Defibrillation Strategies for Refractory Ventricular Fibrillation

Area of Science:

• Emergency Medicine
• Cardiology
• Critical Care

Background:

• Refractory ventricular fibrillation is a common challenge in out-of-hospital cardiac arrest.
• Standard defibrillation may be insufficient for certain cardiac arrest cases.
• Novel defibrillation strategies are needed to improve patient survival rates.

Purpose of the Study:

• To compare the effectiveness of double sequential external defibrillation (DSED) and vector-change (VC) defibrillation against standard defibrillation.
• To evaluate the impact of DSED and VC defibrillation on survival to hospital discharge and neurologic outcomes in refractory ventricular fibrillation.
• To assess these strategies in the context of out-of-hospital cardiac arrest.

Main Methods:

• A cluster-randomized trial with crossover design was conducted across six Canadian paramedic services.
• Adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest were randomized to standard, VC, or DSED defibrillation.
• Primary outcome was survival to hospital discharge; secondary outcomes included termination of ventricular fibrillation, return of spontaneous circulation, and neurologic outcome.

Main Results:

• Survival to hospital discharge was significantly higher in the DSED group (30.4%) and VC group (21.7%) compared to the standard group (13.3%).
• Double sequential external defibrillation (DSED) was associated with a higher percentage of good neurologic outcomes compared to standard defibrillation.
• The trial was stopped early due to the COVID-19 pandemic, with 405 patients enrolled.

Conclusions:

• Both DSED and VC defibrillation strategies significantly increased survival to hospital discharge in patients with refractory ventricular fibrillation compared to standard defibrillation.
• DSED demonstrated a notable improvement in neurologic outcomes, suggesting its potential benefit beyond survival.
• These findings support the adoption of DSED and VC defibrillation as advanced interventions for refractory ventricular fibrillation in out-of-hospital cardiac arrest settings.