RESUMO
Objective:To evaluate the effect of age factors on the pharmacodynamics of intranasal dexmedetomidine for sedation in the pediatric patients undergoing transthoracic echocardiography(TTE).Methods:American Society of Anesthesiologists Physical Status classification Ⅰ-Ⅲ pediatric patients, aged 1-24 months, undergoing TTE from August 2019 to May 2022, were selected. This trial was performed in two parts. Part Ⅰ Pediatric patients were divided into 4 age groups: 1-6 month group, 7-12 month group, 13-18 month group and 19-24 month group. The initial dose of dexmedetomidine was 2.0 μg/kg in 0.1 μg/kg increment/decrement. The dose of dexmedetomidine was determined by using modified Dixon′s up-and-down method. The ED 50 and 95% confidence interval of intranasally administered dexmedetomidine for sedation were calculated by the Dexon-Massey method. Part Ⅱ One hundred patients were divided into 4 age groups ( n= 25 each): 1-6 month group, 7-12 month group, 13-18 month group and 19-24 month group. The 4 groups were further divided into 5 subgroups ( n=5 each) according to the dose of dexmedetomidine: 2.1 μg/kg subgroup, 2.2 μg/kg subgroup, 2.3 μg/kg subgroup, 2.4 μg/kg subgroup, and 2.5 μg/kg subgroup. Part Ⅰ and part Ⅱ trials were combined, and the ED 95 and 95% confidence interval of intranasally administered dexmedetomidine for sedation were calculated using the probit method. Results:A total of 220 pediatric patients were enrolled. There was no significant difference in ED 50 and ED 95 of dexmedetomidine intranasally administered for sedation among groups ( P>0.05). Conclusions:The pharmacodynamics of intranasal dexmedetomidine for sedation shows no significant difference in age in the pediatric patients aged 1-24 months undergoing TTE.