Mortality _amp; Morbidity Conference

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					Cognitive Heuristics



           Vignesh Narayanan, M.D
           Denver Health Medical Center
 “An expert is a person who has made all the
mistakes that can be made in a very narrow field”
                               - Neils Bohr


               err
            I think, therefore I am
                         - Descartes,1664
              Heuristics- definition


   ‘Heuriskein’ – ‘to find’ or ‘discover’ (Greek)
       subconscious rules of thumb
       shortcuts in diagnostic reasoning


   ‘Eureka’ has the same origin
              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
                  Case: continued

   Past medical history
       diabetic, hypertensive

       osteomyelitis of L- 5th toe, amputation 2 mos PTA

       CHF: diastolic dysfunction, EF > 55%

       CKD: baseline creatinine of 1.6



   Medications:
      lasix 120 mg BID, stopped 2 wks PTA

      metoprolol, amlodipine, hydralazine, rosuvastatin

      glargine & lispro
            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
           Case: continued
   Examination
       vitals: T:36, HR: 71, BP: 100/75, RR: 18

       normal JVP, normal cardiac exam

       bilateral diffuse crackles

       no edema of ext’s

       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
              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 PFT’s, 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
              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, PFT’s, rheumatology consult, echo
                     Case: hospital day # 2
   More pain L temple/behind ear
   More SOB than admit
   Exam:
          nl vitals, 93% 4L NC            Assessment/plan:
          b/l diffuse crackles                  pleuro-pericardial effusions,
   Other labs                                    temple pain, high ESR,
          UA: 21-50 WBC                          CRP
   PFT:                                         suspect CVD
          restrictive lung defect               echo for dyspnea
   HRCT:
          no ILD
          b/l pleural & moderate
           pericardial effusions
          coronary LAD calcification
               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
     Remaining hospitalization
   Infection W.U
        sinus CT: nl mastoid

        foot X ray- no OM               Discharged on day 4
                                              Diastolic failure with

   Treated for UTI                            pulmonary edema
                                              UTI

   Dyspnea, O2 sat                           Atypical chest pain

       much better with lasix                Acute on CKD



   Echo:
           global hypokinesis
           EF lower than 2 mos ago
2 days after discharge
   Outside hospital
       chest pain, dyspnea



   Cardiac arrest in ED

   Coronary angiogram
       near total block of LAD

       PCI

       doing well
Summary    elderly woman with
               Chest pain



             investigated for
            several diagnoses
          (ILD, CVD, Infection)


             discharged with
           alternate diagnosis
             (diastolic CHF)


          eventually diagnosed
               with different      Missed diagnosis
          disease (critical CAD)
Cognitive Psychology (of diagnosis )


       Diagnosis               Reason




                    Therapy



         Make                 Formulate
        Decisions             Judgments
       Why we take shortcuts
Tom Brady                               ER doctor




      Lack of time
      Memory
        rationality is bounded


                       Lehrer. How We Decide. HMH Press; 2009
                       Simon HA. Annu Rev. Psychology 1990; 41:1-19
   Heuristics: ‘Shortcuts’ in diagnostic reasoning
                                                                 Pitfalls are
                                                                repetitive &
                                                                impalpable




Reduce time, deliberation                            Wrong conclusions




                            Shortcuts in reasoning
                                                     Fever, cough,
                                                      chest pain =
                                                       Acute PE
                                                      Pneumonia
                ‘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. 1973;5: 207-32
             ‘Availability’ Heuristic

   Ease of recalling past cases
     likelihood judged by easily ‘available’ past eg’s



   More convenient than collecting & memorizing
    probabilities



    Common diagnoses                    Un-common diagnoses
    are common                          not considered

                High CRP =        High CRP =
                 infection,        predicts
               inflammation       CAD risks
       ‘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
                             ‘Framing’ Heuristic

                                  DM, recent toe OM
   atypical CP, serositis                  +                  atypical angina, CAD risks
             +                         bronchitis                           +
suspected ILD ,temple pain                 +                new decrease in EF, pulm edema
             +                  mastoid pain: ? sinusitis                  +
   elevated ESR, CRP                       +                    calcified LAD, high CRP
                                abnormal UA, high CRP




 Collagen vascular Dz              Infectious process               Serious CAD
             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
             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 (<10%)



   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 2005;142:115-120
                              ** Berner & Graber- Am J Med 2008;121:S2-S23
      Strategies to minimize heuristic bias

                                Diagnostic error




      Normative                                    Cognitive psychology
      approach                                           approach

- pay more attention                               - awareness about
                                                   heuristic biases
- be thorough
                                                   - adding safeguards
- practice more
                                                   against reflexive decision
- don’t forget this next time                      making
Strategies to minimize heuristic bias


                        2 core strategies
                            Metacognition


                            Cognitive forcing




 Gordian Knot
          Strategy 1: Meta-cognitive training
    Meta-cognition: “thinking about thinking”
    “If at first the idea does not sound absurd, then there is no hope for it ”
                                                           - Albert Einstein

    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




                                         Croskerry- Ann Emerg Med. 2003; 41: 1
                  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. 2002;77(10):981-92
                             Mitchell DJ- J Behav Decis Making. 1989;2:25-38
       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
         Some ‘pills’ for our cognitive ‘ills’
   Clinical shortcut                  Corrective strategy

     ‘Availability’             Decrease reliance on memory
      Easy recall                  verify facts - read more
     ‘Anchoring’               Reconsider in light of new data,
    1st impression                   seek 2nd opinions


     ‘Framing’                       Play devil’s advocate
   Subtle wording
  ‘Blind obedience’        Re-confirm human work/ test accuracy
Deference to authority
 ‘Premature Closure’     “What is the diagnosis that I do not want to
    Narrow belief                          miss?”


                            Reidelmeier D. Ann Intern Med 2005; 142(2): 115-120
                            Croskerry P. Acad. Med 2003; 78: 775-780
Experts might feel like…
                Summary

   Cognitive short-cuts:
       due to lack of time & bounded rationality


   Double edged swords

   Overcome by
       metacognition & cognitive forcing
                      Thanks!


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

				
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