thinking and error in emergency departments

Thinking and error

Anne-Maree Kelly

December 5, 2012

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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

Diagnostic error Common

A top cause of medicolegal actions Up to 20% of autopsies

Emergency Medicine is a high risk environment Why?

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

Cognitive error: My questions

Is it predictable?

Is it unavoidable?

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?

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

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

The cost 4 children under 15 without a mother (or

interested father)

> 1 million dollars settlement

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

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

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

Issues Epiglottis now very uncommon

Dismissed the likelihood despite reasonable evidence

Failure to respect assessment of clinician actually seeing the patient

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



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



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)



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 duckMissing 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



Vertical line failure Thinking in silos; inflexible thinking; failure to consider what else might this be?

Visceral bias Visceral arousal is associated with poor decisionsFeelings towards patients (positive and negative) may result in diagnoses being missed

Our pre-disposition to CDR depends on:•Personality•Experience•Self-awareness•Environment/ situation

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

Cognitive de-biasing strategies

Strategy Mechanism/ Action

Develop insight/ awareness Talking about and analysing diagnostic errorsSharing experience

Consider alternatives Establish processes that ‘force’ consideration of other diagnosesRoutinely 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, etcPersonal level: Don’t rely on memory. Look things up!

Specific training In CDRIn probability theory and Bayesian thinking

Simulation Both as case discussion and in simulator training

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.

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

thinking and error in emergency departments

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