1. Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine , 81 Irwon-ro, Gangnam-gu, Seoul 06351 , Republic of Korea
2. Division of Pulmonology, Department of Internal Medicine, Inje University Haeundae Paik Hospital, Inje University College of Medicine , 875, Haeun-daero, Haeundae-gu, Busan 48108 , Republic of Korea
3. Division of Cardiology, Department of Medicine, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine , 81 Irwon-ro, Gangnam-gu, Seoul 06351 , Republic of Korea