[1] Univ Exeter, Sch Med, Royal Devon & Exeter Hosp, Exeter, Devon, England
[2] Univ Marburg, Univ Med Ctr Giessen & Marburg, German Ctr Lung Res, Dept Med Pulm & Crit Care Med, Marburg, Germany
[3] Boehringer Ingelheim Pharma GmbH & Co KG, Resp Dis Res, Biberach, Germany
[4] Boehringer Ingelheim Pharma GmbH Co KG, Ingelheim, Germany
[5] Univ Texas Hlth Sci Ctr San Antonio, Dept Med, Div Pulm Dis, Crit Care Med, San Antonio, TX 78229 USA
[6] Audie L Murphy Mem Vet Hosp Div, South Texas Vet Hlth Care Syst, San Antonio, TX USA