1. Division of Trauma and Surgical Critical Care, Osaka General Medical Center, Osaka, Japan
2. Department of Emergency and Critical Care Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
3. Emergency and Critical Care Center, Hokkaido University Hospital, Sapporo, Japan
4. Department of Biostatistics and Data Management, National Cerebral and Cardiovascular Center, Osaka, Japan