NODRAIN study protocol: a non-interventional, prospective study for evaluating the effectiveness of intraoperative ventilation for the prediction of postoperative air leak in major pulmonary resections by conventional or robotic thoracoscopy.

Background: Air leak remains the most common complication following thoracic surgery, despite advances in minimally invasive techniques, and the main reason for chest tube drainage after major lung resections. The chest tube is associated with increased postoperative pain and, therefore, increased postoperative complications. Nevertheless, there are some patients who will not experience air leak after a major pulmonary resection. These patients may therefore not be drained, and the postoperative pain could be consequently dramatically less. Preliminary evidence suggests that intraoperative air leak measurement via mechanical ventilator may predict postoperative air leak, but current data are insufficient for clinical implementation. The objective of this study is to identify the threshold of air leak rate recorded by the mechanical ventilator device at the end of the intervention, below which there will be no air leaks during spontaneous breathing, after extubation of the patient. Methods: This is a non-interventional, prospective, single-center, and single-cohort study designed to evaluate the effectiveness of intraoperative ventilation for the prediction of postoperative air leakage after major lung resections. The study will enroll a minimum of 50 adults undergoing lobectomy or segmentectomy via conventional or robotic thoracoscopy. All participants will receive standard intraoperative ventilation for leak detection and routine postoperative drainage. The primary analysis will assess concordance between intraoperative and postoperative measurements using Passing-Bablok regression and Pearson correlation. Secondary analyses will include Cohen's Kappa for analysis of agreement between the two techniques, and evaluation of postoperative outcomes (duration of drainage, hospital stay, complications, and re-drainage rates). Discussion: This study aims to provide preliminary evidence supporting intraoperative ventilator-based leak measurement as a predictive tool for postoperative air leak, potentially enabling targeted non-drainage strategies after major lung resection, reducing postoperative pain and complications, shortening hospitalization, and lowering healthcare costs. Trial Registration: This study is registered at ClinicalTrials.gov (NCT07350265) on 20 January 2026.