Abstract 2080: Comparison of Biphasic and Monophasic Waveform Defibrillation for Out-of-Hospital Cardiac Arrest Cases with Ventricular Fibrillation: Observations from a Large-Scale Population-Based Utstein Study in Japan
[Objective] To compare the effects of biphasic defibrillation waveforms and conventional monophasic defibrillation waveforms in terms of the success of initial defibrillation and survival from out-of-Hospital cardiac arrest (OHCA) cases with ventricular fibrillation (VF).
[Methods] Designs: Population-based cohort study. Subjects: Witnessed OHCA cases of cardiac etiology with VF as initially recorded rhythm. Main outcome measure: Initial success of defibrillation by the first electrical shock and neurologically intact one-month survival. We recorded a population-based cohort of six emergency medical service (EMS) systems treated adult patients (age>=18) with witnessed OHCA of cardiac etiology (n=366) from December 1,2003 to April 30,2004 in Osaka ,Japan, by means of the Utstein Style. Among them, seventy-four patients with VF as initially recorded rhythm constituted this study cohort. Resuscitation was performed according to the AHA guideline 2000. The EMS personnel recorded all data concerning CPR on the scene, and two investigators independently reviewed all records of AED including electrocardiogram for this study. We evaluated the proportion of the initial success of defibrillation and patients’ outcome concerning the waveform of AED.
[Results] The proportion of initial success of defibrillation by biphasic AED (84.1%) was higher than that by monophasic AED (66.7%, p=0.10). One-month neurologically intact survival was significantly higher in biphasic AED patients than monophasic ones (22.7% vs. .3.6%, p<0.05; table⇓). The proportion of initial success of first defibrillation by monophasic AED (200 Jules) was 66.7%, but it elevated to 93.3% after sequence shocks up to 360 Jules.
[Conclusions] Outcomes from out-of-hospital VF were better in patients treated by biphasic AED than those by monophasic AED. When using monophasic AED, the initial energy level of 360 J would be needed.