medical error and cognitive bias - csim...rank# # of times bias 1 17 anchoring 2 16 diagnosis...

Medical Errorand Cognitive Bias

Pat Croskerry MD, PhD

Canadian Society of Internal MedicineAnnual Meeting

Halifax, 2019

CSIM Annual Meeting 2019

Pat Croskerry: Medical Error and Cognitive Bias October 4 2019

The following presentation represents the views of the speakerat the time of the presentation. This information is meant foreducational purposes, and should not replace other sources

of information or your medical judgment.

Learning Objectives

1. Understand the dominant model of decision making – dual process theory2. Appreciate how cognitive biases may distort our decision making3. Appreciate how critical thinking and bias mitigation may improve clinical reasoning and decision making

Makary and Daniel, BMJ 2016

Data source: Xu et al, 2016 NVSS

(National Vital Statistics System)

Estimated number of preventable hospital deaths due to diagnostic

failure annually in the US

40,000 – 80,000

Leape, Berwick and Bates JAMA 2002

For the UK for 2018 this would translate to

9000 – 18,000

Preventable deaths due to diagnostic failure in hospitalized patients

Diagnostic failure is the biggest problem in

patient safety

Newman-Toker, 2017

Many physicians are reluctant to believe this

Diagnostic Failure

15%

Sources of Diagnostic Failure

Graber M, Gordon R, Franklin N. Reducing diagnostic errors in medicine: what’s the goal?

Acad Med. 2002

The Individual75%

The System25%

Kachalla et al, Annals of Emergency Medicine 2007

Presenter

Presentation Notes

ED rate of diagnostic errors is unclear, but probably quite low on the whole: 0.6%

It varies by specialty

DermatologyRadiology (1-2%)Anatomic pathology

Internal medicineFamily medicine (~15%+)Emergency medicine

Diagnosis is the canary in the coal mine for decision failure

Legal outcome by critical incident

0

40

80

120

160

200

240

Perform Comm Diagnosis Admin Medication Conduct

CMPA Data : 347 legal actions closed 2005 - 2009

Number of patients

Presenter

Presentation Notes

Diagnostic issue due to deficient history and general evaluation Failure to perform specific diagnostic tests (cardiac enzymes, spinal diagnostic imaging, EKG, eye exam, head CT, and neurological exam) Misread reports This is measured at the case/patient/Critical Incident CODE level. Illustrates the types of critical incidents a patient encountered and how those incidents faired in terms of favourable/unfavourable outcomes. Note: A patient may have multiple incidents of a particular critical incident (i.e. two or more performance issues accompanied with a medication issue. Three CI’s would be counted in this case, two under performance and one medication). Critical Incidents not reported in this slide - Due to any unacceptable, extraordinary or untoward event that caused injury during the course of care (example is UNTOWARD Critical Incident previously IATRO). Slide Name : S25

Legal outcome by critical incident

0

40

80

120

160

200

240

Perform Comm Diagnosis Admin Medication Conduct

CMPA Data : 347 legal actions closed 2005 - 2009

Presenter

Presentation Notes

Diagnostic issue due to deficient history and general evaluation Failure to perform specific diagnostic tests (cardiac enzymes, spinal diagnostic imaging, EKG, eye exam, head CT, and neurological exam) Misread reports This is measured at the case/patient/Critical Incident CODE level. Illustrates the types of critical incidents a patient encountered and how those incidents faired in terms of favourable/unfavourable outcomes. Note: A patient may have multiple incidents of a particular critical incident (i.e. two or more performance issues accompanied with a medication issue. Three CI’s would be counted in this case, two under performance and one medication). Critical Incidents not reported in this slide - Due to any unacceptable, extraordinary or untoward event that caused injury during the course of care (example is UNTOWARD Critical Incident previously IATRO). Slide Name : S25

The complexity of diagnostic reasoning

Gender

Ethnicity

Perseverance

Mindfulness

Reflection

Age

Intellect ActiveOpen-minded

Culture Critical thinkingRationality

Adaptiveness

Experience

Experientiality

Need for cognition

PersonalityLogicality

Metacognition

BA

C

Fatigue Cognitive load

Sleep deprivation

Sleep debtStress

Affectivestate

Teamfactors

Lateral thinking

Religion

Knowledge

DSystem design

IT

Communication

Scheduling

ESymptoms Signs

Pathognomonicity

Co-morbidities

Progression

FPatient

Family

Friends

CaregiversOnset

Ergonomic factors

MimicsOther

patients

Understanding clinical decision making

Dual Process Theory

Decision Making

Intuitive (System 1)

Rational(System 2)

Fast Informal

SubjectiveContext-dependent

QualitativeFlexible

SlowFormal

ObjectiveContext-independent

QuantitativeRigourous

Dual Process Decision Making

Dual Process Decision Making

System 1: Automatic/streamlined System 2:Cautious/complex

Presenter

Presentation Notes

My metaphor is a carbon fibre racing bicycle. It is awesome on a smooth road, with a great field of vision, no sharp turns and in great weather. Take it mountain biking in the mud and you are in trouble! When using system 1, action is triggered by fewer information points (more weak points, or fewer strong ones); the action threshold for system 2 is higher.

