribe calcium gluconate, followed by insulin and dextrose. You also prescribe IV frusemide, which will begin to address his APO as well. You ask for BiPAP, and in anticipation of it causing a decrease in his blood pressure, chart a 250 mL bolus of IV crystalloid to begin with. While you know that GTN would help his cardiac workload by decreasing preload, you are concerned that it will make him

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more hypotensive at this stage. You consider the options for rate control, and while wary that both magnesium and metoprolol are also likely to lower his blood pressure, you balance that against the strain on his myocardium and compromised cardiac output from ongoing tachycardia. While rate control is your primary aim, you plan that if he becomes more haemodynamically compromised, your next step will be rhythm control by electrical cardioversion. You begin to weigh your pharmacological procedural sedation options, and their potential impacts on his hypotension, tachycardia, and hypoxia. Anne becomes tearful as the BiPAP mask is applied to Bob. It occurs to you that you have not explained anything to his Bob’s family so far, but as you turn to do so, Bob begins pulling at the BiPAP mask, and pushing away at the nursing staff who are trying to keep it on him. You try to talk Bob down, but he is in no state to be reasoned with. You realise that you will need to give Bob some sedation to enable him to tolerate the BiPAP, but also know that this is potentially the point at which he could deteriorate further, necessitating intubation and ventilation. Anne is now properly crying, and Kate tries to comfort her, saying repeatedly that Bob will be fine, that he will not die. You say aloud tersely, “He could die”. You see Kate’s face fall as you do, and Anne sobs even louder. You realise that decision fatigue has clouded your usual tact and empathy. Your impulsive statement has had a negative impact on Bob’s family during a stressful time for them. This may affect their trust in you when it comes to difficult discussions, like Bob’s treatment limitation decisions. You quickly organise for Bob to be given a small dose of fentanyl, and give instructions for a second aliquot shortly. You take Anne and Kate aside to apologise to them, and briefly summarise Bob’s current situation in layperson’s terms. This also allows you to recap his issues and the decision points for yourself. Bob’s family seem less upset after the explanation, and you feel that you are able to restore some rapport with them. Bob is more settled after the aliquots of fentanyl, and is able to tolerate the BiPAP. After a couple of hours on BiPAP, and as the other treatments start to work, his condition improves and stabilises. He is referred to the medical team, and is subsequently able to be transferred to the ward for ongoing care under them after he is weaned off BiPAP. The large number of complex decisions that needed to be made in a short amount of time resulted in a high cognitive load. The decision fatigue caused you to respond to additional demands in a more impulsive and less considered manner. This can lead to poor communication patterns not only with patients and their families, but also within teams in a resuscitation.

17.2 Case 2 Tina is a 16-year-old with type 1 diabetes. This is her second presentation to the Emergency Department in a week. The triage states that she has been brought in by ambulance with nausea and abdominal pains. Her BSL was 18 at triage, and she

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looks listless from the end of the bed. The notes indicate that her family called the ambulance, but no one seems to have accompanied her to hospital. Tina’s pulse rate is a little tachycardic at 120, and her blood pressure is at the low end of normal for her age. She is afebrile. She barely makes eye contact with you, and gives brief answers to your questions. She tells you that she has not had much of an appetite for the last couple of days, so has been skipping some of her insulin doses. You organise blood tests, including a venous gas, and chart a litre of IV fluids to begin with. As you go to examine her abdomen, you are called to see a patient in the resuscitation room. Before you leave Tina’s bedside, you grab an insulin chart, scribble in the sliding scale for subcutaneous insulin doses, and tell the nursing staff attending Tina to give her a dose of Actrapid based on her blood sugar level. Stabilising the patient in the resuscitation room takes a little while, but you return to Tina’s cubicle after this. IV fluids are running, and she has been given a subcutaneous dose of insulin as you requested. Her venous blood gas result is now available, and it shows that despite having a high BSL, she is not acidotic. You check through the breakdown to make sure that it is not just because she has good respiratory compensation. Reassuringly, her finger prick ketones are 0.4. You want to exclude an infective cause for her symptoms, so ask her about respiratory and urinary symptoms. Tina mumbles a “no” to each question. You ask her if you can examine her abdomen, as you want to check for appendicitis. She shrugs in response. As you are about to examine her, one of the nursing staff asks you to review an ECG. A patient has presented complaining of palpitations, and the nurse in that section has proactively done an ECG on him. You evaluate the ECG. It shows a sinus arrhythmia, with a rate of around 90. You cannot see any ectopic beats on the page. The intervals and QRS morphologies look appropriate. You scan the trace for ischaemic changes, and do not note any. You hand the ECG back, and ask for some blood tests to be done, and for the patient to be placed on telemetry so his rhythm can continue to be monitored. You return to Tina, and finally manage to examine her abdomen. Her abdomen is soft on exam, with no masses or guarding. You ask if she is feeling any better. She shrugs, and says “maybe”. She looks less uncomfortable than when you initially saw her. You ask what you can do to help her. She declines your offers of antiemetics and analgesia. When you ask about her family and other supports, she tells you that her parents don’t really care about her, and she doesn’t have many friends at school. She talks to a few people online, but there isn’t anyone close by she can actually meet and hang out with. You think that Tina seems quite socially isolated and depressed. You consider how to have this discussion with her. There are adolescent-­focussed resources that might help her, but you think that this might be an involved discussion. You put off the conversation, and focus on the medical aspects of her presentation first. You ask for a repeat BSL and ketones, as it has been over an hour since Tina has been given the insulin and fluids. You check her formal blood test results, which, apart from mildly elevated WCC and neutrophil counts, do not raise new concerns. Her B-hCG is negative. Her urine microscopy does not show any signs of infection.

