1. Department of Emergency Medicine, Seoul National University Boramae Medical Center, Seoul, Korea.
2. Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, Korea.
3. Department of Emergency Medicine, Seoul National University Hospital, Seoul, Korea.
4. Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, Korea.
5. Department of Emergency Medicine, Chonnam National University Hospital, Gwangju, Korea.
6. Department of Emergency Medicine, School of Medicine Kyungpook National University and Kyungpook National University Hospital, Daegu, Korea.
7. Department of Emergency Medicine, Chungbuk National University Hospital, Cheongju, Korea.