Definition

COPD is a chronic pulmonary disease characterized by persistent respiratory symptoms and airflow limitation (postbronchodilator FEV1/FVC < 0.70), which is caused by a mixture of small airway obstruction and parenchymal destruction

• COPD was formerly subdivided into chronic bronchitis and emphysema. These terms are still widely used to describe patient findings and found as subclasses of COPD in outdated literature.

  • Chronic bronchitis: productive cough (cough with expectoration) for at least 3 months each year for 2 consecutive years

  • Emphysema: permanent dilatation of pulmonary air spaces distal to the terminal bronchioles, caused by the destruction of the alveolar walls and the pulmonary capillaries required for gas exchange