ED50 of Intranasal Dexmedetomidine Sedation for Transthoracic Echocardiography in Children with or without a History of Cardiac Surgery for Cyanotic Congenital Heart Disease

Abstract

Background and Objective. Dexmedetomidine (DEX) can provide adequate sedation during short procedures. However, the median effective dose (ED50) of intranasal DEX sedation has not been well established in children with a history of correction surgery for cyanotic congenital heart disease (cCHD). This study was to determine ED50 of intranasal DEX sedation for transthoracic echocardiography (TTE) in young children with a history of correction surgery for cCHD. Methods. This prospective single-blinded clinical trial included 72 ASA I-II stage children aged 1-36 months with cCHD who were scheduled to undergo TTE under sedation. Children were assigned to group A ( $n=37$ ) with a previous history of cardiac surgery and group B ( $n=35$ ) with no history of cardiac surgery. Doses of intranasal DEX were analyzed by up-down sequential allocation at an initial dose of 2.3 μg/kg and an increase in steps of 0.2 μg/kg. Intranasal DEXED50 values were analyzed by the up-and-down method of Dixon-Massey and probit regression to determine ED50 and 95% confidence interval (CI) for sedation. The time to effective sedation, time to regaining consciousness, vital signs, oxygen saturation, time of performing TTE, clinical adverse effects, and characteristics of regaining consciousness were compared between the two groups. Results. ED50 of intranasal DEX sedation was 2.530 μg/kg (95% CI, 1.657-4.156) in group A and 2.500 μg/kg (95% CI, 1.987-3.013) in group B. There was no significant difference in sedation onset time and time to regaining consciousness between the two groups. Additionally, no significant adverse hemodynamic or hypoxemic effect was observed. There was no significant difference in sedation-onset time and wake-up time between the two groups ( $15\pm 4$  min vs. $16\pm 5$  min; $50\pm 11$  min vs. $48\pm 10$  min). This trial is registered with the China Clinical Trials Registry (ChiCTR-IOR-1800015038). Conclusions. ED50 of intranasal DEX sedation for TTE is similar in children with and without a history of cardiac surgery for cCHD.