HNFO With or Without Helmet NIV for Oxygenation Support in Acute Respiratory Failure Pilot RCT

Inclusion Criteria:

1. Intensive care unit admission (orders written)

2. Age ≥18 years

3. Hypoxemic acute respiratory failure for at least 1 hour and still present at time ofscreening for eligibility (symptom onset during last 14 days) with the following:

4. Respiratory rate >21bpm or clinical evidence of increased work of breathing and

5. Documented Hypoxemia defined as any one of: i. PaO2:FiO2 < 300 ii. If no arterial blood gas available, then SpO2:FiO2 < 315 iii.Oxygen saturation <98% on FiO2 >= 0.4 or higher by Venturi mask, TAVISH mask 10Litres / minute, or any non-invasive oxygenation strategy

6. Not already intubated or with tracheostomy

Exclusion Criteria:

1. Already on HFNO or other non-invasive ventilation strategy at FiO2>=0.4 for the last 24 hours in the ICU.

2. Immediate need for intubation (e.g., inadequate airway protection or refractoryhypoxemia or cardiopulmonary arrest, massive hemoptysis, etc)

3. Extubated in the ICU within past 72 hours

4. Clinician deems that face mask NIV is indicated to treat a primary diagnosis ofhypercapnic respiratory failure or acute congestive heart failure

5. Known neuromuscular disease

6. Patients being transitioned to Palliative care or unlikely to survive more than 24hours

7. ICU discharge is planned or anticipated on the day of screening

8. Previously enrolled in this trial

9. Trauma patients who remain in a cervical spine collar at the time of recruitment orwho have upper limb/torso fractures that would preclude them from safe applicationof the helmet

10. Clinician decision that positive pressure to face and/or nasal pharynx is acontraindication (eg. Transphenoidal surgery, basal skull fracture etc.)