Pulmonologists at First California Physician Partners diagnose and treat pulmonology diseases of the lungs, including:
- Chronic obstructive pulmonary disease (COPD)
- Pulmonary fibrosis
- Lung nodules
- Lung Cancer
- Obstructive sleep apnea
To rule out pulmonary diseases, you should have a complete pulmonary evaluation with a pulmonary doctor if you are experiencing or have had:
- Shortness of breath
- Chest pain
- Gasping for breath at night
- Tiredness during the day
- An abnormal lung scan or X-ray
A pulmonologist conducts pulmonary function tests (PFTs) to measure how well your lungs take in and exhale air. The tests also check how well your lungs transfer oxygen into the blood. There are several different tests:
- Spirometry measures how well the lungs exhale (breathe out)
- Lung volume measures how well the lungs inhale (breathe in)
- Tests of the diffusion capacity for carbon monoxide (DLCO) show how efficiently the lungs transfer oxygen into the bloodstream
Pulmonary function tests help:
- Diagnose diseases of the lung such as asthma, chronic bronchitis, and emphysema
- Determine the cause of shortness of breath
- Measure the effects of chemicals, coal dust, and other toxins on lung function
- Measure the effectiveness of medicines and other treatments
PFTs can help detect lung disease at an early stage, before symptoms develop.
How do you prepare for pulmonary function tests?
Eat a light meal and do not smoke for 4 to 6 hours before your test. If you have asthma, ask your health care provider if you need to stop using asthma medicine before the test.
How are the pulmonology tests done?
For spirometry, you will breathe into a mouthpiece that is connected to an instrument called a spirometer. The spirometer measures the volume of air you can force out of your lungs in 1 second after inhaling as much air as you can. You will be asked to hold the tube of the spirometer in your mouth, breathe in as much air as possible, and then blow out as hard as you can into the spirometer for 1 second. The amount of air you can force out is called your forced expiratory volume, or FEV1.
For a Lung volume test, you will breathe nitrogen or helium gas through a tube for a certain amount of time. The concentration of the gas in a chamber attached to the tube is then measured.
For Diffusion capacity, you will breathe carbon monoxide for a very short time (often 1 breath). The concentration of carbon monoxide in the air you exhale is then measured. The difference in the amounts of carbon monoxide you inhale and exhale shows how well gas can travel from your lungs into the blood.
PFTs are not painful. If you have more than 1 test, you will be given time to rest between the breathing tests. The tests may be repeated 2 or more times to get the most accurate results.
Ask your doctor when and how you will get the results of your tests.
Symptoms of Pulmonary Diseases
If you do not have lung disease, you will be able to blow out 80% or more of the air in your lungs in 1 second. If you have lung disease, it can take longer to get all of the air out of your lungs. For example, you might only be able to blow out 20% to 40% of the air in your lungs in 1 second.
PFTs can show what type of lung disease you have
- If you have an obstructive lung disease such as emphysema, chronic bronchitis, or asthma, you will likely exhale less air than normal, but your lung volume might still be normal.
- If you have a restrictive lung disease such as asbestosis, pulmonary fibrosis, or sarcoidosis, you might have less lung volume than is normal, but you might still exhale a normal amount of air.
A low diffusion capacity may be a sign of emphysema. It also might result from a restrictive lung disease that thickens the lung membrane.
Test results are only a part of many things, including your medical history and current overall health, your doctor will consider when determining your diagnosis. Sometimes a test must be repeated to confirm the first result. Talk with and ask questions of your health care provider about your test results. He or she can help you understand your results and explain what they mean for you.
If your test results are not normal, ask your pulmonologist:
- If you need additional tests
- What you can do to work toward normal values
- When you must be tested again