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Page 1: Diagnostic error
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Diagnostic ErrorDiagnostic Error How EP Doctor Thinks How EP Doctor Thinks

Dr.Idris Al FarsiDr.Idris Al Farsi

Senior ConsultantSenior Consultant

Adult Emergency Department – Royal Adult Emergency Department – Royal HospitalHospital

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OutlinesOutlines IntroductionIntroduction Why thinking is important?Why thinking is important? Rate Diagnostic Error in EDRate Diagnostic Error in ED Why is the ED especially error-proneWhy is the ED especially error-prone Approaches to Decision MakingApproaches to Decision Making Dual process theory approach toDual process theory approach to

decision makingdecision making Practical Suggestions to Improve the Way Practical Suggestions to Improve the Way

That EPs ThinkThat EPs Think ReferencesReferences

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IntroductionIntroduction "The emergency department is a natural "The emergency department is a natural

laboratory for the study of error,“laboratory for the study of error,“

Croskerry suggested that the ED, with its Croskerry suggested that the ED, with its multiple interacting processes in the multiple interacting processes in the context of high degrees of uncertainty, is a context of high degrees of uncertainty, is a uniquely error-prone environment. uniquely error-prone environment.

Croskerry P. Critical thinking and decisionmaking: avoiding the perils of thin-slicing. Croskerry P. Critical thinking and decisionmaking: avoiding the perils of thin-slicing. Ann Emerg Med. 2006;48:720-722Ann Emerg Med. 2006;48:720-722

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Why thinking is importantWhy thinking is important??

The underlying patterns of thinking The underlying patterns of thinking that can lead to misdiagnosis are that can lead to misdiagnosis are crucial for EPs to understand and crucial for EPs to understand and incorporate into training programs.incorporate into training programs.

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Croskerry's recent study on critical Croskerry's recent study on critical thinking and decision making thinking and decision making categorized errors seen in EDs in the categorized errors seen in EDs in the United States, Canada, and Australia. United States, Canada, and Australia.

He was able to identify 25 processes He was able to identify 25 processes that contribute to errors. that contribute to errors.

Approximately half of these processes Approximately half of these processes were individual mistakes -- faulty were individual mistakes -- faulty decision making, mistriage, and decision making, mistriage, and cognitive and emotional biases -- and cognitive and emotional biases -- and all involve the way that EPs think. all involve the way that EPs think.

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Diagnostic ErrorDiagnostic Error Diagnostic error is the most important source of Diagnostic error is the most important source of

adverse events in the ED, where there is a adverse events in the ED, where there is a discrepancy between clinical diagnosis and discrepancy between clinical diagnosis and postmortem findings 20% to 40% of the time. postmortem findings 20% to 40% of the time.

Overall, according to Croskerry, 50% of closed Overall, according to Croskerry, 50% of closed malpractice claims are due to misdiagnosis. malpractice claims are due to misdiagnosis.

According to a recent study of malpractice claims According to a recent study of malpractice claims due to diagnostic failure, 48% resulted in serious due to diagnostic failure, 48% resulted in serious harm and 39% in death.harm and 39% in death.

75 to 95% of these error are preventable75 to 95% of these error are preventable

Kachalia A, Gandhi TK, Puopolo AL, et al. Missed and delayed diagnoses in the Kachalia A, Gandhi TK, Puopolo AL, et al. Missed and delayed diagnoses in the emergency department: a study of closed malpractice claims from 4 liability insurers. emergency department: a study of closed malpractice claims from 4 liability insurers. Ann Emerg Med. 2007;49:196-205 Ann Emerg Med. 2007;49:196-205

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Why is the ED especially error-Why is the ED especially error-proneprone??

Most patients are strangers; they present with Most patients are strangers; they present with atypical manifestations atypical manifestations

decisions of care must be made within limited decisions of care must be made within limited period of time. period of time.

history may be sparse or unobtainable, history may be sparse or unobtainable, definitive studies are often not available for definitive studies are often not available for

potentially life-threatening conditions. potentially life-threatening conditions. EP must make multiple decisions on a number of EP must make multiple decisions on a number of

patients simultaneously, with differing degrees of patients simultaneously, with differing degrees of acuity. acuity.

The density of decision making is greater in the The density of decision making is greater in the ED than any other area of medicine.ED than any other area of medicine.

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black box approachblack box approach

This "black box This "black box approach" inherent approach" inherent in the practice of in the practice of emergency medicine emergency medicine makes it difficult to makes it difficult to gain insight and gain insight and develop critical develop critical thinking skills in thinking skills in either training or in either training or in the practice. the practice.

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Error-Producing Conditions in the Error-Producing Conditions in the EDED

As in all organizations, there are system As in all organizations, there are system errors and intrinsic errors in the ED. errors and intrinsic errors in the ED.

