Effect of ketamine on intravenous patient-controlled analgesia using hydromorphone and ketorolac after the Nuss surgery in pediatric patients

BACKGROUND: Nuss surgery is preferred in pectus excavatum repair because this procedure produces excellent cosmetic results and prevents postoperative distressed pulmonary function. However, the procedure causes severe pain due to thoracic expansion. This study was designed to investigate the analgesic effect of small doses of ketamine on an intravenous patient-controlled analgesia (IV-PCA) using hydromorphone and ketorolac for pain control after Nuss surgery. METHODS: Forty-four patients undergoing elective Nuss surgery were randomly assigned to receive hydromorphone 3 µg/kg/hr, ketorolac 0.05 mg/kg/hr and ondansetron 0.1 mg/kg/day (Group HO, n = 22) or hydromorphone 3 µg/kg/hr, ketorolac 0.05 mg/kg/hr, ondansetron 0.1 mg/kg/day and ketamine 0.15 mg/kg/hr (Group HK, n = 22) via an IV-PCA pump after surgery. A blind observer evaluated each patient using the Modified Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) for the assessment of pain control. The total administered PCA volume, side effects and parents satisfaction with pain control were assessed at postoperative 1, 4, 8, 12, 24, and 48 hours. RESULTS: There were no significant differences in Modified CHEOPS between the groups during postoperative 48 hours. The total PCA volume in group HK was significantly lower than that in group HO (P < 0.05). The side effects in both groups did not significantly differ except for pruritus. The levels of satisfaction from the parents were not significantly different between the groups. CONCLUSIONS: A small dose of ketamine on IV-PCA reduced the total administered dose of IV-PCA with hydromorphone and ketorolac and reduced the incidence of pruritus after the Nuss procedure in pediatric patients.