Evaluation of gas exchange between D0 / D4 /D7 /D14 evaluated through the PO2 / FIO2 ratio; days without mechanical ventilation (within 28 days of follow-up; how many days were out of mechanical ventilation; if the patient dies before 28 days of follow-up; it is considered that he did not stay any day out of mechanical ventilation)

Evaluation of gas exchange between D0 / D4 /D7 /D14 evaluated through the PO2 / FIO2 ratio; days without mechanical ventilation (within 28 days of follow-up; how many days were out of mechanical ventilation; if the patient dies before 28 days of follow-up; it is considered that he did not stay any day out of mechanical ventilation)