1. Department of Pulmonary and Critical Care Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
2. Department of General Practice, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
3. Institute of Respiratory Diseases, Department of Pulmonary and Critical Care Medicine, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China