1. Division of Pulmonology, Department of Internal Medicine, Konyang University Hospital, Daejeon, Republic of Korea
2. Myunggok Medical Research Institute, College of Medicine, Konyang University, Daejeon, Republic of Korea
3. Department of Internal Medicine, Konyang University Hospital, Daejeon, Republic of Korea
4. Department of Anesthesiology and Pain Medicine, Eulji University Medical Center, Daejeon, Korea