A large multicentre, randomized, controlled trial to demonstrate that non invasive ventilation given at an early stage of acute respiratory failure (ARF) outside the intensive care unit (ICU) can prevent the deterioration of ARF and the need for ICU when compared to the best available treatment usually performed in the non-ICU wards.

Inclusion Criteria:

• Informed consent
• Age >= 18 years
• Admission in a non-intensive-care department
• Radiological evidence of new pulmonary consolidation or atelectasis
• Peripheral Oxygen saturation less than 92% while breathing room air or PaO2/FiO2 ratio less than 300 at blood gas analysis
• Decompensated hypercapnia (pCO2 > 45 mmHg and pH < 7.35)
• Clinical signs of respiratory distress (dyspnoea, utilization of accessory respiratory muscles, paradox movements of thoraco-abdominal wall) in air.

Exclusion Criteria:

• Respiratory failure due to chronic obstructive pulmonary disease exacerbation, defined as PaCO2 > 45 and pH < 7.35 (in these patients NIV is considered to be the standard/first line treatment and we do not want to deny these patients the opportunity to receive this treatment because of randomization)
• Severe, hypercapnic ARF defined as PaCO2 > 45 and pH < 7.30
• Severe, hypoxic ARF defined as PaO2/FiO2 < 200
• Need for immediate mechanical ventilation or ICU as judged by the ICU physician in charge
• Extremely poor short term prognosis (imminent death with decision for palliative treatment only)
• Invasive or non-invasive mechanical ventilation during the same hospitalization due to respiratory failure.
• Clear contraindication to NIV treatment: respiratory arrest, failure to correct positioning of a face mask, hemodynamic instability due to hypotensive shock, ongoing myocardial ischemia, arrhythmia, massive bleeding from upper gastrointestinal tract, patient uncooperative and upset, inability to protect airways, alterations of deglutition, inability to clear secretion also with external aspiration, multiple organs dysfunction, recent surgery of airways or upper gastrointestinal tract, not-drained pneumothorax, bowel obstruction, active vomit.