||Association of Repeated Defibrillation with Outcomes for Out-of-Hospital Cardiac Arrest Associated with Ventricular Fibrillation
Takaya, Tsubota ,
Mitsuru, Honda ,
Katsunori, YoshiharaTakanori, Ikeda
60 , 2016-6 , The Medical Society of Toho University
Background: Ventricular fibrillation (VF) is a life-threatening arrhythmia, and the success rate for defibrillation decreases rapidly with increasing time since collapse. Chest compression must be interrupted during rhythm analysis and defibrillation, and this may adversely affect outcomes. This study investigated the effectiveness of repeated defibrillation for persons with cardiogenic out-of-hospital cardiac arrest (OHCA) associated with VF. Methods: Using Utstein template data collected throughout Japan during the period from July 2006 through December 2010, we identified patients with VF on an initial electrocardiogram who underwent defibrillation within 10 minutes of collapse (N=9865). To determine the optimal frequency of defibrillation, we evaluated rates of return of spontaneous circulation (ROSC) and survival at 1 month with a good neurologic outcome (cerebral performance category [CPC] 1-2). Results: ROSC was achieved in 38.2% of patients, and 28.5% had a CPC score of 1 or 2 at 1 month post-event. Receiver operating characteristic curve analysis showed that a defibrillation frequency cutoff value of 1.5 (p＜0.001; 95% confidence interval, 0.61-0.63) was optimal for ROSC. The same cutoff was associated with a CPC of 1 to 2 (p＜0.001; 95% confidence interval, 0.57-0.60). As the number of shocks increased, the rates of ROSC and good neurologic outcomes decreased. Among patients who achieved ROSC and a good neurologic outcome, half had received 1 defibrillation. Conclusions: Repeated defibrillation may be associated with worse outcomes.