Abstract 304: The Effects of Compression Waveforms on the Outcomes of Cardiopulmonary Resuscitation in a Porcine Model of Cardiac Arrest

Abstract

Background: Previous studies have demonstrated that different mechanical compression waveforms yield different hemodynamic efficacy. In the present study, we investigated the effects of two different compression waveforms on the hemodynamics and defibrillation efficacy in a pig model of CPR. Methods: Ventricular fibrillation was electrically induced in ten male domestic pigs weighing between 35 - 40 kg and untreated for 7 mins. The animals were then randomized to receive chest compression with either trapezoidal (TW) or sinusoidal (SW) waveform. After a total 5 mins of CPR, defibrillation was attempted. ECG, aortic blood pressure (AP), right atrium blood pressure (RAP) and carotid blood flow (CBF) were continuously record and analyzed after the experiments were completed. Results: All animals were resuscitated. The total defibrillation attempts in the TW group were significantly fewer than the SW group (1.6±0.9 vs. 11±7.8, p=0.03) prior to successful resuscitation. Amplitude spectrum analysis (AMSA) and signal integral were significantly greater in each minute of CPR in the TW group when compared with the SW group (Figure 1). Significantly greater CPPs were observed in the TW group during the last 3 mins of CPR. Mean CBF showed no difference during CPR between the two groups, but the dynamic forward CBF in the first 4 mins of CPR was significantly greater in the TW group (Figure 2). Conclusions: Chest compression with trapezoidal waveform improved hemodynamics and defibrillation efficacy in the pig model of CPR. Compression waveform therefore became another important factor to be considered during mechanical chest compression.