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

•Higher concentration of levobupivacaine shortens the onset time of caudal blockade.•Dexmedetomidine does not have a significant effect on the onset time.•Caudal dexmedetomidine prolongs the duration of analgesia in children.

Study objectiveTo investigate the onset and analgesic effect of adding dexmedetomidine to levobupivacaine for caudal block in young children.DesignRandomized, prospective, double-blind study.SettingWomen and Children Medical Center and university hospital.PatientsTwo 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.InterventionsChildren were randomly allocated, using a computer-generated sequence of numbers, into 1 of 3 groups: caudal 0.25% levobupivacaine (Group L0.25), caudal 0.20% levobupivacaine (Group L0.20), or caudal 0.20% levobupivacaine plus 2 μg/kg dexmedetomidine (Group LD).Measurements and main resultsThe 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 L0.25, 10.16 minutes (8.90-11.41) and 15.85 minutes (13.14-18.57) in Group L0.20, 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 L0.25, L0.20, and LD, respectively. There were no significant differences in postoperative residual motor block among the 3 groups.ConclusionsDexmedetomidine 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.