II. Background
- Diagnostic Inference
- Revise opinion based on imperfect information
- Associated with predictable patterns of bias (see cognitive mistakes below)
- Blois' Funnel
- Differential diagnosis is honed and refined during the course of patient evaluation
III. Precautions: Shift Fatigue
- Energy and focus diminish over the course of a work shift
- End of shift Fatigue is common and may result in less ideal management decisions
- Corrective Strategies
- Take a 5-10 min break to recharge, walk, eat, drink every 3-4 hours
- Remove yourself from distracting conversations or activities
- Reassess your patient list every 2-3 hours
- Write down each patient, their acuity, and remaining barriers to disposition
- Starting with highest acuity patient, complete next task
- Make an exit plan in the final 1-2 hours of a shift
- Which patients will need admission, transfer to another facility, or signout to oncoming provider?
- Which patients need additional information or Consultation to make a disposition decision?
- Examples
- Antibiotics are more often prescribed for likely Viral Infections towards shift end
- References
- Orman in Herbert (2017) EM:Rap 17(3): 7-8
IV. Precautions: Interruptions are frequent in the emergency department (6-7/hour)
- Multi-tasking is a misnomer, and instead tasks are switched
- Task displaced by interruption is returned to after a mean delay of 23 minutes
- High cognitive load and frequent task switching is a risk for errors
- Corrective Strategies
- Offload tasks to other members of the team or to a list
- Example: Observation of monitor while performing high cognitive load tasks
- Example: Write down tasks that need to be completed when at a computer
- Delay or defer interruptions during important tasks
- Critical patient decision making
- Patient sign-out
- Offload tasks to other members of the team or to a list
- References
- Lin and Skaugset in Herbert (2017) EM:Rap 17(3): 5-6
- Westbrook (2010) BMJ Qual Saf 19(4)
- Skaugset (2016) Ann Emerg Med 68(2): 189-95 +PMID:26585046 [PubMed]
V. Causes: Cognitive Mistakes
- Anchoring Bias
- Basing decisions on a single piece or cluster of initial information
- Focusing on a single diagnosis early in the decision making process
- May result in mis-interpretation or ignoring conflicting later data
- Confirmation Bias
- Data acquisition and interpretation is used to confirm rather than refute a single hypothesis
- Exacerbates Anchoring Bias
- Diagnosis Premature Closure (Search Satisfaction)
- Differential diagnosis evaluation stops after one diagnosis is found or ruled-out
- Alternative diagnoses are not considered and additional data is not pursued
- Diagnosis Momentum
- Previous treating physician's working diagnosis is carried forward
- May be exacerbated by labels or stereotypes (e.g. intoxicated or mentally ill)
- Availability Bias (Availability Heuristic)
- Likelihood of diagnosis is based on the ease of recall of similar cases or episodes
- May be influenced by dramatic cases (e.g. litigated cases)
- Representative Restraint
- Clinicians focus on classic, but rare disease presentations
- At the expense of missing atypical, but common disease presentations
- Representative heuristics have an insensitivity to pretest probability
- Countered by the mantra, "When you hear hoof beats, think horses, not zebras"
- Clinicians focus on classic, but rare disease presentations
- Visceral Bias
- Clinicians may be misguided by their own emotions and state of mind
- Medical decision making may be impacted by negative impressions of the mentally ill or intoxicated
- Value-Induced Bias
- Overestimation of disease outcome probability based on an outcome value
- Example: Imaging is ordered for a new onset Headache without red flags
- Ordered due to the value of missing the rare Brain Tumor
- Environment (example Emergency Department)
- High levels of diagnostic uncertainty
- Decision making at a rapid pace and a high volume
- Frequent interruptions
- Loss Aversion
- Humans are risk averse and often over emphasize risks or losses, and under emphasize benefits or gains
- This is typically applied to financial decisions (e.g. losing $20 has a greater impact than finding $20)
- Offer equivalent patient options (e.g. aggressive Resuscitation versus aggressive comfort measures)
- Diminishing Sensitivity to Losses and Gains
- Small additive risks are underestimated (e.g. CT radiation)
- Outweighed by greater theoretical risk concern (e.g. Abdominal Pain of unclear cause)
- Non-linear Probability Weighting
- We over-estimate the risk of rare events (plane crash)
- We under-estimate the risk of common events (Motor Vehicle Accidents)
- Base Rate Fallacy (Base Rate Neglect, Base Rate Bias)
- When presented with both general information as well as specific information
- People are guided by the specific information
- Specific information may lead to assume an alternative, rare diagnosis
- Whereas the most likely diagnosis is the much more common one
- For a dry cough of 1-2 weeks, Bronchitis would be much more likely than Coccidioidomycosis
- Even if you are told they just traveled to Arizona
- When presented with both general information as well as specific information
- Risk Shifting
- Medical decision making requires some amount of shifting a patients risk to the provider
- Providers assume a risk of missed diagnosis by avoiding additional testing (e.g. CT Imaging)
- Evaluation is a balance between a patient's condition risk and a provider's level of risk acceptance
- Shared Decision Making is an educated negotiation of what level of investigation is sufficient
- Diagnostic Overshadowing
- Known underlying condition results in medical provider mistaken assumptions and misdiagnosis
- New and serious condition is missed, confused for an exacerbation of the underlying condition
- Iezzoni (2019) N Engl J Med 380(22): 2092-3 [PubMed]
- Lazris (2023) Am Fam Physician 108(3): 292-4 [PubMed]
VI. Prevention: Mnemonic - "When U RACE, tie your LACES"
- When U RACE
- Unexplained complaint
- Initial hypothesis-driven data does not result in a diagnosis to explain symptom presentation
- Return Visit
- Risk of Anchoring Bias and Diagnosis Momentum based on the evaluation already undertaken
- Return visit is an opportunity to take a fresh look and possibly catch prior diagnostic error
- At-Risk patient
- Very young or very old patients
- Mentally ill patients
- Intoxicated patients
- Immunocompromised patients
- Critical Condition
- Time sensitive diagnosis and management (e.g. MI or CVA)
- Results in harmful intervention (e.g. TPA in Aortic Dissection)
- End of Shift
- Fatigue is a ripe milieu for diagnostic error
- End-of-shift hand-offs are complicated by incomplete communication
- Risk of Anchoring Bias and Diagnosis Momentum
- Unexplained complaint
- Tie your LACES
- Life-threatening diagnoses fully considered?
