inclusion criteria: - at least 18 years - intensive care unit admission. - intubation and mechanical ventilation since less than 72h. - positive end-expiratory pressure ≥ 5 cmh2o. - acute respiratory distress syndrome following berlin definition. - covid-19 - pao2/fio2 ratio < 150 mmhg during at least 3 hours despite pep trial. - compliance of the respiratory system < 50 ml/cmh2o

inclusion criteria: - at least 18 years - intensive care unit admission. - intubation and mechanical ventilation since less than 72h. - positive end-expiratory pressure ≥ 5 cmh2o. - acute respiratory distress syndrome following berlin definition. - covid-19 - pao2/fio2 ratio < 150 mmhg during at least 3 hours despite pep trial. - compliance of the respiratory system < 50 ml/cmh2o