1. Department of Critical Care Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
2. Department of Health Statistics, Faculty of Preventive Medicine, Air Force Medical University, Xi’an, Shaanxi, China
3. Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China