Shorter defibrillation interval promotes successful defibrillation and resuscitation outcomes

Aim: Current cardiopulmonary resuscitation guidelines recommend performing defibrillation every 2 min during resuscitation. This study aimed to compare the rate of successful defibrillation using 1- and 2-min defibrillation intervals.

Methods: Twenty-six pigs were randomly assigned to 1- or 2-min interval groups. After inducing ventricular fibrillation (VF), we observed pigs for 2 min. Thereafter, basic life support was initiated with a 30:2 compression-to-ventilation ratio for 8 min. Defibrillation was performed with an energy of 2 J/kg at 10 min after VF and was repeated every 1 or 2 min according to randomization. Advanced cardiac life support, including continuous chest compression with ventilation every 6 s and intravenous injection of 1 mg epinephrine every 3 min, was performed until the return of spontaneous circulation (ROSC) or until 20 min after VF induction. Haemodynamic parameters and baseline arterial blood gas profiles were compared between groups. ROSC, 24 -h survival, and the neurologic deficit score (NDS) were evaluated at 24 h.

Results: Haemodynamic parameters during resuscitation and baseline arterial blood gas profiles did not differ between groups. ROSC was more frequently observed in the 1-min interval group (p = 0.047). Time to ROSC was not different between groups (p = 0.054). The 24 -h survival was higher (p = 0.047) and NDS at 24 h was lower (92 ± 175) in the 1-min interval group than in the 2-min interval group (272 ± 190) (p = 0.028).

Conclusions: Defibrillation success and resuscitation outcomes were superior when using a 1-min defibrillation interval in animal models of cardiac arrest.