Transcript Error Shortlist

Cognitive Error
The 2012 shortlist
Over-attachment to a particular diagnosis
• Anchoring = (The most common biases)
– ‘Jumping to conclusions based on first impression’
– ‘Premature Closure’
• Confirmation Bias = searching only for confirmatory
evidence to support early conclusions
– Interpretation of ambiguous evidence as supporting their existing
position
– greater reliance on information encountered first in a series
• Sunk Costs (‘Concorde fallacy’)
Two specific features:
- An overly optimistic probability bias
- Sunk cost appears to operate chiefly in those who feel personal
responsibility for the investments that are to be viewed as sunk.
• Colloquially known as "throwing good money after bad".
Concorde Fallacy
The sunk cost fallacy , also known as the
"Concorde Fallacy” , refers to the British
and French governments continued
funding of the joint development of the
Concorde even after it became apparent
that there was no longer an economic
case for the aircraft. The project was
regarded privately by the British
government as a "commercial disaster"
which should never have been started.
Failure to consider alternative Diagnoses
• Representativeness Restraint
– Looking only for classic presentation
– “Doesn’t quack so it can’t be a duck”
– Common in inexperienced clinicians
• Sutton’s slip
– Sutton’s Law - “go where the $ is.”
– Going for the obvious, dismissing inconsistent data
and other possibilities
– E.g. Chest pain and ECG suggest AMI. Missing wide
mediastinum on CXR and aortic dissection.
Error due to Inheriting Someone else’s thinking
• Diagnostic Momentum
– Handover prone time
• Bandwagon effect
– As more people come to believe in
something, others also "jump on the
bandwagon" regardless of the underlying
evidence
Other
• Attentional Bias
– We normally give increased attention or hyperattention to both attractive and threatening materials.
In cognitive psychology attentional bias refers to
hyper-attention to threatening information despite the
absence of evidence that the threat may be
unrealistic.
– suggestion a hyper-vigilant cognitive style that gives
high processing priorities to threat-related stimuli,
thereby promoting escalation of fear
Error in Prevalence Perception or
Estimation
• Playing the odds
• Posterior Probability Error
– Applying what happened previously without
searching for new evidence
– e.g assuming migraine when meningitis or
SAH
Errors Involving Patient Characteristics or
presentation Context
• Psych-out Error
– patient’s symptoms attributed to psychiatric illness or condition (similar
to attribution error)
• Triage cueing
– Patient location affects the differential diagnosis e.g. Wait Room v
Resus
• Yin-Yang out
– “has been worked up the ying-yang”
• process may have evolved
• may be a new/different process
• fresh approach/unbiased thinking required
• Visceral bias
– influence of affective sources of error on decision making; as with
countertransference, negative and positive feelings toward patients may
result in diagnoses being missed
Errors associated with physician affect
personality or decision style
• Commission Bias
– Inappropriate urge toward action
– Common if patient colleague/ healthcare worker
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Overconfidence Bias
Belief Bias
Ego Bias
Zebra Retreat
– Retreat from rare diagnosis
– “Nah, it can’t be.”
– Especially if timely diagnosis is important
Case 1
Patient fell 15 ft from ladder onto concrete; brought by ambulance to ED
without immobilization; x-rays of both ankles showed fractured right ankle
(swollen and deformed); referred to ortho who put on walking cast; 6 wk
later, cast removed (patient complaining of foot pain); 4 wk later, foot x-ray
(ordered by another physician) revealed calcaneal fracture; orthopedic shoe
ineffective; bone fusion required
Analysis: considerations in fall from height—calcaneal fracture; injuries to
lumbar spine; jump (suicide attempt)
Errors:
• deficient knowledge (about falls from heights)
• search satisficing (ankle fracture found, no search for other injuries; 15%20% of traumatic injuries missed on initial examination)
• diagnostic anchoring (orthopaedic team fixated on ankle fracture, despite
further information about foot pain)
• diagnosis momentum (diagnostic label of ankle fracture stuck to patient
• premature diagnostic closure (once diagnosis made, no investigation of
further complaints)
Case 2:
Patient presents to ED with stroke-like symptoms; stroke protocol started; computed tomography (CT)
appeared normal; ED physician makes diagnosis of conversion reaction and gives psychiatric
referral; symptoms improved, then worsened next day, and she presented to same ED; subtle
findings and positive Babinski reflex; diagnosed with conversion disorder again and referred to
psychiatric institute; ED physician noted patient “medically cleared and otherwise stable,” but
requested electroencephalography (EEG) and neurology consult (cancelled by staff psychiatrist);
no further tests ordered; repeated falls, urinary incontinence, and confusion during 3 wk as
psychiatric inpatient; discharged to outpatient mental health facility despite poor ambulation; 18
days later, patient had severe disabling stroke; neurologist diagnosed stroke secondary to
thrombotic thrombocytopenic purpura (TTP; cause of psychiatric symptoms)
Analysis:
•
psych-out error—all problems attributed to psychiatric diagnosis (patient had no previous
psychiatric problems); term “medical clearance”—misleading and medicolegally dangerous;
implies no organic basis for patient’s condition; better to describe patient as stabilized; caveat—
physician should never rely on another physician to do his or her work; ED physician should have
obtained neurologic consult himself; error to think problem neurologic, yet admit patient to
psychiatric facility;
•
other errors—diagnosis momentum; premature diagnostic closure (conversion disorder diagnosis
of exclusion); once patient in psychiatric care, one-half of major medical diagnoses missed, so ED
physician must rule out medical causes for delirium or confusion;
•
errors of staff psychiatrist—vertical line thinking (concentrated on conversion disorder despite
patient’s ataxia and urinary incontinence); overconfidence (canceled neurologic consult and EEG);
diagnostic anchoring; premature closure
Case 3:
Patient (39-yr-old woman) has history of 9 ED visits for complaints of chest pain
during 6 mo following motor vehicle accident (MVA); no steps taken to
diagnose chest pain; patient repeatedly told pain result of MVA trauma;
patient had family history of risk factors (not obtained) and was smoker;
patient had fatal cardiac arrest; $2 million awarded
Analysis of case 3:
• fundamental attribution error—patient labeled “frequent flyer”; problem
attributed to disposition of patient rather than to underlying medical
condition; malingering, secondary gain, possible drug-seeking behavior, all
attributed to patient over series of visits
• negative countertransferance—ED physician develops dislike of patient
because of repeated visits
• diagnostic anchoring—also fostered by repeat visits; posterior probability
error—seventh, eighth, and ninth physicians to see patient continue
diagnosis of chest wall pain from MVA
• other errors—diagnostic momentum; premature diagnostic closure
• possible solutions—ECG at triage; risk factor analysis; observation unit; low
threshold for stress testing in patients complaining of chest pain