1. Department of Pulmonary and Critical Care Medicine, the Second Xiangya Hospital , Central South University , Changsha, Hunan 410011, China
2. Research Unit of Respiratory Disease , Central South University , Changsha, Hunan 410011, China
3. Clinical Medical Research Center for Pulmonary and Critical Care Medicine in Hunan Province, Changsha , Hunan 410011, China
4. Diagnosis and Treatment Center of Respiratory Disease , Central South University , Changsha, Hunan 410011, China