1. Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine and Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
2. Department of Respiratory and Critical Care Medicine, Changsha Central Hospital, Changsha, China
3. Department of Respiratory and Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
4. Department of Respiratory and Critical Care Medicine, Beijing Renhe Hospital, Capital Medical University, Beijing, China