The prone position consists of placing the patient on his or her stomach with the head on the side, during sessions lasting several hours a day and could help spontaneous ventilate the patient.

SARS-CoV-2 is an RNA virus whose tropism for the respiratory system is responsible for many cases of acute respiratory failure. This can lead to acute respiratory distress syndrome (ARDS) requiring orotracheal intubation and mechanical ventilation. The prone position is a validated intensive care technique in the treatment of ARDS in mechanically ventilated patients. Performing prone position sessions improves patient oxygenation by optimizing the ventilation/perfusion ratios of the posterior areas of the lungs.

There is limited data in the literature on the ventral decubitus in spontaneous ventilation. They are mainly case series or retrospective studies. In the case of the SARS-CoV-2 epidemic, we are seeing patients with posterior lung involvement who may benefit from prone position sessions prior to mechanical ventilation. This maneuver, usually done in an intubated-ventilated-curarized patient, will be done in our spontaneous ventilation study in a conscious patient.The patient will then be placed in prone position with the help of physiotherapists so that the patient is correctly positioned.

The maneuver and the clinical monitoring of the patient's tolerance to the prone position will be done under medical and paramedical supervision, including monitoring of saturation during and after the procedure. A polygraph will also be installed on the patient in order to monitor the patient's position (on the back vs. on the stomach), saturation and heart rate during the entire prone position session. An arterial gasometry will be performed before the patient is placed in the prone position, one hour after and after returning to the supine position.

Inclusion Criteria:

• Patient aged at least 18 years;
• Hospitalized in a COVID unit or intensive care unit;
• Spontaneously breathing and with oxygen therapy with nasal canula, mask or High Flow Oxygen Therapy;
• Requiring oxygen therapy ≥ 1l for Sat ≥ 90%;
• COVID 19 positive in RT-PCR or diagnosis on clinicals symptoms and highly evocatives scannographics lesions in an epidemic period;
• Chest scanner without injection within 72 hours prior to inclusion;
• Bilateral scannographic lesions, including posterior condensations and/or posterior predominance of lesions;
• Patient benefiting from French social security, under any regime

Exclusion Criteria:

• acute respiratory distress (polypnea >25 or use of accessory respiratory muscles);
• Alteration of consciousness;
• Active or recent hemoptysis (<1 month);
• Recent Thrombo-Embolic Venous Disease (< 1 month);
• Pericardial effusion;
• Pleural effusion of high abundance, clinical or scannographic;
• Chronic back or cervical pain/ history of spinal surgery/ bone metastases;
• Wounds, facial trauma, tracheal, sternal or facial surgery < 15 days;
• Recent abdominal surgery (< 1 month);
• Intracranial HyperTension > 30mmHg;
• Patient deprived of liberty, under guardianship or curatorship;
• Pregnant or lactating woman.