We frequently encounter cognitive impairments in patients over 65 undergoing Lower extremity surgery, depending on comorbidities and the choice of anesthesia method. The current development of neuraxial anesthesia techniques and close monitoring devices helps us prevent and detect cognitive impairment early in these patients. In this study, we aimed to investigate the effects of different anesthesia techniques (general anesthesia/spinal anesthesia) applied in orthopedic cases on patient fluid status (pleth variablity index) and regional cerebral oxygenation (NIRS), and their relationship with cognitive dysfunction.

Inclusion Criteria:

• Patients over the age of 65
• Patients with an American Society of Anesthesiologists (ASA) score of II-III
• Patients with a Mini Mental State Examination (MMSE) score of ≥24 on the first day before surgery

Exclusion Criteria:

• Patients with coagulation disorders
• Patients with a history of anticoagulant medication use
• Patients with advanced organ failure
• Patients with Alzheimer's disease or advanced dementia
• Patients with allergies to the medications used in the study
• Mental Retardation
• Patients with a wound infection at the site of spinal anesthesia
• Patients with a history of cerebrovascular hemorrhage
• Patients who did not consent;

Patients undergoing Lower extremity surgery