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Lung Function Evaluation

It does amaze me how many clients present for their initial histories with me and share they have a history of #asthma, but have never had their lung function tests evaluated. Many have expired rescue inhalers while others are using them daily without any evaluation by their practitioner. This is an important consideration in primary care. Not only do we want to understand your baseline lung function because over time this can worsen with little awareness by the individual so that a severe attack can sneak up on you requiring hospitalization or even worse, death; however, why is your body so inflamed and responding this way? What is the trigger? How can we resolve these episodes and move you into a more optimal state of health?

When I have a new client in the office with a history of asthma, I always want to understand the onset of symptoms and how the client has managed those symptoms. How often do they feel short of breath? What causes these symptoms? Do they happen at night, are they seasonal, are they related to exercise? Do they have a cough at night, heart palpitations, anxiety, history of strep, allergies otherwise, or eczema? I also want to know if they have had lung function testing, which measures airflow into and out of the lungs.


These are small instruments which can be performed in any primary care office, but are often done with pulmonology clinics. This medical device records the amount of air you breathe in and out and the speed of your breath. Spirometry can help diagnose COPD, asthma, restrictive lung diseases, and other disorders affecting lung function. They are also a great way to monitor the progress of your lung disease.

When planning a spirometry reading, don't smoke or drink alcohol the day of testing. Don't eat too large a meal either, so you can offer your best breathing for evaluation. Restrictive clothing should be avoided and of course, any medications that may impact your breathing.

The test takes only about 15 minutes and generally provided by the nurse. They will offer you a clip for your nose so both nostrils are sealed, and then you'll be provided a cup-like breathing mask. You'll be asked to take in a deep breath and hold for a few seconds, and then exhale as hard as you can into the mask. This will be repeated three times. Sometimes clients experience difficulty breathing as the result of these deep breaths, so a bronchodilator may be offered to help your lungs open up after this first round of testing. This will also help your clinical evaluate how effective medications are in increasing your airflow.

Monitoring Lung Function

At the onset of diagnosis, I typically order lung function testing as this offers us an initial baseline so that if symptoms later worsen, we know our initial goal. I also like to reevaluate this annually or every other year to monitor for changes the client may be unaware are progressing. This is true for both asthma and chronic obstructive pulmonary disease (COPD). If your lung disease is more significant, more frequent spirometry testing may be warranted.

Results of spirometry testing depend on your age, height, race, and gender. This is calculated using an algorithm, and a predicted value is obtained which helps us understand how your lung function compares to others similar to yourself. The goal is to achieve 80 percent of the predicted value. If you already know your spirometry readings, you can use the calculator provided by the Centers for Disease Control and Prevention.

The Nitty Gritty Details

Spirometry measures two key factors: expiratory forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). Your provider will also evaluate the combined number known as the FEV1/FVC ratio. If you have obstructed airways, the amount of air you're able to quickly breath in as deeply as possible. If your FVC is lower than normal, something is restricting your breathing but additional tests are necessary to determine what type of lung disease is present.

The second key spirometry measurement is forced expiratory volume (FEV1). This is the amount of air you can force out of your lungs in one second and again, less than 80% of the predicted FEV1 value is abnormal. The higher the percentage derived from your combined FEV1/FVC ratio, in the absence of restrictive lung disease, the healthier your lungs. A low ratio suggests something is blocking the airway.

If results are abnormal, typically I'll order a chest and sinus X-rays along with blood tests. A CAT scan can help evaluate COPD severity. The primary lung conditions that will cause abnormal spirometry results are #COPD and asthma, as well as interstitial pulmonary fibrosis. I may also screen for conditions that commonly occur together with breathing disorders that can make symptoms worse, such as heartburn, hay fever, and sinusitis. More often than not, I'll order sensitivity testing to identify why there is an increased inflammatory response. What is the trigger? This is a blood test and one of my more adored functional tests in the practice. If you'd like to discuss lung function testing or how we might dig into the underlying cause of your asthma, schedule an appointment. I'd love to work with you!

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