High-flow Nasal Oxygenation and Non-invasive Ventilation Strategies for the Treatment of Covid-19 Pneumonia

"Patients meeting the inclusion criteria will be treated alternately with 2 hours of HFNO and 1 hour of NIV (HFNO-NIV for the same patient in turn). In 24 hours, there will be 16 hours of HFNO, 8 hours of NIV.~Parameters to record~* Respiratory parameters (respiratory rate)~* SpO2~* Ventilator settings~* Patient's tolerance (VAS; between 0-100)~* Arterial blood gas (HFNO and NIV at 1 hour)~* Clinical parameters (D dimer, CRP, ROX index)~Intubation criteria~* Loss of consciousness~* Agitation~* Persistent hypotension~* Need for fluid resuscitation~* Need for vasopressor~* Respiration rate ≥40/min~* SpO2 \<92~* pH\<7.30"