During a pulmonary function test, the patient uses a mouthpiece attached to a machine that measures the amount of air the patient inhales and exhales, according to MedlinePlus. The patient also sits in a booth so that the volume of gas in his lungs can be measured.Continue Reading
During the spirometry part of the test, the patient breathes deeply with a mouthpiece and nose clip attached. The patient may be asked to inhale medications or gases. A tracer gas can be used to determine how the lungs exchange carbon dioxide and oxygen, states Healthline. The plethysmography test requires the use of a clear booth in which the pressure is increased or decreased. The patient breathes through a tube while the pressure changes, notes MedlinePlus.
During the pulmonary function test, the patient may start feeling discomfort in the booth, or he may experience shortness of breath, asserts MedlinePlus. The doctor can perform the components of the test repeatedly to obtain many measurements, and faintness or dizziness can occur, states Johns Hopkins Medicine. Some patients who have certain medical conditions, such as eye pressure problems, chest pain, history of heart attacks, or a respiratory infection, may forgo the test. Pulmonary function tests are generally used to determine treatment options for lung conditions or to check the health of the lungs, notes MedlinePlus.Learn more about Diagnostics & Imaging