Pulmonary Function Testing
(a.k.a. P.F.T., Spirometry, Spiro)
What is pulmonary function testing?
Pulmonary function testing is a way to assess how well air moves in and out of your lungs and how well oxygen enters your body. The test can include spirometry and plethysmography. Sometimes only the spirometry is done and sometimes both.
Why is pulmonary function testing done?
Pulmonary function testing is done to assess lung function, measure the effect of chronic lung diseases (for example: C.O.P.D), assess response to treatment, detect narrowing of the airways, show presence or severity of interstitial lung diseases, or determine your ability to tolerate surgical procedures.
How is spirometry done?
Spirometry is done by having the patient take a deep breath and then, as fast as they can, blow out all of the air into a tube connected to a machine. This test is often repeated after a breathing medicine is administered to find out how much better breathing is with this medicine.
How are plethysmography and diffusion studies done?
Plethysmography measures the amount of air that is in the lungs after a deep breath and the amount of air that is in the lungs after breathing out completely. The test is done while the patient sits in a clear plastic box. The test is done with a nose clip on the nose and breathing through a mouthpiece. Diffusion studies are also done while breathing into a mouthpiece after emptying the lungs and then taking a deep breath and holding.
What are the requirements for taking the test?
- Do not smoke for at least one hour before the test
- Do not drink alcohol for at least 4 hours before the test
- Do not exercise heavily for at least 30 minutes before the test
- Do not wear tight clothing
- Do not eat a large meal within 2 hours before the test
- Try not to use bronchodilator inhalers prior to the test
**Remember that these tests take effort and you may become tired. If you do not understand the instructions given during the test please ask the technician to repeat them. If you become dizzy or light headed during the test, stop blowing and let the technician know.
