What is spirometry and why do I need it?

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Spirometry is a common test that is done to assess how well your lung works. It means the ‘measuring of breath’, and is the most common of the pulmonary function tests. Here is a brief summary of what to expect with a spirometry test.

What is it used for?  

Spirometry is used diagnose conditions that affect breathing such as asthma, pulmonary fibrosis, cystic fibrosis, chronic bronchitis, emphysema and chronic obstructive pulmonary disease (COPD). If you already have already been diagnosed with a chronic lung condition, spirometry is used periodically to assess whether breathing problems are under control and how well your medications are working.

How to prepare for the test?

Follow instructions from your doctor regarding whether you should take inhaled breathing medications or other medications prior to the test. Wear loose clothing that will not interfere with deep breathing and it is better to avoid eating a large meal before the test, so it is easier to breathe.

How is the test done?

The test is simple and requires you to breathe into a tube attached to a machine called a spirometer. Listen to instructions given to you by the nurse, technician or doctor, and be sure to ask questions if you are not clear. By conducting the test properly, you will be able to have accurate and meaningful results. During the test you will most likely be seated, and a clip will be placed on your nose to keep your nostrils closed. You will have to take a deep breath in, and breathe out as hard as you can for a few seconds into the tube, while making sure that your lips are sealed around the tube, so that no air leaks out. The test will need to be repeated at least three times to ensure consistency, and the entire process takes less than 15 minutes. Your doctor can give you inhaled medication to open your lungs in between tests to compare measurements to see if the medication improved airflow.

What do test results mean?

Key measurements include Forced vital capacity (FVC) and Forced expiratory volume (FEV-1). FVC is the largest amount of air that you can exhale after deep inhalation – lower than normal readings indicate restricted breathing, and FEV-1 is the amount of air you force from your lungs in one second, which is used to detect the severity of breathing conditions. Lower readings indicate significant obstruction in breathing.

Are there any risks involved?

In general, spirometry is a safe test. Patients may feel dizzy or shortness of breath for a moment after the test. If you have had a recent heart attack or heart conditions, then the test is not performed as it requires some exertion.