Clinical Research Directory

Inclusion Criteria: * Patients over the age of 65 undergoing ASA I-IV receiving general anaesthesia * All elective surgery patients who are not laparoscopic and last longer than 30 minutes Exclusion Criteria: * 1\) American Society of Anesthesiologists (ASA) grade V or VI * Whether the surgery is cranial or laparoscopic * Preoperative neuropsychiatric (dementia, epilepsy, etc.) disease or drug use * Previous cranial surgery or known vertebrobasilar insufficiency, carotid stenosis * Those with a pain score above 4 in the postoperative evaluation unit (PACU) * Patients with a 15% decrease in cerebral oxygenation from onset in oximetry monitoring during follow-up * Patients with bleeding greater than 20% of total body volume during follow-up * Patients with a decrease of more than 20% from their baseline systolic value (based on follow-up in the service) during follow-up * Those with hypercarbia or hypocarbia due to intraoperative ventilation insufficiency * Patients whose PSI value is reduced to a depth of 25, which is sufficient for anaesthesia, with anaesthetic drugs administered during anaesthesia induction or maintenance * Presence of preoperative cognitive dysfunction * Patients requiring postoperative intubation and intensive care follow-up