Anaesthesia with desflurane-nitrous oxide in elderly patients. Comparison with isoflurane-nitrous oxide

BACKGROUND: Desflurane is a new volatile anaesthetic, very little soluble. We wished to compare efficacy, safety, and emergence and recovers; profiles of desflurane-N2O versus isoflurane-N2O anaesthesia in elderly patients. METHODS: Experimental design: single blind, prospective randomised study. Setting: operating rooms of two major teaching hospitals affiliated with the University of Milan. Patients: fifty-seven patients ASA physical status II or III, aged 65 or older, undergoing urological (non-endoscopic), orthopaedic or gynaecological (non-laparoscopic) surgery of at least one hour duration, were randomly assigned to receive general anaesthesia with either desflurane or isoflurane in 60% N2O- 40% O2, after standardised premedication and induction. MEASUREMENTS: vital signs, end-tidal agent, narcotic requirement, and adverse event appearance were monitored throughout the study. RESULTS: Twenty-eight patients received desflurane and 29 isoflurane. Demographics, anaesthesia duration and exposure, and intraoperative fentanyl requirement were comparable in the two groups. Immediate emergence from anaesthesia (time to extubation and hand grip on command) was faster in desflurane group, albeit not significantly (8.4 +/- 6.4 vs 11.0 +/- 6.5 min and 8.6 +/- 6.0 vs 11.8 +/- 6.0); on the contrary, early recovery (time to state the name and date of birth) was significantly shorter in patients receiving desflurane (11.1 +/- 6.2 vs 17.3 +/- 7.8 min and 13.1 +/- 6.0 vs 20.9 +/- 10.9 min). Only 24 patients (12 in desflurane and 12 in isoflurane group) did need postoperative fentanyl administration; among them, requirement was significantly higher in desflurane patients (3.4 +/- 1.1 vs 2.4 +/- 1.3 micrograms.kg-1. Total time in recovery room was not different between anaesthetics, as well as adverse event prevalence and severity. CONCLUSIONS: Early recovery in elderly patients is faster after desflurane than isoflurane anaesthesia; this might contribute to increased requirement of postoperative analgesia. Occurrence of adverse event is comparable between the two anaesthetics.