[1] Univ La Frontera, Fac Med, Dept Internal Med, Head Resp Div, Temuco, Chile
[2] Univ La Frontera, Fac Med, Dept Surg, Temuco, Chile
[3] Inst Nacl Enfermedades Resp & Cirugia Toracica, Dept Surg, Santiago, Chile
[4] Inst Nacl Enfermedades Resp & Cirugia Toracica, Dept Lung Dis, Santiago, Chile
[5] Univ New Mexico, Sch Med, Dept Internal Med, Div Pulm & Crit Care, Albuquerque, NM 87131 USA