The Effects of Pulsatile Flow Upon Renal Tissue Perfusion During Cardiopulmonary Bypass: A Comparative Study of Pulsatile and Nonpulsatile Flow

Abstract

This study was conducted to directly compare the effects of pulsatile and nonpulsatile blood flow in the extracorporeal circulation upon renal tissue perfusion by using a tissue perfusion measurement system. A total cardiopulmonary bypass circuit was constructed to accommodate twelve Yorkshire swine, weighing 20 approximately 30 kg. Animals were randomly assigned to group 1 (n = 6, nonpulsatile centrifugal pump) or group 2 (n = 6, pulsatile T-PLS pump). A tissue perfusion measurement probe (Q-Flow 500) was inserted into the renal parenchymal tissue, and the extracorporeal circulation was maintained for an hour at a pump flow rate of 2 L/min after aortic cross-clamping. Tissue perfusion flow in the kidney was measured before bypass and every 10 minutes after bypass. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout bypass (ranging 48.5-64.1 ml/min/100 g in group 1 vs. 51.0-88.1 ml/min/100 g in group 2). The intergroup difference was significant at 30 minutes (47.5 +/- 18.3 ml/min/100 g in group 1 vs. 83.4 +/- 28.5 ml/min/100 g in group 2; p = 0.026). Pulsatile flow achieves higher levels of tissue perfusion of the kidney during short-term extracorporeal circulation. A further study is required to observe the effects of pulsatile flow upon other vital organs and its long-term significance.

An evaluation of renal functions in pulsatile and non-pulsatile cardiopulmonary bypass in the elderly

“…[22] Ji and Undar, [23] reported that the blood flow into the kidneys was four times higher with pulsatile CPB. Kim et al [16] concurred by stating that renal oxygen consumption increases at two hours and that the oxygenation of the renal cortical and medullar tissues increases during pulsatile flow. In our study, we observed a significantly higher incidence of AKI in group NP, but no patient required hemodialysis.…”

“…Peripheral vascular resistance is one of the major determinants that affects tissue perfusion during CPB, and pulsatile flow provides lower peripheral vascular resistance and higher blood supply than nonpulsatile flow. [15,16] This might be explained by various mechanism. For example, pulsatile flow triggers the vasomotor reflex and reduces the vasomotor discharge; thus, peripheral vascular resistance is also reduced.…”

A Validated System for Simulating Common Carotid Arterial Flow In Vitro: Alteration of Endothelial Cell Response

“…9,10,43,51 Furthermore, the importance of maintaining pulsatile blood flow in patients requiring mechanical interventions with left-ventricular assist devices or total artificial hearts continues to be debated. 12,27,39,56 Current cardiac prostheses provide pulsatile flow, but many second-and third-generation blood pumps that circumvent shortcomings of first-generation devices (e.g., size, mechanical and control complexities, durability, and implantability) only generate steady flow, constraining or eliminating the contributions of the different frequencies inherent in normal blood flow. 26,53 Whether a loss of physiological flow profiles affects vascular physiology or end organ function(s) requires further investigation.…”

Cardiopulmonary Bypass

“…Previously, research comparing pulsatile to nonpulsatile fl ow has not shown the superiority of one type over the other. More recently, however, pulsatile fl ow has demonstrated improved coronary artery fl ow [34], renal perfusion [35] and function [36], and pulmonary function, as well as lower interleukin-8, endothelin-1, and catecholamine levels [36,37].…”