ABSTRACT
Chronic obstructive pulmonary disease (COPD) is defined physiologically as a
disorder characterized by a slowly progressive airflow obstruction, only partially
reversible (1-3). Cigarette smoking is by far the main risk factor for COPD but
genetic, environmental, and occupational risk factors also contribute. Most of the
airflow limitation is due to varying combinations of emphysema and chronic
bronchitis. The airway component consists mainly of decreased luminal diameters
of the larger airways due to increased wall thickening and mucus gland hyperplasia
as well as small airways inflammation, edema, fibrosis, and obliteration (4-8).
