Ryoji Iida1, Junpei Konishi2, Takahiro Suzuki2. 1. Department of Anesthesiology, Nihon University School of Medicine, 1-6, Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8309, Japan. ryoiida03@gmail.com. 2. Department of Anesthesiology, Nihon University School of Medicine, 1-6, Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8309, Japan.