1. Emergency Department, The Peking University Third Hospital, No. 49 North 9 Garden Road, Haidian District, Beijing 100191, China
2. Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing 19, China
3. Emergency Department, Peking University Shenzhen Hospital, 1120 Lianhua 20 Road, Futian District, Shenzhen City 518306, Guangdong, China