Application of intranasal dexmedetomidine in magnetic resonance imaging of preterm infants: the ED50, efficacy and safety analysis

Abstract Background Infants undergoing magnetic resonance imaging (MRI) often require pharmacological sedation. Dexmedetomidine serves as a novel sedative agent that induces a unique unconsciousness similar to natural sleep, and therefore has currently been used as the first choice for sedation in infants and young children. Objective To determine the 50% effective dose (ED50) and 95% confidence interval (95%CI) of intranasal dexmedetomidine for MRI in preterm and term infants, and to observe the incidence of adverse events. To explore whether there were differences between the two groups, so as to provide guidance for clinical safe medication for the meanwhile. Methods A total of 68 infants were prospectively recruited for MRI examination under drug sedation (postconceptional age <60 weeks or weight <5kg). The children were divided into two groups according to whether they had preterm birth experience (Preterm group, Atterm group). The Dixon’s up-and-down method was used to explore ED50. The basic vital signs of the two groups were recorded, and the heart rate and SpO2 were recorded every 5 minutes until the infants were discharged from the hospital. The induction time, wake-up time and adverse events were recorded. Results The ED50 (95%CI) of intranasal dexmedetomidine in the Preterm group and the Atterm group were 2.23 (2.03-2.66) μg/kg and 2.64 (2.49-2.83) μg/kg, respectively (p<0.05). the wake-up time was longer in Preterm group (98.00min) than in Atterm group (81.00min) (p0.05）, and there was no significant difference in other adverse events. Conclusions Intranasal dexmedetomidine can be safely used for sedation in preterm infants undergoing MRI. Compared with term infants, the preterm infants have a lower dose of dexmedetomidine, a higher incidence of bradycardia, and a longer weak-up time.