CAUDAL CLONIDINE AND BUPIVACAINE FOR COMBINED EPIDURAL AND GENERAL-ANESTHESIA IN CHILDREN

Background: Clonidine produces analgesia by actions on alpha(2)-adreno ceptors and enhances both sensory and motor blockade from epidural inj ection of local anaesthetics. Low-dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperati ve effects of high-dose caudal clonidine when added to low concentrati on of bupivacaine for combined epidural and general anaesthesia in chi ldren. Methods: After induction of general anaesthesia caudal block wa s performed either with 1 ml . kg(-1) bupivacaine 0.175% with the addi tion of clonidine 5 mu g.kg(-1) (n=20), or with 1 ml.kg(-1) bupivacain e 0.175% (n=20). The intraoperative anaesthetic requirements, the peri operative haemodynamic effects, respiratory rate, sedation score, post operative pain scores and side effects were assessed by a blinded obse rver. A patient-controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed us ing Smiley's pain analogue scale. Results: Intraoperative haemodynamic responses did not differ between the groups. However, during emergenc e from general anaesthesia children in the clonidine group had signifi cantly lower heart rates and blood pressures compared to children in t he control group. In addition, heart rates and blood pressures were al so lower in the clonidine group in the early postoperative period (P<0 .05). Postoperative analgesia was significantly better in the clonidin e group as evidenced by the total number of requests (3 vs 12, P<0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P<0.05) adminis tered. The duration of the caudal analgesia was significantly longer i n the clonidine group (20.9+/-7.4 h vs 14.4+/-10.9 h, P<0.05). Conclus ion: Our results suggest that caudal clonidine 5 mu g.kg(-1) enhances and prolongs caudal blockade with bupivacaine 0.175% in children. It a lso blocks sympathoadrenergic responses during emergence from anaesthe sia. Sedation and cardiovascular effects are observed up to 3 h into t he postoperative period.