Assess the superiority of early non invasive ventilation in comparison to Oxygen therapy only, for immuno-compromized patients with acute respiratory failure

Inclusion Criteria:

• Age over 18 years old
• ICU admission
• Acute respiratory failure defined by (PaO2<60 mmHg at room air) or (polypnea >30/min or dyspnea at rest) or respiratory distress. Since less than 72 hours.
• Immuno compromized patient defined by solid tumor (treated since less than 5 years) or haematological malignancy (treated since less than 5 years) or Solid organ transplantation or Stem cell transplantation or Immunosuppressive treatment (steroid > 1mg/kg/d or >1 month or other immunosuppressive treatment >1 month)

Exclusion Criteria:

• Hypercapnia >50 mmHg or increased of hypercapnia >10 mmHg under Oxygen treatment
• Need of immediate mechanical ventilation
• Obvious cardiogenic oedema
• Vasopressor use >0.03 µg/kg/min
• Glasgow Score <13
• End of life decision
• Acute myocardial infarction
• Patient refusal
• Pregnancy
• No national health insurance