We investigated three different concentrations of levobupivacaine (0.125%, 0.20%, and 0.25%; n = 20 in each group) for caudal blockade in a prospective, randomized, observer-blinded fashion in children (1-7 yr) undergoing subumbilical surgery. The duration of postoperative analgesia was assessed as the time to first administration of supplemental analgesia (based on a Childrens and Infants Postoperative Pain Scale score of >or=4), and the degree of immediate postoperative motor blockade was determined by use of a 3-point scale. A dose-response relationship was observed both with regard to median duration of postoperative analgesia (0.125%, 60 min; 0.20%, 118 min; 0.25%, 158 min) and the number of patients with evidence of early postoperative motor blockade (0.125%, 0; 0.20%, 4; 0.25%, 8). The 0.125% concentration was associated with significantly less early motor blockade (P = 0.003) but was found to result in a significantly shorter duration of postoperative analgesia (P < 0.05). Based on these results, the use of 0.20% levobupivacaine might represent the best clinical option if a plain levobupivacaine solution is to be used for caudal blockade in children.
Implications: The use of 0.125% levobupivacaine for caudal blockade (1 mL/kg) in children (1-7 yr) was associated with less early postoperative motor blockade but a shorter duration of postoperative analgesia compared with 0.20% and 0.25% solutions.