Inclusion Criteria:  Age > 18 years SARS-CoV-2 PCR positivity in the last 21 days Mechanical ventilation for Covid-19 pneumonia Presence of lung infiltrations on the chest X-ray or ground glass opacity, crazy paving or lung infiltrations on the chest CT Oxygenation disorder according to ARDS definition: PaO2 / FiO2 <300 mmHg with PEEP at least 5 cmH2O  Exclusion Criteria:  Disagreement with the inclusion in the trial