 Dexmedetomidine sedation is commonly utilized at Cincinnati Childrens Medical Center CCHMC and other pediatric institutions. This compound is delivered intravenously or intranasally for sedation in children with and without congenital heart disease. Intranasal DEX, though very effective for sedation, has significant variability in its onset and peak effect. Patient care will be significantly improved if factors that determine this variability in onset and peak effect can be determined. Investigators will determine the important early clinical variables of peak plasma DEX concentration Tmax and Cmax and the 0 - 2 hour bioavailability of intranasal DEX in children. 