This study aims to investigate whether using 50% FiO₂ during one-lung ventilation, compared with 100% FiO₂, reduces postoperative atelectasis in the non-dependent (healthy) lung of patients undergoing VATS right pulmonary lobectomy, based on individualized PEEP titration. This is a single-center, prospective, assessor- and patient-blinded randomized controlled trial. A total of 100 patients (50 per group, including a pilot phase of 10 per group) will be enrolled and randomized 1:1 to the high-oxygen group (FiO₂=100%) and the low-oxygen group (FiO₂=50%). The primary endpoint is the percentage of atelectasis volume in the non-operated lung relative to the total non-operated lung volume, assessed by CT at 90±10 minutes postoperatively.
Inclusion Criteria:
Age 18-65 years Elective thoracoscopic (VATS) right pulmonary lobectomy Anticipated one-lung ventilation duration >1 hour ASA physical status I-III
Exclusion Criteria:
Previous lobectomy or lung volume reduction surgery Pre-existing significant atelectasis (large collapse on preoperative CT) Contraindications to PEEP: intracranial hypertension, bronchopleural fistula, hypovolemic shock, right heart failure, giant bullae, pneumothorax FiO₂ restrictions: preoperative continuous oxygen therapy or mechanical ventilation, moderate-severe COPD BMI ≥ 30 kg/m² Patient refusal to participate
Withdrawal Criteria / Major Protocol Deviations:
Surgery changed to simple wedge resection Severe pleural adhesions (found intraoperatively) Ventilation protocol interrupted Intraoperative blood loss >500 ml Severe hypotension (MAP<55 mmHg despite high-dose vasopressors) Unexpected non-thoracic surgical procedure FiO₂ exposure <80% of planned time (experimental group) Postoperative CT not completed or image quality unusable
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Patients are blinded pre- and postoperatively; postoperative data collectors, CT readers, and biostatisticians are blinded to allocation; only the attending anesthesiologist is unblinded due to the nature of the intervention (setting FiO₂), but does not participate in data collection or outcome assessment
FiO₂=100% throughout one-lung ventilation.
Initial FiO₂=50% during one-lung ventilation (maintaining SpO₂≥92%) with individualized PEEP titration. If SpO₂\<92%, increase FiO₂ by 10% increments; if SpO₂\<90% and FiO₂ already at 100%, initiate rescue ventilation.
The Effect of Decreasing the Inspired Oxygen Concentration on Post-Operative Oxygenation After Primary Lobectomy
Titration of Inspired Oxygen to Decrease the Incidence of Postoperative Pulmonary Complications
Effect of Different Oxygen Concentration on Postoperative Pulmonary Complications After Pulmonary Reexpansion
Atelectasis After Pulmonary Lobectomy: The Effect Of Air During One-Lung Ventilation (OLV) On Postoperative Atelectasis
Clinical Trial of Thoracoscopic Lobecotmy Under Spontaneous Ventilating Anesthesia
Ventilation Strategies Impact on Oxygenation and Postoperative Pulmonary Complications in Lung Surgery Patients
Individualized Perioperative Open-Lung Ventilatory Strategy During One-Lung Ventilation
Effects of Nonintubated Thoracoscopic Lobectomy on Lung Protection