Median Effective Dose of Intranasal Dexmedetomidine Sedation for Transthoracic Echocardiography Examination in Postcardiac Surgery and Normal Children: an Up-and-down Sequential Allocation Trial.

BACKGROUND:Dexmedetomidine (DEX) has been used for sedation in young infants and children undergoing transthoracic echocardiography (TTE). The median effective dose of intranasal DEX has not been described for postcardiac surgery children. Postcardiac surgery children could require more DEX to achieve satisfactory sedation for TTE examination than children suspected of congenital heart disease.OBJECTIVES:To study whether postcardiac surgery children need a larger dose of DEX for TTE than normal children.DESIGN:A double-blind sequential allocation trial with doses determined by the Dixon and Massey up-and-down method.SETTING:A tertiary care teaching hospital from 25 October to 30 November 2016.PATIENTS:Children under the age of 3 years requiring intranasal DEX for TTE.INTERVENTIONS:Children were allocated to a postcardiac surgery group (n = 20) or a normal group (n = 19). The first patient in both groups received intranasal DEX (2 μg kg): using the up-and-down method of Dixon and Massey, the next dose was dependent on the previous patient's response.MAIN OUTCOME MEASURES:Median effective dose was estimated from the up-and-down method of Dixon and Massey and probit regression. A second objective was to study haemodynamic stability and adverse events with these doses.RESULTS:The median effective dose (95% confidence interval) of intranasal DEX was higher in postcardiac surgery children than in normal children, 3.3 (2.72 to 3.78) μg kg versus 1.8 (1.71 to 2.04) (μg kg), respectively (P < 0.05). There were no significant differences in time to sedation, time to wake-up or TTE examination time between the two groups for successful sedation. Additionally, there were no significant adverse events.CONCLUSION:The median effective dose of intranasal DEX for TTE sedation in postcardiac surgery children was higher than in normal children.TRIAL REGISTRATION:chictr.org.cn identifier: ChiCTR-OOC-16009846.