Caudal neostigmine with bupivacaine produces a dose-independent analgesic effect in children

Abstract

Purpose: To evaluate the analgesic efficacy and duration of varying doses of caudal neostigmine with plain bulpivacaine and its side effects in children undergoing genito-urinary surgery. Methods: In a randomized double-blind prospective study 80 boys aged two to eight years scheduled for surgical repair of hypospadias were allocated randomly to one of four groups (n = 20 each) and received either only caudal 0.25% plain bulpivacaine 0.5 mL·kg-1 (Group I) or 0.25% plain bupivacaine 0.5 mL·kg-1 with neostigmine (Groups II-IV) in doses of 2, 3 and 4 μg·kg-1 respectively. Postoperative pain was assessed for 24 hr using an objective pain score. Blood pressure, heart rate, oxygen saturation, total amount of analgesic consumed and adverse effects were also recorded. Results: The duration of postoperative analgesia in Group 1 (5.1 ± 2.3 hr) was significantly shorter than in the other three groups (II - 16.6 ± 4.9 hr; III - 17.2 ± 5.5 hr; IV - 17.0 ± 5.8 hr; P < 0.05). Total analgesic (paracetamol) consumption was significantly more in Group I (697.6 ± 240.7 mg) than in the groups receiving caudal neostigmine (II - 248.0 ± 178.4; III - 270.2 ± 180.8 and IV - 230.6 ± 166.9 mg; P < 0.05). Groups II, III and IV were comparable with regards to duration of postoperative analgesia and total analgesic consumption (P > 0.05). Incidence of nausea and vomiting were comparable in all four groups. No significant alteration in vital signs or any other adverse effects were observed. Conclusions: Caudal neostigmine (2, 3 and 4 μg·kg-1) with bupivacaine produces a dose-independent analgesic effect (≈ 16-17 hr) in children as compared to those receiving caudal bulpivacaine alone (approximately five hours) and a reduction in postoperative rescue analgesic consumption without increasing the incidence of adverse effects.