Background: Survival from ventricular tachycardia (VT) or ventricular fibrillation (VF) arrest is inversely related to delay to defibrillation. The automated external defibrillator (AED) has improved survival after out-of-hospital VT/VF arrest by decreasing time to defibrillation. The purpose of this study was to determine whether survival to discharge after in-hospital cardiac arrest caused by VT/VF could be improved via an institution-wide change from a standard monophasic defibrillator to a biphasic defibrillator with AED capability.
Methods and results: After extensive staff education, all standard defibrillators were replaced by AEDs at a single institution. Outcomes were analyzed for 1 year before the change and 1 year after the change using a prospective database. In patients whose initial rhythm was VT/VF, AEDs were not associated with improvement in time to first shock (median 1 minute for both cohorts, p = 0.79) or survival to discharge (31% vs. 29%, p = 0.8) compared with standard defibrillators. In patients whose initial rhythm was asystole or pulseless electrical activity, AEDs were associated with a significant decrease in survival (15%) compared with standard defibrillators (23%, p = 0.04). The overall AED cohort showed no difference in survival to discharge compared with the standard cohort (18% vs. 23%, p = 0.09).
Conclusions: Replacement of standard monophasic defibrillators with biphasic AEDs was associated with unchanged survival after in-hospital VT/VF arrest and decreased survival after in-hospital asystole or pulseless electrical activity arrest.