Optimization of Positive End Expiratory Pressure by Use of Pulmonary Ultrasound for Patients With Blunt Chest Trauma Treated by Non-Invasive Ventilation (Opti-PEP).

This is an open-label, randomized controlled study comparing two non-invasive ventilation initiation strategies. Patients may be included if they are admitted to intensive care unit or continuing care unit and present with acute respiratory failure related to blunt chest trauma. We will not include patients with another indication for non-invasive ventilation, immediately needing invasive ventilation, a contraindication to non invasive ventilation or an estimated length of stay less than or equal to 48 hours. Both groups will be treated with non-ivasive ventilation according to the medical prescription. The intervention group will benefit from the use by the physiotherapist of pulmonary ultrasound for the adjustment of PEEP during the 1st session. The conventional group will benefit from the non-invasive ventilation according to the usual care. The other non-invasive ventilation settings will be chosen with the same method in both groups. The main endpoint will be the PaO2/FiO2 ratio (Arterial oxygen pressure / inspired fraction of oxygen) after 30 min of non-invasive ventilation treatment. This ratio is the best reflection of the patient oxygenation and currently used for respiratory therapies studies.