1. Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan
2. Faculty of Health and Welfare Science, Okayama Prefectural University, Soja, Okayama 719‑1197, Japan
3. Department of Anesthesiology, Kagawa Prefectural Central Hospital, Takamatsu, Kagawa 760‑8557, Japan