Patients will be eligible for inclusion if they meet all of the below criteria within 14 days of initial ICU admission. Criteria 1-3 must all be present within a 24-hour time period and at the time of enrollment: Acute onset (defined below) of: 1. A need for positive pressure ventilation by an endotracheal or tracheal tube with a PaO2/FiO2 ratio <250 mmHg and ≥5 cm H2O positive end-expiratory airway pressure (PEEP), as per the Berlin Criteria. 2. Bilateral infiltrates consistent with pulmonary edema (defined below) on the frontal chest radiograph, or bilateral ground glass opacities on a chest CT scan. 3. No clinical evidence of left atrial hypertension as a primary explanation for the bilateral pulmonary infiltrates. 4. If the cause of ARDS is trauma, additional inclusion criteria will include ONE of the following relevant risk factors for developing ARDS: 1. Hypotension (systolic blood pressure[SBP] < 90 mmHg) in the field or in the first 24 h after injury, or 2. Transfusion of 3 units of blood products in the first 24 hours following injury, or 3. Meets the new Critical Administration Threshold (CAT) criteria with at least 3 units of blood in one hour, or 4. Blunt or penetrating torso trauma, or 5. Long bone fractures, or 6. The highest level of institutional trauma activation

1. Age less than 18 years 2. Greater than 72 hours since first meeting ARDS criteria per the Berlin definition of ARDS 3. Greater than 14 days since initial ICU admission 4. Inability to administer study product within 14 days of ICU admission 5. PaO2/FiO2 ≥ 250 mmHg after consent obtained and before study product is administered 6. Unable to obtain informed consent/no surrogate available 7. Pregnant or lactating 8. In custody of law enforcement officials 9. Burns > 20% of total body surface area 10. WHO Class III or IV pulmonary hypertension 11. History of cancer treatment in the last 2 years except for non-melanotic skin cancers 12. Underlying medical condition for which 6-month mortality is estimated to be > 50% 13. Moribund patient not expected to survive 24 hours 14. Advanced chronic liver disease (Child-Pugh Score > 12) 15. Severe chronic respiratory disease with the use of home oxygen 16. Severe traumatic brain injury - defined as: 1. A patient who has undergone intracranial neurosurgical intervention for monitoring or therapy (intracranial pressure monitoring, external ventricular drain, craniotomy), or 2. Intracranial injury by head CT (does not include patients with minimal subarachnoid injury and/or minor skull fracture), or 3. Post-resuscitation Glasgow Coma Score (GCS) < 9 assessed after sedation interruption, or 4. Non-survivable head injury as assessed by neurosurgery 17. Evidence of anoxic brain injury 18. History of stroke within the last 3 years 19. No intent/unwillingness to follow lung protective ventilation strategy 20. Currently receiving extracorporeal life support (ECLS) or high-frequency oscillatory ventilation (HFOV) 21. Anticipated extubation within 24 hours of enrollment 22. Clinical evidence of left atrial hypertension as measured by a pulmonary arterial wedge pressure > 18mmHg or left ventricular failure measured by an echocardiogram with a left ventricular ejection fraction less than 40%. Clinical judgement will determine if either of these measurements needs to be carried out.