Bupivacaine 0.125% produces motor block and weakness with fentanyl epidural analgesia in children

Abstract

Purpose: Epidural infusions of fentanyl (2 μg·ml-1) alone or combined with bupivacaine 0.125% were compared for perioperative analgesia, motor block and other side-effects in children who underwent urological surgery. Methods: In a prospective, double-blind study, 42 children, ASA I-II, 1-16 yr, were randomly allocated to receive either epidural F (fentanyl bolus 2 μg·kg-1 in 0.5 ml·kg-1 saline followed by 2 μg·ml-1 fentanyl infusion) or epidural F-B (fentanyl bolus 2 μg·kg-1 in 0.5 ml·kg-1 bupivacaine 0.25% followed by 2 μg·ml-1 fentanyl infusion in bupivacaine 0.125%) after induction of general anaesthesia. Adequacy of analgesia, lower limb motor block and side- effects were assessed four hourly postoperatively. Results: Both infusion regimens provided excellent analgesia (median objective pain scores = 0). Epidural infusion rates were similar in the F (0.29 ± 0.07 ml·kg-1·hr-1) and F-B (0.26 ± 0.05 ml·kg-1·hr-1) groups. Three children in the F group and all children in the F-B group developed lower limb weakness. (P < 0.05) Bromage scores were different in the F group (median 0, range 0-0.66) compared with the F-B group (median 0.33, range 0-1) (P < 0.001). Other side-effects did not differ. Conclusion: Postoperative epidural fentanyl infusion provides equipotent analgesia to administration of a solution including both fentanyl and bupivacaine 0.125% and causes less lower limb weakness. No reduction in the fentanyl requirement resulted from the addition of bupivacaine 0.125%.