A Study for Pressure-Flow Relationship and Oxygenation in the Denervated Canine Liver

Choi, Kyu Taek; Park, Kwang Min; Sung, Kyu Wan; Lee, Jong Hyen; Ahn, Mee Young; Kim, Ki Hoon; Choi, Dong Rak

Abstract

BACKGROUND: Various pressor agents are used to raise systemic vascular resistance (SVR) during liver transplantation. The aim of this study was to investigate the effect of liver denervation on hepatic hemodynamic responses to vasopressors.
METHODS
This study was conducted in eight anesthetized dogs randomly assigned in to 4 groups [epinephrine-Low dose (L): 0.05 microgram/kg/min, epinephrine-High dose (H): 0.5 microgram/kg/min, ephedrine (D): 0.2 mg/kg, phenylephrine (P): 80 microgram/min]. One hour after surgical denervation of the liver, cardiac output, blood gases and hepatic blood flow were measured before and after administration of vasopressors with an electromagnetic flow meter. Oxygen consumption rate (hepatic artery plus portal vein oxygen delivery-hepatic vein oxygen delivery) was calculated. The Wilcoxon signed rank test and Kruskal-Wallis test were used for statistical analysis; The level of significance was assumed at the P < 0.05 level. Results are expressed as mean +/- SE.
RESULTS
The resulting hemodynamic values were not significantly different between groups except for hepatic vascular resistance in the P group. Hepatic blood flow decreased significantly in the P and H groups, whereas it increased significantly in the L group. Hepatic oxygen consumption and Base Excess in hepatic venous blood after vasopressors were not significantly different between groups. These results mean there were no significant differences in hepatic oxygenation between groups.
CONCLUSIONS
Various pressor agents can be used to raise SVR without jeopardizing hepatic oxygenation. However, phenylephrine and high dose of epinephrine are not recommended after liver transplantation because decreased hepatic blood flow might affect the intracellular oxygen environment adversely.