EM Reflections February 2021 – Bias & Error in the ED

Big thanks to Dr. Joanna Middleton for leading discussions this month.

All cases are theoretical, but highlight important discussion points.

Authored and Edited by Dr. Mandy Peach


It’s your 7th evening shift in a row and the department is in critical overcapacity. You are at the latter end of your shift. You’re answering multiple charge doc calls when a new acute chart is put up to be seen. You pick it up: it’s a 62 yo male with 1 day of LLQ pain radiating to the flank. You start your history: his pain has been worsening over the day and he describes loose stools earlier in the week. He denies fever/chills and any other infectious symptoms on review of systems. He has a history of diverticulitis in the past and thinks it feels similar. He denies any previous admissions or surgical interventions for his diverticulitis in the past.

Vitals: BP 108/78 HR 102 RR 20 O2 98% RA T 36.3

On exam he has mild tenderness throughout, you feel perhaps focal LLQ tenderness, but no peritoneal signs. He looks in mild discomfort but is otherwise well. His U/A is negative.

“I’d just like some antibiotics doc, so I can get back home”.

You order basic lab work which is within normal limits except for a slightly elevated CRP. You diagnose him with uncomplicated diverticulitis and discharge him with oral antibiotics.

Could there be any bias ongoing with this patient1?

Anchoring bias:  “Prematurely settling on a single diagnosis based on a few important features of the initial presentation and failing to adjust as new information become available”.

In this patient he has a history of diverticulitis and it seems similar. We anchor on the previous diagnosis.

Diagnosis momentum: “Similar to anchoring. Once a diagnostic label has been assigned to a patient by another individual, it is very difficult to remove that label and interpret their symptoms with fresh eyes.”

Again, here we have an easy diagnosis previously established. The symptoms sound the same – so it’s easy to again label the patient with diverticulitis.

Confirmation bias: “Once you have formed an opinion, you have a tendency to only notice the evidence that supports you and ignore contrary evidence.”

From the triage note you strongly suspected diverticulitis, so you subconsciously push aside the fact that he has tenderness throughout, and that it radiates to the flank, not just focally in the LLQ.

Premature Closure: “This is the tendency to stop too early in a diagnostic process, accepting a diagnosis before gathering all the necessary information or exploring all the important alternatives.”

Here the patient feels it’s diverticulitis, there was some loose stools earlier in the week so we close the possibility of other diagnosis.


You continue your shift – 2 hours later an EMS patches in.

“62 yo male previously discharged from ED today with diverticulitis, found down at home by wife. CPR in progress. Asystole on rhythm checks. Down time 30 min. Intubated on scene. ETA 5 minutes”.


You prepare your team to receive the code. As EMS rolls in you recognize the man you discharged earlier in the day. You rack your brain, but don’t remember getting a detailed past medical history other than he had diverticulitis. You are unsure if he had any cardiac risk factors.

You begin the resuscitation and ask the resident working with you to look up the patient’s PMH. They find a recent IM consult – the patient has a history of RA and is on immunosuppressants. He also has a history of HTN, DM and a known AAA last checked 3 years ago. It measured 5cm at that time.

You grab your ultrasound probe and scan the aorta:

You see a large AAA and potentially some free fluid anterior to the aorta.

You scan the RUQ:


You see a large amount of free fluid.

You suspect a ruptured AAA. You begin Massive Transfusion Protocol and attempt to resuscitate the patient to ROSC. You give the vascular surgeon on call a heads up. Unfortunately the patient has been down 30 min and your resuscitation is unsuccessful. You call the code.

This would be an unfortunate case: the setting in the department is already chaotic, you are mentally fatigued and bias can take over. As ED docs this is a common situation we find ourselves in often. To err is human, but there are ways we can overcome bias.


What are the two types of cognitive approaches we often take2?

Type 1: The Intuitive/Reflexive System: automatic decisions based on pattern recognition. Done quickly and with minimal effort. This is the approach we took with our patient.

Type 2: The Analytical/Problem-Solving System: we step back and critically think about the patient presentation, think about pretest probabilities, other diagnoses and question ourselves more. This is not the fast route.

So, Type 2 must be best then2?

Not really – it’s a blend of the two.  “Experts use their experience and past errors/mistakes to reflect on their knowledge and their biases and develop heuristics (cognitive short-cuts) and cognitive forcing strategies that allow them to use their Type 1 system for rapid decision making in EM rather than having to slow down using their Type 2 system.”

So, we gather knowledge as we see more and more patients, but we also need to use our knowledge wisely.

How do we do this2?

Reflection – learn from your mistakes. Easy in theory but will require some work and time on your part to continue reflecting in a useful manner:

  • Follow up on your cases; try and do so within a few days or on your next shift. Check their inpatient chart. Consider touching base with the patient in some cases.
  • Develop your own cognitive short cuts – ones based on experience and previous analytical problem solving so next time you don’t have to evaluate as critically.
  • Consider dictating your chart, or documenting in the EMR your ED uses – when saying it outloud, or typing it out all at once, it can trigger reflection and may lead you to consider other diagnoses.
  • Before you sign off on a chart and put it in the ‘discharged’ pile look at the evidence one last time – does it have internal congruence? Is there evidence against your diagnosis that may support another?

Try and understand your own personal bias, or any that may exist within your thought process.

When you reflect upon your own personal bias, it can help you develop strategies to prevent it from happening.


Do you find yourself anchoring on a diagnosis from the triage note before you even see it patient? Force yourself to truly broaden your differential.

Have you ever found yourself subconsciously pushing some data aside while focusing on results that support your leading diagnosis? Maybe write the pertinent results on your chart so you can’t ignore them.

