To determine whether a strategy of adding venovenous ECMO to mechanical ventilation, as compared to mechanical ventilation alone, increases the number of intensive care free days at day 60, in patients with moderate to severe acute hypoxic respiratory failure.

Mechanically ventilated patients with moderate to severe acute hypoxic respiratory failure are at increased risk of dying, short and long-term health problems and are often very costly to treat. The mechanical ventilator, whilst often lifesaving, may harm patients in two ways i) directly via damage to the lungs (termed ventilator induced lung injury), and ii) indirectly via paralysis and sedation that patients require to tolerate mechanical ventilation. Paralysis and sedation can increase the risk of secondary infections, weakness, prolonged duration of intensive care, as well as long-term physical disability. There is a need to develop new treatments that support patients and at the same time reduce these complications.

Extracorporeal membrane oxygenation (ECMO) is a device that supports the lungs by adding oxygen and removing carbon dioxide from the blood. By providing non pulmonary gas exchange, veno-venous (VV) ECMO can reduce the need for the mechanical ventilator. This in turn can reduce the risk of lung damage, and also removes the need for sedating medications so that activities like physiotherapy can begin earlier.

The REDEEM trial is a phase 2, investigator initiated, multicentre randomised controlled trial that will recruit 140 patients with moderate to severe acute hypoxic respiratory failure. It is designed to test whether adding ECMO to the mechanical ventilator, as compared to using the mechanical ventilator on its own, leads to an increase in the number of patients who survive and are discharged earlier from the intensive care unit. If the REDEEM trial confirms adding ECMO is more effective than mechanical ventilation alone, it has the potential to change the current paradigm of intensive care treatment of hypoxic respiratory failure, and could lead to changes in practice globally.

Inclusion Criteria:

1. Patients ≥18 to 65 years old
2. Acute hypoxemic respiratory failure characterised by new or worsening respiratory symptoms developing within 2 weeks prior to the onset of need for oxygen or respiratory support
3. Mechanical ventilation of <7 days
4. Moderate to severe respiratory failure, as demonstrated by two P:F ratios <150mmHg at least 6 hours apart. Arterial Blood Gases (ABG) with P:F ratio > 150mmHg are permitted between the two trial inclusion ABGs.
5. Trial of proning (unless contraindicated)

Exclusion Criteria:

1. The patient will be extubated today or tomorrow (i.e. will not remain intubated and ventilated the day after tomorrow)
2. Cardiogenic cause of respiratory failure
3. Chronic hypercapnic respiratory failure defined as PaCO2 > 60 mmHg in the outpatient setting
4. Home mechanical ventilation (non-invasive ventilation or via tracheotomy) except for CPAP/BIPAP used solely for sleep disordered breathing
5. Confirmed diffuse alveolar haemorrhage from vasculitis
6. Neurologic conditions, i.e. undergoing treatment for intracranial hypertension
7. Currently receiving any form of ECMO (e.g., venovenous, venoarterial, or hybrid configuration)
8. Patient needing immediate VV ECMO (as per EOLIA criteria)
9. The patient is moribund and deemed unlikely to survive past 24 hours (as determined by the clinical team)
10. The patient is being transitioned to palliative care
11. Contraindications to anticoagulation (e.g., active GI bleeding, bleeding predisposition, severe trauma)
12. Previous hypersensitivity/anaphylactic reaction to heparin or heparin-induced thrombocytopenia
13. Participation or Consent is declined, OR
14. Unable to identify or Contact surrogate decision maker.

The Management Committee support the view of the International Committee of Medical Journal Editors and the World Health Organisation (WHO) with reference to the ethical obligation to responsibly share data acquired by interventional clinical trials. At the conclusion of the study, the management committee will consider requests from researchers who provide a methodically sound scientific proposal as per the Data Sharing Policy set out in the Australian and New Zealand Intensive Care Research Centre (ANZIC-RC) Terms of Reference. Only de-identified data will be shared and all requests for data must comply with the ethical, regulatory, and legislative requirements governing their jurisdiction.