May noninvasive mechanical ventilation and/ or continuous positive airway pressure increase the bronchoalveolar lavage salvage in patients with pulmonary diseases? Randomized clinical trial- Study protocol

Purpose: Bronchoalveolar lavage (BAL) procedure is a useful tool in the diagnosis of patients with interstitial lung disease (ILD) and is helpful in clinical research of chronic obstructive pulmonary disease (COPD) patients. Still little is known about predictors of poor BAL salvage. The trial aims to find the most efficient way to improve BAL recovery.Material and methods: Our study is a prospective, multicenter, international, two-arm randomized controlled trial. We aim to obtain BAL samples from a total number of 300 patients: 150 with ILD and 150 with COPD to achieve a statistical power of 80 %. Patients with initial BAL salvage <60 % will be randomized into the non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) arm. The NIV and CPAP will be set according to the study protocol. The influence on BAL salvage will be assessed in terms of BAL volume and content. Multivariable analysis of the additional test results to determine predictors for low BAL recovery will be con-ducted. In a study subgroup of approximately 20 patients per specific disease, a metabolomic assessment of exhaled air condensate will be performed. All procedures will be assessed in terms of the patient's safety. The trial was registered on clinicaltrials.gov (ID# NCT05631132). Interested experienced centers are invited to join the research group by writing to the corresponding author.Conclusion: The results of our prospective study will address the currently unsolved problem of how to increase BAL salvage in patients with pulmonary diseases without increasing the risk of respiratory failure exacerbation.