In patients with novel coronavirus pneumonia, the main manifestations of severe disease are respiratory distress, a respiratory rate of ≥30 breaths/min, and an oxygen saturation of ≤93% on finger pulse oxygen in a resting calm state. A blood gas analysis reveals an oxygen partial pressure and oxygen concentration ratio of ≤300 mmHg, and a diagnosis of severe novel coronavirus pneumonia is made when one of these criteria is met. Patients with critical disease are managed according to the criteria for severe disease if the lung imaging shows a significant progression of >50% within 24-48 h. Patients with critical disease will meet the following criteria: 1) respiratory failure and require mechanical ventilation; 2) shock; 3) other organ failure in combination and require ICU admission for treatment.