Cognitive Heuristics

1
Cognitive Heuristics

• Vignesh Narayanan, M.D
• Denver Health Medical Center

2

• An expert is a person who has made all the
  mistakes that can be made in a very narrow field
• - Neils Bohr
• I think, therefore I am
• - Descartes,1664

err
3
Heuristics- definition

• Heuriskein to find or discover (Greek)
• subconscious rules of thumb
• shortcuts in diagnostic reasoning
• Eureka has the same origin

4
Case presentation

• 63 y.o female, could speak only Spanish
• CC chest pain, progressive dyspnea
• HPI Chest pain X 2 wks
• sub-sternal, recurrent, episodic
• non-radiating, non-exertional
• worsened by deep inspiration
• Other complaints
• progressive dyspnea x 2 wks
• non-productive cough, no orthopnea/PND
• subjective fevers 3 wks

5
Case continued

• Past medical history
• diabetic, hypertensive
• osteomyelitis of L- 5th toe, amputation 2 mos PTA
  
• CHF diastolic dysfunction, EF gt 55
• CKD baseline creatinine of 1.6
• Medications
• lasix 120 mg BID, stopped 2 wks PTA
• metoprolol, amlodipine, hydralazine, rosuvastatin
• glargine lispro

6
Case continued

• Surgeries
• amputation of L- 5th toe 2 mo PTA
• Social history
• life long non-smoker, no alcohol
• Family history
• mom with heart problems NOS
• ten children
• No allergies

7
Case continued

• Examination
• vitals T36, HR 71, BP 100/75, RR 18
• normal JVP, normal cardiac exam
• bilateral diffuse crackles
• no edema of exts
• left 5th toe amputation site- normal
• Labs/data
• Na 126, BUN 48, Creat 1.9
• WBC 11K, TnI normal
• CxR consistent with pulmonary edema
• EKG NSR, no new changes

8
Case initial A P

• Chest pain/cough
• pleuritic in nature
• c/w acute bronchitis- p.o azithromycin
• SOB Pulmonary edema unlikely given nl JVP
• dry by labs- hyponatremia, BUN/creat ratio
• ? ILD- check PFTs, HRCT, pulmonology consult
• Acute on chronic renal failure Likely volume
  depletion
• check UA, U.lytes, U.Osm
• substantiated by hyponatremia IVF 500 ml NS
• Subjective fevers, mild leukocytosis occult
  infection ?
• recent osteomyelitis- amputation site- well
  healed
• check UA, ESR, CRP

9
Case hospital day 1

• Improvement in symptoms
• Complaint pain over left temple behind ear
• Exam
• HR 81, BP 105/60, RR 18, Sat 92 2L NC
• B/L diffuse crackles
• Labs
• Na 135, creat 1.8, WBC 11K
• CRP 170, ESR 110
• Assessment
• dyspnea, hypoxia, diffuse crackles- ? ILD
• pain L temple, elevated ESR, CRP- ? Temporal
  arteritis/PMR
• Plan
• HRCT, PFTs, rheumatology consult, echo

10
Case hospital day 2

• More pain L temple/behind ear
• More SOB than admit
• Exam
• nl vitals, 93 4L NC
• b/l diffuse crackles
• Other labs
• UA 21-50 WBC
• PFT
• restrictive lung defect
• HRCT
• no ILD
• b/l pleural moderate pericardial effusions
• coronary LAD calcification

• Assessment/plan
• pleuro-pericardial effusions, temple pain, high
  ESR, CRP
• suspect CVD
• echo for dyspnea

11
Case hospital day 2

• Rheumatology
• no evidence of CVD by history or exam
• alternate etiology for high CRP/ESR- r/o
  infection
• tap pleural effusion, check labs
• Pulmonology
• HRCT, PFT abnormalities likely due to
  CHF/pulmonary edema
• diuresce with IV lasix

12
Remaining hospitalization

• Infection W.U
• sinus CT nl mastoid
• foot X ray- no OM
• Treated for UTI
• Dyspnea, O2 sat
• much better with lasix
• Echo
• global hypokinesis
• EF lower than 2 mos ago

• Discharged on day 4
• Diastolic failure with pulmonary edema
• UTI
• Atypical chest pain
• Acute on CKD

13
2 days after discharge

• Outside hospital
• chest pain, dyspnea
• Cardiac arrest in ED
• Coronary angiogram
• near total block of LAD
• PCI
• doing well

