Department of Emergency Medicine, Seoul Metropolitan Government - Seoul National University Boramae Medical Center, 20, Boramae-ro 5-gil, Dongjak-gu, Seoul, 07061, Republic of Korea. Department of Emergency Medicine, Gachon University Gil Medical Center, 21, Namdong-daero 774 Beon-gil, Namdong-gu, Incheon, 21565, Republic of Korea. yongem@gilhospital.com. Department of Emergency Medicine, Seoul National University Bundang Hospital, 82, Gumi-ro 173 Beon-gil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea. Department of Emergency Medicine, Gachon University Gil Medical Center, 21, Namdong-daero 774 Beon-gil, Namdong-gu, Incheon, 21565, Republic of Korea. Department of Emergency Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, 158, Palyong-ro, Masanhoewon-gu, Changwon-si, Gyeongsangnam-do, 51353, Republic of Korea.