System errors includes:System errors includes: physical design: structure and equipments.physical design: structure and equipments. process design. process design. ED overcrowding and boarding, unpredictable ED overcrowding and boarding, unpredictable

patient surges.patient surges. inadequate staffing. inadequate staffing.

For these issues protocols and proactive For these issues protocols and proactive management can help move toward their management can help move toward their resolution. resolution.

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the potential sources for intrinsic errors the potential sources for intrinsic errors include: include: High levels of diagnostic uncertainty; High levels of diagnostic uncertainty; "Decision density," or the volume of decisions "Decision density," or the volume of decisions

that are made in a given amount of time; that are made in a given amount of time; A high amount of cognitive load needed to A high amount of cognitive load needed to

process a large volume of data; process a large volume of data; Narrow time windows for patient assessment; Narrow time windows for patient assessment; Multiple care transitions for any given patient; Multiple care transitions for any given patient; A multitude of interruptions and distractions A multitude of interruptions and distractions

throughout the thought process. throughout the thought process.

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Other Error-Producing ConditionsOther Error-Producing Conditions

• • Novel or infrequently occurring situations Novel or infrequently occurring situations • • Time limitations for detection and correction of error Time limitations for detection and correction of error • • Low signal-to-noise ratio Low signal-to-noise ratio • • Overcrowding/channel capacity overload Overcrowding/channel capacity overload • • Mismatch between real and perceived risk Mismatch between real and perceived risk • • Poor feedback Poor feedback • • Poor quality of person-to-person information transfer Poor quality of person-to-person information transfer • • Experience, training, or education limitations Experience, training, or education limitations • • Disruption of circadian rhythms by shift work Disruption of circadian rhythms by shift work • • Compromised task pacing through interruptions or Compromised task pacing through interruptions or

interventions interventions • • High physical and emotional stress levels High physical and emotional stress levels

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the "signal-to-noise ratio" in the EDthe "signal-to-noise ratio" in the ED the danger of "attributional the danger of "attributional

judgments," which involve premature judgments," which involve premature labeling and/or categorizing patients labeling and/or categorizing patients and which can solidify a mistaken and which can solidify a mistaken diagnosisdiagnosis

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So it is importantSo it is important

To understand To understand

1.1. why misdiagnosis occurs, and why misdiagnosis occurs, and

2.2. which underlying patterns of which underlying patterns of thinking can lead to misdiagnosis. thinking can lead to misdiagnosis.

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What is the significance of the high What is the significance of the high cognitive loadcognitive load ? ?

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Urgency of Decision MakingUrgency of Decision Making Every case seen in the ED requires a hierarchy of Every case seen in the ED requires a hierarchy of

decisions, and each of these must be decisions, and each of these must be accompanied by a second analysis to determine accompanied by a second analysis to determine whether the action is to be expedient or delayed. whether the action is to be expedient or delayed.

Does the patient need immediate airway Does the patient need immediate airway control, or can we use a temporizing measure control, or can we use a temporizing measure

(noninvasive ventilation)? (noninvasive ventilation)? Each decision must also be judged as to whether Each decision must also be judged as to whether

it is major or minor and assigned a priority level. it is major or minor and assigned a priority level. If a diagnosis is missed, will it have catastrophic If a diagnosis is missed, will it have catastrophic

results? results? Is the decision clinical or managerial? Is the decision clinical or managerial?

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Having to make many decisions in a Having to make many decisions in a context of limited and ambiguous data, context of limited and ambiguous data, EPs must recognize patterns of their EPs must recognize patterns of their thought processes and impediments to thought processes and impediments to correct their reasoningcorrect their reasoning

The majority of diagnostic failures, The majority of diagnostic failures, probably over 75%, can be attributed to probably over 75%, can be attributed to physician thinking failure (Graber 2005)physician thinking failure (Graber 2005)

Graber, M. (2005). Diagnostic errors in medicine. Joint Commission Journal on Quality and Graber, M. (2005). Diagnostic errors in medicine. Joint Commission Journal on Quality and Patient Safety, 31(2), 106–113Patient Safety, 31(2), 106–113

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Approaches to Decision MakingApproaches to Decision Making

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""cookbook" approachcookbook" approach

One method of clinical decision making is One method of clinical decision making is the "cookbook" approach, in which EPs the "cookbook" approach, in which EPs employ algorithms or clinical decision employ algorithms or clinical decision rules in order to arrive at a diagnosis. rules in order to arrive at a diagnosis.

This approach is useful and often This approach is useful and often necessary in high-stress moments, as in necessary in high-stress moments, as in with clear emergencies, such as multiple with clear emergencies, such as multiple trauma or ventricular arrhythmia. trauma or ventricular arrhythmia.

