Soon-Ho Chon1, Kyung Oh Kang2, Duk Yong Kim3. 1. Department of Thoracic and Cardiovascular Surgery, S-Jungang Hospital, Jeju, South Korea. Electronic address: sh.chon@hotmail.com. 2. Department of Anesthesiology, S-Jungang Hospital, Jeju, South Korea. 3. Department of Neurosurgery, S-Jungang Hospital, Jeju, South Korea.