1. Department of Emergency Medicine, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, People's Republic of China.
2. The Cadre Ward, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, People's Republic of China.
3. Department of Cardiovascular Medicine, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, People's Republic of China.
4. Department of Respiratory Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, People's Republic of China.