Use of a New Pediatric Cardiopulmonary Bypass Pump to Investigate the Effects of Pulsatile and Nonpulsatile Perfusion on Blood Flow to Vital Organs

Abstract

Background: Previously, we documented that pulsatile roller pumps generate significantly higher hemodynamic energy than nonpulsatile pumps and that this extra energy directly enhances blood flow to vital organs during and after cardiopulmonary bypass (CPB) with deep hypothermic circulatory arrest (DHCA). In the present study, our objectives were twofold: 1) to investigate the effects of pulsatile perfusion (with a new pediatric pulsatile pump that has a miniature roller head) and the effects of nonpulsatile perfusion on cerebral, renal, and myocardial blood flow and on regional cerebral oxygen saturation (rSO2) and 2) to quantify the pressure and flow waveforms in terms of hemodynamic energy, using the energy, equivalent pressure (EEP) formula, for direct comparison. Methods: Fourteen piglets (mean weight, 3 kg) underwent perfusion with either the new pulsatile pediatric pump (n=7) or a conventional nonpulsatile pediatric pump (n=7). After initiation of CPB, all animals were subjected to 25 minutes of core cooling (rectal temperature, 18°C), followed by 60 minutes of DHCA, 10 minutes of cold reperfusion, and 40 minutes of rewarming. Blood flows to vital organs were assessed with radiolabeled microspheres, and rSO2 levels were assessed with near-infrared spectroscopy. Results: The results (see table) are expressed as mean ± standard error (ml/100g/min).Table*P<0.05 vs. NP group; †P<0.05 vs. Pre-CPB within the P group; ‡P<0.05 vs. Pre-CPB within the NP group; CBF = cerebral blood flow, CPB = cardiopulmonary bypass; DHCA = deep hypothermic circulatory arrest; MBF = myocardial blood flow; NP = nonpulsatile; P = pulsatile; RBF = renal blood flow; rSO2 = regional cerebral oxygen saturation level The pulsatile and nonpulsatile groups had no significant differences in cerebral, renal, and myocardial blood flow. The post-CPB rSO2 was higher in the pulsatile group. The average change in arterial pressure (MAP) (from MAP to EEP) was −0.3% ± 1.6% in the pulsatile group and −0.17% ± 1.8% in the nonpulsatile group (P = NS). The average increase in extracorporeal circuit pressure (ECCP) (from ECCP to EEP) was 1.16% ± 3% in the pulsatile group and 1.28% ± 1.8% in the nonpulsatile group (P = NS). Conclusions: The P and NP groups had no significant differences in hemodynamic energy, and CPB with DHCA impaired cerebral, renal, and myocardial blood flow in this pediatric model. Therefore, not all pulsatile roller pumps generate sufficient energy to provide adequate blood flow to vital organs.