Effect of Continuous Prolonged Prone Position Versus Intermittent Daily Prone Position in ARDS

Inclusion Criteria: * Age ≥ 18 years * Endotracheal intubation and mechanical ventilation for less than 72 hours * Moderate-severe ARDS defined as: 1. Within 1 week of a known clinical insult or new or worsening respiratory symptoms 2. Bilateral infiltrates not fully explained by effusions, lobar/lung collapse, or nodules 3. Respiratory failure not fully explained by cardiac failure or fluid overload 4. PaO2/FiO2 \< 150 mmHg in supine position * Prone positioning has been indicated by the attending physician, OR has already been initiated within the last 16 hours Exclusion Criteria: * Contraindications for prone positioning such as intracranial pressure \> 20 mmHg, massive hemoptysis, recent tracheal surgery or sternotomy or abdominal surgery with an open wound, recent facial trauma or facial surgery, unstable spine, femur, or pelvic fractures, or a single anterior chest tube with air leaks * Patient on extracorporeal membrane oxygenation (ECMO) before randomization * Chronic respiratory failure requiring oxygen therapy or non-invasive ventilation (NIV) * Known pregnancy * Anticipating withdrawal of life support or shift to palliative care