Cardioplegia defibrillation of circulatory and metabolic phase ventricular fibrillation in a swine model.

INTRODUCTION

We previously found potassium cardioplegia followed by rapid calcium reversal (Kplegia) can achieve defibrillation in a swine model of electrical phase of ventricular fibrillation (VF) comparable to standard care.

HYPOTHESIS

Exploring 3 possible potassium dose and timing protocols, we hypothesize Kplegia may benefit resuscitation of longer duration untreated VF.

METHODS

Three separate blinded randomized placebo-controlled trials were performed with electrically-induced VF untreated for durations of 6, 9, and 12min in a swine model. Experimental groups received infusion of 1 or 2 boluses of intravenous (IV) potassium followed by a single calcium reversal bolus. Potassium was replaced by saline in the control groups. Outcomes included: amplitude spectrum area (AMSA) during VF, resulting rhythms, number of defibrillations, return of spontaneous circulation (ROSC), and hemodynamics for 1h post ROSC. Binomial and interval data outcomes were compared with exact statistics. Serial interval data were assessed with mixed regression models.

RESULTS

Twelve, 12, and 8 animals were included at 6, 9, and 12min VF durations for a total of 32. ROSC was achieved in: 4/6 Kplegia and 3/6 control animals in the 6min protocol, (p=1.00), 4/6 Kplegia and 2/6 control animals in the 9min protocol,(p=0.57), and 0/5 Kplegia and 1/3 control animals in the 12min protocol,(p=0.38). Two of 8 Kplegia animals achieved ROSC with chemical defibrillation alone.

CONCLUSIONS

The majority of animals achieved ROSC after up to 9min of untreated VF arrest using K plegia protocols. K plegia requires further optimization for both peripheral IV and intraosseous infusion, and to assess for superiority over standard care. Institutional Animal Care and Use Committee protocol #15127224.