Adenotonsillectomy in children: a comparison of morphine and fentanyl for peri-operative analgesia.

This study compared the effectiveness and side-effects of intra-operative fentanyl with fentanyl and morphine for elective adenotonsillectomy in a double-blind study, in 60 children randomly allocated to receive either intravenous fentanyl 1 microg x kg(-1) intra-operatively or intramuscular morphine 100 microg x kg(-1) at induction. All children received a standard anaesthetic induction with intravenous fentanyl 1 microg x kg(-1) and propofol 4-5 mg x kg(-1) and maintenance with oxygen, nitrous oxide and isoflurane. Pain scores, emetic episodes and supplemental morphine requirements were recorded for 24 h postoperatively. The overall incidence of postoperative vomiting was high in both groups: 70% in the fentanyl group and 78% in the morphine group. The incidence of postoperative vomiting was lower in the fentanyl group (p < 0.03) in the first 4 h, but similar by 24 h. Children who received morphine at any time in the first 24 h had more median (range) episodes of vomiting [2 (0-7)] than children receiving fentanyl only [l (0-3); p < 0.03]. Administration of rescue anti-emetics, pain scores in recovery and pain scores over the next 24 h were similar between the two groups.