External cardiac defibrillation during wet-surface cooling in pigs

Abstract

Objective During surface cooling with ice-cold water, safety and effectiveness of transthoracic defibrillation was assessed. Methods In a pig ventricular fibrillation cardiac arrest model, once (n = 6), defibrillation was done first in a dry and then in a wet condition using the ThermoSuit System (Life Recovery Systems, HD, LLC, Kinnelon, NJ), which circulates a thin layer of ice-cold water (≈4°C) over the skin surface. Another time (n = 6), defibrillation was done first in a wet and then in a dry condition. Success of defibrillation was defined as restoration of spontaneous circulation, and the current and voltage of the defibrillation signal was measured. Results There was a tendency toward less number of shocks needed for achieving restoration of spontaneous circulation in the wet condition as compared with the number of shocks needed in the dry condition. The energy delivered in both dry and wet conditions was 144 ± 3 J. Discussion Transthoracic defibrillation is safe and effective in a wet condition after cooling with ice-cold water.