CABG (coronary artery bypass graft) surgery is among the most common heart surgeries performed in the heart pump. In CABG surgery, operations performed on the beating heart without the use of CPB (off-pump) are frequently performed (30-60%) (1).

To the best of our knowledge, there has been no study examining cerebral oxygenation values, oxidative stress levels and postoperative results in CABG operations.

CABG (coronary artery bypass graft) surgery is among the most common heart surgeries performed in the heart pump. In CABG surgery, operations performed on the beating heart without the use of CPB (off-pump) are frequently performed (30-60%) (1). Off-pump coronary artery bypass surgery is also called beating-heart surgery, and its purpose is to avoid cardiopulmonary bypass completely without the support of a heart lung machine, thereby avoiding its adverse effects (3-5). It has been reported that the off-pump CPB surgical method is associated with a decrease in the incidence of early stage and major complications compared to the traditional CPB method (2). Exposure to surgical stress leads to autonomic, visceral, and immunological responses, leading to oxidative stress, neurochemical and hormonal abnormalities (3).In addition to the non-physiological hemodynamic conditions that occur during CABG surgery, a significant increase is observed in inflammatory response and oxidative stress biomarkers due to surgical trauma, cardiopulmonary bypass (CPB) and organ reperfusion injury (4).For this reason, it is important to detect the presence and severity of postoperative adverse outcomes after CABG early. To the best of our knowledge, there has been no study examining cerebral oxygenation values, oxidative stress levels and postoperative results in CABG operations.

This prospective observational study is planned to include 64 adult patients aged 30-80 years who will undergo CABG surgery. Patients will be grouped according to the surgical technique (on-pump and off-pump) determined (indicated) according to the cardiovascular risk status of the patient by the Cardiovascular Surgery department.

Patients' perioperative cerebral hemoglobin oxygen saturations will be recorded with the Regional Oximeter (non-invasive cerebral oxygenation measurement device).

In patients undergoing On-Pump bypass, at the beginning of the CABG surgery (basal), during the aortic clamp, 15 minutes after the clamp is lifted, the remaining 3 ml of blood will be centrifuged at 3000 rpm for 5 minutes and the serum part will be separated.

In off-pump bypass surgery patients, 3 ml of blood will be centrifuged at the beginning of the operation, at the beating phase and 15 minutes after the beating process is completed.

Total antioxidant status, Total oxidant status, Superoxide dismutase, Malondialdehyde will be measured in the Enzyme-Linked ImmunoSorbent Assay device from blood samples taken from all patients in the study, and their concentrations will be determined.

Inclusion Criteria:

• Undergo CABG surgery with on-pump and off-pump technique,
• Volunteer to participate in the study,
• 30-80 years old

Exclusion Criteria:

• Those with chronic kidney failure
• Those with liver failure
• Under 30 and over 80

It is planned to participate in this prospective observational study of 64 volunteer patients undergoing Coronary artery bypass grafting (CABG) surgery by the Department of Cardiovascular Surgery.