Inclusion Criteria:  COVID-19 positive by RT-PCR Age≥ 18 years Both gender Classical radiological lesions of COVID-19 on HRCT chest. Respiratory rate > 30/ min and not responding to non-rebreather masks. COVID-related pneumonia requiring non-invasive ventilatory support (high-flow nasal cannula, and / or non-invasive ventilation and / or CPAP)  Exclusion Criteria:  Age < 18 years Patients who refuse to participate in the study Severe respiratory failure requiring invasive ventilatory support Indication of immediate tracheal intubation Significant acute progressive circulatory insufficiency Impaired conscious level Nasal blockade