Inclusion Criteria:  written informed consent patients with ASA physical status of I-II aged 18-65 years  Exclusion Criteria:  Age under 18 or above 65 ASA > II coagulation disorders history of cardiovascular and cerebrovascular disease poor Blood Pressure control anemia, pregnancy, addiction to opioids body mass index (BMI) > 35 intraoperative systolic BP < 65 mmHg surgical duration less than 30 minutes or more than 160 minutes need for an intraoperative sympathomimetic drug and the use of other hypotensive drugs preoperative Mini-Mental State Examination (MMSE) score of 23 or less.