Diagnostic error

Diagnostic Error How EP Doctor Thinks Dr.Idris Al Farsi Senior Consultant Adult Emergency Department – Royal Hospital

Outlines Introduction Why thinking is important? Rate Diagnostic Error in ED Why is the ED especially error-prone Approaches to Decision Making Dual process theory approach to decision making Practical Suggestions to Improve the Way That EPs Think References

Introduction "The emergency department is a natural laboratory for the study of error,“ Croskerry suggested that the ED, with its multiple interacting processes in the context of high degrees of uncertainty, is a uniquely error-prone environment. Croskerry P. Critical thinking and decisionmaking: avoiding the perils of thin-slicing. Ann Emerg Med. 2006;48:720-722

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

Croskerry's recent study on critical thinking and decision making categorized errors seen in EDs in the United States, Canada, and Australia. He was able to identify 25 processes that contribute to errors. Approximately half of these processes were individual mistakes -- faulty decision making, mistriage, and cognitive and emotional biases -- and all involve the way that EPs think.

Diagnostic Error Diagnostic error is the most important source of adverse events in the ED, where there is a discrepancy between clinical diagnosis and postmortem findings 20% to 40% of the time. Overall, according to Croskerry, 50% of closed malpractice claims are due to misdiagnosis. According to a recent study of malpractice claims due to diagnostic failure, 48% resulted in serious harm and 39% in death. 75 to 95% of these error are preventable 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. Ann Emerg Med. 2007;49:196-205

Why is the ED especially error-prone? Most patients are strangers; they present with atypical manifestations decisions of care must be made within limited period of time. history may be sparse or unobtainable, definitive studies are often not available for potentially life-threatening conditions. EP must make multiple decisions on a number of patients simultaneously, with differing degrees of acuity. The density of decision making is greater in the ED than any other area of medicine.

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

Error-Producing Conditions in the ED As in all organizations, there are system errors and intrinsic errors in the ED. System errors includes: physical design: structure and equipments. process design. ED overcrowding and boarding, unpredictable patient surges. inadequate staffing. For these issues protocols and proactive management can help move toward their resolution.

the potential sources for intrinsic errors include: High levels of diagnostic uncertainty; "Decision density," or the volume of decisions that are made in a given amount of time; A high amount of cognitive load needed to process a large volume of data; Narrow time windows for patient assessment; Multiple care transitions for any given patient; A multitude of interruptions and distractions throughout the thought process.

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

the "signal-to-noise ratio" in the ED the danger of "attributional judgments," which involve premature labeling and/or categorizing patients and which can solidify a mistaken diagnosis

So it is important To understand why misdiagnosis occurs, and which underlying patterns of thinking can lead to misdiagnosis.

What is the significance of the high cognitive load?

Urgency of Decision Making Every case seen in the ED requires a hierarchy of decisions, and each of these must be accompanied by a second analysis to determine whether the action is to be expedient or delayed. Does the patient need immediate airway control, or can we use a temporizing measure (noninvasive ventilation)? Each decision must also be judged as to whether it is major or minor and assigned a priority level. If a diagnosis is missed, will it have catastrophic results? Is the decision clinical or managerial?

Having to make many decisions in a context of limited and ambiguous data, EPs must recognize patterns of their thought processes and impediments to correct their reasoning The majority of diagnostic failures, probably over 75%, can be attributed to physician thinking failure (Graber 2005) Graber, M. (2005). Diagnostic errors in medicine. Joint Commission Journal on Quality and Patient Safety, 31(2), 106–113

"cookbook" approach One method of clinical decision making is the "cookbook" approach, in which EPs employ algorithms or clinical decision rules in order to arrive at a diagnosis. This approach is useful and often necessary in high-stress moments, as in with clear emergencies, such as multiple trauma or ventricular arrhythmia. However, algorithms take the thinking out of decision making, which may be the safest approach in these situations.

Intuitive Approach similar to "gut feelings." This thinking is characterized by mental shortcuts and tends to be reflexive and automatic. The experienced physician will often recognize patterns of disease presentation, rapidly come to diagnostic closure, and proceed with a treatment plan. It is efficient, but not reliable. Predictive power is not strong and there may be an emotional component that influences the conclusion.