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One of the junior doctors asks to discuss antibiotic choice for a patient with a urinary tract infection that they would like to discharge home. The complicating factor is that the patient has a number of medication sensitivities, including many antibiotics. You work through the options, and decide on one that the patient will hopefully find tolerable. You recommend safety netting and follow up with their GP. You return to Tina. She tells you that she is feeling better and wants to go home. Her latest fingerstick ketone was 0.1, and her BSL was 12. You have not mentioned your concerns about depression to Tina, but as she is clinically improved and is keen to go, now does not seem the time to delve into the issue. You remind Tina of the importance of having her insulin regularly, tell her about symptomatic management over the next few days if she continues to have nausea, and give her a letter for her GP. A couple of days later when you are next on shift, Tina is brought in by ambulance again. She is seen by your colleague instead. This time, Tina is in DKA. After initial management in ED, she is admitted under Endocrinology. You find out that after her previous discharge from the ED, Tina continued to skip her insulin. Her medication neglect was a form of self-harm. Thinking back, you realise that decision fatigue from having to make multiple decisions on that previous shift led you to choose the easiest available option, and avoid the difficult conversation with Tina. Allowing Tina to go home also meant that you would not have to make further decisions around her care. That reduced the demand on you in the short term, but at the cost of complicating her care in the longer term.

17.3 Case 3 Susan is a 25-year-old woman who presents with lower abdominal pain. This pain started a couple of hours ago, and she looks very uncomfortable. She tells you that she has a history of endometriosis, but is otherwise well usually. She tells you that she has tried the usual analgesia that she takes when she has flares of her endometriosis pain, but this is bad compared to what she has had before. She states that she was nauseated because of the pain, and vomited not long after she took the medication. She is slightly tachycardic, with a pulse rate of 95, but her vitals are otherwise within normal range. Susan is the tenth patient you have seen in this shift. There are 15 patients still waiting to be seen in the department. You have not had a break yet, and it looks like it will be a while yet before you get a chance. You organise bloods on her, including a B-hCG. You chart IV analgesia, as you think that it is likely she will not keep oral analgesia down. You think that Susan’s pain might not be well controlled because she vomited up the analgesia she had initially taken at home, so it did not have a chance to work. You write up some antiemetic for her as well, in the hope that when her nausea settles, she will tolerate some oral analgesia. Susan’s abdominal exam does not suggest appendicitis to you. You think that there is little indication to request an ultrasound, as given her history, a flare of her endometriosis is the most likely cause of her symptoms. You decide to

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give the analgesia some time to work, and plan to review her when blood results are back. You return to check on Susan later. Her B-hCG is negative, and her other bloods are unremarkable, apart from a mildly raised WCC.  She is still grimacing, and despite having received multiple doses of IV fentanyl, the analgesia seems to barely have improved her pain. You wonder if you might have missed something after all, and organise an ultrasound scan of her pelvis. It takes a while for the scan to be done, as the Radiology department is similarly busy. Not long after she returns from the ultrasound however, one of the reporting radiologists contacts you. They tell you that Susan’s ultrasound shows that she has a large left-sided ovarian cyst, and decreased blood flow to that ovary, suggesting ovarian torsion. You phone Gynaecology, who arranges to take Susan to theatre urgently. Fortunately, they are able to salvage her ovary. Decision fatigue led you to oversimplify and anchor to what seemed to be the most obvious diagnosis, rather than work through possible differentials in detail. Although you did consider a couple of alternative causes, endometriosis was the easiest potential cause to focus on, as she had previously had it, and it did not require further workup. Delaying decisions is also a recognised consequence of decision fatigue. In this situation, when Susan’s pain was out of keeping with the pain she had previously experienced from endometriosis, you delayed instead of immediately making the decision to do imaging to investigate further.

