1 Department of Anesthesiology, Sapporo Medical University School of Medicine, West 16, South 1, Chuouku, Sapporo, Hokkaido, 060-8556, Japan. sakaiwataru1128@gmail.com.
2 Department of Anesthesiology, Sapporo Medical University School of Medicine, West 16, South 1, Chuouku, Sapporo, Hokkaido, 060-8556, Japan.