1. Department of Emergency Medicine, Korea University Guro Hospital, Seoul, Korea.
2. Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
3. Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, Korea.
4. Department of Emergency Medicine, Seoul National University Boramae Medical Center, Seoul, Korea.
5. Department of Emergency Medicine, Hanyang University Seoul Hospital, Seoul, Korea.
6. Department of Emergency Medicine, Korea University Anam Hospital, Seoul, Korea.
7. Department of Emergency Medicine, Seoul National University Hospital, Seoul, Korea.
8. Department of Emergency Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea.