Figure 1 Chest CT, fiberoptic bronchoscopy findings, and main therapeutic process. (A) Chest CT on hospital day 1 showed a lung infection, obviously in the inferior lobe of the left lung. (B) Chest CT on hospital day 4 showed aggravated infection in the left lung and new inflammation in the right lung. (C) Chest CT on hospital day 17 showed improved left lower lung lesions. (D) Chest CT on hospital day 14 (follow-up) showed infectious lesions in the bilateral lung had significantly improved. (E) Fiberoptic bronchoscopy on hospital day 2 found a large amount of thick sputum in the left lung and some submucosal bleeding spots in the inferior lobe of the left lung. (F). Fiberoptic bronchoscopy on hospital day 8 found mild tracheal edema in both lungs, with frothy thin sputum in the left lung, and no bleeding spots seen in the left lung. (G) Main therapies process diagram. Ce/Su – cefoperazone and sulbactam; CT – computed tomography; ET – endotracheal tube; HFNC – high-flow nasal cannula; MV – mechanical ventilation; NC – nasal catheter oxygen inhalation; NGS – next-generation sequencing technology.