1. Severe nasal obstruction or other contraindication to high flow nasal cannulae 2. Patient unable to lay prone or in the face forward position 3. Immediate need for intubation 4. Severe and/or uncontrolled hemodynamic instability 5. Previous intubation for COVID-19 pneumonia (i.e. step down patients) 6. Pregnancy 7. Known terminal illness with life expectancy less than 1 year 8. Decision not to intubate 9. Inability to understand oral or written study information and/or to cooperate with instructions necessary to complete the allocated intervention 10. Inability to understand oral or written study information

1. Severe nasal obstruction or other contraindication to high flow nasal cannulae 2. Patient unable to lay prone or in the face forward position 3. Immediate need for intubation 4. Severe and/or uncontrolled hemodynamic instability 5. Previous intubation for COVID-19 pneumonia (i.e. step down patients) 6. Pregnancy 7. Known terminal illness with life expectancy less than 1 year 8. Decision not to intubate 9. Inability to understand oral or written study information and/or to cooperate with instructions necessary to complete the allocated intervention 10. Inability to understand oral or written study information