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

• Pulse oximetry

Spirometry and pulse oximetry 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 (plethysmography, nitrogen washout, helium dilution)

• Measurement of diffusing capacity

• Arterial blood gases

• Measurement of lung, chest wall, and respiratory system compliance and resistance (maximal voluntary ventilation and respiratory pressures)

• Bronchoprovocation challenge

• 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.