Recovery from sevoflurane and isoflurane anaesthesia after outpatient gynaecological laparoscopy

As the low blood solubility (blood gas partition coefficient 0.69) of sevoflurane suggests a rapid emergence from anaesthesia, recovery from sevoflurane anaesthesia was compared to isoflurane in outpatient gynaecological laparoscopy. Fifty ASA I or II, consenting women participated in a randomised, controlled and single blind study. The patients received, after induction of anaesthesia with propofol, either sevoflurane or isoflurane, both with 67% nitrous oxide in oxygen, for maintenance of anaesthesia. The study drug was administered at 1 MAC (end tidal concentration 0.6% for sevoflurane and 0.5% for isoflurane) but adjusted in 0.5 MAC steps, if clinically indicated. Before the end of surgery the end tidal concentration of the study drug was reduced to 0.5 MAC. Recovery assessments were made from the time anaesthetic gases were discontinued. The subjects were able to open eyes in 2.3 (0.8–7.0) min and 4.1 (2.0–6.8) min, orientate in 2.8 (1.0–6.8) min and 4.7 (2.2–8.3) min and follow orders in 2.6 (0.7–6.8) min and 4.3 (1.2–7.3) min, in the sevoflurane and isoflurane groups, respectively ( P <0.05) median (range)]. Walking was achieved in 72 (24–464) min and 66 (35—134) min, tolerance of oral fluids in 37 (15–88) min and 35 (45–161) min and voiding in 262 (96–459) min and 217 (52–591) min in the sevoflurane and isoflurane groups, respectively (NS). Overall home readiness was achieved in 281 (96–708) min after sevoflurane group and 242 (96–591) min after isoflurane (NS). Postoperative nausea and vomiting was common in both groups (55% for sevoflurane and 45% for isoflurane) and contributed to three subjects in the sevoflurane group and four in the isoflurane group being admitted to hospital.