The efficacy of caudal ropivacaine 1, 2 and 3 mg x l(-1) for postoperative analgesia in children.

ABSTRACT

BACKGROUND: The aim of this double blind, randomized, comparative study was to assess the analgesic efficacy and incidence of motor block after caudal block using three different concentrations of ropivacaine, 1, 2 and 3 mg x l(-1), in children 4-12-year-old. METHODS: One hundred and ten children ASA I-II, scheduled for inguinal surgery, were included in the study. After induction of a standardized general anaesthetic technique, all patients received 1 ml x kg(-1) of the ropivacaine solution for a caudal block and were assessed for 8 h after the injection. RESULTS: The ropivacaine was well tolerated in all patients. Median time to treatment with analgesics was 3.3, 4.5 and 4.2 h in the 1, 2 and 3 mg x ml(-1) groups, respectively. During the first 4 h, the pain scores for both a 6-graded faces scale and a 4-graded observer scale were higher in the 1 mg x ml(-1) group than the 3 mg x ml(-1) group. The median sensory block reached T12 in all groups 1 h after the caudal block. Thereafter, the speed of regression was correlated with the ropivacaine concentration. In the patients with a sensory block from T12 and above, the median time to treatment with analgesics was longer than in the children with a sensory block below T12. The incidence of motor block was 28% in the 3 mg x ml(-1) group in comparison with 0 and 13% in the 1 and 2 mg x ml(-1) groups. CONCLUSIONS: It was concluded that 1 ml x kg(-1) of ropivacaine 2 mg x ml(-1) for caudal block provided satisfactory postoperative pain relief after inguinal surgery in 4-12-year-old children. Ropivacaine 1 mg x ml(-1) showed less efficacy while the use of ropivacaine 3 mg x ml(-1) was associated with a higher incidence of motor block with minimal improvement in postoperative pain relief.