[1] Hallym Univ, Kangnam Sacred Heart Hosp, Dept Pulm Allergy & Crit Care Med, Seoul, South Korea
[2] Inha Univ, Coll Med, Dept Pulm & Crit Care Med, Incheon, South Korea
[3] Yeungnam Univ Hosp, Dept Pulm & Crit Care Med, Daegu, South Korea
[4] Inje Univ, Sanggye Paik Hosp, Dept Pulm & Crit Care Med, Seoul, South Korea
[5] Myongji Hosp, Dept Internal Med, Goyang, South Korea
[6] Kyung Hee Univ Hosp Gangdong, Dept Pulm & Crit Care Med, Seoul, South Korea
[7] Chungnam Natl Univ Hosp, Dept Pulm & Crit Care Med, Daejeon, South Korea
[8] Pusan Natl Univ Hosp, Dept Internal Med, Busan, South Korea
[9] Catholic Univ Korea, St Pauls Hosp, Coll Med, Dept Pulm Crit Care & Sleep Med, Seoul, South Korea
[10] Inje Univ, Ilsan Paik Hosp, Dept Internal Med, Div Pulm & Crit Care Med, Goyang, South Korea
[11] Hanyang Univ, Guri Hosp, Dept Internal Med, Guri, South Korea
[12] Jeonbuk Natl Univ Hosp, Dept Pulm Allergy & Crit Care Med, Jeonju, South Korea
[13] Hallym Univ, Sacred Heart Hosp, Dept Pulm Allergy & Crit Care Med, Anyang, South Korea
[14] Yonsei Univ, Coll Med, Gangnam Severance Hosp, Dept Internal Med, Seoul, South Korea