1. Teaching and Research Section of Emergency Medicine, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang, 050017, P.R. China
2. Department of Emergency Medicine, Cangzhou Central Hospital, No. 16, Xinhua West Road, Cangzhou, 061000, P.R. China
3. Department of Emergency Medicine, The Third Hospital of Hebei Medical University, No. 139, Ziqiang Road, Shijiazhuang, 050051, P.R. China