[1] Chiba Hokusoh Hosp, Dept Emergency & Crit Care Med, Nippon Med Sch, Inba, Chiba 2701694, Japan
[2] Nippon Med Coll, Tokyo 113, Japan
[3] Kyorin Univ, Dept Emergency & Crit Care Med, Sch Med, Tokyo, Japan
[4] Kawasaki Med Sch, Dept Emergency & Crit Care Med, Kurashiki, Okayama, Japan
[5] Toho Univ, Dept Emergency & Crit Care Med, Sch Med, Tokyo, Japan
[6] Osaka Prefectural Hosp, Dept Emergency & Crit Care Med, Osaka, Japan
[7] Tokai Univ, Sch Med, Dept Gen Med, Isehara, Kanagawa 25911, Japan
[8] Sapporo Municipal Hosp, Dept Emergency & Crit Care Med, Sapporo, Hokkaido, Japan
[9] St Paul Univ, Dept Sociol, Tokyo, Japan