1. Anesthesiology and Critical Care, Faculty of Medicine Graduate School of Biomedical and Health Science, Hiroshima University, Hiroshima, Japan
2. Department of Anaesthesiology, Hiroshimakenritu-Syougaisya Rehabilitation Centre, Hiroshima, Japan
3. Department of Neuromuscular Research, National Centre of Neurology and Psychiatry, National Centre Hospital, Tokyo, Japan