1. Department of Anesthesiology, Kasumigaura Medical Center Hospital, National Hospital Organization, Tsuchiura, Japan
2. Department of Anesthesiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
3. Tsuchiura Clinical Education and Training Center, Kasumigaura Medical Center Hospital, National Hospital Organization, Tsuchiura, Japan
4. Department of Surgery, Kasumigaura Medical Center Hospital, National Hospital Organization, Tsuchiura, Japan