1. Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Kangnam Sacred Heart Hospital, Seoul, Korea.
2. Department of Allergy, Pulmonary and Critical Care Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
3. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.
4. Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea.
5. Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
6. Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
7. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Korea.
8. Division of Pulmonology and Critical Care, Department of Internal Medicine, Inha University School of Medicine, Incheon, Korea.