High-dose dexmedetomidine sedation for pediatric MRI

To test the hypothesis that high-dose dexmedetomidine can be successfully used for pediatric magnetic resonance imaging (MRI) sedation without significant hemodynamic compromise.

The dexmedetomidine dose required to achieve optimal sedation is often higher than its recommended dose. High doses of dexmedetomidine can lead to significant hemodynamic side effects.

Dexmedetomidine use for pediatric MRI over a 1-year period was retrospectively reviewed. A dexmedetomidine bolus of 2 μg·kg(-1) intravenous followed by 1 μg·kg(-1)·h(-1) infusion was used. Dexmedetomidine efficacy, side effects, timing of side effects, and additional use of medications were analyzed. Data were compared by t-test, Mann-Whitney rank-sum test, Fisher's exact test, and anova.

High-dose dexmedetomidine was used in 77 patients, and MRI was completed in 76 (99%) patients. A second bolus of dexmedetomidine was required in 28 (36%) patients, and 22 (29%) patients required additional medications (midazolam, fentanyl, or ketamine) for adequate sedation. A 25% decrease in blood pressure (BP) was observed in 10.5%, a transient increase in BP in 3.9%, and a heart rate <60 min(-1) in 7.9% of cases. These side effects resolved spontaneously. There were no apneas or respiratory depression. Vital sign changes, recovery time, and discharge time were not significantly different in subgroups of patients receiving one or two boluses of dexmedetomidine with or without additional medications. Transient hypertension was more common in patients receiving two boluses of dexmedetomidine (P = 0.048).

High-dose dexmedetomidine can be successfully used for pediatric MRI sedation, but a significant number of children require additional medications for optimal control. Hemodynamic side effects resolved spontaneously. High-dose dexmedetomidine did not result in respiratory depression.