The study drug infusion will be started as either dexmedetomidine (1gram per kilogram over 10 min as a loading dose, followed by a maintenance infusion 0.2 to 1.5 grams per kilogram or propofol (started at 75gram per kilogram per minute and ranging from 12.5 to 125 gram per kilogram per minute titrated to maintain the Observer's Assessment of Alertness/Sedation Scale (OAA/SS) between 0-1. Intraoperative fluids will be restricted to 500 milliliter + 100mililiterml of Lactated Ringer's solution. At the onset of the procedure, the anesthesiologist will administer 0.7gram/kilogram bolus of fentanyl intravenous, followed by additional 25-50gram boluses for any patient movement to surgical stimulus. All patients will receive ondansetron 4 milligram IV 15-20 minutes prior to the end of surgery. Patients will receive glycopyrrolate 0.2 mg IV if HR decreases below 50 bpm.