Caudal analgesia for herniotomy: Comparative evaluation of two dose schemes of bupivacaine

Abstract

Objective: There is currently a wide range of volume schemes for bupivacaine caudal anesthesia. This study evaluated the quality of caudal analgesia achieved with a dosing scheme of 0.75 ml/kg compared with 0.5 ml/kg of 0.25% plain bupivacaine for herniotomy.
Methods: After the institutional approval, American Society of Anesthesiologists I–II patients aged between 1 and 6 years scheduled for unilateral inguinal herniotomy with consenting parents/guardian were recruited. The subjects were randomized to receive 0.5 ml/kg (Group 1) or 0.75 ml/kg of 0.25% bupivacaine. Anesthesia was maintained solely with halothane 0.5–1% in 100% oxygen. Postoperatively, pain was assessed using the objective pain scale (OPS). A favorable pain score was defined as <4 (8 point scale) or <5 (10 point scale). The primary outcome was the proportion of subjects with favorable pain scores.
Results: Fifty‑six patients were enrolled and there was no difference in sociodemographic parameters, preoperative hemodynamic variables, or duration of surgery. Proportions of subjects with favorable OPS scores showed marked differences from 45 min and peaking at 180 min (11 [39%] favorable scores in Group 1 compared to all [100%] favorable scores in Group 2, P < 0.0001). Mean time to first analgesic requirement was 126 ± 34.2 min in Group 1 compared to 249 ± 23.7 min in Group 2 (P < 0.0001). There was no difference in the incidence of adverse events between groups.
Conclusion: This study shows that 0.75 ml/kg of 0.25% plain bupivacaine is superior to the use of 0.5 ml/kg of the same concentration for postherniotomy caudal analgesia with low side effect profile.

Key words: Bupivacaine, caudal anesthesia, herniotomy, postoperative analgesia