[1] Chung Ang Univ, Chung Ang Univ Hosp, Dept Internal Med, Div Pulm & Crit Care Med,Coll Med, Seoul, South Korea
[2] Chung Ang Univ, Coll Pharm, Seoul, South Korea
[3] Univ Ulsan, Ulsan Univ Hosp, Coll Med, Dept Pulm & Crit Care Med, Ulsan, South Korea
[4] Hallym Univ, Dongtan Sacred Heart Hosp, Dept Internal Med, Div Pulm Allergy & Crit Care Med,Coll Med, Hwaseong, South Korea
[5] Natl Med Ctr, Dept Internal Med, Div Pulm & Crit Care Med, Seoul, South Korea
[6] Seoul Natl Univ, Seoul Metropolitan Govt, Dept Internal Med, Div Pulm & Crit Care Med,Borame Med Ctr, Seoul, South Korea
[7] Soonchunhyang Univ, Bucheon Hosp, Dept Internal Med, Div Allergy & Pulmonol,Coll Med, Bucheon, South Korea
[8] Sungkyunkwan Univ, Samsung Med Ctr, Sch Med, Dept Crit Care Med, Seoul, South Korea
[9] Seoul Natl Univ, Coll Med, Dept Internal Med, Div Pulm & Crit Care Med, Seoul, South Korea
[10] Seoul Natl Univ, Bundang Hosp, Dept Internal Med, Div Pulm & Crit Care Med,Coll Med, Seongnam, South Korea
[11] Ajou Univ, Ajou Univ Hosp, Sch Med, Dept Pulm & Crit Care Med, Suwon, South Korea
[12] Soonchunhyang Univ, Soonchunhyang Univ Hosp, Coll Med, Dept Radiol, Seoul, South Korea
[13] Univ Ulsan, Coll Med, Asan Med Ctr, Dept Pulm & Crit Care Med, Seoul, South Korea