1. Department of Anaesthesia, Chiba Hokusoh Hospital, Nippon Medical School, Chiba, Japan.
2. Center for Anesthesiology Research, The Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A.
3. Department of Anaesthesia, Tama-Nagayama Hospital, Nippon Medical School, Department of Anaesthesiology, Tokyo Jikeikai Medical School, Tokyo, Japan.
4. Department of Anaesthesiology, Nippon Medical School, Tokyo, Japan.