A prospective study comparing the onset and analgesic efficacy of different concentrations of levobupivacaine with/without dexmedetomidine in young children undergoing caudal blockade.

STUDY OBJECTIVE: To investigate the onset and analgesic effect of adding dexmedetomidine to levobupivacaine for caudal block in young children. DESIGN: Randomized, prospective, double-blind study. SETTING: Women and Children Medical Center and university hospital. PATIENTS: Two hundred twelve children, American Society of Anesthesiologists physical status I or II, aged between 1 and 3 years and weighing between 8 and 18 kg, who were scheduled for elective inguinal hernia repair or hydrocele. INTERVENTIONS: Children were randomly allocated, using a computer-generated sequence of numbers, into 1 of 3 groups: caudal 0.25% levobupivacaine (Group L(0.25)), caudal 0.20% levobupivacaine (Group L(0.20)), or caudal 0.20% levobupivacaine plus 2 µg/kg dexmedetomidine (Group LD). MEASUREMENTS AND MAIN RESULTS: The primary end point of the study was the onset time of caudal levobupivacaine in children. The secondary end points of the study were the duration of analgesia and the degree of motor block in children. The 50% and 95% effective onset time (95% confidence interval) values of levobupivacaine were 8.19 minutes (7.30-9.08) and 11.17 minutes (9.44-12.91) in Group L(0.25), 10.16 minutes (8.90-11.41) and 15.85 minutes (13.14-18.57) in Group L(0.20), and 9.91 minutes (8.55-11.28) and 16.39 minutes (13.32-19.46) in Group LD, respectively. The mean durations of analgesia in these children were 7.23, 5.84, and 19.6 hours in Groups L(0.25), L(0.20), and LD, respectively. There were no significant differences in postoperative residual motor block among the 3 groups. CONCLUSIONS: Dexmedetomidine added to levobupivacaine does not have a significant effect on the onset time; however, it prolongs the duration of analgesia during caudal block in children.