Face-Down position may cut deaths in severe ARDS

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Adult patients aged 18 years or more, both gender 2. Receiving endotracheal intubation and mechanical ventilation for less than 36 hours 3. Presenting with a Severe ARDS : * Acute onset * PaO2/FiO2 ≤ 200 (≤ 26.7 kPa) * Bilateral pulmonary infiltrates on frontal chest radiography * Capillary wedge pressure \< 18 mm Hg if measured or no evidence for left atrial hypertension 4. During since 12-24 hours 5. AND with severity criteria : PaO2/FiO2 \< 150 mm Hg (\< 20 kPa) under FiO2 ≥ 0.6, PEEP ≥ 5 cm H2O and a tidal volume equal to 6 ml/kg PBW. 6. Written consent from patient's next of kin Exclusion Criteria: 1. contra-indication to the prone position * Intracranial pressure \> 30 mm Hg or cerebral perfusion pressure \< 60 mm Hg * Massive haemoptysis needing urgent surgical or radiological treatment * Tracheal or thoracic surgery in the last 15 days * Facial trauma or surgery in the last 15 days * Deep venous thrombosis or pulmonary embolism treated in the last 2 days * Cardiac pace maker implantation in the last 2 days * Unstable bone dislocations of rachis, femur, rib cage, pelvis * Mean systolic arterial pressure less than 70 mm Hg despite vasopressive therapy * Pregnancy * Bronchopleural fistula treated with a single anterior chest tube (risk of kinking in prone position) 2. Exclusion criteria for respiratory raisons * Necessity to use NOi or almitrine * Extra body circulation for oxygenation and/or CO2 epuration 3. Exclusion criteria linked to clinical context * Pulmonary transplantation * Burns ≥ 20% of body surface * Chronic respiratory insufficiency under home oxygen therapy or non invasive ventilation * Chronic disease supposed to be fatal in less than 1 year * Non invasive ventilation for more than 24 hours before enrollment 4. Other exclusion criteria * Decision to stop life-supportive therapies before enrollment * Enrollment in an other trial testing an intervention and with mortality as primary end point in the last 30 days * Prior enrollment in the same study * Prone position before enrollment