Monday, March 23, 2015

Cognitive pills for Cognitive ills: Errors in Emergency Medicine

Cognitive errors underlie most diagnostic errors that are made in the ED. And with time I have realised that our speciality is a vulnerable one, because we often commit some errors (delayed diagnosis, missed diagnosis, unnecessary imaging) which look like no-brainers to people upstairs in the ICUs and wards. Then why do we commit such errors?

May be because as everyone else, we often have a tendency to pursue more readily attainable goals.

There is a story about a jogger who came across a man on his knees under a streetlight one evening. He explained that he had dropped his wedding ring. The jogger offered to help him search, and he accepted. With no luck after a half hour, the jogger asked the man if he was sure he had dropped the ring at the place where they were searching. The man replied that he actually dropped it several yards away in the shadows. ‘‘Then why are we looking here?’’ asked the jogger. ‘‘Because the light is better,’’ came the reply. 

This is a topic in medicine which is rarely talked about, despite being a really important one for patient safety. These errors are universal but since we are often the first responders as Emergency Physicians, the brunt falls on us and we face the limelight. So, we need to find out a way to minimise these errors by developing a conceptual framework and strategies in this critical aspect of patient safety.

Diagnostic errors arising through cognitive errors are those that are associated with failures in perception, failed heuristics, and biases are referred to as cognitive dispositions to respond (CDRs). There are a number of strategies for reducing them (‘‘cognitive debiasing’’)  like METACOGNITION, a reflective approach to problem solving that involves stepping back from the immediate problem to examine and reflect on the thinking process.

Some unique operating characteristics of ED predisposing to medical error:

  • High Diagnostic Uncertainity
  • High Decision Density
  • High Cognitive Load
  • High level of activity
  • Inexperience
  • Interruptions and Distractions
  • Shift Work
  • Shift Changes
There is huge list of errors which we can come across as clinicians and not surprisingly, all of them are evident in Emergency Medicine, a discipline that has been described as a ‘‘natural laboratory of error.’’ Lets familiarise ourselves with some of them:  

Various biases leading to errors:
  1. Anchoring BiasAnchoring bias causes physicians to stay with their initial impression of a case and fail to adjust to new information that would make the initial impression less likely. This often leads to prematurely ending their search or premature closure.
  2. Gender Bias: the tendency to believe that gender is a determining factor in the probability of diagnosis of a particular disease when no such pathophysiological basis exists. Generally, it results in an overdiagnosis of the favored gender and underdiagnosis of the neglected gender.
  3. Availability: Recent experience with a disease may inflate the likelihood of its being diagnosed. Conversely, if a disease has not been seen for a long time (is less available), it may be under diagnosed.
  4. Premature closure: a powerful bias accounting for a high proportion of missed diagnoses. It is the tendency to apply premature closure to the decision- making process, accepting a diagnosis before it has been fully verified (When the diagnosis is made, the thinking stops)
  5. Search satisfying: reflects the universal tendency to call off a search once something is found. Comorbidities, second foreign bodies, other fractures, and coingestants in poisoning may all be missed. 
  6. Ascertainment bias: occurs when a physician’s thinking is shaped by prior expectation; stereotyping and gender bias are both good examples.
  7. Fundamental attribution error: the tendency to be judgmental and blame patients for their illnesses rather than examine the circumstances that might have been responsible. In particular, psychiatric patients, minorities, and other marginalized groups. 

Few Cognitive de-biasing Strategies to Reduce Diagnostic Error
  1. Develop insight/ awareness: Provide detailed descriptions and thorough characterizations of known cognitive biases, together with multiple clinical examples illustrating their adverse effects on decision-making and diagnosis formulation.
  2. Consider alternatives: Establish forced consideration of alternative possibilities. Encourage routinely asking the question: What else might this be? eg: any pt who presents with flank pain/hematuria, force yourself to consider aortic dissection.
  3. Metacognition: Train for a reflective approach to problem solving: Metacognition is the process of actively stepping back from the pushes and pulls of the immediate situation (de-anchoring), reminding oneself of the limitations and failings of memory, seeing the clinical problem in a wider perspective than that dictated by the obvious presentation, perhaps reminding oneself of specific lapses or failures in the past, and finally activating known cardinal rules or caveats.  
  4. Decrease reliance on memory: Improve the accuracy of judgments through cognitive aids: mnemonics, clinical practice guidelines, algorithms, hand-held computers.
  5. Simulation: Develop mental rehearsal, ‘‘cognitive walkthrough’’ strategies for specific clinical scenarios to allow cognitive biases to be made and their consequences to be observed. Construct clinical training videos contrasting incorrect and correct approach.
  6. Make task easierProvide more information about the specific problem to reduce task difficulty and ambiguity. Make available rapid access to concise, clear, well-organized information.Write the ddx in chart upon initial evaluation and re-visit the ddx when initial tests are back and when deciding disposition. Formalizing Handover: 'S BAR' Mneumonic for Handover - Situation, Background, Assessment, Recommendation
  7. Minimize time pressuresProvide adequate time for quality decision- making. Have the the attending doc and and the handover doc seeing patient/imaging together, its always better to review the H&P for handed over cases. 
  8. Feedback: Provide as rapid and reliable feedback as possible to decision makers so that errors are immediately appreciated, understood, and corrected, resulting in better calibration of decision makers.
  9. Understanding "how we think": 
Type 1: The Intuitive/Reflexive Approach involves automatic decision making based on pattern recognition. It's fast, requires little effort and usually brings you the correct diagnosis, but it's very prone to error.

Type 2: The Analytical/Problem-Solving Approach is more critical and logical. This is when you step back and think more carefully about the patient's presentation. It involves estimating pretest probabilities, continuous self-questioning, and considering alternative diagnoses. While it takes more effort, more time and is more resource intensive, it's reliability is much better than the intuitive approach, and is more likely to give you the correct diagnosis. 

High Risk Situations where errors are likely:
Night shifts, during handover, with patients at the extremes of age, the 'difficult patient' and the "difficult relatives"

Some Classic Errors:
  1. Failure to consider a closed-head injury in an intoxicated patient
  2. Incomplete consideration of AMI mimics before initiating thrombolysis 
  3. Inadequate assessment of immunocompromise status in patients with animal bite wounds
  4. Failure to fully assess the medical status of psychiatric patients before transferring to a psychiatric facility
  5. Failure to consider tetanus immune status in patients with open wounds. 

Take Home:
  1. Learn, practise and teach Metacognition.
  2. Develop your own strategies to reduce errors (discussion, checklists, Incorporating simulation)
  3. Use a Problem Solving approach instead of a Reflexive Approach.


  1. good read dr lakshay. i think every new ED physician should be comfortable with oneself and keep an open mind and approach towards the patient and remembering that you can make mistakes is the best way to avoid one.