Human hepatic blood flow and its relation to systemic circulation during intravenous infusion of bupivacaine or etidocaine

Abstract

Fifteen healthy young volunteers were studied before and during an intravenous infusion of a local anaesthetic agent. Seven received bupivacaine and eight etidocaine in a dose rate of 2 mg/min over a period of 150 min. Variables of the central systemic circulation and also the hepatic blood flow were measured repeatedly. The circulatory alterations during administration of the two drugs were compared. Comparisons with previous results concerning lidocaine and a placebo were also made. It was found that bupivacaine increased the heart rate, mean arterial blood pressure and cardiac output significantly more than did etidocaine in an equal plasma concentration. Lidocaine was intermediate between bupivacaine and etidocaine. In contrast, these three drugs had the same decreasing effect upon the splanchnic vascular resistance, which caused an almost identical increase in the estimated hepatic blood flow. The calculated vascular resistance in the systemic circulation, excluding the splanchnic, was unchanged during the infusion of etidocaine, while it decreased during the infusion of bupivacaine. Most of this discrepancy was due to the different plasma concentrations of the drugs.