Errors in clinical decision making in the emergency department can be fatal! Through case studies, this presentation explores the factors contributing to error and strategies to overcome them.

1. Thinking and error
Anne-Maree Kelly
December 5, 2012

2. Permissions
 This presentation may be reproduced in full or in part
on the condition that each slide used carries the
following:
‘Reproduced with the permission of Professor Anne-
Maree Kelly, Joseph Epstein Centre for Emergency
Medicine Research @Western Health, Melbourne,
Australia’.
@kellyam_jec

3. Diagnostic error
 Common
 A top cause of medicolegal actions
 Up to 20% of autopsies
 Emergency Medicine is a high risk environment
 Why?

4. Diagnostic error
 “No fault’ error
 Silent or atypical disease
 Mimics something more common
 Lack of patient co-operation or presentation of symptoms
 Limitation of medical knowledge
 Systems error
 Technical: test error, lack of test/resource
 Organisational: supervision, unavailability of expertise,
inefficient processes, cultural issues
 Cognitive error
 Faulty data collection or interpretation
 Flawed reasoning
 Incomplete knowledge

5. Cognitive error: My questions
 Is it predictable?
 Is it unavoidable?

6. Your experience
 Work with the two or three people around you.
 Can you identify a case that you were involved in or
heard about where thinking processes contributed to
a diagnostic error?

7. Cases from the medicolegal world
 Ms X aged 42
 Single mother of 4
 Abdominal pain and vomiting
 Exam difficult due to obesity
 Three presentations to ED of a tertiary referral hospital
over 5 days
 Diagnosis #1: gastro (xray and bloods performed)
 Diagnosis #2: gastro; no further tests
 Diagnosis #3: bowel obstruction, ARF, gangrenous gut
 Outcome: death

8. The issues
 #1:
 Assessment was reasonable
 Xray was performed and clearly showed small bowel
obstruction
 #2:
 Assessment was brief
 Assumed that previous diagnosis was correct
 Did not check results/ xray

9. The cost
 4 children under 15 without a mother (or interested
father)
 > 1 million dollars settlement

10. Case 2
 HG aged 3
 Rural setting, experienced mum
 24 hours of D&V
 Seen by GP 1: gastro, home for fluids
 Seen by GP 2 next day: gastro; home for fluids
 Presented in ED in next town: gastro; home for fluids
 Day 3 admitted to small rural hospital by GP registrar for oral fluids.
Mother concerned re lack of urine.
 Day 4 evident that there had been no urine output for ~24 hours
 IV therapy
 Transferred to large hospital on Day 5
 Cardiac arrest, died

11. The issues
 First GP assessment fine
 Second GP assessment
 Failure of data collection: weight
 Assumption that all gastro settles with oral fluids
 Not listening to mum re intake / output
 ED assessment
 Failure of data collection: weight
 Assumption that all gastro settles with oral fluids
 Not listening to mum re intake / output
 In hospital management
 Failure of data collection: weight, fluid balance chart, frequent obs
 Assumption that all gastro settles with oral fluids
 Not listening to mum re intake / output
 ‘It will all be alright’ mentality blocking escalation of care to
specialist centre

12. Something closer to home
 30-something woman
 Sore throat 24-48 hours
 Unable to swallow saliva
 Epiglottis suspected by ED team
 Difficulty engaging ENT team
 Eventually came and attempted endoscopic exam
 Acute hypoxia
 Surgical airway
 Alive...but close run thing

13. Issues
 Epiglottis now very uncommon
 Dismissed the likelihood despite reasonable evidence
 Failure to respect assessment of clinician actually
seeing the patient

14. Types of cognitive predispositions to respond
Type of CDR Explanation
Aggregate bias Failure to believe aggregate data, eg guidelines
‘My patient is different’
Anchoring Locking on to features in presentation too early and
failing to adjust with further data
Ascertainment bias Thinking shaped by prior expectation eg gender
bias, stereotyping
Availability Diagnosis is more likely if it readily comes to mind
Base-rate neglect Tendency to ignore the true prevalence of a
disease, impacts Bayesian thinking
Commission bias Belief that harm can only be prevented by action;
tendency to action rather than inaction
Confirmation bias The tendency to look for confirming evidence rather
than evidence to refute
Diagnosis momentum Diagnoses are like sticky labels; once attached hard
to remove

