1. Department of Emergency Medicine, Qilu Hospital; Shandong University; Qingdao Shandong 250012 China
2. Qingdao Hiser Medical Center; Qingdao Shandong 250012 China
3. The Affiliated Hospital of Qingdao University; Qingdao Shandong 250012 China
4. School of Medicine, Tsinghua University; Beijing 100084 China