COMPARISON OF INDUCTION, MAINTENANCE, AND RECOVERY CHARACTERISTICS OF SEVOFLURANE-N2O AND PROPOFOL-SEVOFLURANE-N2O WITH PROPOFOL-ISOFLURANE-N2O ANESTHESIA

Induction of, maintenance of, and recovery from sevoflurane anesthesia were compared with propofol and isoflurane anesthesia when administered with nitrous oxide to patients undergoing gynecologic surgery. Seventy-five healthy (ASA I or II), consenting patients were randomly assigned to receive either (I) propofol for induction of anesthesia and isoflurane-nitrous oxide for maintenance (control), (II) propofol for induction and sevoflurane-nitrous oxide for maintenance, or (III) sevoflurane-nitrous oxide for induction and maintenance of anesthesia. Inhaled induction of anesthesia with sevoflurane-nitrous oxide was rapid (109 +/- 25 s to loss of consciousness) and without any untoward hemodynamic changes or episodes of coughing and laryngospasm. Mean arterial blood pressure after induction of anesthesia with propofol (71 +/- 11, 73 +/- 12 mm Hg for groups I and II, respectively) was lower than when sevoflurane (80 +/- 14 mm Hg) was used. The emergence time after discontinuation of isoflurane-nitrous oxide (6.7 +/- 2.2 min) was significantly longer than after propofol-sevoflurane-nitrous oxide or sevoflurane-nitrous oxide alone (4.1 +/- 2.2 and 4.0 +/- 2.0 min for groups II and III, respectively). However, later recovery events did not differ between groups. Serum fluoride levels increased after administration of sevoflurane but not isoflurane. The levels of fluoride ions correlated with the degree of exposure to sevoflurane in MAC-hours. In conclusion, induction of anesthesia with either propofol or sevoflurane-nitrous oxide was rapid and without significant side effects. Emergence and early recovery after maintenance of anesthesia with sevoflurane-nitrous oxide was significantly faster than that after an isoflurane-nitrous oxide combination.