THE EFFECT OF PROSTAGLANDIN E1 (PGE1) ON HEPATIC CIRCULATION IN PATIENTS UNDERGOING CARDIOPULMONARY BYPASS

Abstract

S474 INTRODUCTION: Since prostaglandin E1 (PGE1) has potent vasodilative effects upon arterial vascular smooth muscles, it has been utilized as a hypotensive agent in clinical anesthesia. This agent is also suggested to improve hepatic circulation by increasing splanchnic blood flow in spite of inducing hypotension. In the present study, we evaluated the protective effect of PGE1 on hepatic circulation during cardiopulmonary bypass (CPB) in patients undergoing elective open heart surgery by the indocyanine green (ICG) test. METHODS: Fourteen patients without hepatic dysfunction scheduled for aortic valve replacement were chosen. Anesthesia was induced and maintained by 30-50 [micro sign]g [center dot] kg-1 of fentanyl, diazepam, vecuronium and O2. Patients were divided into two groups: the control group (without PGE1, n=7) and the PGE1 group(0.025 [micro sign]g [center dot] kg-1 [center dot] min-1 of PGE1 was administered intravenously from the start of CPB,n=7) Effective hepatic blood flow was measured by detecting the plasma clearance rate of ICG (KICG) by the finger-piece method using an ICG clearance meter, before CPB and one hour after the start of hypothermic CPB. RESULTS: There is no significant difference in perfusion pressure or flow rate of CPB between the two groups. The mean value of KICG during CPB decreased by 59.9% in the control group, and decreased by 33.7% in the PGE1 group. The decrease is significantly smaller in the PGE1 group. DISCUSSION: Hepatic dysfunction after heart surgery and CPB has been frequently reported in clinical situations, and a quantitative decrease of hepatic blood flow could play an important role in post operative hepatic failure. We reported that hepatic blood flow measured by electromagnetic flowmeter decreased by 59% during hypothermic CPB with 50 [micro sign]g [center dot] kg-1 [center dot] h-1 of fentanyl in our previous animal study [1]. This result is well consistent with the result of a decrease of KICG in the control group of the present study, suggesting that hypothermic CPB would upset hepatic circulation. However, the better-maintained KICG value in the PGE1 group supported the hypothesis that administration of PGE1 during CPB could improve hepatic circulation, as the KICG value has been considered to represent effective hepatic blood flow. In conclusion, administration of a small dose of PGE1 during CPB would maintain hepatic blood flow and possibly protect liver function.