[1] Univ Athens, Sch Med, Resp Med Dept 2, GR-11527 Athens, Greece
[2] Univ Thessaly, Sch Med, Dept Resp Med, Larisa, Greece
[3] Sismanogle Gen Hosp, Resp Med Dept 3, Athens, Greece
[4] Cleveland Clin, Pulm & Crit Care Med Resp Inst, Cleveland, OH 44106 USA