[1] Kyoto Univ, Dept Resp Med, Grad Sch Med, Sakyo Ku, Kyoto 6068507, Japan
[2] Kobe City Med Ctr Gen Hosp, Dept Resp Med, Kobe, Hyogo, Japan
[3] Kyoto Univ, Dept Resp Care & Sleep Control Med, Grad Sch Med, Kyoto 6068507, Japan
[4] Kobe City Med Ctr W Hosp, Dept Resp Med, Kobe, Hyogo, Japan