Ketamine for caudal analgesia in children: comparison with caudal bupivacaine.

Fifty children undergoing inguinal herniotomy were allocated randomly to three groups to receive a caudal injection of either 0.25% bupivacaine 1 ml kg-1 with or without ketamine 0.5 mg kg-1 or ketamine 0.5 mg kg-1 with normal saline 1 ml kg-1. There was no significant difference in quality of pain relief, postoperative behaviour or analgesic requirements between the ketamine group and the two other groups. The bupivacaine-ketamine mixture provided better analgesia than the bupivacaine solution alone. Side effects such as motor weakness or urinary retention were not observed in the ketamine group.