What are pulmonary function tests?
Pulmonary function tests (PFT’s) are a group of tests that allow specific measurements of the volume capacity of your lungs. These tests are usually performed in a laboratory where a respiratory therapist or technician has a spirometer.

A spirometer is a device that measures the amount of air that you are able to inhale and exhale. A computer compares your test results with 'predicted values', based on a person's gender, weight and age.

When is it used?
When planning treatment for lung cancer, it is very important to assess the function of the lungs. Many of the risk factors for lung cancer are also risk factors for other lung diseases, such as emphysema or chronic obstructive pulmonary disease (COPD).

The PFT results can help your health care team predict how surgery, drugs, or other tests may affect your lungs. For example, if you are a patient who has severe lung disease, you may not be able to tolerate the removal of part of your lung. In this case, it may be best to avoid a surgical intervention.

How do I prepare for pulmonary function tests?
Do not smoke or use inhalers for two to four hours before the test. Other than that, there are no special preparation needed for pulmonary function testing.

What happens during the procedure?
The testing itself is not painful or otherwise difficult to tolerate. What is most important is that you cooperate fully and provide the best effort possible. The technician will explain to you what should be done in each maneuver and will coach you to give your best effort.

You will be asked to perform a number of respiratory maneuvers during the testing. These maneuvers are similar to blowing out birthday candles on a cake, or breathing in and out as fast as you can. You will be breathing through a mouthpiece with a soft nose clip in place. You will have an opportunity to rest between maneuvers. Pulmonary function testing usually lasts less than an hour.

What happens after the procedure?
When the testing is complete your results will be forwarded to the requesting physician, who will interpret and explain your pulmonary function based on your individual condition and expected treatment.

What are the benefits of this procedure?
The results may help your team recommend the safest treatment for you.

What are the risks associated with this procedure?
There are no significant risks associated with pulmonary function tests.

This article is intended as a resource for patients receiving their cancer care at Duke University Hospital or Duke Clinic. It is not intended to substitute for medical advice from your healthcare team. If your doctor’s instructions differ from the information in this article, please talk with your doctor before making any changes.

Source: Duke Cancer Patient Education Program / Patient & Family Education Committee 8/00