A 50-something woman with atypical chest pain

This was provided by Mustafa Alwan, an internist from Jordan, on Facebook EKG Club   

A 50-something female presented with atypical chest pain described as stabbing, with no radiation 
PMHx : DM poorly controlled 
VITAL signs stable 

Here is the initial ECG with the question "should the cath lab be activated?"
This is suspicious for ischemia because of the T-wave inversion in aVL.
However, this is very nonspecific and one would not activate the cath lab!


Another ECG was recorded 20 minutes later:
This has more obvious T-waves and T-wave inversion in aVL
Here is my response:
"This 2nd one is an extraordinarily subtle but real change!!" (i.e., this is diagnostic of MI).  "These often resolve with nitro, so I would try that first. It depends on your resources: if activating at night tires out your team for the next day, you try to avoid if possible.
But this pain and ECG may not resolve, in which case you must activate."

In other words, this is diagnostic of inferior MI, but not of STEMI, and may not need emergent cath lab activation.

If the pain and ECG findings resolved with nitroglycerine, it will need at least maximal medical therapy and continuous 12-lead ST segment monitoring

See these cases for the importance of ST segment monitoring:
http://hqmeded-ecg.blogspot.com/search/label/ST%20Segment%20Monitoring

A third ECG was recorded at 45 minutes:
Now it is unequivocally diagnostic of inferior MI, even though it does not meet millimeter criteria for inferior STEMI.
The cath lab must be activated.

Here are all 3 ECGs, one after another, so you can see the changes:




The cath lab was not activated, but a 4th ECG was recorded at one hour:
Now it meets STEMI criteria.
Cath lab was activated
What else do you notice?









There is also new ST elevation in V1.  So this is a right ventricular MI also

Echo: Basal inferior wall hypokinetic, pseudonormal LV filling pattern

Initial Troponin T: less than 0.01 ng/mL initial
Troponin T after 2 hours: 0.49 ng/mL


Troponin T after 4 hours: 1.6 ng/mL (this is a large MI)

Cath showed a 100% proximal RCA occlusion.


Learning Points:

1. T-wave inversion in aVL may be the first sign of inferior MI
2. Pay attention to slightly enlarged T-waves
3. When you see these subtle, nonspecific abnormalities, make certain you get serial ECGs!
4. Any patient with ongoing potentially ischemic chest pain should get serial ECGs!




EM Cases: Decision Making in EM – Cognitive Debiasing, Situational Awareness & Preferred Error

Originally published at EM Cases – Visit to listen to accompanying podcast . Reposted with permission.

Follow Dr. Anton Helman on twitter @EMCases

how-we-think

EM Cases:  Decision Making in EM – Cognitive Debiasing, Situational Awareness & Preferred Error

 

Type 1 & Type 2 Cognitive Decision Making Systems & The Nature of Expertise

 “The definition of experience is the capacity to make more and more mistakes with increasing confidence” – Walter Himmel

  • Type 1: The Intuitive/Reflexive System involves automatic decision making based on pattern recognition. It’s fast and requires little effort.
  • Type 2: The Analytical/Problem-Solving System is more critical and logical. It involves stepping back and thinking more carefully about the patient’s presentation. It involves estimating pretest probabilities, continuous self-questioning, and considering alternative diagnoses.

The traditional view of this decision making in EM model is that while reasoning will invariably try to default to the Type 1 intuitive/reflexive approach, the most economical and fastest mode, the key to successful decision making is to step back and think analytically when you realize that there are subtle inconsistencies that arise.

The current view of this decision making in EM model is that it’s not a matter of whether Type 2 is better than Type 1 but rather, how expert decision makers blend these two systems. 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.

 

The Nature of Expertise

“Experts tackle problems that increase their expertise, whereas non-experts tend to tackle problems for
which they do not have to extend themselves.” – Carl Bereiter

Decision making in EM expertise comes about, not only through the acquisition of knowledge and gaining experience, but by actively using the knowledge they’ve acquired wisely. How does do we use knowledge wisely?

