"One-lung ventilation (OLV) is an essential technique during thoracic surgery but preventing atelectasis during OLV remains a key challenge in thoracic anesthesia.

Several previous randomized controlled trials have demonstrated that alveolar recruitment maneuvers (ARMs) can significantly reduce driving pressure, peak airway pressure, plateau pressure, and anatomical dead space. However, the optimal method for implementing ARMs has not yet been standardized, as the timing and target of ARM application vary among studies. Some protocols involve applying ARMs to both lungs immediately prior to the initiation of OLV (bilateral ARM), while others apply ARMs solely to the non-operative lung after OLV has begun (unilateral ARM). Bilateral ARM may provide prolonged improvement in gas exchange but carry the risk of insufficient collapse of the operative lung. Conversely, unilateral ARM may facilitate better collapse of the operative lung compared to bilateral ARMs, though potentially at the expense of gas exchange. To date, no study has directly compared these two approaches. This study aims to compare and evaluate the effects of bilateral versus unilateral ARM performed immediately prior to thoracic incision on intraoperative gas exchange and the incidence of intraoperative and postoperative complications."

Inclusion Criteria:

• -Adult patients aged 20 to 80 years scheduled for thoracoscopic lung resection.
• American Society of Anesthesiologists (ASA) physical status classification of I to III.

Exclusion Criteria:

• Anticipated duration of one-lung ventilation (OLV) less than 1 hour.
• Diagnosis of heart failure.
• History of pneumothorax or radiologic evidence of pulmonary blebs or bullae prior to surgery.
• Patients receiving supplemental oxygen therapy or mechanical ventilation prior to surgery.

Dropout Criteria

• Actual duration of OLV less than 1 hour.
• Surgery is canceled or converted to an open thoracotomy or another surgical approach.
• Inability to maintain peripheral oxygen saturation ≥90% despite adjustments in inspired oxygen fraction.
• Inability to maintain ventilator settings due to extensive pulmonary adhesions.