Age above or equal to 18 years, SARS-covid-19 infection confirmed through RT-PCR, Severe forms confirmed by the presence of ARDS according to the Berlin classification ( bilateral infiltrate on chest X-ray, arterial hypoxemia with a PaO2 / FIO2 ratio <300, absence of structural heart disease or evidence of insufficiency acute cardiac arrest, Presence of severe clinical presentation with respiratory failure requiring orotracheal intubation or mechanical ventilation or maintenance of RF> 24 ipm and saturation <90% after the administration of supplemental oxygen through a nasal catheter at 4 liters / min, Dosage of D-dimer greater than and equal to 0.5 pg / ml, Presence of prothrombin time (TP / INR) <1.5 and APTT (activated partial thromboplastin time (APTT) <1.5, Platelet count greater than 100,000 / mm3

Age above or equal to 18 years, SARS-covid-19 infection confirmed through RT-PCR, Severe forms confirmed by the presence of ARDS according to the Berlin classification ( bilateral infiltrate on chest X-ray, arterial hypoxemia with a PaO2 / FIO2 ratio <300, absence of structural heart disease or evidence of insufficiency acute cardiac arrest, Presence of severe clinical presentation with respiratory failure requiring orotracheal intubation or mechanical ventilation or maintenance of RF> 24 ipm and saturation <90% after the administration of supplemental oxygen through a nasal catheter at 4 liters / min, Dosage of D-dimer greater than and equal to 0.5 pg / ml, Presence of prothrombin time (TP / INR) <1.5 and APTT (activated partial thromboplastin time (APTT) <1.5, Platelet count greater than 100,000 / mm3