Dexamethasone versus neostigmine as an adjuvant to bupivacaine 0.25% for caudal analgesia in children undergoing open inguinal hernia repair

Background
Co-administration of dexamethasone or neostigmine with local anesthetic solution for caudal block (CB) can prolong postoperative analgesia duration. We aimed to evaluate and compare the effectiveness of dexamethasone (0.1 mg/kg) versus neostigmine (2 μg/kg) when used as adjuvant to 0.25% bupivacaine for CB in children undergoing unilateral open inguinal hernia repair on the quality of postoperative analgesia.
Methods
105 children aged 1–6 years scheduled for unilateral open inguinal hernia repair were randomly allocated into three groups. Ultrasound guided CB was performed with 0.25% bupivacaine (0.75 ml/kg). 1 ml saline, dexamethasone (0.1 mg/kg) in 1 ml saline and neostigmine (2 μg/kg) in 1 ml saline were added in bupivacaine, bupivacaine-dexamethasone and bupivacaine-neostigmine respectively. Duration of postoperative analgesia, postoperative consumption of analgesic, the modified objective pain score, postoperative sedation and side effects were recorded.
Results
Duration of postoperative analgesia was prolonged in bupivacaine-dexamethasone and bupivacaine-neostigmine groups as compared to the bupivacaine group (P < 0.05). Bupivacaine-neostigmine provided the longest duration of postoperative analgesia. Postoperative analgesic consumption was lower in bupivacaine-dexamethasone and bupivacaine-neostigmine groups as compared to the bupivacaine group (P < 0.05). Bupivacaine-neostigmine provided lowest postoperative analgesic consumption. Postoperative nausea and vomiting was insignificantly different among the three groups.
Conclusion
Co-administration of dexamethasone (0.1 mg/kg) or neostigmine (2 μg/kg) with 0.25% bupivacaine for CB in pediatric patients undergoing unilateral open inguinal hernia repair prolonged postoperative analgesia duration and decreased postoperative analgesic utilization as compared to bupivacaine alone. Caudal bupivacaine-neostigmine provided more pronounced analgesic effect as compared to bupivacaine-dexamethasone.