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

Clustering of approaches on an intuitive-analytical continuum at unconscious

Dual process theory approach to decision making in some circumstances, an intuitive approach may be appropriate, whereas in others an analytical approach might be preferred (Simon 1990), and at times a blend of the two may be optimal

" dual - process thinking ."

As noted, dynamic oscillation may occur between the two systems. Stanovich (Stanovich 2004) describes four major operating features of the model. 1. Repetitive operation of a particular process using Type 2 reasoning may allow it to be relegated to a Type 1 level of automaticity. 2. Type 1 processes may override Type 2 for a variety of reasons including irrational behaviors. 3. Type 2 reasoning may override Type 1 in a surveillance/governor-like fashion. 4. There is an overall tendency for the system to default to the state requiring the least cognitive effort, the ‘cognitive miser’ function.

Diagnostic failure There are several loci in the model where the diagnostic process might fail

Firstly, the pattern associated with the initial presentation might be misidentified the rash of herpes zoster and the rash of poison oak. ureteral colic but, in fact, may be a dissecting aneurysm. acute pericarditis or myocardial infarction. The veracity of pattern recognition depends mostly on how manifest the features of a particular disease are (i.e. its pathogonomicity), as well as on the clinician’s prior experience with it. Diseases or conditions with poorly differentiated features are easily mimicked and physician calibration may suffer in consequence

Secondly, the over-learning that occurs through repeated processing in Type 2 and allows the response to default to Type 1 might occur prematurely. With limited experience, the clinician might be overconfedent that the pattern is one that is recognized i.e. an error of representativeness occurs. Instead, exposure to more exemplars would satisfy the Law of Large Numbers which says that more experience will generally reveal more exceptions to the rule, and perhaps invite more caution.

Thirdly, the surveillance/monitoring performance of Type 2 over Type 1 may become compromised for a variety of reasons. Cognitive overload, occurring at times of extreme busyness, Other factors such as fatigue, sleep deprivation, Physician mood and affect

Fourthly, there are many instances in which Type 1 processes override Type 2 reasoning in medical practice Most commonly occur in over confidence and dysrationalia dysrationalia, ‘…a level of rationality, as demonstrated in thinking and behavior, that is signifcantly below the levelof the individual’s intellectual capacity…’ (Stanovich 1993) acting against one’s better judgment, or when, despite knowing what the best thing to do is, one does something else

How can dual process models mitigate diagnostic error? An understanding of the model allows for more focused metacognition i.e. the decision maker can identify which system they are currently using and determine the appropriateness and the relative benefits of remaining in that mode versus switching to the other

Practical Suggestions to Improve the Way That EPs Think Reduce reliance on memory : Use cognitive aids, handheld devices, mnemonics, and algorithms. Learn to use metacognition for a reflective approach to problem solving : This entails the ability to step back from the immediate problem to examine the way the thought process has led to the conclusion. Optimize ambient work conditions: Understand the way in which thought processes can be impaired by noise levels, sleep deprivation, staffing patterns, and lack of accessible treatment protocols. Provide clinical decision support and ongoing feedback: This is necessary to understanding how cognitive errors occur and how to use dual-process thinking.

References 1 . Croskerry P . Critical thinking and decisionmaking : avoiding the perils of thin - slicing . Ann Emerg Med . 2006;48:720-722 . Abstract 2 . Brennan TA, Leape LL, Laird NM, et al . Incidence of adverse events and negligence in hospitalized patients . N Engl J Med . 1991;324:370-376 . Abstract 3 . 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 . Ann Emerg Med . 2007;49:196-205 . Abstract 4. Robert D. Glatter,; Richard E. Martin,; Joseph Lex,, How Emergency Physicians Think Medscape Emergency Medicine. 2008 5. Pat Croskerry, Clinical cognition and diagnostic error: applications of a dual process model of reasoning , Adv in Health Sci Educ (2009) 14:27–35

Diagnostic error

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