COVID-19, bLOod Coagulation and Thrombosis

Coronavirus 2 (SARS-CoV2) has been identified as the pathogen responsible for severe acute respiratory syndrome associated with severe inflammatory syndrome and pneumonia (COVID-19). Described at the end of 2019 in China, the pandemic sees the number of patients increasing worldwide, Europe being still in the ascending phase of the epidemic and the American continent at the very beginning of it. Haemostasis abnormalities have been shown to be associated with a poor prognosis in these patients with this pneumonia. In a Chinese series of 183 patients, the hemostasis balance including thrombin time, fibrinogenemia, fibrin degradation products and antithrombin III were within normal limits. Only the D-Dimer assay was positive in the whole cohort with an average rate of 0.66 µg / mL (normal \<50 µg / mL). These hemostasis parameters were abnormal mainly in patients who died during their management; the levels of D-dimers and fibrin degradation products were significantly higher while the antithrombin III was reduced. The findings on the particular elevation of D-dimers in deceased patients as well as the significant increase in thrombin time were also reported in another series. Higher numbers of pulmonary embolisms have been reported in patients with severe form of SARS-COV2 (data in press). This research is based on the hypothesis that the existence of deep vein thrombosis (DVT) could make it possible to screen patients at risk of pulmonary embolism and to set up a curative anticoagulation. This is all the more important since the occurrence of a pulmonary embolism can clearly worsen the right ventricular failure possibly observed during mechanical ventilation in these patients. Cohort study, non-interventional, multicentric, prospective, non-comparative, longitudinal. The main objective of the research is to describe the prevalence of deep vein thrombosis in patients hospitalized in intensive care for acute respiratory failure linked to documented SARS-COV2 pneumonia, within 24 hours of their admission. The secondary objectives of the research are: * Identify the factors associated with the existence of deep vein thrombosis * Describe the relationship between the inflammatory status of patients on admission and the existence of DVT during follow-up. * Describe the relationship between the results of the hemostasis assessment and the existence of deep vein thrombosis during follow-up. * Describe the relationship between a right ventricular failure or dysfunction during follow-up and the existence of DVT. * Describe the relationship between mortality and the existence of DVT, within 28 days of the patient's admission to intensive care or intensive care. Describe the lung parenchyma if a CT scan is performed