ABSTRACT
Thirty- nine boys aged 3-7 yrs. ASA I. undergoing inguinal hernia repair were randomly allocated in this double-blind study. After induction of general anaesthesia, patients were given caudal injection [1 ml/kg] of bupivacaine 0.25% [B 0.25 group], ropivacaine 0.2% [R 0.2 group], or ropivacaine 0.375% [R 0.375 group]. The clinical effectiveness, the degree of motor block and any adverse effects were determined. Data were available for 36 children. The groups were comparable for demographic data and duration of surgery. The onset time of block was similar for B 0.25 and R 0.2 groups, but it was shorter for R 0.375 group [7.2 +/- 1.2 min, P<0.05]. A significantly longer [P <0.05] duration of analgesia was observed in the R 0.375 group [366 +/- 72 min], whereas the B 0.25 group [246 +/- 64 min] and the R 0.2 group [[268 +/- 81 min] were comparable. There was no difference [p >0.05] in the number of patients who did not require postoperalive analgesia in all groups. The degree of motor block was significantly lower [P <0.05] in the R 0.2 group than in the two other groups at 1.2 and 3 hours postoperatively. The mean time to first voiding was longer [P<0.05] in R 0.375 group compared to the two other groups. The mean time to first ambulation was significantly shorter [P< 0.05; in R 0.2 group compared to the two other groups. No significant difference was detected in the incidence of vomiting between the three groups. These findings suggest that caudal administration of 1 ml/kg of 0.2% ropivacaine provide equivalent analgesia to 1 ml/kg of 0.25% bupivacaine with less degree and duration of motor block. On the other hand ropivacaine 0.375% provides longer duration and better quality of analgesia but more intense motor block