Clonidine administered as adjuvant for bupivacaine in ilioinguinal-iliohypogastric nerve block does not prolong postoperative analgesia

Background: Coadministration of clonidine with local anesthetics is associated with improvement of the quality of peripheral nerve block and significant prolongation of postoperative analgesia. Better analgesia has been reported with clonidine in ilioinguinal nerve block compared with caudal use. The object of this study was to determine whether adding of 1 mu g.kg(-1) clonidine to bupivacaine 0.25% in ilioinguinal-iliohypogastric nerve block prolongs postoperative analgesia in children. Methods: Ninety-eight children ASA I-II aged between 1 and 12 years, scheduled for elective outpatient herniorrhaphy or orchidopexy were randomly allocated to receive an ilioinguinal-iliohypogastric nerve block either with 0.3 ml.kg(-1) bupivacaine 0.25% plus 1 mu g.kg(-1) clonidine or only bupivacaine. Postoperative analgesic needs, time to the first analgesic supplementation and sedation score were assessed in hospital for 6 h postoperatively and at home by telephone call. Results: Demographic data were similar in both groups. There was no statistical difference in the rate of rescue analgesia between the two groups during the first six postoperative hours (20.4% group clonidine vs 30.6% group no clonidine) (P = 0.17). A slight decrease in systolic blood pressure during surgery was reported in the clonidine group. There was no difference in the scores of sedation between the two groups. At home, 10 patients in the clonidine group and nine patients in the nonclonidine group received analgesic medication. There was no difference between the two groups regarding the number of patients receiving analgesic rescue during the first 24 h (log rank = 0.39). Parental satisfaction was high in both groups. Conclusions: Our study failed to demonstrate any advantage in addition of 1 mu g.kg(-1) clonidine to 0.25% bupivacaine for ilioinguinal-iliohypogastric nerve block compared with bupivacaine 0.25% alone.