Addition of midazolam to continuous postoperative epidural bupivacaine infusion reduces requirement for rescue analgesia in children undergoing upper abdominal and flank surgery.

STUDY OBJECTIVE: To investigate the effect of adding midazolam to continuous epidural infusion of bupivacaine for postoperative analgesia in children.

DESIGN: Prospective, randomized, double-blind, controlled study.

SETTING: Tertiary-care center.

PATIENTS: 44 ASA physical status I and II children in age groups of two to 10 years, undergoing elective upper abdominal and flank surgery.

INTERVENTIONS: At the end of surgery, patients were randomly allocated to receive epidural infusion of 0.125% bupivacaine alone (Group B) or with 20 microg/kg/hr midazolam (Group BM) for 12 hours at the rate of 0.2 mL/kg/hr.

MEASUREMENTS: Pain, motor block, and sedation were assessed at predetermined times over 24 hours. Intravenous fentanyl was used as rescue analgesic for the first 12 hours, and tramadol for next 12 hours. Patients were followed at one week, one month, and one year for any neurological deficits.

MAIN RESULTS: The number of patients requiring rescue analgesia during infusion was significantly lower in Group BM (7 vs. 17 in Group B; P < 0.001). Time to first rescue analgesia was significantly prolonged in Group BM compared with Group B (P < 0.001). Frequency of fentanyl (P < 0.001) and tramadol (P = 0.001) administration as rescue analgesia was significantly less in Group BM. Significantly lower median pain scores were obtained in Group BM than Group B at all time intervals (P < 0.05). Greater sedation scores were noted in Group BM at all time intervals postoperatively except at 4 hours (P < 0.05). No motor block was observed in any child during the study. No neurological deficit was reported in any child in the one year of follow-up.

CONCLUSION: Addition of 20 microg/kg/hr of midazolam to postoperative continuous epidural infusion of 0.125% bupivacaine reduces the requirement for rescue analgesia in children following upper abdominal and flank surgery.