1 Department of Emergency Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2 National Emergency Medical Center, National Medical Center, Seoul, Korea.
3 Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Technology (SAIHST), Sungkyunkwan University, Seoul, Korea.
4 Department of Emergency Medicine, Chosun University Hospital, Gwangju, Korea.