Spirometry and other pulmonary function tests for the screening and evaluation of patients with chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is a disease state characterized by airflow limitation that is not fully reversible. The existence of airflow limitation can be determined by spirometry that measures the forced expiratory volume in one second (FEV1) and its ratio (FEV1/FVC) to the forced vital capacity (FVC). Airflow limitation is defined as FEV1 /FVC<70% after the inhalation of short-acting bronchodilator. In addition, FEV1% predicted, a ratio of FEV1 to the predicted value determined by age, gender and height, is utilized to define the severity degree of COPD. Some of the other pulmonary function tests are useful for understanding the pathophysiology of COPD. These tests include the diffusing capacity measurement of carbon monoxide per liter of alveolar volume (DLco/VA), measurement of lung volume using the nitrogen washout technique and whole body plethysmography, and measurement of lung compliance.