Impact of continuous oxygen flow application with or without airway pressure in the non-dependent lung during one-lung ventilation on postoperative complications in lung resection surgery: a randomized controlled clinical trial

Structured Abstract Background : Pulmonary resection surgery (PRS) requiring one-lung ventilation (OLV) is associated with hypoxemia and an exacerbated inflammatory response, contributing to postoperative complications. Strategies such as continuous positive airway pressure (CPAP) or apneic oxygenation (AO) applied to the non-dependent lung may mitigate these effects without or with minimal interference with surgical technique. Methods : This is a single-center, double-blinded, randomized controlled trial including 177 patients undergoing PRS. Patients will be randomized into three groups: (1) complete lung collapse (control), (2) apneic oxygenation at 3 L/min and (3) CPAP at 2 cmH₂O. Randomization will follow a 1:1:1 allocation. Except of the anesthesiologist involved on surgery, all care providers, data collectors, and analysts will remain blinded. Predefined intraoperative ventilation protocols and postoperative care will be applied across groups. Blood and Bronchoalveolar lavage samples will be analyzed at specified intra- and postoperative time points. Objectives : The primary outcome is to assess whether AO or CPAP reduces the incidence of postoperative complications classified by the C-D scale. Secondary outcomes include the comparison between groups of hypoxemia episodes, lung and systemic inflammatory and oxidative stress biomarker levels, and surgeon-rated lung management. Expected Results : The study is expected to demonstrate that maintaining oxygenation in the non-dependent lung, even without positive pressure, may reduce episodes of hypoxemia, attenuate systemic and lung inflammation, and lower the incidence of postoperative complications, although CPAP will be less well tolerated by the surgeons. Details of Trial Registration. After we obtained the approval of the local ethics committee on January 23, 2025, we included the first patient in the study on January 29, 2025. We plan to spend around 25 months to include 177 patients and complete the trial January-March 2027. Protocol number ECAOI-22 version 2.2 December 2024. The study was registered in Clinical Trials Information System (CTIS) on 10th October 2024 (EUCT NUMBER: 2024-517599-39, https://euclinicaltrials.eu/search-for-clinical-trials/?lang=en&EUCT=2024-517599-39-00).