Shunsuke Tachibana1, Tomo Hayase2, Michiaki Yamakage2. 1. Department of Anesthesiology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan. shunsuke.tachibana@gmail.com. 2. Department of Anesthesiology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan.