Early Non-invasive Ventilation and High-flow Nasal Oxygen Therapy for Preventing Delayed Respiratory Failure in Hypoxemic Blunt Chest Trauma Patients.

In the experimental strategy, NIV is performed after inclusion in patients with moderate hypoxemia, defined by a PaO2/FiO2 ratio \< 300 mmHg. The minimally required duration of NIV was 4 hours per day for at least 2 calendar days. The daily duration of NIV can be increased at the discretion of the physician in patients with signs of delayed respiratory failure under HFNC-O2 and improving under NIV. Beyond the first 48 hours, NIV and HFNC-O2 can be stopped and the patient switched to COT if respiratory rate \< 25/min and SpO2 \> 92% under FiO2 \< 30% for at least 6 hours.

In the control group, patients receive oxygen from nasal cannula or high concentration oxygen mask according to the FiO2 needed to achieve SpO2 \> 92%. NIV is initiated only in patients having PaO2/FiO2 ratio \< 200 mmHg under COT. A trial of curative NIV is allowed at the discretion of the physician in patients who have signs of delayed respiratory failure and no other organ dysfunction. The non-improvement of respiratory conditions after 1 hour of NIV, the NIV-dependence (≥ 12 consecutive hours) or NIV-intolerance should be considered as criteria for endotracheal intubation.