Efficacy of different doses of intranasal dexmedetomidine in preventing emergence agitation in children with inhalational anaesthesia: A prospective randomised trial.

Background: Emergence agitation is a common paediatric complication after inhalational anaesthesia. Intranasal dexmedetomidine can prevent emergence agitation effectively, but the optimal dose is uncertain.

Objective: 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.

Design: A prospective, randomised, placebo-controlled, double-blind, clinical trial.

Setting: The study was conducted in Guangzhou Women and Children's Medical Center in China from August 2017 to December 2018.

Patients: 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.

Interventions: 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.

Main Outcome Measures: The primary outcome was the ED 95 dose of intranasal dexmedetomidine for preventing emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery.

Results: 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).

Conclusion: 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.

Trial Registry: chictr.org.cn: ChiCTR-IOR-17012415.