Apnoea and unconsciousness after apparent recovery from alfentanil-supplemented anaesthesia.

Several cases of recurrent respiratory depression progressing to apnoea and unconsciousness after apparent recovery from sufentanil have been reported recently. Alfentanil has the shortest elimination half-time of the narcotics used in anaesthesia, suggesting that it should be the least likely to cause postoperative respiratory depression. A case of recurrent unconsciousness and respiratory arrest after apparent recovery from alfentanil-isoflurane-nitrous oxide anaesthesia is reported. A total dose of 137 micrograms.kg-1 alfentanil was given over a 3.25-hr period to a 45-year-old female undergoing partial gastrectomy. Naloxone, 0.16 mg IV, rapidly restored spontaneous ventilation and consciousness. This case demonstrates that apnoea and unconsciousness can also recur after apparent recovery from alfentanil. Recovery room personnel should be aware of this phenomenon. Earlier detection may permit treatment before apnoea occurs. Patients given narcotic-supplemented anaesthesia should be monitored by capnography and/or pulse oximetry in the early postoperative period.