The main objective of the core study is to measure a number of biochemical, cellular and inflammatory mediators in the BALF of C-ARDS patients and evaluate their correlation with the course of disease in terms of respiratory mechanics, complications and outcomes.~The mediators selected have been previously used in ARDS investigation to attempt prognostic and predictive enrichment.~Patients hospitalized in the ICU following C-ARDS and requiring invasive mechanical ventilation will be candidates for enrollment.~Patients enrolled in the study (Informed consent obtained from next of kin) will be subject to the realization of optic bronchoscopy within the first 72 h of mechanical ventilation to obtain BALF for analysis. A second and third bronchoscopy and sampling of BALF will be performed every 7-10 days if mechanical ventilation and the clinical conditions allow it. A sample of whole blood will be taken contemporary to each bronchoscopy in order to perform parallel measurements (lungs and peripheral blood). Patients will be followed up until hospital discharge.~BALF samples will be divided to perform different analysis in the immunology, cytology and microbiology labs.
Patients older than 18 years of age, with COVID-19 related ARDS (C-ARDS) hospitalized in the ICU and invasively mechanically ventilated will be included in the study.~This is an observational cohort study. After informed consent by the next of kin, and within the first 72 hours of invasive mechanical ventilation a blood and a Broncho Alveolar Lavage Fluid (BALF) sample will be collected. If the patients remain invasively mechanically ventilated a second and third blood and BALF sample will be collected every 7-10 days.