Comparison of Resuscitation Outcomes Between 2‐ or 3‐Stacked Defibrillation Strategies With Minimally Interrupted Chest Compression and the Single Defibrillation Strategy: A Swine Cardiac Arrest Model

Background There is controversy over whether the number and mode of electrical shock are optimal for successful defibrillation. Methods and Results Fifty‐four pigs were randomly assigned to 3 groups. After inducing ventricular fibrillation and a 2‐minute downtime, basic life support was initiated with a 30:2 compression/ventilation ratio for 8 minutes. Subsequently, 20 minutes of advanced life support, including asynchronous ventilation, every 10 chest compressions with 15 L/min of oxygen, was delivered. Animals of the single shock group received a single shock, animals of the 2‐stacked shock group received 2 consecutive shocks, and animals of the 3‐stacked shock group received 3 consecutive shocks. Animals with the return of spontaneous circulation underwent post–cardiac arrest care for 12 hours. The rates of successful defibrillation, return of spontaneous circulation, 24‐hour survival, and 48‐hour survival and neurological deficit score were compared between the groups. Hemodynamic parameters, arterial blood gas profiles, troponin I, and cardiac output were not different between the groups. There was a significant difference in chest compression fraction between the single and 3‐stacked shock groups ( P <0.001), although there was no difference between the single and 2‐stacked shock groups ( P =0.022) or the 2‐stacked and 3‐stacked shock groups ( P =0.040). The rates of successful defibrillation, return of spontaneous circulation, 24‐hour survival, and 48‐hour survival were higher in the 2‐ and 3‐stacked shock groups than in the single shock group ( P =0.021, P =0.015, and P =0.021, respectively). Neurological deficit score at 48 hours was not different between the groups. Conclusions A stacked shock strategy was superior to a single shock strategy for successful defibrillation and better resuscitation outcomes in treating ventricular fibrillation.