1. Aged 18 to 85 years old, 2. It conforms to the diagnostic criteria of severe and critical type in Diagnosis and Treatment Plan for Pneumonia Infected in novel coronavirus (6th Edition) , 3. Sign the informed consent form.

1. Aged 18 to 85 years old, 2. It conforms to the diagnostic criteria of severe and critical type in Diagnosis and Treatment Plan for Pneumonia Infected in novel coronavirus (6th Edition) , 3. Sign the informed consent form.