Median Effective Dose of Intranasal Dexmedetomidine Sedation for Transthoracic Echocardiography in Pediatric Patients with Noncyanotic Congenital Heart Disease: An Up-and-down Sequential Allocation Trial

Background: Intranasal dexmedetomidine can provide adequate sedation during short procedures. However, previous literature investigating the single-dose use of intranasal dexmedetomidine for sedation during transthoracic echocardiography in younger children is scarce, and the effects of age on sedation with intranasal dexmedetomidine remain controversial.

Objective: This study was to determine the 50% effective dose and estimate the 95% effective dose of single-dose intranasal dexmedetomidine to induce sedation in pediatric patients with noncyanotic congenital heart disease, and also determine the effect of age on the dose required for sedation.

Methods: Patients were stratified into three age groups of 1-6 months, 7-12 months, and 13-36 months. Intranasal dexmedetomidine started at a dose of 2 μg kg on the first patient. The dose of dexmedetomidine for each subsequent patient was determined by the previous patient's response using Dixon's up-and-down method with an interval of 0.25 μg kg . Sedation scale and recovery were assessed by the Modified Observer Assessment of Alertness and Sedation Scale and Modified Aldrete Recovery Score. The 50% effective dose was determined by Dixon's up-and-down method. In addition, both 50% effective dose and 95% effective dose were obtained using a probit regression approach. Other variables included sedation onset time, echocardiography time, wake-up time, discharge time, heart rate, blood pressure, oxygen saturation, respiratory rate, and adverse events such as vomiting, regurgitation, and apnea.

Results: The study population was comprised of 70 patients. The 50% effective dose (95% confidence interval) and the 95% effective dose (95% confidence interval) of intranasal dexmedetomidine for sedation were 1.8 (1.58-2.00) μg kg and 2.2 (1.92-5.62) μg kg in patients aged 1-6 months, 1.8 (1.61-1.95) μg kg and 2.1 (1.90-2.85) μg kg in patients aged 7-12 months, 2.2 (1.92-2.37) μg kg and 2.7 (2.34-6.88) μg kg in patients aged 13-36 months, respectively. The 50% effective dose in age group 13-36 months was higher than those of age group 1-6 months (P = .042) and 7-12 months (P = .043). There were no differences in sedation onset time, echocardiography time, wake-up time, and discharge time between groups. None of the patients experienced oxyhemoglobin desaturation, hypotension, or bradycardia during the procedure. No significant adverse events occurred.

Conclusion: Single-dose of intranasal dexmedetomidine was an effective agent for patients under the age of 3 years requiring sedation for transthoracic echocardiography. The 50% effective dose of intranasal dexmedetomidine for transthoracic echocardiography sedation in children aged 13-36 months was higher than in children <13 months.