[1] Nippon Med Sch, Dept Emergency & Crit Care Med, Tokyo, Japan
[2] Nippon Med Sch, Fac Med, Tokyo, Japan
[3] Hiroshima Univ, Dept Publ Hlth & Hlth Policy, Hiroshima, Japan
[4] Nippon Med Sch Chiba Hokusoh Hosp, Dept Neurosurg, Chiba, Japan
[5] Natl Disaster Med Ctr, Inst Clin Res, Tokyo, Japan