17.4 Case 4 You are charting medications for a patient, when nursing staff bring you an ECG to review. Michael is a 48-year-old man who has come to the emergency department with chest pain. You review the trace. It shows him to be in sinus rhythm. You notice that the rate is a little fast, at 90. You do not see acute ST or T-wave changes that suggest he needs the cath lab urgently though. You sign off the ECG, and plan to see him next. You ask the nursing staff if he has had analgesia, and when they answer in the negative, you write up aspirin and GTN on a medication sheet. You finish working out what antibiotics your patient with multiple allergies can have for their pneumonia, then phone the inpatient medical team to refer her to them. After you have done this, you can finally turn your attention to Michael. He has had chest pain since a few hours ago. He was doing work in the garden when it started and thought that he had strained something, but it did not settle down after he stopped and rested. He tells you that the pain makes him feel a bit winded. He had not had anything for pain relief until the analgesia he was given in the department. He thinks that that helped a bit, but the pain is still there. He is an active smoker, but denies any other medical history. He admits that he doesn’t go to see doctors much though. He is not sure about a family history of ischaemic heart disease, as they never really discussed health conditions. You had another patient on the go, an elderly man from a nursing home who also presented to the Emergency Department with chest pain. His family have now

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arrived, and want to speak to the doctor looking after him. You tell Michael that your aim today is to rule out serious causes of his pain, in particular from his heart and lungs. You tell him that these will be investigated with blood tests and imaging. The monitor shows his blood pressure to be a reassuring 135/80, and his saturations at 97%. You organise for him to have more analgesia, and order tests. You request basic bloods and a troponin. You decide to throw a D-dimer in as well. Michael has described chest pain with shortness of breath, and you think that this could be an easy way to determine whether he needs more investigation for pulmonary embolism. You can decide on further testing after those initial results are back. You talk to the family of your other patient with chest pain, and discuss the utility of admitting him for further investigations, in the context of his dementia and multiple other medical comorbidities. It is quite an involved discussion, and by the time you have reached consensus, Michael’s pathology results are ready. His first troponin is negative, but he has a positive D-dimer. You think that there is little point doing a chest X-ray, and request a CTPA instead. You check the scan report when it becomes available. Michael does not have a pulmonary embolism, but he does have a pneumothorax. Reviewing the case, if you had used appropriate clinical decision rules, you might not have requested a D-dimer on Michael to begin with. If you had done a chest X-ray instead of skipping ahead to a CTPA, that would have shown the pneumothorax. It was easier to request the tests than expend the cognitive energy to think things through. Unfortunately, the shortcuts you took due to decision fatigue led you down the wrong path, and resulted in Michael having unnecessary radiation exposure from an unneeded CT.

17.5 Conclusions Clinicians working in Emergency Medicine are prone to decision fatigue due to the environment and nature of Emergency Medicine. To compensate, the brain falls back to options that take less energy in the short term, such as defaulting to pattern recognition, and avoiding complexity or challenge [3]. This can result in oversimplifying, taking shortcuts, putting off decisions, and acting impulsively. Decision fatigue causes mental and emotional strain, and makes you more prone to other cognitive biases. In the longer term, decision fatigue can spill over to life outside of work, and lead to burnout [4, 5]. Potential Solutions 1. Be aware of other factors that can contribute to fatigue, and manage them. Hunger, thirst, and tiredness all have a negative impact on your cognitive function and energy levels. Do regular self-checks on your mental and physical state. Make sure that you take breaks, and replenish your blood glucose. 2. Recognise when you are prone to make errors. This is more likely after you have had to make many decisions (towards the end of a shift), or after you have had an intense period of decision making (after a complex case or resuscitation). Take the time to deliberately consider the decisions you are making in that situation.

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3. Prioritise major and complex decisions. These should be done early, while you have more mental energy to expend. 4. Share the cognitive load. Delegate tasks and decision-making where appropriate to other qualified clinicians. Discuss complex cases with a colleague if available. 5. Avoid putting off decisions that need to be made by you. These will continue to add to your cognitive load otherwise. 6. Make use of algorithms and checklists. These safety defaults reduce the number of decisions you have to actively make. 7. Look at organisational interventions, such as limiting the duration of clinical shifts in high demand areas, and having good rostering practices that do not contribute to fatigue.

