Pharmacokinetics of Isoflurane in a Semiclosed-to-Closed System

Isoflurane was administered to eight patients initially in a semiclosed inhalation system for 30 min., and then in a closed system for 150 min. Isoflurane was administered according to a pharmacokinetic model in which the muscle was postulated to take up most of anesthesia. The blood isoflurane concentrations of the patients were measured every 15 min, during closed system anesthesia, and they remained constant. The application of the pharmacokinetic model to the semiclosed-to-closed anesthetic system is thought to be very useful.