Biphasic defibrillation waveform resulted in a significantly higher rate of return of spontaneous circulation compared with monophasic waveform (41.2% vs 5.9%; p=0.04).
RCT (n=34)
blinded
randomized
Absolute Event Rate: 41.2% vs 5.9%
p-value: p=0.04
OBJECTIVES: To determine whether a biphasic defibrillation waveform (BDW) would produce a superior rate of converting prolonged ventricular fibrillation (VF) into a perfusing rhythm and delay the occurrence of asystole and/or pulseless electrical activity (PEA) during the resuscitation attempt, when compared with a monophasic defibrillation waveform (MDW). METHODS: The authors performed a prospective, randomized, blinded experiment using an established swine model of prolonged VF. Thirty-four mixed-breed domestic swine (mean mass 22.9 kg) were sedated (ketamine/xylazine), anesthetized (isoflurane), and intubated. Aortic and femoral venous catheters were placed. ECG was monitored continuously. The animals were shocked into VF (3-s, 100-mA, 60-Hz shock), and were untreated for 8 minutes. Advanced Cardiac Life Support (ACLS) began with 1 minute of standardized (Thumper) chest compressions and ventilation. The animals were randomized to treatment with either BDW or MDW. Standard ACLS protocols were followed. The energy sequence was 2.5 J/kg first, 3.5 J/kg second, and 4.5 J/kg for all subsequent shocks. Outcome variables were time to event of asystole/PEA, return of spontaneous circulation (ROSC), and one-hour survival. Data were analyzed with two-tailed Fisher's exact test and Kaplan-Meier survival plots (alpha = 0.05). RESULTS: ROSC occurred more frequently in the BDW group (7/17) compared with the MDW group (1/17); p = 0.04. Survival analysis showed that the BDW significantly delayed the occurrence of asystole/PEA during the resuscitation attempt when compared with the MDW; log-ranked p = 0.02. One-hour survival rates (5/17 BDW and 1/17 MDW, p = 0.17) did not differ. CONCLUSIONS: BDW resulted in a superior rate of ROSC and delay in the occurrence of asystole/ PEA during the resuscitation attempt when compared with MDW.
Scheatzle et al. (Wed,) conducted a rct in prolonged ventricular fibrillation (n=34). Biphasic defibrillation waveform vs. Monophasic defibrillation waveform was evaluated on Return of spontaneous circulation (ROSC) (p=0.04). Biphasic defibrillation waveform resulted in a significantly higher rate of return of spontaneous circulation compared with monophasic waveform (41.2% vs 5.9%; p=0.04).