1. Department of Anesthesia and Perioperative Medicine, Ehime University Graduate School of Medicine, Ehime, Japan
2. Department of Palliative Care Medicine, Matsuyama Bethel Hospital, Ehime, Japan
3. Department of Anesthesiology, Uwajima City Hospital, Ehime, Japan
4. Department of Palliative Care Medicine, Japanese Red Cross Society Himeji Hospital, Hyogo, Japan
5. Pain Clinic Unit, Nakatani Hospital, Hyogo, Japan