Prospective randomized controlled comparison of caudal bupivacaine and ropivacaine in pediatric patients

Bupivacaine and ropivacaine are commonly used agents for caudal anesthesia in pediatric patients. Several studies have shown different motor and cardiovascular effects of two drugs.

The primary objective of this study was to evaluate the efficacy of both drugs and secondary objective was to compare motor blockade and hemodynamic effects caused by them.

This was a prospective randomized controlled study including 50 consecutive patients in the age group of 1-10 years, who underwent urogenital surgeries under general anesthesia. Caudal block was given with either bupivacaine (0.25%) 1 ml/kg (Group I) or ropivacaine (0.25%) 1 ml/kg (Group II). Heart rate (HR) and systolic blood pressure (SBP) were recorded as a baseline, before the anesthesia induction and then at 30, 60 and 90 min after incision. Pain scores were assessed post-operatively by a single observer at 30 min and then at 2, 4, 8 and 12 h with a 5-point observer pain score (OPS). Patients and observer were blinded to the medication given. The duration of absolute analgesia was defined as the time from caudal injection until the pain score was >2. Motor block was assessed by modified Bromage scale. Statistical analysis was performed with Chi-square test, Student's t-test and log-rank test. P < 0.05 were considered as significant.

HR and SBP measured at a specific time intervals showed no significant difference. All the patients had adequate intraoperative analgesia. Mean OPS were comparable between two groups. Duration of absolute analgesia was 276.8 (11) min in Group I and 284.8 (12) min for Group II. The only significant difference was the motor-block score at 2, 3 and 4 h after surgery, although the score was same 1 h post-operatively.

The efficacy of both ropivacaine and bupivacaine is almost same in terms of onset and duration of analgesia. Therefore, the motor blockade caused by ropivacaine is less; there is no significant difference in cardiovascular events.