1. Department of Anesthesiology, Kyoto Prefectural University of Medicine , 465 Kajiicho, Kamigyo-Ku, Kyoto-Shi , Kyoto-Fu 604-8404 , Japan
2. Department of Anesthesiology, Akashi City Hospital , 1-33, Takasho-Machi, Akashi-Shi , Hyogo-Ken, 673-8501 , Japan