Comparison of caudal ropivacaine coadministered with fentanyl and ketamine in pediatric surgery

Background Caudal blockade with local anaesthetics is a well-known regional technique for postoperative analgesia in infants and children. It has the disadvantage of a relatively short duration of postoperative analgesia. Many analgesic additives have been suggested to increase the duration and effectiveness of analgesia. The aim of this study was to evaluate and compare the analgesic properties of fentanyl and ketamine as additives to caudal ropivacaine in paediatric surgery. MethodsSeventy-five children, 1–6 years of age, undergoing surgical procedures below the umbilicus were enrolled in the present double-blind study. The patients were evenly and randomly divided into three groups; each received ropivacaine 0.2%, 1 mg/kg, caudally after sevoflurane induction of anaesthesia. Group I received ropivacaine alone, group II received fentanyl 1 mg/kg with ropivacaine and group III received ketamine 0.5 mg/kg with ropivacaine. Heart rate, mean arterial pressure and arterial oxygen saturation were recorded preoperatively and every 10 min intraoperatively. Postoperatively, the duration of caudal analgesia was determined, the analgesic effect of the caudal block was evaluated using the Hannallah Pain Scale and motor blockade was assessed using a modified Bromage Scale at 1-, 2-, 4-, 6-, 8-, 10- and 12-h time intervals. The incidence of any side effects, for example vomiting, psychomimetic effects, etc., was also determined. Results The three groups were comparable in terms of demographic data and duration of anaesthesia. The changes in heart rate and mean arterial pressure were clinically nonsignificant. No patient experienced respiratory depression or oxygen desaturation. The duration of caudal analgesia was highly and significantly longer in group RK (10± 0.5 h) than both group RF (4 ±0.76 h) and group R (4 ± 0.04 h) (P 0.001). In group RF, the duration of analgesia was minimally longer than group R, with anonsignificant difference (P 0.05). Therefore, group RK had the longest duration and group R had the shortest duration of analgesia. Postoperatively, there were highly significant differences (P 0.001) between the Hannallah Pain Scale scores of both group RK and group RF and group R at 2 h, and a highly significant difference (Po .001) at 4, 6, 8, 10 and 12 h between the Hannallah Pain Scale scores of group RK and group RF, in favour of the analgesic effect in group RK, with the least pain scores. There were insignificant differences (P 0.05) between all groups in the postoperative motor block scores at 1, 2, 4, 6, 8, 10 and 12 h. The incidence of vomiting was significantly higher in group RF (eight patients) and group RK (six patients) than group R (only one patient) (P 0.05). Only two children developed emergence agitation in group RK, whereas there were no psychomimetic effects in the other two groups. Conclusion It was found that the addition of ketamine 0.5 mg/kg to ropivacaine 0.2% prolonged the duration of caudal analgesia highly and significantly, whereas the addition of fentanyl 1 mg/kg to ropivacaine 0.2% led to a nonsignificant increase in the duration ofcaudal analgesia over ropivacaine 0.2% alone. The best quality of analgesia was in group RK.