Pulmonary function tests (PFTs) are performed to help measure how well your lungs are able to inhale and exhale air, and they can also show how efficiently oxygen is being transferred from your lungs into your bloodstream. PFTs also help predict the risk of complications after bariatric surgery.
There are three primary types of PFTs:
This test measures your ability to exhale the air in your lungs. It is used to help determine if you have any lung diseases such as asthma or chronic obstructive pulmonary disease (COPD).
To perform this test, you will be asked to breathe into a mouthpiece that is attached to a circular device called a spirometer. The spirometer will record the amount of air that you are breathing in and out. You may be asked to breathe normally or to take a deep breath and to blow the air out of your lungs as if you were blowing up a balloon. Your technician may use a nose clip to get a better reading.
Lung Volume Measurement
A lung volume measurement test helps to detect a restrictive lung disease. A patient with restrictive lung disease cannot inhale a normal volume of air, which is typically the result of inflammation or scarring of the lung tissue. It can also be a result of abnormalities of the muscles or bones in the chest area.
This test can be conducted in a number of ways, and the staff at the location where you have the test performed will provide you with specific instructions.
Diffusion Capacity Test (DLCO)
A diffusion capacity test will give an estimation of how effective your lungs are at transferring oxygen from the air you breathe into your bloodstream. You will be asked to take a breath (usually one) of carbon monoxide. This test is safe; it will not hurt or poison you. When you exhale, the technician will measure the amount of carbon monoxide. By comparing the amount of carbon monoxide inhaled with the amount exhaled, your physician can determine how quickly oxygen travels from your lungs to your blood.
PFTs do not hurt, but you might experience some lightheadedness or shortness of breath after each test. It is important that you tell the technician how you feel during the tests and follow testing instructions very carefully to ensure accurate results.
After the test, you can eat normally and perform normal activities. Your results will be ready in a few days. If any risk factors or underlying conditions are detected, your bariatric care team will address these issues before performing your bariatric procedure.