1Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea
2Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, Anyang, Korea
3Department of Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
4Department of Anesthesiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
5Department of Internal Medicine, St. Paul’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
6Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea
7Department of Anesthesia and Pain Medicine, Pusan National University School of Medicine, Busan, Korea
8Department of Anesthesia and Pain Medicine, Yonsei University College of Medicine, Seoul, Korea
9Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Korea
10Department of Software Convergence, Seoul Women’s University, Seoul, Korea
11Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea