inclusion criteria: * clinical diagnosis of covid-19 confirmed by rt-pcr; * thorax ct image suggestive of viral pneumonia; * respiratory failure (sao2 \<93% with o2 at 5l / min) * tracheal intubation (first 48 h);

inclusion criteria: * clinical diagnosis of covid-19 confirmed by rt-pcr; * thorax ct image suggestive of viral pneumonia; * respiratory failure (sao2 \<93% with o2 at 5l / min) * tracheal intubation (first 48 h);

inclusion criteria: - clinical diagnosis of covid-19 confirmed by rt-pcr; - thorax ct image suggestive of viral pneumonia; - respiratory failure (sao2 <93% with o2 at 5l / min) - tracheal intubation (first 48 h);

inclusion criteria: - clinical diagnosis of covid-19 confirmed by rt-pcr; - thorax ct image suggestive of viral pneumonia; - respiratory failure (sao2 <93% with o2 at 5l / min) - tracheal intubation (first 48 h);