Hepatic injury induced by anesthetic agents in rats

Recent studies on rats pretreated with phenobarbital indicate that anesthetic agents may produce hepatic injury even when metabolism of the anesthetic is almost negligible. This implies that anesthesia per se may cause hepatic injury. To evaluate this possibility, we determined the amount of hepatic injury produced by halothane, enflurane, isoflurane, thiopental, and fentanyl in rats pretreated with phenobarbital. Anesthetics were administered in doses ranging from 0.04-1.1 MAC (or their equivalent for thiopental or fentanyl) and were given with 10% oxygen for 2 h. Liver specimens taken 24 h later were examined microscopically for hepatic injury. At concentrations of 5-40% of MAC, all anesthetics produced more hepatic injury than did control conditions (i.e., exposure to only 10% oxygen for 2 h). There were no systematic differences among agents, nor did starvation before anesthetic exposure produce a difference among agents. Therefore, mechanisms other than anesthetic metabolism are needed to explain hepatic injury produced by anesthetic agents.