[1] Sapporo Med Univ, Dept Emergency Med, Sapporo, Japan
[2] Sapporo Med Univ, Dept Publ Hlth, Sapporo, Japan
[3] Teine Keijinkai Hosp, Emergency & Crit Care Med Ctr, Sapporo, Japan
[4] Hyogo Emergency Med Ctr, Dept Emergency & Crit Care Med, Kobe, Japan
[5] St Lukes Int Hosp, Dept Emergency & Crit Care Med, Tokyo, Japan
[6] Teikyo Univ, Sch Med, Dept Emergency Med, Tokyo, Japan
[7] Kagawa Univ, Sch Med, Dept Emergency Med, Takamatsu, Kagawa, Japan