The aim of the study is to compare two methods of oxygen therapy in patients with acute respiratory distress syndrome in the course of SARS-CoV2 pneumonia. The initial method of oxygen supply during coronavirus pneumonia is conventional oxygen therapy using a face mask or nasal cannula. However, there have been reports in the literature that early initiation of high-flow oxygen therapy with a nasal cannula is associated with better prognosis. The study we perform is intended to provide reliable evidence for confirmation this hypothesis.

Inclusion Criteria:

1. The diagnosis of a current SARS-CoV2 infection (confirmed RT-PCR test or antigen test [allowed in Poland, with sensitivity ≥90 and specificity ≥97]);
2. Hospitalization in the Oxygen Sector of the Temporary Hospital in Szczecin;
3. Pneumonia during SARS-CoV2 infection;
4. ARDS (PaO 2 / FiO 2 ratio ≤300);
5. Oxygen flow 8-12 l / min on mask with reservoir and ≤ 60 mmHg paO2 and / or SpO2 < 92%;
6. TNo current indications for treatment in the ICU;
7. Permisson of the patient.

Exclusion Criteria:

1. Probable lack of cooperation with patient;
2. Severe Disease disease, eg generalized neoplastic disease;
3. Concomitant pulmonary diseases (eg, fibrosis lungs);
4. Respiratory acidosis - pH <7.3 with pCO2> 50 mmHg;
5. Disturbances of consciousness - GCS < 12;

Groups are designed by web randomizer.