ABSTRACT
COPD is a chronic disease, which is characterized by not fully reversible airflow limitation and progressive decline of lung function, exercise capacity, and health status. Stable COPD is characterized by a chronic inflammation of the entire bronchial tree with increased numbers of macrophages and CD8+ T lymphocytes in the airway wall and of neutrophils in the airway lumen (1-4). Episodes of symptom exacerbations punctuate the natural course of the disease and are associated with acute worsening of the existing airway inflammation (5). Exacerbations of COPD may be defined by a change in the patient’s baseline dyspnea, cough, and/or sputum that is beyond day-to-day variations, is acute in onset and may require a change in regular medication (6,7).
