Postoperative extradural analgesia in children: comparison of morphine with fentanyl

We have compared the efficacy and side effects of extraduralmorphine with extradural fentanyl for postoperative pain relief.Thirty children (ages 1–16 yr) were allocated randomlyto receive, after extradural administration of 0.5% bupivacaine0.75 ml kg^–1 and before surgical incision, extreduralmorphine 0.75 µg kg^–1 (group M), with an additionaldose administered 24 h later or extradural fentanyl 2 µgkg^–1 (group F) followed by a continuous extradural infusion(during 48 h). There was no major complication (respiratorydepression). Pain scores were satisfactory in both groups for48 h. Ventilatory frequency was greater in group M 20, 21, 22,23 and 25 h after the beginning of analgesia (P < 0.05).Pruritus, nausea and vomiting were less common with extraduralfentanyl (20% vs 53%, P < 0.05 and 0% vs 33%, P < 0.05)than with morphine. Urinary retention occurred with equal frequency(25%) in the two groups. After a bolus of 2 µg kg^–1,continuous extradural infusion of fentanyl 5 µg kg^–1day^–1 provided analgesia comparable to that from a dailybolus of extradural morphine 0.75 mg kg^–1 and producedfewer side effects.