1. Patients are eligible for inclusion if they meet all of the following criteria within 5-7 days after the first admission to the ICU. 2. The patients met the diagnostic criteria of 2019-nCoV pneumonia (new coronavirus infection) pneumonia treatment plan (Fifth version), the National Health Office [2020] No.103., 3. The primary disease is 2019 nCoV infection, 4. Respiratory distress, RP >=30 times/unit, 5. Under resting state, blood oxygen saturation <=93%, 6. PaO2 / FiO2 <=300nnhg (1mmhg = 0.133kpa), 7. Imaging data suggest bilateral lesions 8. Volunteer to participate in clinical research, understand and sign informed consent.

1. Patients are eligible for inclusion if they meet all of the following criteria within 5-7 days after the first admission to the ICU. 2. The patients met the diagnostic criteria of 2019-nCoV pneumonia (new coronavirus infection) pneumonia treatment plan (Fifth version), the National Health Office [2020] No.103., 3. The primary disease is 2019 nCoV infection, 4. Respiratory distress, RP >=30 times/unit, 5. Under resting state, blood oxygen saturation <=93%, 6. PaO2 / FiO2 <=300nnhg (1mmhg = 0.133kpa), 7. Imaging data suggest bilateral lesions 8. Volunteer to participate in clinical research, understand and sign informed consent.