However, algorithms take the thinking out However, algorithms take the thinking out of decision making, which may be the of decision making, which may be the safest approach in these situations. safest approach in these situations.

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Intuitive ApproachIntuitive Approach similar to "gut feelings." similar to "gut feelings." This thinking is characterized by mental shortcuts This thinking is characterized by mental shortcuts

and tends to be reflexive and automatic. and tends to be reflexive and automatic. The experienced physician will often recognize The experienced physician will often recognize

patterns of disease presentation, rapidly come to patterns of disease presentation, rapidly come to diagnostic closure, and proceed with a treatment diagnostic closure, and proceed with a treatment plan. plan.

It is efficient, but not reliable. It is efficient, but not reliable. Predictive power is not strong Predictive power is not strong and there may be an emotional component that and there may be an emotional component that

influences the conclusion.influences the conclusion.

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Analytic ApproachAnalytic Approach

analytic, slow, and rational. analytic, slow, and rational. There is less opportunity for error; There is less opportunity for error; predictive power is strong;predictive power is strong; and emotional components are and emotional components are

minimized. minimized.

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Clustering of approaches on an intuitive-analytical continuum at Clustering of approaches on an intuitive-analytical continuum at unconsciousunconscious

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Dual process theory approach toDual process theory approach todecision makingdecision making

in some circumstances, an intuitive in some circumstances, an intuitive approach may be appropriate,approach may be appropriate,

whereas in others an analytical whereas in others an analytical approach might be preferred (Simon approach might be preferred (Simon 1990), 1990),

and at times a blend of the two may and at times a blend of the two may be optimalbe optimal

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""dualdual--process thinkingprocess thinking."."

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As noted, dynamic oscillation may occur As noted, dynamic oscillation may occur between the two systems. between the two systems.

Stanovich (Stanovich 2004) describes four Stanovich (Stanovich 2004) describes four major operating features of the model.major operating features of the model.

1. Repetitive operation of a particular process 1. Repetitive operation of a particular process using Type 2 reasoning may allow it to be using Type 2 reasoning may allow it to be relegated to a Type 1 level of automaticity.relegated to a Type 1 level of automaticity.

2. Type 1 processes may override Type 2 for a 2. Type 1 processes may override Type 2 for a variety of reasons including irrational variety of reasons including irrational behaviors.behaviors.

3. Type 2 reasoning may override Type 1 in a 3. Type 2 reasoning may override Type 1 in a surveillance/governor-like fashion.surveillance/governor-like fashion.

4. There is an overall tendency for the system to 4. There is an overall tendency for the system to default to the state requiring the least default to the state requiring the least cognitive effort, the ‘cognitive miser’ function.cognitive effort, the ‘cognitive miser’ function.

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Diagnostic failureDiagnostic failure

There are several loci in the model There are several loci in the model where the diagnostic process might where the diagnostic process might failfail

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Firstly, the pattern associated with Firstly, the pattern associated with the initial presentation might be the initial presentation might be

misidentifiedmisidentified the rash of herpes zoster and the the rash of herpes zoster and the

rash of poison oak. rash of poison oak.

ureteral colic but, in fact, may be a ureteral colic but, in fact, may be a dissecting aneurysm. dissecting aneurysm.

acute pericarditis or myocardial acute pericarditis or myocardial infarction. infarction.

The veracity of pattern recognition The veracity of pattern recognition depends mostly on how manifest depends mostly on how manifest the features of a particular disease the features of a particular disease are (i.e. its pathogonomicity), as are (i.e. its pathogonomicity), as well as on the clinician’s prior well as on the clinician’s prior experience with it.experience with it.

Diseases or conditions with poorly Diseases or conditions with poorly differentiated features are easily differentiated features are easily mimicked and physician calibration mimicked and physician calibration may suffer in consequence may suffer in consequence

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Secondly, the over-learning that Secondly, the over-learning that occurs through repeated processing in occurs through repeated processing in Type 2 and allows the response to Type 2 and allows the response to default to Type 1 might occur default to Type 1 might occur prematurely. prematurely. With limited experience, the clinician With limited experience, the clinician

might be overconfedent that the pattern might be overconfedent that the pattern is one that is recognized i.e. an error of is one that is recognized i.e. an error of representativeness occurs. representativeness occurs.

Instead, exposure to more exemplars Instead, exposure to more exemplars would satisfy the Law of Large Numbers would satisfy the Law of Large Numbers which says that more experience will which says that more experience will generally reveal more exceptions to the generally reveal more exceptions to the rule, and perhaps invite more caution. rule, and perhaps invite more caution.

