1. Department of Anesthesiology and Resuscitology, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan
2. Perioperative Management Center, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama, Japan
3. Medical School, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama, Japan