1. Department of Pediatrics, Linfen Central Hospital, Linfen 041000, China
2. Department of Respiratory and Critical Care Medicine, Peking University People’s Hospital, Beijing 100044, China
3. Linfen Clinical Medicine Research Center, Linfen 041000, China
4. Department of Respiratory and Critical Care Medicine, Linfen Central Hospital, Linfen 041000, China
5. Institute of Chest and Lung Diseases, Shanxi Medical University, Taiyuan 030001, China