References 1. Pignatiello GA, Martin RJ, Hickman RL.  Decision fatigue: a conceptual analysis. J Health Psychol. 2020;25(1):123–35. 2. Oto B. When thinking is hard: managing decision fatigue. EMS World. 2012;41:46–50. 3. Howard J. Cognitive errors and diagnostic mistakes: a case-based guide to critical thinking in medicine. Cham: Springer; 2019. 4. Persson E, Barrafrem K, Meunier A, Tinghög G. The effect of decision fatigue on surgeons’ clinical decision making. Health Econ. 2019;28:1194–203. 5. Burgess DJ. Are providers more likely to contribute to healthcare disparities under high levels of cognitive load? How features of the healthcare setting may lead to biases in medical decision making. Med Decis Mak. 2010;30(2):246–57.

Deformation Professionnelle Bias

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Khin Moe Sam

18.1 Introduction A patient presents to you with a headache. Let’s put ourselves in different scenarios and imagine what will our top differential diagnosis be. What will the top differential be if you were a general practitioner—a tension headache? What will the top differential be if you were a neurosurgeon—a brain tumour? What will the top differential be if you were an emergency physician—a migraine, perhaps? Our judgement and actions depend greatly upon what we encounter in our day to day practice. Once a patient is referred to a specific discipline, the bias within that discipline to look at the patient only from the specialist’s perspective is referred to as ‘Deformation Professionnelle Bias’ [1]. In other words, this concept is equivalent to the ‘law of instrument’, otherwise known as Maslow’s hammer represented by the popular quote of ‘to a man with a hammer everything is a nail’. Let’s review some cases to have a better understanding about this specific type of bias and let’s try to have a solution to the each of the issue we will be identifying in the following cases.

K. M. Sam (*) Emergency Department, Dandenong Hospital, Monash Health, Dandenong, VIC, Australia Faculty of Medicine, Nursing and Health Sciences, School of Clinical Sciences at Monash Health, Monash University, Melbourne, VIC, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 M. Raz, P. Pouryahya (eds.), Decision Making in Emergency Medicine, https://doi.org/10.1007/978-981-16-0143-9_18

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18.2 Case 1 A 38-year-old female was brought to your urban district ED  (emergency department) by an ambulance around 22:45. Her family called the ambulance since they thought she was going ‘hysterical’ and anxious after dropping her 8-month-old child on the floor about an hour ago. The child was uninjured since her husband was able to catch the child. The patient had limited English. The suburban ED sees a great number of patients with mental health and drug and alcohol issues. It has an excellent culturally diverse staffing. A junior doctor who is fluent in the patient’s language did the initial assessment. The doctor just finished a 10-week rotation in mental health. A senior doctor overheard the ambulance handover to  the nursing staff and thought the case was atypical. Hence, the senior doctor approached the junior doctor and asked their clinical assessment. The junior doctor reported that the patient looked anxious, was hyperventilating and stuttering. The patient was able to talk in her own language, but it was difficult to make sense of what she spoke because of her ‘anxiety attack’. Her only past history was anxiety and occasional insomnia. A collateral history was also obtained. She had an argument with her husband earlier during the day and she was walking while carrying her child and suddenly dropped the child and then she started screaming. The family was unable to communicate with her or settle her and so they called the ambulance. She had normal vital signs. She had normal heart sounds, equal air entry to both lungs and no tenderness on abdominal examination. Further investigations were deemed unnecessary by the treating doctor since this clearly was a case of anxiety and the patient just needed anxiolytic and ECAT (Emergency Crisis Assessment Team) review. After listening to the story, the senior doctor thought something was amiss. Upon review by the senior doctor, the patient was tearful while talking in her own language. She seemed to be able to apprehend what the senior doctor was talking. She nodded when being asked if something was wrong. She nodded again when being asked if it was her speech. Expressive dysphasia was suspected and a gross motor examination was performed. It was apparent then that the patient was unable to lift her left arm and left leg up. A bedside glucose was checked and it was normal (6.2 mmol/L). An urgent discussion with Stroke team was made and a code stroke was activated. A CT brain and perfusion CT scan revealed right middle cerebral artery (MCA) territory infarct. The patient was thrombolysed and was transferred to a stroke centre. A junior doctor who just finished a rotation in mental health working in suburban ED which sees a great number of mental health presentations easily had fallen into the trap of ‘Deformation Professionnelle Bias’. In this case, an optimal outcome was obtained from the senior doctor’s gestalt prompting a repeat assessment of patient which in turn led to the timely intervention required by the patient.

