The comparison of caudal ketamine, alfentanil and ketamine plus alfentanil administration for postoperative analgesia in children.

Background: Our aim was to compare the effect of single dose caudal ketamine, alfentanil or a mixture of both drugs in the treatment of pain after hypospadias repair surgery in children.

Methods: The group comprised 109 boys, ASA I-II, aged 1-9 years, who were undergoing hypospadias repair surgery as day cases. The children were randomly divided into three groups for postoperative analgesia: group 1, only alfentanil (20 microg x kg(-10) was given caudally; group 2, ketamine (0.5 mg x kg(-1)) alone; and group 3, alfentanil (20 microg x kg(-1))-ketamine (0.5 mg x kg(-1)) was given caudally. The analgesic effect of caudal block was evaluated using the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) and sedation was assessed using a five-point sedation score. The first analgesic requirement time and the number of supplementary analgesics required by each child in a 24-h period were also recorded.

Results: No statistical differences were found in demographic characteristics, haemodynamic and respiratory parameters, objective pain scores, postoperative sedation scores and duration of surgery among the groups. The median time to first analgesia was significantly shorter in group 1 than in groups 2 and 3 (P=0.009, P=0.001). Significantly more patients in group 1 required additional postoperative analgesia (paracetamol 15 mg x kg(-1)) compared with groups 2 and 3 (P < 0.001).

Conclusions: Caudal administration of ketamine 0.5 mg.kg-1 with or without alfentanil in children produced satisfactory postoperative analgesia without respiratory depression or other side-effects.