Background and Objective:

Intravenous pentobarbital has been used in the past to sedate pediatric patients in preparation for MRI; however, the drug has unpredictable sedation time. Dexmedetomidine, because of its short half-life, is gaining popularity for pediatric MRI sedation in settings where the use of propofol is restricted for nonanesthesiologists. The objective was to compare induction time, recovery time, total sedation time, sedation failure rate, and adverse outcomes of patients sedated with pentobarbital and dexmedetomidine in preparation for pediatric MRI.


We reviewed a sedation database that contains clinical data for all children undergoing MRI studies while sedated with pentobarbital or dexmedetomidine between May 15, 2008, and October 30, 2010.


During the study period, 281 sedations were induced in preparation for MRI (160 with pentobarbital, and 121 with dexmedetomidine). The 2 groups were comparable with regard to age, weight, gender, and American Society of Anesthesiologists status. The dexmedetomidine group had a significantly shorter recovery time (39 ± 21 vs 49 ± 27 minutes [P = .002]) and total sedation time (107 ± 28 vs 157 ± 44 minutes [P = .0001]). Induction time was similar between the groups. The adverse event rate for the study population was 3%.


Dexmedetomidine and pentobarbital can both be used successfully for MRI sedation in children. However, dexmedetomidine had a significantly shorter recovery time and total sedation time in our population.

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