Fig. 2

Distribution of patients by pneumonia severity. Note: ARDS, acute respiratory distress syndrome; CT, computed tomography; NOM, nonoperative management; OS, open surgery; AG/AG + TAE, angiography/angiography + transarterial embolization; bacterial pneumonia* (also includes patients with mixed pneumonia). The following grading scale was used to classify the severity of lung involvement: CT 0–0%, CT 1–1–25%, CT 2–26–50%, CT 3–51–75%, CT 4–76–100%.