Methods
We conducted a cluster-randomized, crossover trial among six Canadian paramedic services to evaluate DSED and VC defibrillation compared with standard defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest. Patients were treated with one of these three techniques according to the strategy randomly assigned to the paramedic service. The primary outcome was survival to hospital discharge. Secondary outcomes included termination of ventricular fibrillation, return of spontaneous circulation, and a good neurologic outcome, defined as a modified Rankin scale score of 2 or lower (indicating no symptoms to mild disability) at hospital discharge.
Results
A total of 405 patients were enrolled before the data and safety monitoring committee stopped the trial due to the 2019 coronavirus disease pandemic. A total of 136 patients (33.6%) were assigned to receive standard defibrillation, 144 (35.6%) to VC defibrillation, and 125 (30.9%) in DSED. Survival to hospital discharge was more frequent in the DSED group than in the standard group (30.4% vs. 13.3%; relative risk, 2.21; 95% confidence interval [CI], 1.33 to 3.67) and more frequent in the VC group than in the standard group (21.7% vs 13.3%; relative risk, 1.71; 95% CI, 1.01 to 2, 88). DSED but not VC defibrillation was associated with a higher proportion of patients with good neurologic outcome than standard defibrillation (relative risk, 2.21 [95% CI, 1.26 to 3.88] and 1.48 [95% CI, 0.81 to 2.71]respectively).
conclusions
Among patients with refractory ventricular fibrillation, survival to hospital discharge occurred more frequently among those who received DSED or VC defibrillation than among those who received standard defibrillation. (Funded by the Heart and Stroke Foundation of Canada, ClinicalTrials.gov number DOSE VF, NCT04080986.)
