Overview of Tests of Pulmonary Function
Pulmonary function tests provide measures of airflow, lung volumes, gas exchange, response to bronchodilators, and respiratory muscle function. Basic pulmonary function tests available in the ambulatory setting include spirometry and pulse oximetry; these tests provide physiologic measures of pulmonary function and can be used to quickly narrow a differential diagnosis and suggest a subsequent strategy of additional testing or therapy. More complicated testing includes measurement of lung volumes; lung, chest wall, and respiratory system compliance (which requires measurement of esophageal pressure); and complete cardiopulmonary exercise testing. These tests provide a more detailed description of physiologic abnormalities and the likely underlying pathology. The choice and sequence of testing are guided by information taken from the history and physical examination.