Exclusion criteria
obesity, allergic, bradycardia, hepatic disorder, upper respiratory tract infection, cardiac rhythm abnormality, nasal congestion, hypotension, chronic respiratory failure
OBESITY, UPPER RESPIRATORY TRACT INFECTIONS, LUNG DISEASE, HEPATIC DISORDER, HYPERSENSITIVITY REACTION, SLEEP APNEA, PATHOLOGY, CHRONIC RESPIRATORY FAILURE

Contraindications to MRI (cardiac pacemaker, neurostimulator, ferromagnetic implant)Emergency MRIPresence of head traumaPresence of nasal congestion or upper respiratory tract infection on the day of sedationMultiple procedures during the same sedation (operating room, evoked potentials, etc.)Children with pathology requiring airway safetyAny known allergic or hypersensitivity reaction to dexmedetomidineAny known allergic or hypersensitivity reaction to benzodiazepinesConcomitant use of negative chronotropes, such as DigoxinePatient known with chronic respiratory failure or myastheniaPatient known with anatomical abnormality of the airway, lung disease, or sleep apnea syndromePatient with known cardiac rhythm abnormality or cardiovascular diseasePatient with known hepatic disorder or chronic kidney diseasePatient with hypotension or bradycardia on the day of the examinationPatient with a BMI > 97th percentile (which corresponds to overweight, including obesity)