Dexmedetomidine-ketamine Versus Propofol-ketamine for Sedation During Endoscopy in Hepatic Patients

70 Patients will be randomly allocated into two groups; Group (KD): Ketamine/dexmedetomidine (35 patients), will receive IV ketamine 0.25mg/kg and dexmedetomidine1µg/kg over 10 min as loading followed by dexmedetomidine infusion with a rate of 0.5µg/kg/hr and Group (KP): ketamine/propofol (35 patients) will receive IV ketamine 0.25 mg/kg loading and propofol 1 mg/kg over 10 min followed by propofol infusion with a rate of 0.5 mg/kg/hr as a control group.