[Double-blind testing of alfentanyl and fentanyl in total intravenous anesthesia]

Fentanyl or alfentanil (at a dose ten times that of fentanyl) was administered to fifty healthy patients undergoing elective surgery. They were given in a double-blind manner for analgesia in a total intravenous anaesthesia technique to see if differences existed in their respiratory depressant, analgesic or sedative effects. They were combined in the same syringe with etomidate and given by intravenous bolus injection followed by a continuous intravenous infusion. Analgesia was generally adequate for the operations in this study. Respiratory depression (respiratory rate less than ten) lasted about ten minutes after drug administration, ceased in all patients. The return of respiratory rate, consciousness, and psychomotor performance to control was similar in the groups receiving fentanyl or alfentanil. This study showed that alfentanil and fentanyl have equivalent potency and duration of action when used in a ten to one ratio. Furthermore, the technique provided good operating conditions but there was a high incidence of postoperative drowsiness, nausea and vomiting.