1. Reflect on your experience – learn from your mistakes by

  • following up on all but your trivial cases within a few days
  • developing your own personal heuristics based on on your experience
  • consider dictating your chart which forces you to reflect on your assessment and plan
  • before signing off the chart ensure that it has internal congruence – look for disconfirming evidence before you decide on a disposition

AND

2. Understand your personal cognitive biases and your particular system’s biases

3. Employ cognitive debiasing strategies based on 1 and 2

* note that only using your experience without reflection can result in excessive confidence and insecurity which may lead to more errors

  “It’s not what you know, it’s what you use– how do you use your knowledge? By developing better heuristics” – Walter Himmel

 

Cognitive Biases discussed in this Decision Making in EM Episode

  • Anchoring bias – locking on to a diagnosis early in the assessment and failing to adjust to new information
  • Diagnosis momentum – accepting a previous diagnosis without considering the differential diagnosis adequately
  • Confirmation bias – looking for evidence to support a pre-conceived opinion, rather than looking for dis-confirming information
  • Premature closure – once you have found one diagnosis (eg: a fracture on a set of x-rays) you stop to searching for others (eg: the second fracture on the same set of x-rays)

 

Cognitive De-biasing Strategies: Cognitive Forcing Strategies & Heuristics

“Perception is not a passive process. Perception is an active one” – Walter Himmel

In order to identify and help mitigate some of these negative cognitive biases it is not enough to identify them. We must employ cognitive de-biasing strategies for effective decision making in EM.

Cognitive Forcing strategies can be general such as “rule out the most deadly diagnosis” or they can be be related to your own experience based on reflection on previous mistakes.

Examples of Cognitive Forcing Strategies discussed in this Decision Making in EM Episode

Missing trifascicular block on ECG –  for any ECG that shows a Right Bundle Branch Block (RBBB), if the axis is pointing left then search for the findings of trifascicular block

Missing a Maisonneuve fracture  – For any ankle injury, examine the proximal fibula for tenderness to assess for a Maisonneuve fracture

One important aspect of effective cognitive forcing strategies is to apply them across all clinical encounters of that kind.

 

Strategies to Mitigate Affective Bias & Decision Fatigue

  1. Overlapping shift start times where the next doc arrives an hour before the first doc finishes
  2. Casino shifts – preserves the anchor period (2am-6am when it is the most important for your circadian rhythm to get some sleep in order to adjust properly) and is associated with more total sleep, reduced sleep debt, shorter recovery time, reduced cognitive impairment, improved work performance and improved career longevity (listen to Episode 11 for details)
  3. Mutual support of colleagues working at the same time, having 2 or more physicians at each resuscitation, and ‘calling a friend’ – asking for an opinion on a case from your colleague, especially when you are at or near the end of your shift and suffering from decision fatigue

 

Decision Density and Anticipatory Guidance in Resuscitation Management

Human cognition has its limits. There is good evidence to suggest that our brains are not designed to function well during critical events in which multiple points of potentially unrelated information need to processed rapidly.

In critical and stressful situations we tend to ‘tunnel down’ on the task at hand and become less receptive to extraneous information that may be important. Our ability to take in this information is reduced even more when we feel high degrees of stress.

As explained below, a high performance team in which tasks and decision making responsibilities are divided up in ateam huddle, having 2 doctors rather than one at every resuscitation, improving your situational awareness, andstress inoculation training can mitigate the problem of high decision density in stressful situations by cognitive unloading and managing the negative influence of stress effectively.

 

Mental Rehearsal & Anticipatory Guidance

Practicing or visualizing procedures ‘in your head’ (psychophysical rehearsal) before you do them has been shown to improve performance and success of procedural tasks. There is also some evidence to suggest that it may improve team performance in team-based trauma resuscitation.

The Team Huddle

Take a few minutes when you get the call from EMS about a patient who will soon be arriving in your ED to do a team huddle: predict the potential diagnoses, delegate roles, expectations and responsibilities, think about logistics in your hospital, anticipate which procedures might be necessary and set up the appropriate gear for them.

For a discussion on anticipating logistics over strategy in resuscitation go to this podcast at EMCrit

Anticipatory Guidance

There is a powerful effect on your team of stating the obvious (e.g. “this patient is in septic shock and they will get worse unless we do x, y and z”).