Axial view of fMRI activation of the brain as a function of practice over 60 minutes

Hill and Schneider, 2006

A schematic model of how the systems work together

Pattern Recognition

Repetition

Executiveoverride

Irrationaloverride Calibration Diagnosis

PatientPresentation

RECOGNIZED

NOTRECOGNIZED

Type1

Processes

Type2

Processes

TPattern

Processor

95%95%

5%

“Getting” medicine is not easy

Decision making involves learning the basic patterns

COW

“Getting” medicine is not easy

The best calibrated decisions are described as

‘rational’ – they come from a blend of System 1 and

System 2 decisions

Being rational

The best possible decision given the available evidence and the prevailing conditions

Assuming you are well-slept, well-rested, well-fed, and can give the problem your undivided attention

And you are aware of and know how to deal with bias i.e. have the ‘mindware’

Mindware

The software of the brain

Processing problems Content problems

Mindwarecontamination

Mindware gaps

Cognitive miserliness

WYSIATIMinimising cognitive effort

Accepting things at face valueInsufficient breadth and depth

Avoiding complexity

Failures of tools of rationalityKnowledge deficits

Impaired scientific thinkingImpaired probability thinking

Being illogical

Knowledge deficitsImpaired scientific thinking

Impaired probability thinkingIgnoring alternate hypothesesSub-optimal critical thinking

Cognitive biasesCultural conditioning

Group cultureIllogical reasoningEgocentric thinking

(Hasty judgments)Hasty Judgments Distorted Probability estimates

Biased Judgments

RationalityFailure

Biased Judgments

Dobler et al, BMJEBM 2018

A root cause analysis of thinking

The Behaviour of Biases

Detailed cognitive analysis of 42 cases from EM Biases are common – 232 instances Few instances of knowledge-based errors Usually 5-6 per case Typically appear at certain points in the diagnostic

process

Top 12Rank# # of times Bias

1 17 Anchoring2 16 Diagnosis Momentum3 14 Confirmation Bias4 13 Unpacking Failure5 12 Search Satisficing6 12 Framing7 11 Ascertainment Bias8 11 Psych-Out Error9 10 Fundamental Attribution Error10 10 Triage Cueing11 9 Premature Closure12 9 Omission Error

Breakdown by discipline (42 cases)

• Medicine 18• Neurosurgery 5• Surgery 6• Ophthalmology 3• Orthopedics 3• ObGyn 2• Urology 2• Psychiatry 1

Cognitive autopsy of a medical case

Case A 21 y/o male arrives at the ED with multiple stab wounds to the chest, arms and

head. One of the chest wounds is inferior to the L scapular. OE: Talking, cooperative, inebriated, no dyspnoea or SOB, AE = bilaterally, 02

Sat N; 130/80, HR 80-90. Lac on scapula deep – local wound exploration did not penetrate the pleural cavity, ribs palpable with pleura behind. EDTUS: good views, no free fluid. Serial abdominal exams N, rectal exam N. CXR N.

Lacerations irrigated, explored, and repaired. Discharge Dx: Stab wound chest. D/C Home

5 days later presented to a different hospital with vomiting, blurred vision and difficulty concentrating

CT scan of brain

Cognitive biases

Anchoring: locking onto specific features of a problem and failing to adjust to other aspectsSearch satisficing: after potentially most serious injury is addressed, search is called off for other serious injuries. Posterior probability error: vast majority of scalp wounds previously seen have been benign and WYSIATI.Overconfidence (hubris): Resident is in year 5Cognitive miserliness: ED very busy, fatigue, sleep deprivation, dysphoria

Ambient Dx Risk Situations

• Cognitive overloading• Interruptions/distractions• Sleep deprivation/sleep debt• Negative mood• Fatigue

Main Points

The barometer for failed clinical reasoning is diagnostic failure The current estimate of diagnostic failure is 10-15% The sources of diagnostic failure are the System (25%) and the Individual

(75%) The principle source of individual failure is how the individual thinks and

less what they know The main factor that determines thinking competence is rationality A major cause of rationality failure is vulnerability to cognitive bias Medical education needs to promote rationality

No longer an option…

medical error and cognitive bias - csim...rank# # of times bias 1 17 anchoring 2 16 diagnosis...

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