A prospective double-blind randomized controlled trial on the effect of dexmedetomidine towards preventing emergence agitation in patients undergoing general anaesthesia for limb surgeries

Background : Emergence agitation is a common occurrence after general anaesthesia with reported prevalence ranging from 10% to 80%. It can cause adverse implications on patients’ outcome, also can be traumatizing for the anaesthetists, staff, patients and the family members. Many theories postulates the causes and risks for emergence agitation but the exact answer is still unknown. Objectives : To investigate whether dexmedetomidine can reduce the incidence of emergence agitation, to determine whether patients’ demographic (age, gender and race), preoperative anxiety level, duration of anaesthesia and type of procedures are risk factors for emergence agitation and to observe the side effects associated with intraoperative infusion of dexmedetomidine. Design : Prospective randomized double-blind controlled trial. Methods : Fifty patients undergoing limb surgeries were recruited. Their preoperative anxiety levels were assessed using the Hamilton anxiety rating scale prior to the operative procedure. They were randomized into two groups; the dexmedetomidine group received dexmedetomidine infusion at a rate of 0.4mcg/kg/hr starting 10 minutes after induction of anaesthesia until right after extubation while the control group received volume-matched normal saline as placebo. Sevoflurane was used for maintenance of anaesthesia. Patients were assessed for emergence agitation using the Richmond agitation-sedation scale around the time of extubation. The incidence of agitation, time-to-extubation and risk factors were evaluated. Side effects of dexmedetomidine (bradycardia, hypotension and delayed awakening) were documented. Results : The incidence of emergence agitation was lower in the dexmedetomidine group than the control group (8.3% versus 40%), and this was statistically significant (P = 0.008). Although there was a considerable number of side effects (10 cases from dexmedetomidine group from total of 11 cases of side effects), the complications were mild and did not result in serious sequelae. There was no statistical significance in the difference of the mean extubation time between dexmedetomidine and control group (P = 0.098). Patient’s demographic (age, gender and race), preoperative anxiety level, duration of anaesthesia and type of surgery was determined not to be the risk factors for emergence agitation from this study. Conclusion : Dexmedetomidine infusion intraoperatively can effectively reduce the incidence of emergence agitation and its use is relatively safe without serious side effects and without prolonging the extubation time