Patients in the Ketamine-only group will receive an intravenous dose of 1.0 mg/kg Ketamine and patients in the Ketamine-Propofol group will receive an intravenous dose of 0.5 mg/kg Ketamine and 1.0 mg/kg Propofol at time zero. Two minutes after the initial dose of sedative agent, and every 2 minutes thereafter, the attending physician will assess the patient's level of sedation using the Children's Hospital of Wisconsin Sedation Scale (Appendix A). If the attending physician determines the level of sedation is not adequate (Sedation score ≥ 3), additional study drugs (Ketamine group: 0.25 mg/kg Ketamine; Ketamine-Propofol group: 0.5 mg/kg Propofol) will be administered every 2 minutes until adequate sedation is achieved (deep conscious sedation = Children's Hospital of Wisconsin Sedation Scale Score < 3). Once a sedation score < 3 is achieved, the procedure will begin.