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Pulmonary Function Testing

What are Pulmonary Function Tests (PFTs)?

Pulmonary functions tests tell us how well you breathe. They measure how much air you breathe in and out, how well your breathing muscles work, and how well your lungs exchange gas (move oxygen from the small air sacs in the lungs to the bloodstream).

Why are PFTs done?

Your doctor uses these tests to screen for health problems, keep a watch on your condition or prescribe medication or therapy. They can determine the cause of respiratory symptoms and help confirm lung diseases such as asthma or emphysema. They are also used to evaluate lung function prior to surgery. Pediatric screenings often begin at the age of 5.

Where is the lab?

The PFT lab is located in the outpatient department in the Ambulatory Care Center on the first floor of the Main campus of Lawrence + Memorial Hospital, New London, CT.

How PFTs are done?

PFTs are done in exam rooms that house the testing equipment. The test is administered by a specially trained respiratory therapist. For most tests, you will wear a nose clip to make sure that no air passes in or out of your nose during the test. You will be asked to breathe into a mouthpiece connected to a measuring/recording device.

  • The exact procedure is different for each type of test. The therapist will explain and coach you through the test.
  • The accuracy of the tests depends on your ability to follow all of the instructions. The therapist may strongly encourage you to breathe deeply during some of the tests to get the best results.
  • The testing may take from 30 to 60 minutes. You will be able to rest between tests if you find it tiring.
  • PFTs present little or no risk. There are usually no after effects and you may resume your normal activities when the tests are over.

Preparation for your test.

There is no preparation for PFTs but you should wear comfortable clothing and avoid a large meal before the test. You should avoid medications that could affect the test results. In general, you should not take inhaled breathing medications for 8 hours prior to the test. If you have questions about your medications, ask your doctor or the pulmonary function therapists.

Your doctor may also order

Bronchial Challenge

In the bronchial challenge, a patient performs repeated spirometry tests following the inhalation of increasing concentrations of the medications. In patients with hyperactive airways, this may cause a change in the airways function which is detected by the testing. Following this test, patients are given albuterol, a drug which reverses the effects of the medications. This test is used to help diagnose asthma.

Pulse Oximetry

The test estimates the amount of oxygen in the arterial blood by shining a light through a fingertip.

Six Minute Walk Test (Exercise Oximetry)

The technologist will monitor your oxygen saturation, heartrate and respiratory status as you walk, accessing changes during exercise.

Arterial Blood Gas Analysis

This test measure the amounts of oxygen, carbon dioxide, and PH of an arterial blood sample, which provides information about lung function.