Differential effects of halothane, enflurane, isoflurane, and sevoflurane on the hemodynamics and metabolism in the perfused rat liver in fasted rats.

The effects of volatile anesthetics on hepatic hemodynamics and metabolism were studied using isolated liver perfusion. The liver was isolated from overnight-fasted male Sprague-Dawley rats and placed in a recirculating perfusion-aeration system. The liver was perfused through the portal vein at a constant pressure of 12 cmH2O. Four volatile anesthetics, halothane, enflurane, isoflurane, and sevoflurane, were administered at concentrations identical to 1 and 2 times the minimal alveolar concentration (MAC). All the anesthetics maintained hepatic flow and decreased hepatic oxygen consumption. Among the anesthetics tested, isoflurane produced the largest decrease in hepatic oxygen consumption. At 2 MAC, the percent decrease in oxygen consumption by isoflurane was significantly greater than that by halothane. The increase in lactate concentration in the recirculating perfusate was significantly enhanced by the volatile anesthetics, and the enhancement was less remarkable in the isofluranetreated group than in the enflurane-or sevoflurane-treated groups. These results indicate that volatile anesthetics alter hepatic carbohydrate metabolism but maintain hepatic blood flow when the perfusion pressure is kept constant. Isoflurane exerts exceptional influence on hepatic oxygen consumption and lactate production, and may be preferable for operations that limit the oxygen supply to the liver.