This week, I wanted to quickly review some of the latest resuscitation literature. Let’s look at 3 studies.

STUDY 1

Yamamoto M et al. Diagnostic value of lead aVR in electrocardiography for identifying acute coronary lesions in patients with out of hospital cardiac arrest. Resuscitation 2019 142:97-103

Background

Emergency coronary angiography is currently recommended in patients with ST elevation, post return of spontaneous circulation(ROSC), in cardiac arrest. There is however, controversy regarding those patients without ST elevation. A recent publication showed reduced mortality and improved neurological outcomes in those who had percutaneous coronary intervention(PCI), where ST elevation was not present(1)

The study by Yamamoto et al., specifically looked at ST segment elevation in lead aVR following ROSC, in out of hospital cardiac arrest and found that abnormalities in this lead identified patients with lesions, where there was no ST segment elevation in other leads.

It has been shown that ST segment elevation in aVR may indicate a left main coronary artery or triple vessel disease where there is non ST segment elevation(2). Read the case study which looked at ST elevation in aVR here.

Type of study

• Retrospective, single centre, observational study
• Multiple exclusions
• n=74
• Carried out ECG analysis after ROSC and at early follow-up(median time = 137 minutes)

Findings

The study found that patients with ST segment elevation in aVR of >0.5mm had a significantly higher prevalence of multi vessel coronary artery disease.

ST segment elevation in aVR of >0.5mm was found to be an independent indicator for the presence of acute coronary syndrome with a specificity of 85% and a negative predictive value of 82%

Limitations of the study

• Retrospective
• Single centre
• Specifically targeted patients with presumed cardiac causes
• Patients used had a higher prevalence of VF or VT, which indicates a higher rate of cardiac causes.

What I take away from this

• Do serial ECGs
• Pay attention to aVR as it is important and will give us clues
• Talk to cardiology early when ST elevation in aVR is found

STUDY 2

Bergum D et al. ECG patterns in early pulseless electrical activity-Association with aetiology and survival of in-hospital cardiac arrest. Resuscitation 2016;104:34-39.

Background

I’ve recently written and spoken about the Littmann paper(3), where the evaluation and management of pulseless electrical activity was based on the width of the QRS complex. It appeared to be a simple and elegant approach. Read my review here. In summary a narrow QRS was associated with obstruction to flow such as outflow tract obstruction, pulmonary embolism and tension pneumothorax, whereas a wide QRS was considered to represent hyperkalaemia, Na channel blockade or ischaemia.

Type of study

• Cardiac arrests in one hospital in Norway
• n=51

Findings

• No ECG pattern was uniquely associated with an underlying cause.
• Widened QRS complexes were found in 90% of cases.

Limitations

• Only 37% had normal ECG at admission, which may show a bias towards cardiac causes
• Single centre
• Not validated
• Small number
• Other studies don’t agree with this(4).

What I take away from this

We may not always see wide or narrow complexes, however wide complexes will always make me think of metabolic causes such as hyperkalaemia or Na channel blockade.

A more empirical approach to these patients is appropriate as we can’t always remember the 4H’s and 4T’s. I’ll be covering this at the Cardiac and Resuscitation Bootcamp, where we’ll look at a blanket approach such as; oxygen, fluid, ultrasound the heart and perhaps even consider bicarb(I’ll be reviewing the studies on this shortly)

STUDY3

Holmberg M et al. Vasopressors during cardiac arrest: A systematic review and meta-analysis. resuscitation 2019;133:106-112

This was a systematic review and meta-analysis of vasopressors during cardiac arrest. This is an updated review since the 2015 ILCOR review.

Background

Since the previous ILCOR guidelines there has been a large randomised trial comparing adrenaline(epinephrine) to placebo. This is an updated review of the literature.

Findings

Adrenaline vs Placebo

• Adrenaline is associated with increased ROSC regardless of initial rhythm and is better than placebo
• It has a more pronounced effect(results trended towards statistical significance) when the initial rhythm is non-shockable.

Vasopressin vs Adrenaline

• There is no difference between the two groups

Adrenaline + Vasopressin vs Adrenaline only

• No difference between the two groups

What I take away from this

• Adrenaline
  • Improves ROSC
  • Improves survival to hospital discharge
  • Improves 3 month survival
  • May have a greater benefit for non-shockable rhythms, so give it early
• Other drugs or combinations confer no greater benefit.

References

1. Khan MS et al. Early coronary angiography in patients resuscitated from put of hospital cardiac arrest without ST-segment elevation: a systematic review and meta-analysis. resuscitation 2017;121:127-34.
2. Kosuge M et al. An early and simple predictor of severe left main and/or three-vessel disease in patients with non ST-segment elevation acute coronary syndrome. Am J Cardiol 2011;107:495-500
3. Littmann L et al. A structured teaching tool for the evaluation and management of pulseless electrical activity. Med Princ Prac. 2014;23:1-6
4. Aufderleide Tp et al. Electrocardiographic characteristics of EMD. resuscitation 1989;17:183-193

Peter Kas
MBBS MArch BArch FACEM