Comparative effects of desflurane and isoflurane on recovery after long lasting anaesthesia

Increasing the duration of exposure could lead to amplification of the pharmacokinetic differences between halogenated anaesthetic agents. The aim of our study was to compare anaesthesia recovery after desflurane and isoflurane, administered for more than three hours.

After informed consent, patients were randomly assigned to either desflurane (n = 15) or isoflurane (n = 15) groups. At the end of surgery, halogenated agents were discontinued and fresh gas flow was increased to 6 l.min-1 oxygen 100%.

Mean anaesthesia duration was 292 +/- 63 and 304 +/- 91 min in the desflurane and isoflurane groups respectively. After desflurane and isoflurane discontinuation, the time to opening eyes was 12 +/- 7 and 24 +/- 11 min respectively (P < 0.001); to squeeze fingers at command was 17 +/- 11 and 35 +/- 19 min (P < 0.001); to extubation was 16 +/- 6 and 33 +/- 13 min (P < 0.001); to give their name was 22 +/- 12 and 43 +/- 21 min (P < 0.001); to achieve a Steward score of 6 was 28 +/- 16 and 57 +/- 33 min (P < 0.001), to be fit for discharge from the recovery room was 46 +/- 19 and 81 +/- 37 min (P < 0.003). Ranges of times to reappearance of recovery variables in the desflurane group were less than those after isoflurane (P < 0.05).

After long duration anaesthesia lasting up to three hours, desflurane allowed recovery and extubation in approximately half the time required by isoflurane. Less variability in results suggests better predictability of recovery with desflurane.