A 67-year-old man presents to the emergency department (ED) in cardiac arrest. He was found by bystanders after he collapsed and 911 was called. EMS physicians report he was found in ventricular fibrillation. Multiple attempts at defibrillation, epinephrine, and amiodarone have been unsuccessful. On ED presentation, he is unresponsive and the monitor shows ventricular fibrillation.

Problem

What is the best defibrillation strategy to treat refractory ventricular fibrillation?

Out-of-hospital cardiac arrest unfortunately occurs relatively commonly and emergency physicians must be equipped to diagnose and treat this rapidly. It is estimated that approximately 100,000 patients present with ventricular fibrillation or pulseless ventricular tachycardia annually.¹ Overall, survival is poor following cardiac arrest, and is affected by factors including age, comorbidities, witnessed arrest, early CPR, early defibrillation, and return of spontaneous circulation (ROSC).^2,3 Multiple published studies have addressed treatment of ventricular fibrillation with defibrillation and medications such as amiodarone and lidocaine.^4,5,6 Extracorporeal membrane oxygenation (ECMO) has been studied and found to improve survival after ventricular fibrillation.⁷

In attempts to improve survival of this devastating condition, investigators have reported alternative defibrillation techniques. Double sequential external defibrillation (DSED) is a technique in which rapid sequential shocks are placed from two defibrillators, with defibrillation pads in two planes, such as anterior-lateral and anterior-posterior.

Another alternative defibrillation technique is vector-change defibrillation (VC). In this technique, defibrillation pads are changed from the anterior-lateral position to the anterior-posterior position.

Published reports have demonstrated variable success rates for DSED and VC.^8-12 A recent scoping review published in The American Journal of Emergency Medicine reviewed articles between 2016 and 2019, and found 18 observational studies, which failed to demonstrate sufficient evidence for widespread implementation of DSED.¹³

A recent article published in the New England Journal of Medicine addressed defibrillation strategies for refractory ventricular fibrillation.¹⁴ This study was a randomized trial with crossover, conducted in Canada, to study DSED and VC defibrillation compared to standard defibrillation among patients with refractory ventricular fibrillation. The primary outcome was survival to hospital discharge. The investigators studied 405 patients who were randomized to standard defibrillation, VC defibrillation, or DSED. The study found that survival to hospital discharge was more common in the DSED and VC groups compared to the standard defibrillation group.

Should Practice Change on the Basis of a Single Published Study?

Medical practice rarely changes as a result of a single published study. The scientific method ensures that reliable data are reproducible, and other related studies should verify scientifically accurate facts. The results of this study verify findings of several published studies. A recently published study found higher rates of VF termination and ROSC using DSED and VS defibrillation.¹⁵ Other studies have demonstrated or suggested benefit of double sequential external defibrillation.¹⁶

In conclusion, this recent study adds to the body of knowledge that DSED and VC defibrillation can be important techniques to treat refractory ventricular fibrillation. Utilization of these techniques can be expected to improve survival for patients with refractory ventricular fibrillation.

Disclaimer

This article is not intended to be a thorough review of the topic, but rather a discussion of a recently published article and its impact on the practice of emergency medicine.

Dr. Marco is professor of emergency medicine at Penn State Health-Milton S. Hershey Medical Center and associate editor of ACEP Now.

References

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