inclusion criteria: * age ≥18 years * hospitalized in icu * presence of all of the following conditions, within one week of a clinical insult or new or worsening respiratory symptoms: * pao2/fio2 \<300 mmhg with positive end-expiratory pressure (peep) ≥5 cmh2o * bilateral opacities not fully explained by cardiac failure or fluid overload * intubated and sedated for mechanical protective ventilation * affiliation to the french sociale security * beta hcg negative for women for covid-19 subgroup: - covid-19 infection (rt-pcr \< 7 days and/or another approved diagnostic technique and/or typical ct appearance of covid-19 pneumonia

inclusion criteria: * age ≥18 years * hospitalized in icu * presence of all of the following conditions, within one week of a clinical insult or new or worsening respiratory symptoms: * pao2/fio2 \<300 mmhg with positive end-expiratory pressure (peep) ≥5 cmh2o * bilateral opacities not fully explained by cardiac failure or fluid overload * intubated and sedated for mechanical protective ventilation * affiliation to the french sociale security * beta hcg negative for women for covid-19 subgroup: - covid-19 infection (rt-pcr \< 7 days and/or another approved diagnostic technique and/or typical ct appearance of covid-19 pneumonia

inclusion criteria: - age ≥18 years - hospitalized in icu - presence of all of the following conditions, within one week of a clinical insult or new or worsening respiratory symptoms: - pao2/fio2 <300 mmhg with positive end-expiratory pressure (peep) ≥5 cmh2o - bilateral opacities not fully explained by cardiac failure or fluid overload - intubated and sedated for mechanical protective ventilation - affiliation to the french sociale security - beta hcg negative for women for covid-19 subgroup: - covid-19 infection (rt-pcr < 7 days and/or another approved diagnostic technique and/or typical ct appearance of covid-19 pneumonia

inclusion criteria: - age ≥18 years - hospitalized in icu - presence of all of the following conditions, within one week of a clinical insult or new or worsening respiratory symptoms: - pao2/fio2 <300 mmhg with positive end-expiratory pressure (peep) ≥5 cmh2o - bilateral opacities not fully explained by cardiac failure or fluid overload - intubated and sedated for mechanical protective ventilation - affiliation to the french sociale security - beta hcg negative for women for covid-19 subgroup: - covid-19 infection (rt-pcr < 7 days and/or another approved diagnostic technique and/or typical ct appearance of covid-19 pneumonia