Comparison of caudal and intravenous clonidine in the prevention of agitation after sevoflurane in children.

Background: In children, sevoflurane anaesthesia is associated with postanaesthetic agitation, which is treated mainly with opioids. We compared the effectiveness of epidural and i.v. clonidine in the prevention of this postanaesthetic agitation.

Methods: Eighty children aged 3-8 yr (ASA I-II) received standardized general anaesthesia with inhaled sevoflurane and caudal epidural block with 0.175% bupivacaine 1 ml kg-1 for minor surgery. The children were assigned randomly to four groups: (I) clonidine 1 microgram kg-1 added to caudal bupivacaine; (II) clonidine 3 micrograms kg-1 added to caudal bupivacaine; (III) clonidine 3 micrograms kg-1 i.v. and caudal bupivacaine; and (IV) caudal block with bupivacaine, no clonidine (control). A blinded observer assessed the behaviour of the children during the first postoperative hour. Secondary end-points were the time to fitness for discharge from the postanaesthesia care unit, and haemodynamic and respiratory variables.

Results: The incidence of agitation was 22, 0, 5 and 39% in groups I, II, III and IV respectively (P < 0.05 for groups II and III compared with group IV). During the first hour after surgery, patients in groups II and III had significantly lower scores for agitation than group IV patients. Time to fitness for discharge did not differ between the four groups.

Conclusions: Clonidine 3 micrograms kg-1 prevented agitation after sevoflurane anaesthesia, independently of the route of administration. The effect of clonidine appears to be dose-dependent, as an epidural dose of 1 microgram kg-1 failed to reduce it.