Fentanyl supplementation of sevoflurane induction of anaesthesia

Sevoflurane induction of anasthesia has been examined extensively, but little is known about the usefulness of other drugs as adjuncts to hasten and smooth the process. Sixty patients, undergoing surgery of a type suitable for a spontaneous respiration, laryngeal mask airway anasthetic technique, were randomly allocated to receive 1.0 microgram.kg-1 intravenous fentanyl or the equivalent volume of normal saline, 30 s prior to triple-breath induction with sevoflurane. The study was double-blind. There were no differences between the groups for the times to loss of eyelash reflex, jaw relaxation, insertion of the laryngeal mask airway or regular settled breathing. However, there was a difference in the incidence of adverse airway events (breath-holding, coughing and laryngospasm) between the two groups (16.5% in the fentanyl group and 40% in the placebo group); this did not reach statistical significance. Both groups were haemodynamically stable throughout induction, although the fentanyl group had a statistically significant decrease in systolic blood pressure at 4 min compared with the placebo group, which was not considered clinically relevant. We conclude that fentanyl has no significant influence over the speed and quality of sevoflurane induction.