Our aim in this study is to compare fixed and individualized PEEP (driving pressure guided ) application for intraoperative lung protective ventilation in patients undergoing on-pump CABG surgery.

Researcher aimed to compare the effects of two different PEEP application methods on intraoperative hemodynamics, respiratory mechanics, and gas exchange, as well as postoperative extubation times, respiratory complications (atelectasis, need for non invasive mechanical ventilatıon, need for re-entubatıon) length of stay in the intensive care unit, and discharge times.

The primary goal of the researchers: To compare the effects of fixed PEEP versus driving pressure guided individualized PEEP in lung protective mechanical ventilation during on-pump open heart surgery effect of PaO2/ FiO2 ratio end of surgery.

The secondary goals of the researchers: To compare intraoperative hemodynamics, lung compliance and airway pressures, extubation time and respiratory complications [development of atelectasis, need for noninvasive mechanical ventilation (high-flow nasal cannula or CPAP application), need for re-intubation], length of stay in the ICU and discharge times.

Inclusion Criteria:

• Patients scheduled for elective on-pump coronary artery bypass graft surgery via median sternotomy
• Patients between the ages of 18 and 70
• ASA (American Society of Anesthesiologists) physical status classification II-III

Exclusion Criteria:

• Patients with an ejection fraction below 35%
• Patients who did not consent to participate in the study
• Patients undergoing emergency surgery
• Patients who are allergic to the anesthetic drugs used
• Patients who have undergone lung resection
• Those with a history of mechanical ventilation in the 2 months before surgery
• Patients who have undergone total circulatory arrest and deep hypothermia
• Patients with obstructive sleep apnea syndrome requiring long-term ventilation assistance
• Morbid obesity (Body Mass Index>35kg/m2)
• Patients with refractory hypoxemia (arterial oxygen saturation below 88% despite 100% oxygen inhalation)
• COPD (FEV1<70%)
• Patients with chronic renal failure (serum creatine>1.8 mg/dl)
• Anemia (Hg<10 gr/dl)
• Patients who have had an intraaortic balloon pump placed.

Patients who will undergo elective on-pump coronary artery bypass graft surgery under general anesthesia