Exclusion criteria include known allergy or hypersensitivity to midazolam or dexmedetomidine, uncorrected congenital heart disease or history of cardiac arrhythmia, children at risk for airway obstruction (OSA or cranio facial syndrome) and pregnant minors Patients will be randomly assigned to one of two groups M (midazolam) or D (dexmedetomidine) using computer-generated numbers in sealed envelopes.