The aim of this study was to evaluate whether the addition of clonidine, or sufentanil, or both, to a bupivacaine solution for a caudal block prolonged the period of analgesia after operation in children. Sixty ASA class I or II boys, aged between 8 months and 13 years, admitted for hypospadias repair were enrolled into a prospective randomised study. After induction of general anaesthesia and endotracheal intubation the children were allocated into four groups. Group I received 0.5 mL kg−1 bupivacaine 0.25% caudally, in addition group II received 1 mg kg−1 clonidine, group III 0.5 mg kg−1 sufentanil and group IV 0.5 mg kg−1 clonidine and 0.25 mg kg−1 sufentanil. The concentrations of clonidine and sufentanil in group IV were halved to reduce possible side-effects with higher dosages. Analgesia and side-effects were assessed 2, 4, 6, 8 and 12 h after operation. No significant differences were found among the four groups for the pain scores at 2, 4, 6, 8 and 12 h. All groups had a similar frequency of vomiting and a comparable appetite and quality of night rest during the first 24 h following the operation. There was no signficant difference in the requirement for additional doses of analgesics. The addition of sufentanil, or clonidine, or both, to bupivacaine for caudal administration provides no additional clinical benefit over bupivacaine alone.

In a prospective randomized study in children, we compared caudal bupivacaine–clonidine with bupivacaine–morphine to evaluate whether clonidine can be used as an alternative to morphine in caudal anaesthesia. Caudal anaesthesia was administered in 36 children undergoing orchidopexy, hernia repair or circumcision, using 1.5 mL kg−1 bupivacaine 0.18% with either 1 μg kg−1 clonidine (group 1) or 30 μg kg−1 morphine (group 2). Haemodynamic and respiratory parameters, anaesthetic requirements, recovery time and pain score were monitored for 24 h. Eleven children in group 1 and nine children in group 2 did not need any supplementary systemic analgesics throughout the 24-h observation period. Mean (±SD) duration of analgesia in the remaining patients was 6.3 h (±3.3 h) in group 1 and 7.1 h (±3.4 h) in group 2 (P=0.43). Recovery time after anaesthesia was significantly longer in group 1 (16.6±8.8 min) than in group 2 (11.5±4.7 min) (P< 0.05). We conclude that analgesia provided by 1 μg kg−1 clonidine added to caudal bupivacaine is comparable with that provided by 30 μg kg−1 caudal morphine with bupivacaine. Clonidine at this low dose did not cause respiratory depression.

Irrigation of the bladder after transurethral resection of the prostate is often distressing because of pain arising from detrusor muscle spasm. The effect of post-operative oral diazepam was compared with sacral epidural (caudal) block at the time of surgery, both treatments together and a control group, assessed by three-point rank scoring. Either treatment significantly reduced the incidence of pain reported by patients, P < 0.001. No patient experienced pain after both treatments.