Respiratory effects of intraoperative alfentanil infusion in post-abdominal hysterectomy patients: A comparison of high versus low dose

A number of reports have been published describing (recurrent) respiratory depression after the use of alfentanil intraoperatively. To evaluate the severity of respiratory depression after the administration of alfentanil, 49 patients undergoing general anaesthesia for abdominal hysterectomy were randomly allocated to one of three groups and studied in a double-blind manner. During surgery patients received no opioids (group 1), low dose (group 2) or high dose of alfentanil (group 3). Postoperatively patients were monitored with pulse oximetry and respiratory inductive plethysmography. Postoperative pain was managed with PCA morphine.

Thirty-nine patients completed the study. Respiratory depressant effects were found in all three groups. A higher number of apnoeas (at 60 minutes in group 1: 3.3 ± 1.6; group 2: 3.5 ± 1.8; group 3: 12.2 ± 2.8) and a higher morphine consumption was found in group 2 when compared with group 1 and 3. No differences were found among the groups in the other respiratory parameters or in terms of the number of patients with respiratory depression at any one time. No cases of clear-cut recurrent respiratory depression were identified.