Comparison of Low-Dose Sevoflurane Inhalation With Intranasal Ketamine as Rescue Sedation After Intranasal Dexmedetomidine Failure in Outpatient Children Undergoing MRI: A Randomized Control Trial.

Abstract Purpose The present study aimed to evaluate the effectiveness and safety of low-dose inhalation of sevoflurane through a face mask as a rescue remedy for sedation compared with intranasal ketamine in outpatient children undergoing magnetic resonance imaging (MRI). Design A prospective randomized control study. A total of 336 children scheduled for 3.0T MRI but were inadequately sedated after initial intranasal dexmedetomidine (3 μg/kg) were randomly divided into two groups. Methods We used the following protocol for each group: group S, inhalation of low-dose sevoflurane (end-expiratory concentration, 0.4%) through a face mask; group K, intranasal ketamine (2 mg/kg). The success rates were compared between groups as the primary endpoint. The induction time, scan time, recovery time, time to return to baseline functional status, parental and radiologist satisfaction, occurrence of adverse events, and other secondary endpoints were also compared. Findings Successful rescue sedation in groups S and K was achieved in 160 (95.2%) and 138 (82.1%) patients, respectively. Compared with group K, group S needed fewer repeat sequences and showed a significantly shorter induction time (5.7 ± 0.5 vs. 10.9 ± 2.7 min; P Conclusion Our results suggest that the inhalation of low-dose sevoflurane through a face mask can provide effective and safe rescue sedation in 1- to 6-year-old outpatient children undergoing MRI, and yields a higher success rate, shorter induction and recovery times, and higher satisfaction than the intranasal ketamine method.