Hepatic Circulation and Oxygen Supply-Uptake Relationships After Hepatic Ischemic Insult During Anesthesia with Volatile Anesthetics and Fentanyl in Miniature Pigs

The objective of the present study was to quantitate the effects of several anesthetics on hepatic circulation, oxygenation, and function after hepatic ischemic insult and during reperfusion. We examined the effects of different anesthetics on hepatic circulation, oxygenation, and function after hepatic ischemic insult in 28 miniature pigs weighing 20-27 kg. The preparation allowed a stepwise decrease followed by a complete cessation for 1 h of hepatic blood and oxygen supply. Immediately after the unclamping of both vessels supplying the liver and restoration of the hepatic circulation, systemic mean arterial pressure decreased to approximately 75% of preischemic values in animals anesthetized with pentobarbital and fentanyl and to 60% of preischemic values in pigs anesthetized with halothane, enflurane, or isoflurane. Total hepatic blood flow immediately returned to preischemic values without significant difference between the groups. Subsequently, hepatic oxygen delivery returned to 75%-95% of preischemic values. Hepatic oxygen uptake returned to 50%-60% of preischemic values in animals anesthetized with pentobarbital and with volatile anesthetics and up to 80% and then later to baseline values with fentanyl anesthesia. Lactate uptake by the liver returned to preischemic values only in animals given fentanyl or isoflurane but remained at approximately 50% of preischemic values during enflurane and 20%-40% during halothane and pentobarbital anesthesia. Thus, the study indicates that both isoflurane and fentanyl anesthesia provide more protection from ischemic insult than do halothane, enflurane, or pentobarbital anesthesia.