Bottom line – it takes work and time to reflect upon your practice. We all change our practice based on previous mistakes – this is a type of cognitive forcing strategy. The physician in our case will likely scan each aorta in high risk patients with flank pain from now on. This case has forced them to consider AAA in future cases. He/she has created a cognitive heurisitic to consider AAA in abdo pain presentations.

Emergency Medicine is a team -oriented environment. What other ways can we prevent bias2?

Two minds are better than one . During critical situations our brains often focus on one task and can’t process more outside information. Situational awareness can be lost – having a second doc on board if possible can be exceedingly helpful; If you both have your ‘jobs’ you can cognitively unload some of the information.

Practice, practice, practice – evidence shows that mentally rehearsing critical procedures increases chance of success. See Dr. George Kovac’s approach to taking an airway (start at 3 min mark) for a great example.3


Prep your team – have a huddle when the EMS dispatch is received. Review the differential and logistically have medications/equipment you anticipate being needed within arms reach. Assign tasks to each person so everyone knows their job. Call any consultants you suspect will be needed.

Talk to your team – no matter how obvious it may (or may not) seem, confirmatory statements can bring everyone on the same page. “This trauma patient is altered and not protecting their airway, we need to take the airway and urgently get a CT head”. Communication on a patient plan doesn’t need to be only in critical resuscitation situations. We are all involved in patient care. When you see a patient talk to the nursing staff, state your suspected diagnosis, how you plan to investigate and any interventions ongoing in the meantime. Paramedic nearby? Discuss the case with them as well, they have firsthand information from the scene that can be incredibly insightful. Plus, they are as much a part of the team as in hospital staff. They will want an update on the patient as well.

Think ahead – when you communicate your confirmatory statement to your team, it’s also a good time to consider what could go wrong and how to prepare. “This patient likely has a significant intracranial injury and could potentially herniate. We need to monitor for signs of herniation, have mannitol at the bedside and be prepared for urgent neurosurgical intervention”.

Practice, practice, practice some more – with simulation. Acclimatize yourself to stressful situations so you become more desensitized to your body’s physiologic response when faced with a critically ill patient.

Checklists – you can be a pro at resuscitation and stressful situations, but everyone has an off day. Everyone can suffer from fatigue. Take some of the thinking out of the picture – trauma checklists, airway checklists, etc. These can prevent errors by allowing you to follow the list when giving care and can provide a ‘fail-safe’ approach.

When are we more likely to make errors4?

  • Nightshift – especially around 5AM. The EM witching hour.
  • Handover – especially from nightshift
  • The overconfident physician/learner
  • Extremes of age – very young or very old patients
  • High patient volumes with many interruptions
  • The ‘difficult’ or frustrating patient

One study showed an emergency doctor was interrupted on average 30 times during an 180 min work window, while seeing/responsible for on average 12 patients during this time. 5

What can we do to prevent errors4?

  • Rest well before your nights – sleep deprivation is cumulative. It can lead to tolerance of more risk, increased distractability and poor performance at tasks. This is more likely to happen at the latter end of your shift. Ensure you take breaks to eat and hydrate.
  • Formalize handover – consider handover sheets with pertinent information and plan. Similar to SBAR – “Situation, Background, Assessment, Recommendation”
  • If no formal handover sheet, write a clear plan on the chart as well as verbalize it
  • When handing over a patient you are worried about, consider seeing them together with the doc taking over
  • If possible, try and request a ‘no interruption’ time during physician handover unless crucial. We should extend the same courtesy to our nursing staff.

After errors occur how do we learn from them4?

  • Follow up on cases by reading discharge summaries
  • M&M rounds – not to place blame, but for everyone to learn
  • A system in place to make docs aware of bouncebacks or mortality
  • Schedule ED follow up for patients you are concerned about who have poor follow up or no family doctor

Once an error has occurred, how to we disclose to family/loved ones4?

  • “inform the patient and the family of the mishap at the earliest convenient time in the presence of a 3rd party such as a department chief
  • express your concern, lay out the next steps in the course of care and answer any questions
  • notify CMPA
  • consider writing a ‘late note’ in the chart the next day and write a personal note to yourself outlining all the details for your personal file”


Errors will happen. Bias will happen. Do your best to reflect upon your practice and take away skills that will help you overcome these barriers.


References & further reading

  1. Justin Morgenstern, “Cognitive errors in medicine: The common errors”, First10EM blog, September 15, 2015. Available at: https://first10em.com/cognitive-errors/.
  2. Helman, A, Himmel, W, Hicks, C, Dushenski, D. Decision Making in EM – Cognitive Debiasing, Situational Awareness & Preferred Error. Emergency Medicine Cases. January, 2016. https://emergencymedicinecases.com/decision-making-in-em/. Accessed March 17, 2021.
  3. EMCrit # 253 – the Kovacs Kata to Optimize a Failing Laryngoscopy Attempt. https://www.youtube.com/watch?v=jCgpRd1R7gY&ab_channel=EMCrit
  4. Sinclair, D, Hicks, C, Helman, A. Cognitive Decision Making and Medical Error. February, 2011. https://emergencymedicinecases.com/episode-11-cognitive-decision-making-medical-error/. Accessed March 17, 2021.
  5. Chisholm, Collison, Nelson & Cordell (2000). Emergency department workplace interruptions: are emergency physicians “interrupt-driven” and “multitasking”? Academic Emergency Medicine Nov;7(11):1239-43. doi: 10.1111/j.1553-2712.2000.tb00469.x.


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