Effects of clonidine on recovery after sevoflurane anaesthesia in children undergoing cataract surgery

Abstract

This trial assessed the effects of two doses of clonidine compared with placebo on the quality and speed of recovery in children premedicated with oral midazolam and anaesthetised with sevoflurane for cataract surgery. One hundred and twenty American Society of Anesthesiologists physical status I to II children (aged one to six years), premedicated with oral midazolam 0.5 mg/kg and undergoing elective unilateral cataract surgery with sevoflurane anaesthesia were studied. Children were randomised to intravenous clonidine 1 microg/kg (group C1, n=39), 2 microg/kg (group C2, n=41) or normal saline (group NS, n=40). Clinically successful sub-Tenon local anaesthesia block was required for a patient to be included in the analysis. The primary outcome was the incidence of postoperative agitation. Postoperative agitation was defined as a Pain Discomfort Score of -3 using items 3 to 5 only, which was assessed 15 minutely until discharge. Agitation was observed in 11/40 (27.5%) children in the NS group compared to 2/39 (5.1%) in group Cl and none in group C2 (P < 0.001). Rescue medication to treat severe agitation was required in 5/40 (12.5%) in the NS group, 1/39 (2.6%) in group C1 and none in group C2 (P = 0.025). Time to meet discharge criteria was significantly shorter in group C1 compared to the other two groups (48.4 +/- 14.0 minutes compared to C2 79.5 +/- 12.8 minutes and NS 73.1 +/- 20.4 minutes, P < 0.001). There were no significant effects on blood pressure and heart rate. Intravenous clonidine 1 microg/kg is effective for reducing agitation after sevoflurane anaesthesia and midazolam premedication in children undergoing cataract surgery. Intravenous clonidine 2 microg/kg was also effective and for a longer period, but was associated with a longer time to discharge.