[1] Konkuk Univ, Sch Med, Chungju Hosp, Chungju, South Korea
[2] Sungkyunkwan Univ, Sch Med, Samsung Med Ctr, Seoul, South Korea
[3] Yonsei Univ, Coll Med, Anesthesia & Pain Res Inst, Seoul, South Korea
[4] Gyeongsang Natl Univ, Gyeongsang Inst Hlth Sci, Coll Med, Jinju, South Korea
[5] Univ Ulsan, Coll Med, Asan Med Ctr, Seoul, South Korea
[6] Keimyung Univ, Dongsan Hosp, Daegu, South Korea
[7] Ajou Univ, Coll Med, Suwon, South Korea
[8] Catholic Univ Korea, Seoul St Marys Hosp, Seoul, South Korea
[9] Seoul St Marys Hosp, Seoul, South Korea
[10] Korea Univ, Ansan Hosp, Ansan, South Korea
[11] Chung Ang Univ, Coll Med, Seoul, South Korea
[12] Univ Ulsan, Coll Med, Gangneung Asan Hosp, Kangnung, South Korea
[13] Hallym Univ, Sacred Heart Hosp, Anyang, South Korea
[14] Ewha Womans Univ, Sch Med, Seoul, South Korea
[15] CHA Univ, Bundang CHA Hosp, Seongnam, South Korea