BACKGROUND

Clonidine is used increasingly in pediatric anesthesia practice to prolong the duration of action of caudal block with a local anesthetic agent. Which route of administration of clonidine is the most beneficial remains unknown. We compared the effects of caudal and intravenous clonidine on postoperative analgesia produced by caudal levobupivacaine.

METHODS

Sixty ASA I and II children, aged 2-8 undergoing inguinal hernia repair or orchidopexy surgery received standardized premedication with midazolam and general anesthesia. The children were randomized in a double-blind fashion to three groups. Group L (n = 20) patients received 0.75 ml x kg(-1) of caudal 0.25% levobupivacaine and i.v. 5 ml saline, Group L-Ccau (n = 20) patients received 0.75 ml x kg(-1) of caudal 0.25% levobupivacaine + 2 microg x kg(-1) clonidine and i.v. 5 ml saline, Group L-Civ (n = 20) patients received 0.75 ml x kg(-1) of caudal 0.25% levobupivacaine and i.v. 2 microg x kg(-1) clonidine in 5 ml of saline. Mean arterial blood pressure, heart rate, peripheral oxygen saturation, and end-tidal carbon dioxide values were recorded. Postoperative pain [Children and Infants Postoperative Pain Scale (CHIPPS) score], sedation (Ramsay Sedation Scale) and motor blockade (Modified Bromage Scale) were assessed at predetermined time points during the first 24 h after surgery.

RESULTS

Caudal clonidine significantly delayed the time to first rescue analgesic and fewer patients required rescue analgesia in the 24 h after surgery. No motor block was observed in any of the three groups on awakening or during the study period. In Group L-Ccau, the CHIPPS score was lower than in Group L at all times through 240 min (P < 0.05), while the pain scores were lower in Group L-Civ only at extubation and at 240 min (P < 0.05).

CONCLUSIONS

Caudal clonidine prolongs the duration of analgesia produced by caudal levobupivacaine without causing significant side effects and this is because of a spinal mode of action.