Monitored Anesthesia Care: Dexmedetomidine-Ketamine Versus Dexmedetomidine- Propofol For Chronic Subdural Hematoma

patients will receive combination of ketamine 1mg/kg and dexmedetomidine 1ug/kg diluted in 10 ml 0.9% saline infused over 10 min together as an intravenous bolus dose then a maintenance of 0.5ug/kg/h dexmedetomidine and ketamine 0.5 mg/kg/h continuous infusion in two separate syringes pump to achieve modified Observer's Assessment of Alertness and sedation score (OAA/S) 3 and the infusion will stopped by finishing the skin suture.

patients will receive combination from 0.5 mg/kg propofol and dexmedetomidine 1ug/kg diluted in 10 ml 0.9% saline infused over 10 min together as an intravenous bolus dose then a maintenance of 0.5ug/kg/h dexmedetomidine and propofol 0.5 mg/kg/h continuous infusion in two separate syringes pump to achieve modified Observer's Assessment of Alertness and sedation score (OAA/S) 3 and the infusion will stopped by finishing the skin suture.