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 present with acute respiratory failure related to blunt chest trauma.The intervention group will benefit from the use by the physiotherapist of pulmonary ultrasound for the adjustment of Positive End Expiratory Pressure (PEEP) during the 1st session. The conventional group will benefit from the non-invasive ventilation according to the current care.

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.

Eligibility Criteria:
Inclusion Criteria:

* Patients aged 18 or more
* Admitted to intensive care or continuing care for 72 hours or less for blunt chest trauma, defined by the presence of at least one of the following elements on the initial CT scan: fracture(s) of rib(s) / fracture(s) of the sternum / pulmonary contusion / hemothorax
* Acute hypoxemic respiratory failure defined by the administration of oxygen at least 3 L/min with nasal cannula or FiO2≥30% if high flow oxygen therapy.
* Patient with a functional arterial catheter for blood tests

Exclusion Criteria:

* Acute respiratory distress, defined by the presence of at least one of the following clinical signs: respiratory rate ˃ 35 / use of accessory inspirators / paradoxal abdominal or thoracic motion
* Imminent need for invasive mechanical ventilation
* Usual contraindication to non-invasive ventilation (undrained pneumothorax, trauma to the face, vigilance disorders, digestive bleeding, hemodynamic instability, intolerance)
* Hypercapnia (PaCO2˃45mmHg)
* Patient unable to cooperate, communicate
* Therapeutic limitation
* Expected length of stay ≤ 48h
* Severe head trauma
* Pregnant or breastfeeding women
* Participation in other clinical research related to respiratory failure/respiratory therapy
* Vulnerable people
* Protected adults, under guardianship or curatorship, or unable to give consent
* Non-affiliated person or beneficiary of a social security scheme
* Absence of free, informed and written consent, signed by the participant and the investigator