Anticipatory guidance and team communication is important not only in resuscitation, but in all ED patient encounters. Consider discussing with the nurse and the rest of your team what you think the most likely diagnosis is, what you’re worried about, what your management plan is and what you think the disposition might be, rather than only filling out orders for the nurses. This allows everyone to ‘be on the same page’ and may improve efficiency as well as decrease medical error.

 

Situational Awareness Checklist

(adapted from ‘Situational Awareness and Patient Safety – A Short Primer’ from The Royal College of Physicians and Surgeons of Canada website)

1. Get Information

  • Scan and search: be proactive – look for it in your environment or solicit it from your team.
  • Remain watchful: expect the unexpected
  • Communicate: openly talk about your thoughts on the situation with your team, the patient and their family

2. Understand the information

  • Compare: Compare the information to what you know and what you expected
  • Critique: Think critically about the information – check information integrity (accuracy, completeness, source, and relevance)

3. Think Ahead

  • Extrapolate and project: beyond the “now”: How will the situation unfold if the current conditions persist? Persist for how long?
  • Ask “what if?”: Consider various outcomes and contingencies and communicate those possibilities to others

 

To Act or Not to Act – That is the question: Preferred error & Resilience

decision making in EM

From emupdates by Reuben Strayer

Preferred error describes balancing the risks of action vs inaction based on the potential positive vs negative outcome of either. It begs you to consider the consequences of being wrong on both sides of the decision, and determine which course of action fails better. Factoring in how likely you are to be wrong is important in weighing the potential outcomes.

For a detailed explanation of the concept of preferred error visit emupdates

 

Building Resilience & Stress Inoculation Training

3 steps to building resilience

(adapted from the Harvard Business Review)

  1. Have an accurate understanding of the situation that you’re facing
  2. Give it meaning or purpose
  3. Be prepared to do what ever it takes regardless of the outcome, success or failure

Stress Inoculation Training

The goal of Stress Inoculation Training is to limit the impact of acute stress on performance.

Stress Inoculation Training promotes stress resilience by desensitizing the person to the negative behavioural and physiologic effects of acute stress in a simulated environment. A step-wise process involves increasingly stressful situations in a simulation training environment. During the debriefing period of the simulation the triggers of stress are identified and understood. Then, strategies to minimize the physiologic and behavioural consequences of stress are rehearsed so that the person is better prepared for similarly stressful situations.

 

Quote of the Month

“The value of experience is not in seeing much, but is in seeing wisely” -William Osler

Key References on Decision Making in EM

Bereiter, C. Scardamalia, M. Surpassing ourselves: An inquiry into the nature and implications of expertise. Open Court Publishing Company. 1993, 77-120.

Chanmugam, A. Avoiding Common Errors in the Emergency Department, Chapter 78: Understand decision-making fatigue and how it influences your clinical judgement, 2010.

Crosskerry, P. The Importance of Cognitive Errors in Diagnosis and Strategies to Minimize Them. Academic Med. August 2003, 1-6.

Crosskerry, P et al. Patient Safety in Emergency Medicine. Lippincott Williams & Wilkins, 2009.

Lorello GR, Hicks CM, Ahmed SA, Unger Z, Chandra D, Hayter MA. Mental practice: a simple tool to enhance team-based trauma resuscitation. CJEM. 2015:1-7.

Petrosoniak A, Hicks CM. Beyond crisis resource management: new frontiers in human factors training for acute care medicine. Curr Opin Anaesthesiol. 2013;26(6):699-706.

Parush A, et al. Situational Awareness and Patient Safety. The Royal College of Physicians and Surgeons of Canada. 2011. Link

Scott Weingart. EMCrit Podcast 49 – The Mind of a Resus Doc: Logistics over Strategy. Link

Reuben Strayer. The Preferred Error. Emergency Medicine Updates. June 11th, 2014. Link

The post EM Cases: Decision Making in EM – Cognitive Debiasing, Situational Awareness & Preferred Error appeared first on emdocs.

ECG of the Week – 15th August 2016 – Interpretation

The following ECG is from a 58 yr old male who presented following several hours of cardiac sounding chest pain. He was pain free when this ECG was recorded.




