1. Department of Emergency Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2. Department of Emergency Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
3. Department of Emergency Medicine, Dong-A University College of Medicine, Busan, Korea.
4. Department of Emergency Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
5. National Emergency Medical Center, National Medical Center, Seoul, Korea.
6. Department of Emergency Medicine, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.