Caudal bupivacaine-tramadol combination for postoperative analgesia in pediatric herniorrhaphy

Administration of bupivacaine caudally has been used for postoperative analgesia after urogenital, rectal and lower abdominal surgery in children. Caudal opioids may offer analgesic advantages over bupivacaine alone but have been associated with side effects such as respiratory depression. Tramadol is an analgesic assumed to lack a respiratory depressant effect and has been shown to provide effective, long-lasting analgesia after epidural administration in adults and children. The aim of this study was to determine whether the addition of tramadol to bupivacaine caudally prolongs the duration of analgesia compared with bupivacaine alone, with respect to side effects, and whether caudal tramadol alone provides satisfactory analgesia.

Sixty boys, aged 12-84 months, undergoing unilateral herniorrhaphy, were allocated randomly to three groups. Children in group B received 0.25% plain bupivacaine 1 ml kg(-1), group BT received an identical local anesthetic dose mixed with tramadol 1.5 mg kg(-1) and group T received caudal tramadol 1.5 mg kg(-1) in 0.9% sodium chloride in the same total volume (1 ml kg(-1)). Pain and demeanour assessments were made 1, 2, 3, 4, 6, 12 and 24 h after recovery from anesthesia with reference to a three-point scale.

Analgesia time (time between caudal injection and first administration of analgesic) in group BT (13.5+/-2.2 h) was significantly longer than in the other two groups (P<0.05). In group T, more patients required additional analgesia after surgery than in the other two groups (P<0.05). Pain scores in the three groups were similar up to 4 h after operation but the mean score in group T was higher than groups B and BT 4 and 6 h after operation (P<0.05). Significantly more patients who had received caudal bupivacaine alone or with tramadol had lower pain and demeanour scores during the first 24 h after operation compared with those in the tramadol group.

Caudal administration of bupivacaine with the addition of tramadol resulted in superior analgesia with a longer period without demand for additional analgesics compared with caudal bupivacaine and tramadol alone without an increase of side effects.