Individualized PEEP and Pulmonary Complications in On-Pump CABG

Postoperative pulmonary complications (PPCs) are an important cause of morbidity and mortality after major surgery and are frequently observed in cardiac surgery patients undergoing cardiopulmonary bypass (CPB). These complications are associated with prolonged mechanical ventilation, longer intensive care unit and hospital stays, increased healthcare costs, and higher mortality (1,2).

Intraoperative lung-protective ventilation strategies have traditionally focused on individual parameters such as low tidal volume, positive end-expiratory pressure (PEEP), plateau pressure, and driving pressure. However, the effects of these parameters on postoperative pulmonary outcomes in cardiac surgery patients remain unclear. In particular, PEEP- and driving pressure-guided approaches are controversial in terms of feasibility and safety in patients undergoing CPB, who may be hemodynamically vulnerable.

Mechanical power is a comprehensive parameter that reflects the total energy delivered to the respiratory system per unit of time by integrating ventilatory variables such as tidal volume, airway pressures, respiratory rate, and flow. Therefore, mechanical power may provide a more comprehensive assessment of the mechanical load applied to the lungs compared with individual ventilatory parameters. Previous studies have reported that higher mechanical power values may be associated with lung injury, postoperative pulmonary complications, and mortality (3).

The aim of this study is to evaluate the effect of monitoring mechanical power during perioperative mechanical ventilation on postoperative pulmonary complications in patients undergoing cardiac surgery with cardiopulmonary bypass. The study hypothesis is that a mechanical power-based ventilation approach may reduce the incidence of PPCs compared with strategies based on conventional ventilation parameters.

Patients with ASA physical status II-III who are scheduled to undergo elective open-heart surgery via on-pump median sternotomy will be included in the study.

Patients scheduled for emergency surgery, those planned to undergo off-pump cardiac surgery, patients with a history of myocardial infarction within the last 3 months, patients with advanced COPD, patients with an ARISCAT score of 44 or higher, patients with a BMI of 35 kg/m² or higher, patients with NYHA class IV status, patients receiving preoperative immunotherapy, and patients with severe hepatic or renal failure will be excluded from the study.