Pulmonary Function Test: Purpose, Procedure & Results (original) (raw)

How does pulmonary function testing work?

A pulmonary function test is relatively simple.

A PFT consists of a clear, airtight box, soft nose clips, a mouthpiece and a small electronic machine that measures your airflow (spirometer).

How do I prepare for a pulmonary function test?

Before your pulmonary function testing, your healthcare provider may ask you to:

• Stop taking your breathing medicines for a short period.
• Wear loose, comfortable clothing that doesn’t squeeze your chest.
• Avoid any heavy exercise before your test.
• Avoid using tobacco products before your test.

These precautions will help ensure that you get accurate results from your PFT.

Can you eat before a pulmonary function test?

You shouldn’t eat a heavy meal before your PFT.

You should also avoid any caffeine.

What should I expect on the date of pulmonary function testing?

You’ll take a PFT at a pulmonary function lab at an outpatient office or a hospital.

Before the test, your healthcare provider will record some personal information, including your:

• Height.
• Weight.
• Age.
• Race.
• Sex.

Your healthcare provider will use this information to determine a typical value for your demographic.

What should I expect during pulmonary function testing?

After recording your information, your healthcare provider will take you to a room with PFT equipment and give you instructions according to your test.

Spirometry

A healthcare provider will first put soft clips on your nose. The nose clips ensure that you breathe through your mouth, not your nose.

You’ll put your lips around a mouthpiece, and the mouthpiece connects to a spirometer. The provider will then give you directions on breathing in and out.

You may take deep breaths in and out. You may also take deep breaths in and blow out as hard and as fast as you can.

Body plethysmography

A healthcare provider will put on your nose clips, and you’ll sit in the clear box. Your provider will close the door. The door remains closed for about five minutes.

Tell the healthcare provider if you’re uncomfortable in confined spaces (claustrophobic). They can help you feel more comfortable during the test.

You’ll put your lips around the mouthpiece, and the provider will give you directions on breathing in and out.

As you breathe, the spirometer will detect pressure or volume changes in the box to help measure your lung volume.

Gas diffusion study

Your healthcare provider will put on your nose clips.

You’ll put your lips around the mouthpiece, and a healthcare provider will give you directions on breathing in and out a small, safe amount of carbon monoxide.

As you breathe, the spirometer measures how much carbon monoxide you exhale. This measurement indicates how much of the gas your lungs absorbed.

Cardiopulmonary exercise test

A healthcare provider will attach you to machines that measure your heartbeat, blood pressure and blood oxygen. You’ll then walk on a treadmill or ride a stationary bicycle.

The machines will measure various aspects of your heart, lungs and muscles during the test.

How long does a pulmonary function test take?

A PFT may take between 15 and 45 minutes to complete.

Let the healthcare provider know if you get tired during your test. You can take breaks in between parts of the test.

Is pulmonary function testing painful?

No, pulmonary function testing isn’t painful.

What should I expect after pulmonary function testing?

After testing, you may restart any medicines your healthcare provider told you to stop taking. You can also return to your usual activities, including exercise.

If you felt dizzy or lightheaded during the test, the healthcare provider will monitor you until your symptoms go away and you can go home.

The healthcare provider will tell you when to expect your test results.

What are the risks of pulmonary function testing?

Pulmonary function testing is safe. But you may feel dizzy, lightheaded or tired from breathing so deeply. You may also cough from blowing into the mouthpiece or feel tired from exercising. These symptoms should go away shortly after you complete the PFT. Let the healthcare provider know if you need a break during testing.

In very rare cases, pulmonary function testing may cause a collapsed lung (pneumothorax).

A PFT can also increase your heart rate. Tell the healthcare provider if you’ve had a heart attack recently or any other heart condition.