This prospective observational study aims to evaluate the effect of glycemic control level on intraoperative cerebral oxygenation measured by near-infrared spectroscopy (NIRS) and postoperative recovery in patients with diabetes mellitus undergoing elective urologic surgery under general anesthesia.

Patients will be grouped according to HbA1c levels to assess the relationship between long-term glycemic control and intraoperative regional cerebral oxygen saturation, hemodynamic parameters, and postoperative recovery scores.

Diabetes mellitus is associated with increased perioperative morbidity and mortality, particularly in patients with poor long-term glycemic control. Elevated HbA1c levels may impair microcirculation and tissue oxygenation, which can affect cerebral perfusion during general anesthesia. Near-infrared spectroscopy (NIRS) is a non-invasive monitoring technique that allows continuous measurement of regional cerebral oxygen saturation and may help detect intraoperative hypoperfusion.

This prospective observational study is designed to investigate the relationship between glycemic control level and intraoperative cerebral oxygenation as well as postoperative recovery parameters in patients undergoing elective urologic surgery under general anesthesia. Patients will be divided into four groups according to preoperative HbA1c levels, including non-diabetic patients and diabetic patients with different levels of glycemic control.

Intraoperative monitoring will include standard hemodynamic parameters and bilateral regional cerebral oxygen saturation measured with near-infrared spectroscopy. The primary objective of the study is to determine whether poor glycemic control is associated with impaired cerebral oxygenation during anesthesia. Secondary objectives include evaluation of postoperative recovery parameters in relation to glycemic control level.

Inclusion Criteria:

• Age ≥18 years
• Patients scheduled for elective urologic surgery under general anesthesia
• ASA physical status I-III
• Patients with diabetes mellitus or non-diabetic control patients
• Availability of preoperative HbA1c measurement
• Written informed consent obtained

Exclusion Criteria:

• Age <18 years
• ASA physical status >III
• Emergency surgery
• History of cerebrovascular disease or neurological disorder
• Previous brain or neurological surgery
• Inability to communicate or refusal to participate
• Intraoperative hemodynamic instability
• Inadequate NIRS monitoring data

Adult patients scheduled for elective urologic surgery under general anesthesia at a single tertiary university hospital will be included. The study population consists of patients with diabetes mellitus with different levels of glycemic control and non-diabetic control patients. Participants will be grouped according to preoperative HbA1c levels.

Individual participant data will not be shared due to institutional regulations and privacy restrictions.