The addition of clonidine 2 μg·kg^-1 does not enhance the postoperative analgesia of a caudal block using 0.125% bupivacaine and epinephrine 1: 200 000 in children: A prospective, double-blind, randomized study

Background: In this prospective, randomized, double-blind study, we compared the efficacy of 0.125% bupivacaine and epinephrine 1 : 200 000 with and without clonidine 2 μg·kg^-1 for 'single shot' pediatric caudal analgesia. Methods: Thirty ASA I and II children, ages 2-8 years, undergoing outpatient surgical procedures below the umbilicus received 1 ml·kg^-1 0.125% bupivacaine with fresh epinephrine 1 : 200 000 and clonidine 2 μg·kg^-1 (group-C) or 1 ml·kg ^-1 0.125% bupivacaine with epinephrine 1 : 200 000 (group-NC). All patients received a standardized general anesthetic (induction with 67% N ₂O in O₂ and sevoflurane followed by isoflurane maintenance). Primary outcome measures were time to first rescue analgesic and number of patients requiring rescue analgesic at 4, 6, 8, 12, and 24 h after caudal placement. Secondary outcome measures included: extubation times, Objective Pain Scale (OPS) scores, sedation scores, time in postanesthesia care unit (PACU), discharge time, number of analgesic doses given in 24 h following caudal blockade, and adverse effects (vomiting, hypotension, and bradycardia). Results: There were no differences in demographics, investigated parameters, or adverse effects between groups. Conclusions: We found that the addition of clonidine 2 μg·kg^-1 to 0.125% bupivacaine with fresh epinephrine 1 : 200 000 for caudal analgesia did not significantly delay the time to first rescue analgesic or decrease the overall need for rescue analgesics in children 2-8 years undergoing surgical procedures below the umbilicus.