[1] Hallym Univ, Sacred Heart Hosp, Dept Pulm Allergy & Crit Care Med, 22 Gwanpyeong Ro, Anyang 14068, South Korea
[2] Gangnam Severance Hosp, Dept Pulm & Crit Care Med, Seoul, South Korea
[3] Chungnam Natl Univ Hosp, Dept Pulm & Crit Care Med, Daejeon, South Korea
[4] Korea Univ, Guro Hosp, Dept Pulm & Crit Care Med, Seoul, South Korea
[5] Inje Univ, Paik Hosp, Dept Pulm & Crit Care Med, Seoul, South Korea
[6] Kyeimyung Univ, Dongsan Hosp, Dept Pulm & Crit Care Med, Daegu, South Korea
[7] Kangnam Sacred Heart Hosp, Dept Pulm Allergy & Crit Care Med, Seoul, South Korea
[8] Pusan Natl Univ Hosp, Dept Pulm & Crit Care Med, Busan, South Korea