1. Department of Intensive Care Medicine, Center Hospital of the National Center for Global Health and Medicine, Tokyo, Japan.
2. Department of Emergency Medicine and Critical Care, Center Hospital of the National Center for Global Health and Medicine, Tokyo, Japan.
3. Department of Respiratory Medicine, Center Hospital of the National Center for Global Health and Medicine, Tokyo, Japan.
4. Department of Surgery, Center Hospital of the National Center for Global Health and Medicine, Tokyo, Japan.