Effect of Oxygen Administration in the Non-dependent Lung on Postoperative Complications After Lung Surgery

The purpose of this study is to analyze the effectiveness of apneic oxygenation and CPAP applied to the non-dependent lung during pulmonary resection surgery in reducing inflammatory response, ischemia-reperfusion injury, and postoperative complications. We will conduct a randomized, controlled, and blinded study in 177 patients with three arms: * Control Group: Oxygen therapy according to standard clinical practice * Apneic oxygenation group: A probe will be introduced through the lumen of the double-lumen tube (DLT) to administer a continuous source of oxygen without any mechanism that generates airway pressure. * CPAP Group: Continuous positive airway pressure with 3-5 L/min oxygen flow and 2 cm H2O pressure delivered via a Mapleson system. Inflammatory mediators in blood and in both lungs will be measured intraoperatively and 24 hours after surgery. Patients will be followed from hospital admission until discharge and again 30 days after surgery to evaluate the postoperative course, particularly the occurrence of complications according to the revised Clavien-Dindo classification for thoracic surgery, as well as other relevant clinical outcomes.