Abstract 10134: Potassium Cardioplegia During CPR for Porcine VF Arrest: A Blinded Randomized Controlled Trial

Abstract

Introduction: Potassium cardioplegia-induced transient asystole may conserve myocardial energy and improve outcome in ventricular fibrillation (VF) cardiac arrest. Hypothesis: We hypothesized potassium infusion during VF arrest would lead to an increase in intra-arrest amplitude spectrum area (AMSA) prior to defibrillation, and improved hemodynamic parameters in those animals that attained return of spontaneous circulation (ROSC). Methods: Twelve swine were randomized to KCl or placebo in a randomized controlled trial, and 10 were included in an amended protocol. After initiation of monitoring, induction of anesthesia, and instrumentation of the aorta and right atrium, VF was electrically induced. After 4 minutes, 1.5 meq/kg KCl or placebo was infused in blinded fashion in a peripheral ear vein and mechanical chest compressions and ventilations were begun. Initial defibrillation was performed 10 minutes post VF induction, as appropriate. Animals without ROSC received continued resuscitation per Advanced Cardiac Life Support(ACLS) guidelines for 10 more minutes. Animals that achieved ROSC were monitored for 30 more minutes. The primary outcome, change in AMSA from just before study drug infusion to 5 minutes post infusion, was compared using nonparametric statistics. Results: Six animals were randomized to KCl and 4 to Placebo. KCl infusion induced approximately 1 minute of transient asystole at the dosage used. The mean change in normalized AMSA was -0.24 in the KCl and 0.21 in the Placebo group, with a median difference of -0.50 (95%CI -0.79 to -0.09), p=0.038, favoring Placebo. Five of 6 (83%) animals in the KCl group and 2 of 4 (50%) in the Placebo group developed an organized, though not necessarily, perfusing rhythm with the difference in proportion 33% (95% CI -33 to 86). One of 6 (17%) animals in the KCl and 2 of 4 (50%) in the Placebo group achieved ROSC with the difference in proportion -33% (95%CI -93 to 33). Hemodynamics were not quantitatively compared post ROSC due to limited survivors. One animal in each group required norepinephrine infusion. Conclusions: Potassium as a single agent did not benefit AMSA or ROSC in this porcine model of VF arrest.