14
Summary
elderly woman with Chest pain
investigated for several diagnoses (ILD, CVD,
Infection)
discharged with alternate diagnosis (diastolic
CHF)
Missed diagnosis
eventually diagnosed with different disease
(critical CAD)
15
Cognitive Psychology (of diagnosis )
Therapy
16
Why we take shortcuts
ER doctor
Tom Brady

• Lack of time
• Memory
• rationality is bounded

Lehrer. How We Decide. HMH Press 2009 Simon HA.
Annu Rev. Psychology 1990 411-19
17
Heuristics Shortcuts in diagnostic reasoning
Pitfalls are repetitive impalpable
Reduce time, deliberation
Wrong conclusions
Shortcuts in reasoning
Fever, cough, chest pain Pneumonia
Fever, cough, chest pain Acute PE
18
Availability heuristic

• Does the English language have
• more words that start with the letter r
• (or)
• more words that have the letter r in the third
  position?

Tversky Kahneman- Cognitive Psychology. 19735
207-32
19
Availability Heuristic

• Ease of recalling past cases
• likelihood judged by easily available past egs
  
• More convenient than collecting memorizing
  probabilities

Common diagnoses are common
Un-common diagnoses not considered
High CRP infection, inflammation
High CRP predicts CAD risks
20
Anchoring Heuristic First impression - Best
impression?
Easier than constantly re-integrating evidence
Anchored on lab values (Hyponatremia, CRP) Lack
of one finding (Elevated JVP)
Failure to check for disconfirming evidence
21
Framing Heuristic
atypical CP, serositis suspected ILD ,temple
pain elevated ESR, CRP
DM, recent toe OM bronchitis mastoid pain ?
sinusitis abnormal UA, high CRP
atypical angina, CAD risks new decrease in EF,
pulm edema calcified LAD, high CRP
Collagen vascular Dz
Infectious process
Serious CAD
22
Other heuristics, biases

• Blind Obedience
• Technology
• PFT restrictive lung disease
• Superior authority
• rheumatology- consider infection
• Premature Closure
• reluctance to pursue alternate diagnoses
• using evidence that seems confirmatory
• dismissing evidence that is contradictory

23
Avoiding heuristic biases Problems to
acknowledge

• Many clinicians are unaware of their error
• too distal in time or place
• lack of effective feedback
• Overconfidence
• declining autopsy rates (lt10)
• Sense of pessimism in the literature
• cognitive errors are high hanging fruits
• the search for zero error rates is doomed from
  the start

Redelmeier- Ann Intern Med 2005142115-120
Berner Graber- Am J Med 2008121S2-S23
24
Strategies to minimize heuristic bias
Diagnostic error
Cognitive psychology approach
Normative approach

• - pay more attention
• - be thorough
• practice more
• dont forget this next time

• awareness about heuristic biases
• adding safeguards against reflexive decision
  making

25
Strategies to minimize heuristic bias

• 2 core strategies
• Metacognition
• Cognitive forcing

Gordian Knot
26
Strategy 1 Meta-cognitive training

• Meta-cognition thinking about thinking
• 2 processes occurring simultaneously
• awareness of learning process to monitor progress
  
• adaptive strategies based on progress
• Requires the clinician to
• stand apart from his/her own thinking observe
  it
• recognize opportunities for intervention

If at first the idea does not sound absurd, then
there is no hope for it - Albert
Einstein
Croskerry- Ann Emerg Med. 2003 41 1
27
Metacognition Crystal ball experience
This plan is proven faulty does not work.
Please devise an alternate plan

• Promotes open minded thinking
• Helps to step back and rethink
• Ensures multiple possibilities are considered

Graber et al. Acad Med. 200277(10)981-92
Mitchell DJ- J Behav Decis Making. 1989225-38
28
Strategy 2 Cognitive forcing

• Deliberate, conscious selection of a particular
  strategy in a specific situation to optimize
  decision making and avoid error

Croskerry- Ann Emerg Med. 2003 41 1
29
Some pills for our cognitive ills
Reidelmeier D. Ann Intern Med 2005 142(2)
115-120
Croskerry P. Acad. Med 2003 78 775-780
30
Experts might feel like
31
Summary

• Cognitive short-cuts
• due to lack of time bounded rationality
• Double edged swords
• Overcome by
• metacognition cognitive forcing

32
Thanks!

• Too often the shortcut, the line of least
  resistance, is responsible for evanescent and
  unsatisfactory success
• - Louis Binstock