1. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Myongji Hospital, Goyang, Korea.
2. Department of Radiology, Chungnam National University College of Medicine, Daejeon, Korea.
3. Emergency Intensive Units, Daejeon Regional Emergency Center, Chungnam National University College of Medicine, Daejeon, Korea.
4. Department of Anesthesiology and Pain Medicine, Chungnam National University College of Medicine, Daejeon, Korea.
5. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungnam National University College of Medicine, Daejeon, Korea.