Cerebral blood flow changes during different entropy value targeted (entropy value 30-40 versus entropy value 50- 60 ) anesthesia induction with propofol in patients undergoing supratentorial tumor surgery.

INTERVENTION: We have two study group depend on propofol dose that used at anesthesia induction. In all groups, we will use the same anesthetic agent as fentanyl, propofol, and rocuronium. Arm 1 (Group L, low state entropy value target group ): For anesthetic induction, firstly 1 mcg/kg fentanyl will be administered as a bolus intravenously. Then 0.04 % propofol ( 800 mg PROPOFOL %1 Fresenius in 100 ml 0.9% isotonic ) infusion will be given intravenously at the rate of 50 mg/kg/h (10 seconds waited for every 20 seconds infusion period) by infusion pump until state entropy value reaches between 40 to 30 After adequate hypnosis, 0.6mg/kg rocuronium bromide will be administered as a bolus. Arm 2 (Group H highe state entropy value target group ) : For anesthetic induction, firstly 1 mcg/kg fentanyl will be administered as a bolus intravenously. Then 0.04 % propofol ( 800 mg PROPOFOL %1 Fresenius in 100 ml 0.9% isotonic ) infusion will be given intravenously at the rate of 50 mg/kg/h (10 seconds waited for every 20 seconds infusion period) by infusion pump until state entropy value reaches between 60 to 50 After adequate hypnosis, 0.6mg/kg rocuronium bromide will be administered as a bolus. CONDITION: anesthetics effect on cerebral blood flow patients with supratentorial tumor, PRIMARY OUTCOME: Mean blood flow velocity values of bilateral middle cerebral artery which measured by transcranial doppler sonography (DWL Elektronische Systeme GmbH, Sipplingen, Germany ). All doppler measurements will be performed by the same experienced neurologist. The middle cerebral artery will be insonated at 50–55 mm depth through the temporal window by the 2 MHz probe of transcranial doppler sonography device. SECONDARY OUTCOME: Diastolic blood flow velocity value of bilateral middle cerebral artery which measured by transcranial doppler sonography (DWL Elektronische Systeme GmbH, Sipplingen, Germany ). All doppler measurements will be performed by the same experienced neurologist. The middle cerebral artery will be insonated at 50–55 mm depth through the temporal window by the 2 MHz probe of transcranial doppler sonography device. Mean arterial pressure that measured with invasive radial artery cannulation by patient monitor (CARESCAPE Monitor B850; GE Healthcare, Helsinki, Finland ). Systolic blood flow velocity value of bilateral middle cerebral artery which measured by transcranial doppler sonography (DWL Elektronische Systeme GmbH, Sipplingen, Germany ). All doppler measurements will be performed by the same experienced neurologist. The middle cerebral artery will be insonated at 50–55 mm depth through the temporal window by the 2 MHz probe of transcranial doppler sonography device. ; INCLUSION CRITERIA: 1‐ Patients undergoing elective supratentorial tumor surgery. 2‐ Patients need invasive artery monitorization. 3‐ Patients with ASA grade I‐II.