15. Types of cognitive predispositions to respond
Type of CDR Explanation
Feedback sanction Error not temporarily associated with immediate
consequences
Framing effect The way we see things is influenced by how they are
presented to us (gastro and positive stool for blood
story)
Fundamental attribution error Blame patients for illness rather than look at situational
factors
Gambler’s fallacy Pretest probability of a particular diagnosis influenced
by previous but independent events (eg coin toss
example)
Gender bias False belief of difference in probability of a diagnosis
between genders
Hindsight bias Knowing what happened influences the perception of
past events and inhibits realistic appraisal of why error
occurred

16. Types of cognitive predispositions to respond
Type of CDR Explanation
Multiple alternatives bias Multiple options cause uncertainty; tendency to limit
options to those we know and potentially ignore rarer
alternatives
Omission bias Tendency towards inaction, usually for fear of doing
harm
Order effects Information transfer is U shaped; we ‘hear’ better at the
beginning and end. May miss important stuff in the
middle
Outcome bias The tendency to opt for diagnoses with good outcomes
Over-confidence bias Belief that we know more than we do!
Playing the odds In ambiguous situations, a tendency to opt for the less
serious diagnosis
Posterior probability error The tendency to be unduly influenced by what has
gone on before (see case 1)

17. Types of cognitive predispositions to respond
Type of CDR Explanation
Premature closure Very powerful: Tendency to accept a diagnosis before it
is fully verified
Psych-out error Tendency for error in psych patients especially missing
of serious medical issues
Representativeness restraint Looks like a duck, quacks like a duck, is a duck
Missing atypical presentations
Search satisfying Inappropriately calling off the search once something
has been found
Sunk costs The more we ‘invest’ in a diagnosis, the less likely we
are to relese it
Sutton’s slip Going for the obvious
Triage cueing Triage assignment falsely prompts bias towards
serious/ non-serious illness
Unpacking principle Failure to elicit all relevant information

18. Types of cognitive predispositions to respond
Type of CDR Explanation
Vertical line failure Thinking in silos; inflexible thinking; failure to consider
what else might this be?
Visceral bias Visceral arousal is associated with poor decisions
Feelings towards patients (positive and negative) may
result in diagnoses being missed
Our pre-disposition to CDR depends on:
•Personality
•Experience
•Self-awareness
•Environment/ situation

19. Avoiding cognitive error: Exercise
 Group 1:
 In pairs or threes,
describe strategies that
might help clinicians
avoid CDR in patients
they manage
 Group 2:
 In pairs or threes,
describe strategies that
might help supervising
clinicians/ consultants
avoid CDR in cases
they are consulted
about

20. Cognitive de-biasing strategies
Strategy Mechanism/ Action
Develop insight/ awareness Talking about and analysing diagnostic errors
Sharing experience
Consider alternatives Establish processes that ‘force’ consideration of
other diagnoses
Routinely asking What else might this be?
Documenting why you consider something unlikely
and why
Develop reflective approach to
problem solving
Regularly ask yourself how you are thinking about
diagnostic problems and how you might do it better
Decrease reliance on memory System level: cognitive aids, guidelines, etc
Personal level: Don’t rely on memory. Look things
up!
Specific training In CDR
In probability theory and Bayesian thinking
Simulation Both as case discussion and in simulator training

21. Cognitive de-biasing strategies
Strategy Mechanism/ Action
Cognitive forcing strategies Develop specific strategies for particular high risk
situations eg medical clearance of psychiatric
patients
Make it easier More information readily available
Minimise time pressures More time to think usually means better decisions
Accountability Clear accountability and followup of decisions
made
Feedback Rapid and reliable feedback esp. re diagnostic error
or ‘good picks’ assists diagnostic ‘calibration’
Teamwork Two heads are better than one. Information
sharing/consultation with other team members eg
nurses, other doctors, allied health etc.

22. Summary
 Diagnostic error and how we think are intimated
associated
 Cognitive errors can be reduced by:
 System measures to promote information availability and
‘force’ consideration of high risk groups/ diagnoses
 Personal measures such as self-awareness, de-biasing
strategies
 Training
 Teamwork