[1
]
Department of Anaesthesiology, Sapporo Medical University School of Medicine, South1
West16 291, Chuoku, Sapporo 060-8543, Japan. Electronic address: y.yoshikawa@sapmed.ac.jp.
[2
]
Department of Anaesthesiology, Sapporo Medical University School of Medicine, South1
West16 291, Chuoku, Sapporo 060-8543, Japan.