Comparison of Outcomes During MRI Sedation With Midazolam-dexmedetomidine Versus Ketamine-dexmedetomidine

Comparison of Outcomes During MRI Sedation With Midazolam-dexmedetomidine Versus Ketamine-dexmedetomidine

This study will compare 2 different sedation drugs (Ketamine and Midazolam) when they are used with another sedating medicine called Dexmedetomidine for MRI sedation. This study hopes to measure the impact each drug has on what happens during and after MRI sedation with Dexmedetomidine

The will be a randomized, double-blind, prospective study. All patients referred to UCSS for brain MRI and for whom dexmedetomidine would otherwise be the sedation regimen of choice will be eligible for enrollment. The investigators propose to limit the study to patients undergoing only brain MRI as these studies are of a predictable length (25-30 minutes); therefore the sedation regimen can be more easily standardized. Parents of eligible patients would be approached prior to or during the pre-sedation assessment and told about the study and, if they agree to enroll, informed consent would be obtained. Assent will be obtained from children 7 years of age and greater, if they are otherwise developmentally capable of giving assent. The goal is to enroll 50 subjects (25 per treatment group) which would be sufficient to detect a 25% or greater difference in the mean maximal heart rate or blood pressure decrease from baseline between the 2 groups.

Following consent, subjects would be randomized to be sedated with either midazolam-dexmedetomidine or ketamine-dexmedetomidine and, upon achieving an appropriate depth of sedation, undergo their MRI. Monitoring during the MRI and subsequent recovery would occur in compliance with the current Norton Children's Hospital Sedation policy. Recovery-related behavior would be assessed using the Pediatric Anesthesia Emergence Delirium Scale.

Inclusion Criteria:

1. Inpatient at Kosair Children's Hospital.
2. Order placed by treating team for MRI of the brain with sedation.
3. Age less than or equal to 18 years.
4. Plan to sedate with dexmedetomidine, regardless of study participation.

Exclusion Criteria:

1. Previous adverse reaction to dexmedetomidine or clonidine

2. Current use of clonidine as a routine medication

3. Concurrent use of a heart-rate decreasing medication (digoxin, propranolol)

4. Contraindication to ketamine use

   • Intracranial hypertension or traumatic brain injury
   • Intraocular hypertension of eye trauma
   • Pulmonary hypertension requiring medical management

5. Planned additional procedure during the sedation encounter (non-brain MRI, lumbar puncture, EEG etc)