Click to enlarge
Rate:
  • 72 bpm
Rhythm:
  • Regular

Axis:
  • Normal
Intervals:
  • PR - Normal (140ms)
  • QRS - Normal (100ms)
Segments:
  • Cove-shaped ST elevation in lead V1 (<1mm) and V2 (3mm)
  • Obliquely straight ST elevation V3 (4mm)
  • Possible ST depression leads III, aVF - difficult to see due to baseline artifact
Additional:
  • P waves difficult to see due to baseline artifact - best seen in V2-3
  • T wave inversion leads aVR, aVL, V1-2
Interpretation:
  • Brugada Syndrome
    • Type 1 Pattern
  • Given the history of central chest pain the presence of additional ACS must be considered especially given the flat ST elevation in V3 plus subtle inferior ST depression
This is challenging and I've never seen a case of Brugada plus ACS - serial ECG's and comparison with old ECG's are essential.
This patient had known Brugada and thankfully brought his old ECG from 10 yrs ago with him which showed all changes to be longstanding.

What happened ?

Interestingly the patient had been lost to cardiology follow-up and had no AICD inserted for his Type 1 Brugada. Given the typical nature of the pain the patient had a coronary angiogram which revealed no evidence of coronary artery disease and he is awaiting an AICD insertion.

Brugada Resources / Cases

We've had a case of Brugada before on ECG ot the Week here, which also prompted a 'guest editoral' post by Dr Ken Grauer which you can find here.

I've copied the Brugada overview and resource section from our previous post below.

So what is Brugada Syndrome ?

It's an inherited sodium channelopathy, associated with sudden death and syncope due to polymorphic VT and, as in our case, VF. 
Three types of ECG pattern are describe in Brugada, although only type 1 is considered diagnostic, as shown in our ECG.  

Type 1 ECG pattern:

  • Cove-shaped ST elevation of at least 2mm followed by a negative T wave in one or more of leads V1-3
In conjuction with these ECG features you need, at least, one of the following:
  • Document VF / polymorphic VT
  • Family history of sudden cardiac death at <45 years
  • Type 1 pattern ECG i n family members
  • Inducibility of VT with programmed stimulation
  • Syncope
  • Nocturnal agonal respiration
    • Attributed to self-terminating VF/polymorphic VT
The above diagnostic criteria are taken from the CSANZ (Cardiac Society of Australia and New Zealand) Guidelines for the diagnosis and management of Brugada syndrome, this document is well worth a read as it covers pathophysiology, diagnostic criteria, management, and includes examples of the type 2 and type 3 ECG patterns. 

Also check out the following great blog posts on Brugada:

What to do about it ?

As an emergency physician encountering a case of suspected / likely Brugada it's easy, phone your cardiologist. For those patients with a Brugada pattern ECG with a history of syncope, arrest, or arrhythmias, definitive treatment is an AICD insertion. The incidental Brugada pattern in the otherwise well patient is a bit more controversial, again from an Emergency Medicine perspective phone your cardiology team. The CSANZ guideline contains a nice algorithm for the diagnostic approach to Brugada and also discusses management strategies in the incidental and asymptomatic Brugada.

We should also be aware that some drugs can cause Brugada-like ECG changes and should be avoided in patients with known or suspected Brugada. For more information on what not to give go to www.brugadadrugs.org which contains information for both clinicians and patients.

Check out these cases from Dr Smith's blog, here, and here, which illustrate Brugada-like changes secondary to drug therapy.

Avoiding certain drugs raises the question what should we give ?

The simple answer is electricity in the setting of acute arrhythmia. 
In those patients experiencing an arrythmic storm, or having repeated ICD shocks then iv isoprenaline has been proven to be useful and is recommended in the CSANZ guidelines.
For chronic prevention of arrythmia's the only oral agent shown to work is quinidine, but this is often very difficult to source. 

Ii is also worth noting that fever can unmask Brugada, due to impaired sodium channel function and aggressive management of fever should be instigated. Other potential precipitants include alcohol, hypokalaemia, cocaine, large carb meals, and very hot baths.


References / Further Reading

Life in the Fast Lane

Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.