Caudal and intravenous dexmedetomidine similarly prolong the duration of caudal analgesia in children: A randomized controlled trial.

BACKGROUND: Dexmedetomidine can prolong the duration of action of a local anesthetic agent, but the route of administration that is the most beneficial remains unclear. The purpose of this study was to compare the clinical effectiveness of caudal or intravenous dexmedetomidine administration on postoperative analgesia in children undergoing inguinal hernia repair given caudal levobupivacaine.

METHODS: This was a prospective, randomized, double-blinded, placebo-controlled trial. Ninety ASA I subjects, aged 2-5 year, undergoing unilateral inguinal hernia repair were enrolled. The children were randomized in a double-blind fashion to three groups. The L-Dcau group received 1 mL/kg of caudal 0.25% levobupivacaine plus 1 μg/kg dexmedetomidine and IV 20 mL saline. The L-Div group received 1 mL/kg of caudal 0.25% levobupivacaine and IV 1 μg/kg dexmedetomidine in 20 mL saline. The L group received 1 mL/kg of caudal 0.25% levobupivacaine and IV 20 mL saline. The primary outcome was the duration of analgesia, which was defined as the time from the caudal block to a Postoperative Pain Scale (CHIPPS) score ≥4. Secondary outcomes were the number of patients requiring rescue analgesia, pain intensity, the incidence of emergence agitation, intraoperative hemodynamic variations, residual motor block, and adverse effects.

RESULTS: The median duration of analgesia in the L-Dcau group was 14.2 hour compared to 6 hour in the L group with a median difference of 8.5 hour [95% CI (6.5, 10.5), P < 0.001]. The median duration of analgesia in the L-Div group was 12.4 hour compared to 6 hour in the L group with a median difference of 6.4 hour [95% CI (4, 8.5), P < 0.001]. Fewer patients in the L-Dcau and L-Div groups required rescue analgesia in the first 24 hour postoperatively compared to the L group, although there was no significant difference between the L-Dcau and L-Div groups for these outcomes. Both dexmedetomidine routes reduced the pain and the incidence of emergence agitation. No bradycardia, hypotension, or motor block was observed in any of the three groups.

CONCLUSION: Caudal and IV dexmedetomidine similarly prolong the duration of analgesia produced by caudal levobupivacaine.