1. Department of Anesthesiology, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
2. Department of Anesthesiology, Konkuk University Medical Center, Research Institute of Biomedical Science, Konkuk University School of Medicine, Seoul, Korea.
3. Department of Anesthesiology, National Medical Center, Seoul, Korea.
4. Department of Thoracic Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.