Efficacy of different doses of intranasal dexmedetomidine in preventing emergence agitation in children with inhalational anaesthesia

Emergence agitation is a common paediatric complication after inhalational anaesthesia. Intranasal dexmedetomidine can prevent emergence agitation effectively, but the optimal dose is uncertain.The aim of our study was to investigate the 95% effective dose (ED 95 ) of intranasal dexmedetomidine for the prevention of emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery.A prospective, randomised, placebo-controlled, double-blind, clinical trial.The study was conducted in Guangzhou Women and Children's Medical Center in China from August 2017 to December 2018.Three hundred and eighteen children scheduled for ambulatory surgery were enrolled into two age groups of less than 3 years and at least 3 years.The children in each age group were randomised into five equal subgroups to receive either intranasal dexmedetomidine 0.5, 1.0, 1.5 or 2.0 μg kg -1 (Groups D 0.5 , D 1.0 , D 1.5 and D 2.0 ), or intranasal isotonic saline (group C) after induction.The primary outcome was the ED 95 dose of intranasal dexmedetomidine for preventing emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery.The incidences of emergence agitation for Groups C, D 0.5 , D 1.0 , D 1.5 and D 2.0 were 63, 40, 23, 13 and 3% in children less than 3 years, and 43, 27, 17, 7 and 3% in children at least 3 years. The ED 95 of intranasal dexmedetomidine for preventing emergence agitation was 1.99 μg kg -1 [95% confidence interval (CI), 1.83 to 3.80 μg kg -1 ] in children less than 3 years, and 1.78 μg kg -1 (95% CI, 0.93 to 4.29 μg kg -1 ) in children at least 3 years. LMA removal time for groups D 1.5 and D 2.0 was 9.6 ± 2.2 and 9.7 ± 2.5 min, respectively, for children less than 3 years, and 9.4 ± 2.0 and 9.9 ± 2.7 min in children at least 3 years, respectively. Length of stay in the postanaesthesia care unit for Groups D 1.5 and D 2.0 was 34.3 ± 9.6 and 37.1 ± 11.2 min, respectively, in children less than 3 years, and 34.7 ± 10.2 and 37.3 ± 8.3 min in children at least 3 years, respectively. These times were longer in the D 1.5 and D 2.0 subgroups than in the control subgroup in the two age groups of less than 3 years and at least 3 years, respectively: 7.2 ± 1.9 min in children less than 3 years and 7.3 ± 2.5 min in children at least 3 years for LMA removal time, 22.2 ± 7.9 min in children less than 3 years and 22.0 ± 7.7 min in children at least 3 years for PACU stay time in control subgroup, respectively ( P < 0.05).Intranasal dexmedetomidine prevented emergence agitation after paediatric surgery in a dose-dependent manner. The optimal dose of intranasal dexmedetomidine for preventing emergence agitation was higher in younger children.chictr.org.cn: ChiCTR-IOR-17012415.