* pregnancy * presence of a tracheostomy * assistance by any non-invasive cpap or niv at the screening * treatment with high flow nasal cannula at the screening * clinical contraindication to the use of no * patients enrolled in another interventional trial * hospitalized and confirmed diagnosis of covid-19 for more than 7 days * previous intubation for covid-19 * subject not committed to full support (dnr, dni or cmo) * subject requiring oxygen at home for lung comorbidities * the primary cause of hospitalization not due to covid-19 * subject receiving vasopressor at the time of screening * history of malignancy or other irreversible disease/conditions with 6-month mortality \>50% * oxygen saturation of 100% at screening, despite oxygen requirement * patients on dialysis at the time of enrollment

* pregnancy * presence of a tracheostomy * assistance by any non-invasive cpap or niv at the screening * treatment with high flow nasal cannula at the screening * clinical contraindication to the use of no * patients enrolled in another interventional trial * hospitalized and confirmed diagnosis of covid-19 for more than 7 days * previous intubation for covid-19 * subject not committed to full support (dnr, dni or cmo) * subject requiring oxygen at home for lung comorbidities * the primary cause of hospitalization not due to covid-19 * subject receiving vasopressor at the time of screening * history of malignancy or other irreversible disease/conditions with 6-month mortality \>50% * oxygen saturation of 100% at screening, despite oxygen requirement * patients on dialysis at the time of enrollment

pregnancy presence of a tracheostomy assistance by any non-invasive cpap or niv at the screening treatment with high flow nasal cannula at the screening clinical contraindication to the use of no patients enrolled in another interventional trial hospitalized and confirmed diagnosis of covid-19 for more than 7 days previous intubation for covid-19 subject not committed to full support (dnr, dni or cmo) subject requiring oxygen at home for lung comorbidities the primary cause of hospitalization not due to covid-19 subject receiving vasopressor at the time of screening history of malignancy or other irreversible disease/conditions with 6-month mortality >50% oxygen saturation of 100% at screening, despite oxygen requirement patients on dialysis at the time of enrollment

pregnancy presence of a tracheostomy assistance by any non-invasive cpap or niv at the screening treatment with high flow nasal cannula at the screening clinical contraindication to the use of no patients enrolled in another interventional trial hospitalized and confirmed diagnosis of covid-19 for more than 7 days previous intubation for covid-19 subject not committed to full support (dnr, dni or cmo) subject requiring oxygen at home for lung comorbidities the primary cause of hospitalization not due to covid-19 subject receiving vasopressor at the time of screening history of malignancy or other irreversible disease/conditions with 6-month mortality >50% oxygen saturation of 100% at screening, despite oxygen requirement patients on dialysis at the time of enrollment

1. pregnancy 2. presence of a tracheostomy 3. assistance by any non-invasive cpap or niv at the screening 4. treatment with high flow nasal cannula at the screening 5. clinical contraindication to the use of no 6. patients enrolled in another interventional trial 7. hospitalized and confirmed diagnosis of covid-19 for more than 7 days 8. previous intubation for covid-19 9. subject not committed to full support (dnr, dni or cmo) 10. subject requiring oxygen at home for lung comorbidities 11. the primary cause of hospitalization not due to covid-19 12. subject receiving vasopressor at the time of screening 13. history of malignancy or other irreversible disease/conditions with 6-month mortality >50% 14. oxygen saturation of 100% at screening, despite oxygen requirement 15. patients on dialysis at the time of enrollment

1. pregnancy 2. presence of a tracheostomy 3. assistance by any non-invasive cpap or niv at the screening 4. treatment with high flow nasal cannula at the screening 5. clinical contraindication to the use of no 6. patients enrolled in another interventional trial 7. hospitalized and confirmed diagnosis of covid-19 for more than 7 days 8. previous intubation for covid-19 9. subject not committed to full support (dnr, dni or cmo) 10. subject requiring oxygen at home for lung comorbidities 11. the primary cause of hospitalization not due to covid-19 12. subject receiving vasopressor at the time of screening 13. history of malignancy or other irreversible disease/conditions with 6-month mortality >50% 14. oxygen saturation of 100% at screening, despite oxygen requirement 15. patients on dialysis at the time of enrollment