The purpose of this research study is to examine the effects of two commonly used anesthetic drugs, dexmedetomidine and ketamine, have on the shape and muscle tone of the upper airway in children, adolescents, and young adults.

The results of this study will help in making the best decisions regarding the anesthesia medications used for sedation outside of the operating room.

Upper airway obstruction is a common problem in spontaneously breathing patients under anesthesia. This study is examining the effects of combining dexmedetomidine and ketamine on the muscle tone and airway configuration in children under anesthesia. The hypothesis is adding ketamine to dexmedetomidine will not significantly reduce airway caliber or morphology when compared to previously collected data using dexmedetomidine alone.

Inclusion Criteria:

• Patient requires anesthesia for a MRI scan of the brain or MRI brain/spine
• Patient must be 1 to 18 years of age
• Patients legally authorized representative has given written informed consent to participate in the study

Exclusion Criteria:

• Allergy to dexmedetomidine or ketamine
• History or obstructive sleep apnea
• The patient has a life-threatening medical condition (ASA status 4, 5, or 6)
• The patient is not scheduled to receive anesthesia sedation for the MRI
• Patient has a history or a family history of malignant hyperthermia