The administration of short-acting opioids before emergence is useful for preventing emergence cough induced by an endotracheal tube. This study examined the clinically effective dose of alfentanil for suppressing cough during emergence from desflurane anesthesia.

Twenty-nine adult patients undergoing elective oral surgery were enrolled in this study. During emergence from anesthesia, the patients received alfentanil diluted in 10 ml normal saline when the end-tidal vol% of desflurane decreased to 3%. The initial alfentanil dose was 16 µg/kg. The alfentanil dose for consecutive patients, determined by Dixon's up-and-down method, increased or decreased by 2 µg/kg according to a previous patient's result.

The 50% effective dose (ED₅₀) of alfentanil for suppressing cough during emergence from desflurane anaesthesia was 9.3 ± 1.5 µg/kg according to Dixon's up-and-down method. Isotonic regression revealed an ED₅₀ and ED₉₅ (95% confidence interval) of alfentanil 10.0 µg/kg (6.8-13.2 µg/kg) and 14.0 µg/kg (7.7-19.4 µg/kg), respectively.

The ED₉₅ of alfentanil for suppressing emergence cough was 14.0 µg/kg. A single bolus administration of alfentanil during emergence from anesthesia was useful for suppressing emergence cough.