1 Department of Anesthesiology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan. Electronic address: natsuyamamo@gmail.com.
2 Department of Anesthesiology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan.
3 Department of Anesthesiology, Yokohama City University Medical Center, 4-57 Urafune, Minami-ku, Yokohama, Japan.