Microecology and Host Immunity in Patients With Severe COVID-19 Infection

Inclusion Criteria

• •1\) Respiratory distress, respiratory rate ≥ 30 times/minute
• •2\) At rest, oxygen saturation ≤ 93%
• •3）PaO2/FiO2 ≤300mmHg
• •4\) Shock
• •5\) Respiratory failure requires mechanical ventilation
• •6\) Complicated with other organ failure requires ICU monitoring and treatment
• •7\) Or in case of any of the following conditions, even if none of the above conditions is found, it is also managed as a critical case: ① pulmonary imaging shows that the lesion has significantly progressed more than 50% within 24-48 hours; ② Age\>60 years old; ③ Complicated with serious chronic diseases (including diabetes, hypertension, coronary heart disease, malignant tumor, structural lung disease, pulmonary heart disease and immunosuppressed population)