Intra-nasal Dexmedetomidine for Children Undergoing MRI Imaging

Study Overview
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Brief Summary
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This study aims to assess the use of intranasal dexmedetomidine (IN-dex) as a sole agent in aiding the successful completion of a MRI scans in children. Dexmedetomidine, a routinely used anesthetic agent in our institution, has many benefits including sedation with neuro-protective and respiratory sparing features. We will test its effectiveness in completing MRI scans in children that would otherwise be given a full general anesthetic.

Detailed Description
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Purpose: To assess the use of IN-dex as a sole agent in aiding the successful completion of a MRI scan in children. Hypothesis: We hypothesize that the optimal dose for IN-dex to produce appropriate sedation for MRI will be between 1 and 3 mcg/kg. We also hypothesize that this dose will be lower in the older age group. Justification: The dose required for IN-dex to enable safe sedation for MRI scanning as a sole agent is undetermined at present. This study will enable us to find the optimal dose for effective sedation for MRI scanning in a range of age groups. This will avoid the need for propofol and remifentanil general anesthesia (that is the current standard of care) in this group of patients. Our motivation for avoiding general anesthesia is that there is ongoing concern that general anesthesia causes long term neurocognitive effects in children. Finally, identifying a safe yet effective dose of IN-dex, which can be nurse-administered, will also allow us to improve access to MRI scans that are limited by the access to general anesthesia. Objectives: To determine the dose of IN-dex that, when used as a sole agent, produces minimal to moderate sedation that is adequate for successful completion of MRI in children with >90% effectiveness. To explore the logistics of a nurse-administered sedation protocol to increase access to the MRI. Research Design: We propose a dose finding study of IN-dex using the biased coin design (BCD) method in three different age groups (3 to <8 years, 8 to <12 years, 12 to <19 years). The study specific interventions will include identification of children appropriate for the study following detailed assessment using a scoring system developed by our Child Life specialists for use at their MRI preparation session. Statistical Analysis: The dose of IN-Dex that produces mild to moderate sedation in 90% of subjects will be calculated using the pooled adjacent violators algorithm (PAVA) and bootstrap methods will be used to calculate the 95% confidence limits.

Official Title
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Intra-nasal Dexmedetomidine for Children Undergoing MRI Imaging

Conditions
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MRI Sedation

Intervention / Treatment
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* Drug: Dexmedetomidine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA 1 or 2 Scheduled for elective MRI scan on the general anesthesia list Child Life MRI simulation score of 6-10 (Figure 1) Age 3 - 18 Exclusion Criteria: Taking existing opioid, sedative, or cannabinoid medication Severe learning disability defined as the inability to follow simple commands Severe Cardiac disease Chronic hypertension Allergy to dexmedetomidine Nasal anatomical abnormality Known or anticipated difficult airway

Ages Eligible for Study
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Minimum Age: 3 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Intervention Model: Single Group Assignment
Interventional Model Description: Dose finding
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intra-nasal dexmedetomidine<br>A single dose of dexmedetomidine, determined by a biased coin algorithm (min: 1 mcg/kg; max: 4 mcg/kg or 200mcg), will be delivered intranasally 45min before an MRI scan. | Drug: Dexmedetomidine<br>* Highly selective alpha-2 adrenergic agonist with sedative properties.<br>* Other names: Precedex;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dose | The intranasal dexmedetomidine dose in mcg/kg that produces successful completion of MRI scan with acceptable MRI image quality in 90% of individuals (ED 90). | Immediately after completion of the MRI scan. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Uninterrupted scans | Total number of scans that were able to be completed without interruptions | Immediately after completion of the MRI scan. | 
| Respirator support | Total number of occurrences of respiratory support | During MRI scan | 
| Adverse events | Occurrence of haemodynamic disturbance (bradycardia: absolute heart rate ≤ 40 bpm, hypertension: relative mean arterial pressure ≥ 50% baseline, hypotension: relative mean arterial pressure ≤ 50% baseline) | During MRI scan | 
| modified Yale Preoperative Anxiety Scale (mYPAS) | Pre-procedure mYPAS score. The scale is a total summed score (4-22) of 5 areas; Activity (1-4), Vocalizations (1-6), Emotional expressivity (1-4), state of apparent arousal (1-4), and use of parents (1-4). A lower score represents a lower level of anxiety. | Immediately before administration of intranasal dexmedetomidine | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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dexmedetomidine