Comparison of fentanyl-bupivacaine or midazolam-bupivacaine mixtures with plain bupivacaine for caudal anaesthesia in children.

Abstract

The aim of this study was to evaluate the intensity and effectiveness of 0.75 ml.kg-1 bupivacaine 0.25% with the addition of fentanyl or midazolam for caudal block in children undergoing inguinal herniorrhaphy. Seventy-five children were allocated randomly to three groups to receive a caudal block with either 0.25% bupivacaine with fentanyl 1 microg.kg(-1) (group BF) or with midazolam 50 microg.kg(-1) (group BM) or bupivacaine alone (group B) after induction of anaesthesia. Haemodynamic parameters, degree of pain, additional analgesic requirements and side-effects were evaluated. The mean systolic arterial pressure at 10, 20, 30 min after caudal block was higher in group B compared with groups BF and BM. Mean intraoperative heart rate was lower in group BF than the other groups. Adequate analgesia was obtained in all patients (100%) in group BF, 23 patients (92%) in group BM and 21 patients (84%) in group B (P > 0.05). The time to recovery to an Aldrete score of 10 was significantly shorter in group B than group BM (P < 0.05). Although not significant, it was also shorter in group B than group BF. There was no difference in additional analgesic requirements between the groups in the first 24 h. Sedation score was higher in the midazolam group at 60 and 90 min postoperatively than the other groups. Caudal block with 0.75 ml.kg(-1) 0.25% bupivacaine and 50 microg.kg(-1) midazolam or 1 microg.kg(-1) fentanyl provides no further analgesic advantages to bupivacaine alone when administered immediately after induction of anaesthesia in children undergoing unilateral inguinal herniorrhaphy.