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18.3 Case 2 A 44-year-old female presents to ED with left-sided chest pain and exertional dyspnoea. The symptoms started 6 h ago while she was sitting down having a cup of coffee. The chest pain is pleuritic and worse upon deep inspiration. No recent history of upper respiratory tract infection, fever or long-haul travel is reported. No urinary or gastrointestinal symptoms are present either. She has a past history of hypercholesterolemia and depression. She is an active smoker. No family history of ischemic heart disease or stroke is reported. She is not on any regular medication. She states that she has been stressed lately at work. Her vital signs are Temp: 36.6°C, HR 98/min (regular), BP 135/80 mmHg, RR 20/min and SaO2 95% on room air. Her cardiovascular examination is normal and her abdomen is soft and non-tender. There is no calf swelling or pedal oedema. ECG shows a sinus rhythm with HR of 100/min. Blood tests are performed and a Troponin I of 0.13  μg/mL (0.00–0.08) is found. A  Chest  X-ray is reported as normal. The patient is referred to Cardiology unit with the diagnosis of Non-ST Elevation Myocardial Infarction (NSTEMI). She is treated with dual antiplatelet therapy, but anticoagulation is withheld to facilitate cardiac catheterisation. A left heart catheterisation is performed the next morning and reported as normal. Patient’s chest pain is reduced with analgesia during admission, but she has had ongoing dyspnoea. Her care is transferred to the general medicine unit for further investigation of dyspnoea. During the ward round the next day by the  general medical team, the patient is noted to be dyspnoeic at rest and her oxygen saturation dropped to 90% on room air. Supplemental oxygen is applied and her symptoms improve. A CT Pulmonary Angiogram (CTPA) is obtained which shows segmental pulmonary embolism. The patient is then managed accordingly and screening tests for unprovoked pulmonary embolism are performed. She is discharged after 2 days with the plan of continuation of anticoagulation and Haematology outpatient clinic follow-up. Given that the patient was admitted under a specialty unit, in this scenario,  a deformation professionnelle bias was observed as well as a search-satisfaction phenomenon in the ED. The correct diagnosis was made eventually since the patient’s clinical picture became conspicuous. Should awareness of these clinical biases be made and corrected early, the patient would have been prevented from unnecessary invasive investigation and would have had a shorter hospital length of stay.

18.4 Case 3 A 51-year-old male was brought to ED after being found unconscious at home by his wife. He had strong smell of alcohol. He was known to have alcohol dependence issues and had been in detox unit two times over past 5 years. He had past history of alcoholic hepatitis 3  years ago, hypercholesterolemia and post-traumatic stress

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disorder. Patient admitted to drinking half a bottle of whisky and some beers. He had no complaint, but was  frequently dozing off to sleep during medical assessment. The patient didn’t answer the question when asked if he was on any regular medications. As per collateral history from the wife, patient was on thiamine, atorvastatin and sertraline. On arrival, his GCS was 13 (E3 V4 M6). The patient seemed dis-shelved and cachectic. His vital signs were HR 110/min, BP 95/68 mmHg, RR 18/min, SaO2 95% on room air. Bedside glucose level was 5.3 mmol/L. No external evidence of head injury was found. He was moving all four limbs and his pupils were equal and reactive. His cardiovascular and respiratory examination were normal. Mild tenderness over epigastrium and right upper quadrant was noted without guarding or rigidity. He had no clinical sign of jaundice or ascites. No spider naevi or flapping tremor were present. Blood tests were performed and the results were as follow: • Full Blood Examination: Hb 139 g/L (110–160), WCC 13.0 × 109/L (4.0–11.0), Platelet 145 × 109/L (150–450) • Liver Function Tests: Total Bilirubin 23  μmol/L(0–20), ALT 192  U/L (5–35), GGT 455 U/L (5–35), ALP 127 U/L (30–110), Albumin 28 g/L (32–47) • UEC: Sodium 133 mmol/L (135–145), Potassium 3.3 mmol/L (3.5–5.2), Urea 7.0 mmol/L (2.8–7.2), Creatinine 88 μmol/L (45–90) • Lipase: 23 U/L (0–60) • Blood Alcohol level: 0.19% A provisional diagnosis of alcohol intoxication was made, and the patient was admitted under Gastroenterology unit due to deranged liver function tests. IV fluid and IV thiamine were administered. Blood tests were repeated the next morning and noted to have worsening liver functions. A hepatobiliary ultrasound was organised and was reported as moderate steatosis. A hepatitis serology was ordered as part of liver screening and the results were still pending. On day 3, the patient started to develop clinical jaundice and as part of supportive therapy, N-acetylcysteine was commenced. A retrospective paracetamol level was requested and the result came back at 2132 μmol/L (