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""dualdual--process thinkingprocess thinking."."

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Thirdly, the surveillance/monitoring Thirdly, the surveillance/monitoring performance of Type 2 over Type 1 performance of Type 2 over Type 1 may become compromised for a may become compromised for a variety of reasons. variety of reasons.

Cognitive overload, occurring at Cognitive overload, occurring at times of extreme busyness, times of extreme busyness,

Other factors such as fatigue, sleep Other factors such as fatigue, sleep deprivation, deprivation,

Physician mood and affectPhysician mood and affect

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Fourthly, there are many instances in which Type Fourthly, there are many instances in which Type 1 processes override Type 2 reasoning1 processes override Type 2 reasoning

in medical practicein medical practice Most commonly occur in over confidence Most commonly occur in over confidence

and dysrationaliaand dysrationalia dysrationalia, ‘…a level of rationality, as dysrationalia, ‘…a level of rationality, as

demonstrated in thinking and behavior, demonstrated in thinking and behavior, that is signifcantly below the levelof the that is signifcantly below the levelof the individual’s intellectual capacity…’ individual’s intellectual capacity…’ (Stanovich 1993)(Stanovich 1993)

acting against one’s better judgment, or acting against one’s better judgment, or when, despite knowing what the best thing when, despite knowing what the best thing to do is, one does something elseto do is, one does something else

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How can dual process models How can dual process models mitigate diagnostic errormitigate diagnostic error??

An understanding of the model allows An understanding of the model allows for more focused metacognition for more focused metacognition

i.e. the decision maker can identify i.e. the decision maker can identify which system they are currently using which system they are currently using and determine the appropriateness and and determine the appropriateness and the relative benefits of remaining in that the relative benefits of remaining in that mode versus switching to the othermode versus switching to the other

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Practical Suggestions to Improve Practical Suggestions to Improve the Way That EPs Thinkthe Way That EPs Think

Reduce reliance on memoryReduce reliance on memory:: Use cognitive aids, Use cognitive aids, handheld devices, mnemonics, and algorithms.handheld devices, mnemonics, and algorithms.

Learn to use metacognition for a reflective Learn to use metacognition for a reflective approach to problem solvingapproach to problem solving:: This entails the ability to This entails the ability to step back from the immediate problem to examine the step back from the immediate problem to examine the way the thought process has led to the conclusion.way the thought process has led to the conclusion.

Optimize ambient work conditions:Optimize ambient work conditions: Understand the Understand the way in which thought processes can be impaired by noise way in which thought processes can be impaired by noise levels, sleep deprivation, staffing patterns, and lack of levels, sleep deprivation, staffing patterns, and lack of accessible treatment protocols.accessible treatment protocols.

Provide clinical decision support and ongoing Provide clinical decision support and ongoing feedback:feedback: This is necessary to understanding how This is necessary to understanding how cognitive errors occur and how to use dual-process cognitive errors occur and how to use dual-process thinking. thinking.

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ReferencesReferences 11. . Croskerry PCroskerry P. . Critical thinking and decisionmakingCritical thinking and decisionmaking: : avoiding the avoiding the

perils of thinperils of thin--slicingslicing. . Ann Emerg MedAnn Emerg Med. . 2006;48:720-7222006;48:720-722. . Abstract Abstract

22. . Brennan TA, Leape LL, Laird NM, et alBrennan TA, Leape LL, Laird NM, et al. . Incidence of adverse Incidence of adverse events and negligence in hospitalized patientsevents and negligence in hospitalized patients. . N Engl J MedN Engl J Med. . 1991;324:370-3761991;324:370-376. . Abstract Abstract

33. . Kachalia A, Gandhi TK, Puopolo AL, et alKachalia A, Gandhi TK, Puopolo AL, et al. . Missed and delayed Missed and delayed diagnoses in the emergency departmentdiagnoses in the emergency department: : a study of closed a study of closed malpractice claims from 4 liability insurersmalpractice claims from 4 liability insurers. . Ann Emerg MedAnn Emerg Med. . 2007;49:196-2052007;49:196-205. . AbstractAbstract

4. Robert D. Glatter,; Richard E. Martin,; Joseph Lex,, How 4. Robert D. Glatter,; Richard E. Martin,; Joseph Lex,, How Emergency Physicians Think Medscape Emergency Medicine. 2008Emergency Physicians Think Medscape Emergency Medicine. 2008

5. Pat Croskerry, Clinical cognition and diagnostic error: 5. Pat Croskerry, Clinical cognition and diagnostic error: applications of a dual process model of reasoning , Adv in Health applications of a dual process model of reasoning , Adv in Health Sci Educ (2009) 14:27–35Sci Educ (2009) 14:27–35