- Consider worst-case scenarios for a given presentation
- Anything else possible on the differential diagnosis?
- Avoid premature closure by adequately considering alternative diagnoses
- Coherent explanation?
- Consistency between diagnosis and clinical findings
- Everything explained (Adequacy)?
- Normal and abnormal findings are ALL explained by the final diagnosis
- Second problem present?
- Could more than one diagnosis better account for the current presentation
- Life-threatening diagnoses fully considered?
- References
- Gordon and Kemnitz (2013) Crit Dec Emerg Med 27(12): 11-18
VII. Approach: Decision Making Strategy
- Effective emergency decision making is a combination of thin and Thick Slicing
- Thin Slicing (fast and intuitive)
- Formulate initial patient plan based on limited information, gestalt, pattern recognition and intuition
- Allows for rapid emergency decision making
- Often accurate, especially in more expert clinicians (but risky in medical trainees)
- Pitfalls
- Requires experience, training and practice, with constant exposure to cases, simulations, peer review
- Risk of anchor bias and Confirmation Bias
- Processing occurs in the prefrontal cortex (hidden brain)
- Prefrontal cortex is easily overwhelmed by large amounts of incoming information
- Checklists help to avoid major pitfalls and anchoring
- Clinical Decision Rules
- Review of Systems (clusters of outlier symptoms may redirect diagnosis)
- Life-threatening differential diagnosis list (e.g. PE, Aortic Dissection, Mesenteric Ischemia)
- Thick Slicing (slow and logical)
- Deeper evaluation and analysis of clinical data including subtle findings
- Allows for reconsideration of data, differential diagnosis before disposition
- May involve checklists and reference review
- Consider pre-rehearsed scripts for the safe evaluation and management of complex presentations
- Slower than Thin Slicing and requires setting aside time to collect and review available data
- Resources
- Gladwell (2007) The Power of Thinking Without Thinking, Back Bay Books
- Gawande (2011) Checklist Manifesto: How to Get Things Right, Picador
- References
- Herbert and McCollum in Herbert (2016) EM:Rap 16(9): 4-6
- Jaban in Hewrbert (2017) EM:Rap 17(5): 5-6
VIII. Approach: Patient Communication
- At the outset of visit, explain that evaluation and testing is imperfect
- No diagnostic test, exam, imaging is certain
- Miss rates and False Negatives are common
- In the pursuit of a diagnosis, there are risks to testing
- Likelihood of a diagnosis for a specific patient and their presentation should guide testing
- Balance the risks and benefits of testing, the likelihood and risk of a missed diagnosis
- Medications and other treatment are imperfect
- Pain will not be completely relieved
- Medications have adverse effects (e.g. Opioid Abuse, Constipation)
- Medications are often prescribed when not indicated (e.g. Antibiotics) with secondary harm (e.g. c. diff)
IX. Approach: Self-Talk Incrementalization
- Keep the goals in mind
- Commit to maximally aggressive care in Critical Illness
- Resuscitationists err on the side of aggressive care to achieve survival
- Even at low odds of survival, be aggressive if it is in the best interest of the patient
- Proactively anticipate Peri-Arrest situations
- Identify high risk patients early and intervene aggressively to prevent further decompensation
- Break down complicated and high risk situations into manageable tasks
- Concentrate on each single task, with multiple adjustment strategies available if difficult
- Slow down, and perform each task with adequate precision to ensure success
- "Slow is smooth and smooth is fast"
- Self-talk yourself into success at each step
- Perform each task with confidence of success
- Maintain a sense of self efficacy and self confidence
- Control your breathing (employed in yoga, stress reduction, Mindfulness)
- Prepare for stressful, high risk situations
- Simulation, anatomy labs and specialized courses
- Mental rehearsal
- Prepare for catastrophe with a "not IF, but WHEN" mentality (it will eventually happen)
- Prepare for failure
- References
- Mason and Levitan in Herbert (2017) EM:Rap 17(12): 19-20
- Swaminathan and Hicks in Herbert (2018) EM:Rap 18(9): 12-4
- Wiengart and Swaminathan (2024) Mind of the Resuscitationist, EM:Rap, published 4/8/2024
X. Approach: Develop a thorough differential diagnosis (SPIT Mnemonic)
- Serious possible diagnoses
- Exclude life threatening diagnoses (where appropriate)
- Probable diagnoses
- Evaluate and treat likely diagnoses
- Interesting diagnoses
- Consider uncommon, complex diagnoses (where appropriate)
- Treatable diagnoses
- Consider diagnoses with specific, effective treatment regimens (and empiric therapy trial)
- References
- Bukata (2013) EM Bootcamp, Approach to the ED Patient
XI. References
- Gordon and Kemnitz (2013) Crit Dec Emerg Med 27(12): 11-18
- McCollum in Herbert (2018) EM:Rap 18(2): 11-3
- Menchine in Majoewsky (2012) EM:RAP 12(2): 1-2