Background The natural history and time course of the onset of exacerbation events of chronic obstructive pulmonary disease (COPD) is incompletely understood. Methods A prospective cohort of 212 ...

Superseded By 2013 Guideline: British Thoracic Society Guidelines on Diagnostic Flexible Bronchoscopy. Thorax 2001 Feb; 56(Suppl 1): 1–21.