Pulsatile and nonpulsatile flows can be quantified in terms of energy equivalent pressure during cardiopulmonary bypass for direct comparisons.

Abstract

The purpose of this study was to quantify and compare pulsatile and nonpulsatile pressure and flow waveforms in terms of energy equivalent pressure (EEP) during cardiopulmonary bypass in a neonatal piglet model. EEP is the ratio of the area under the hemodynamic power curve and the flow curve. Piglets, mean weight of 3 kg, were used in physiologic pulsatile pump (n = 7), pulsatile roller pump (n = 6), and nonpulsatile roller pump (n = 7) groups. Data (waveforms of the femoral artery pressure, pump flow, and preaortic cannula extracorporeal circuit pressure) were collected during normothermic cardiopulmonary bypass at 35 degrees C (15 minutes on-pump), before deep hypothermic circulatory arrest (pre-DHCA) at 18 degrees C, and after cold reperfusion and rewarming (post-DHCA) at 36 degrees C. The pump flow rate was 150 ml/kg/min in all three groups. During pulsatile perfusion, the pump rate was 150 bpm in both pulsatile groups. Although there was no difference in mean pressures in all groups, EEP and the percentage increase of pressure (from mean pressure to EEP) of mean arterial pressure and preaortic cannula extracorporeal circuit pressure were higher with pulsatile perfusion compared with nonpulsatile perfusion (p < 0.001). In particular, the physiologic pulsatile pump group produced significantly higher hemodynamic energy compared with the other groups (p < 0.001). These results suggest that pulsatile and nonpulsatile flows can be quantified in terms of EEP for direct comparisons, and pulsatile flow generates higher energy, which may be beneficial for vital organ perfusion during cardiopulmonary bypass.