This research study is a continuation of a previous DEX PK study. It is examining the absorption of Dexmedetomidine (DEX) in the blood when given orally and as a nasal spray. This study will help us determine the best dosing amount for children undergoing sedation or anesthesia with DEX.

The study will be a prospective study of plasma concentrations after intranasal or buccal DEX to determine the early pharmacokinetics and bioavailability of a single dose via nasal or oral administration.

Dexmedetomidine sedation is commonly used at Cincinnati Children's Medical Center and other pediatric institutions. This compound is typically delivered intravenously or intranasally for sedation in children with or without congenital heart disease. Intranasal DEX is very effective for sedation although it has significant variability in the onset and peak effect. Patient care will be improved if factors that determine this variability can be determined. Investigators will determine the important clinical variables of peak plasma DEX concentration (Tmax and Cmax) of intranasal and buccal DEX in children.

Inclusion Criteria:

• Children aged 6 - 48 months (inclusive) scheduled to receive anesthesia for elective cardiac surgery
• The subject must be a candidate to receive Dex as determined by one of the study cardiac anesthesiologists
• The attending cardiac anesthesiologists for the case and the Chief of Anesthesia Cardiac Anesthesia will concur with or veto this decision
• The subjects legally authorized representative has given written informed consent to participate in the study

Exclusion Criteria:

• Post-natal age less than 6 months
• The subject is allergic to or has had a contraindication to Dex
• Severely depressed ventricular function on preoperative echocardiogram
• The subject has a high risk of cardiac conduction system disease in the judgement of the attending anesthesiologist or cardiologist
• The subject has a hemodynamically significant aortic coarctation or other left heart outflow obstruction
• The subject has received digoxin, beta-adrenergic antagonist, or calcium channel antagonist on the day of surgery
• The subject has received Dex within 1 week of the study date
• Patients who are to receive intranasal Dex are excluded if they have nasal/respiratory symptoms, which in the opinion of the study anesthesiologist, may affect intranasal drug absorption