Background & Objective: Caudal block with local anesthetic agents has been extensively used in pediatric patients to provide intra and postoperative analgesia for surgical procedures such as herniorrhaphy or orchidopexy. Various additives to local anesthetic solutions have been used to prolong and enhance analgesia after caudal block. The aim of this study was to evaluate effectiveness of bupivacaine 0.25% with the addition of fentanyl or neostigmine for caudal block in children undergoing inguinal herniorrhaphy.

Materials & Methods: This study was clinical trial and seventy five children were randomly allocated to three groups to receive a caudal block with either 0.75 ml/kg of 0.25% bupivacaine with 1µg/kg neostigmine (group BN) or 1µg/kg fentanyl (group BF)or 0.75ml/kg  of 0.25% bupivacaine alone (group B).Haemodynamic variables, degree of pain and sedation, additional analgesic requirements and side effects were evaluated. Mean age, weight and duration of anesthesia and surgery were similar in the three groups. Baseline systolic arterial pressure and heart rate were similar in the three groups.

Results: Mean intra-operative systolic arterial pressure and heart rate was higher in group B than the other groups but this was not statistically significant. Adequate analgesia was obtained in 21 patients (84%) in group B, and 23 (92%) in BN and BF groupd. This difference was not significant. There was no difference in degree of sedation and analgesia between the groups. The incidence of vomiting was similar in the studied groups. No other side effects were seen.

Conclusion: We found that addition of 1µg/kg fentanyl or 1µg/kg neostigmine to 0.75ml/kg of 0.25% bupivacaine provide no further analgesic advantage to 0.75ml/kg of 0.25% bupivacaine alone in caudal block in children undergoing unilateral herniorraphy.