1. The Second Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China;
2. The Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China;
3. Department of Respiratory and Critical Care Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China;
4. State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Institute of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou, Guangdong, China