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 (ED95) 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 D0.5, D1.0, D1.5 and D2.0), or intranasal isotonic saline (group C) after induction.

MAIN OUTCOME MEASURES 

The primary outcome was the ED95 dose of intranasal dexmedetomidine for preventing emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery.

RESULTS 

The incidences of emergence agitation for Groups C, D0.5, D1.0, D1.5 and D2.0 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 ED95 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 D1.5 and D2.0 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 D1.5 and D2.0 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 D1.5 and D2.0 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.