1 Department of Anesthesiology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan, dg274825@cf6.so-net.ne.jp.
2 Department of Clinical Engineering, Kyorin University School of Medicine, Mitaka, Tokyo, Japan.
3 Department of Anesthesiology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan, Department of Clinical Engineering, Kyorin University School of Medicine, Mitaka, Tokyo, Japan.