Why this research?
Refractory ventricular fibrillation is common in patients who suffer cardiac arrest outside the hospital. In these patients, additional resuscitation attempts without adjustment of the defibrillation strategy are usually unsuccessful. Double sequential external defibrillation (DSED) and vector change (VC) defibrillation may provide better outcomes than continuing with standard defibrillation (figure).
The different positions of the defibrillation electrodes: (a) standard defibrillation, (b) alternate vector defibrillation (front-back, vector change defibrillation) and (c) dual sequential external defibrillation (simultaneously with two defibrillators). (edited from a figure published elsewhere[8])Research question
Do DSED and VC defibrillation provide better outcomes than standard defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest?
How was this investigated?
The DOSE VF study, a cluster-randomized crossover study among six Canadian paramedical services, compared the effect of DSED and VC defibrillation with standard defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest. Paramedical services were randomized between DSED, VC defibrillation and standard defibrillation. For all defibrillation strategies, the first three shocks had to be delivered using the standard defibrillation method. A crossover took place every 6 months and each paramedic service had to switch to each of the defibrillation strategies at least once. The primary outcome measure was survival to hospital discharge. Secondary outcomes were: termination of ventricular fibrillation, return of spontaneous circulation and good neurological outcome at hospital discharge, defined as a score ≤ 2 on the modified Rankin scale.
Main results
When the data and safety monitoring board recommended premature termination of the study due to the corona pandemic, 405 patients had been recruited, of whom 125 (30.9%) had DSED, 144 (35.6%) had VC defibrillation and 136 (33.6%) received standard defibrillation. Survival to hospital discharge was more common in the DSED group (30.4 vs. 13.3%; relative risk (RR): 2.21; 95% CI: 1.33-3.67 ) and VC defibrillation group (21.7 vs. 13.3%; RR: 1.71; 95% CI: 1.01-2.88), compared with the standard defibrillation group. Termination of ventricular fibrillation was also more common in the DSED group (84.0 vs. 67.6%; RR: 1.25; 95% CI: 1.09-1.44) and the VC defibrillation group (79, 9 vs. 67.6%; RR: 1.18; 95% CI: 1.03-1.36). Furthermore, patients receiving DSED were more likely to have return of spontaneous circulation (46.4 vs. 26.5%; RR: 1.72; 95% CI: 1.22-2.42) and good neurological outcome at hospital discharge (27.4 vs. 11.2%; RR: 2.21; 95% CI: 1.26-3.88) than patients in whom standard defibrillation was performed; however, this did not apply to patients receiving VC defibrillation.
2023-09-18 04:00:00
#Defibrillation #strategies #refractory #ventricular #fibrillation
