Lateral Positioning and Prone Positioning in ARDS Patients

The addition of repeated periods of 30 minutes of lateralization of 30° amplitude in dorsal decubitus and in ventral decubitus in patients with moderate to severe ARDS. Included patients will benefit from sessions of lateral decubitus for 30 minutes on each side (with an inclination of 30°) with alternation right/left (total one hour). During this period, the upper part of the bed will be inclined by 30°. Patients will then be positioned in strict prone position for a period of 6 hours after which, the same pattern of alternating lateral decubitus will be applied for 12 hours while the patient is still in the prone position. After reversal in supine position, an observation period of 1 hour will be respected before carrying out the last measurements. The total duration of the intervention will be 20 hours.