Effects of certain i.v. anaesthetics on liver blood flow and hepatic oxygen consumption in the greyhound.

The effects of increasing concentrations of thiopentone, Althesin and etomidate on liver blood flow and hepatic oxygen consumption were investigated in the anaesthetized greyhound. All three agents studied produced dose-related decreases in general cardiovascular indices such as mean arterial pressure, cardiac output and systemic vascular resistance; all three anaesthetics produced decreases in liver blood flow. During the low rates of infusion with Althesin and etomidate, significant decreases in hepatic arterial blood flow were recorded at a time when the systemic circulation was not significantly affected. Indeed, during the low rates of infusion with each of the three agents, hepatic arterial resistance and mesenteric vascular resistance increased by up to 40% above baseline values. During the high rates of infusion, hepatic arterial and mesenteric vascular resistances either returned to or decreased below control values and the decreases in liver blood flow were a consequence of generalized cardiovascular depression. Despite relatively unchanged hepatic oxygen consumption, all the anaesthetics produced significant decreases in the hepatic oxygen supply.