Median Effective Dose of Intranasal Dexmedetomidine for Rescue Sedation in Pediatric Patients Undergoing Magnetic Resonance Imaging

Background: The median effective dose (ED50) of intranasal dexmedetomidine after failed chloral hydrate sedation has not been described for children. This study aims to determine the ED50 of intranasal dexmedetomidine for rescue sedation in children aged 1 to 36 months, who were inadequately sedated by chloral hydrate administration during magnetic resonance imaging (MRI). Methods: This study was performed on 120 children, who were 1 to 36 months old and underwent MRI scanning. Intranasal dexmedetomidine was administered as a rescue sedative to children not adequately sedated after the initial oral dose of chloral hydrate (50 mg/kg). Children were stratified into four age groups. ED50 values were estimated from the up-and-down method of Dixon and Massey and probit regression. Other variables included induction time, time to wake up, vital signs, oxygen saturation, MRI scanning time, and recovery characteristics. Results: ED50 of intranasal dexmedetomidine for rescue sedation was 0.4 mu g/kg (95% CI, 0.34 to 0.50) in children aged 1 to 6 months, 0.5 mu g/kg (95% CI, 0.48 to 0.56) in children aged 7 to 12 months, 0.9 mu g/kg (95% CI, 0.83 to 0.89) in children aged 13 to 24 months, and 1.0 mu g/kg (95% CI, 0.94 to 1.07) in children aged 25 to 36 months. There were no significant differences in sedation induction time or time to wake up between the different age groups. Additionally, no significant adverse hemodynamic or hypoxemic effects were noted. Conclusions: The authors determined the ED50 for rescue sedation using intranasal dexmedetomidine after failed chloral hydrate sedation in children. It was found that ED50 increases with advancing age during the first 3 yr of life.