[1] Tokyo Bay Urayasu Ichikawa Med Ctr, Dept Emergency & Crit Care Med, Urayasu, Chiba, Japan
[2] Univ Tokyo, Sch Publ Hlth, Dept Clin Epidemiol & Hlth Econ, Bunkyo Ku, Tokyo, Japan
[3] St Lukes Int Hosp, Dept Crit Care Med, Chuo Ku, Tokyo, Japan
[4] Tokyo Metropolitan Childrens Med Ctr, Dept Pediat Emergency & Crit Care Med, Fuchu, Tokyo, Japan
[5] Univ Washington, Dept Surg, Seattle, WA 98195 USA
[6] Harvard Med Sch, Massachusetts Gen Hosp, Dept Emergency Med, Boston, MA 02115 USA