Effect of Pulsatile Versus Nonpulsatile Blood Flow on Renal Tissue Perfusion in Extracorporeal Circulation

Kim, Hyun Koo; Son, Ho Sung; Fang, Yong Hu; Park, Sung Young; Kim, Kwang Taik; Sun, Kyung; Kim, Hark Jei

Abstract

BACKGROUND: It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. MATERIAL AND METHOD: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20~30 kg. Animals were randomly assigned to group 1 (n=6, nonpulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system (QFlow(TM)-500) was inserted into the renal parenchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. RESULT: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5~4 in group 1 vs. 65.8~8.3 mL/min/100 g in group 2, p=0.026~0.45). The difference was significant at 30 minutes bypass (47.5+/-18.3 in group 1 vs. 83.4+/-28.5 mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS).
CONCLUSION
Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.