What is Spirometry?

Spirometry is a noninvasive breathing test that determines how well a person’s lungs work. It is done with a device called a spirometer. A spirometer measures the amount of air a person can blow out and how fast they can blow the air out of their lungs. This device can detect a change in a person’s ability to breathe even before they do. It takes only a couple of minutes; no needles are involved; it is not painful; and patients do not have to take their clothes off. 

How does it work?

The person being tested is asked to take in a full breath and then seal his or her lips around the mouthpiece of the spirometer. The person will then have to blow out as hard and fast as possible for at least six seconds, which is the approximate time it takes for normal lungs to empty. A nose clip may be applied to ensure no air escapes from the nose.

This routine will be repeated at least three times to ensure that the test is done correctly and provides accurate results. Spirometry is an effort dependent test and some people may become tired, but this is expected.

This routine will be repeated at least three times to ensure that the test is done correctly and provides accurate results. Spirometry is an effort dependent test and some people may become tired, but this is expected.

What does it measure?

Spirometry measures airflow over time. It provides two numeric values that are helpful in the assessment and monitoring of patients with impaired lung function.

FVC (Forced Vital Capacity): total amount of air that can be exhaled following as deep an inhrhation as possible.

FEV1 (Forced Expiratory Volume measured over one second): the flow of air during the first second of the Forced Vital Capacity.

FEV1/FVC: the proportion of air in a person’s lungs which can be blown out in one second.

What can the measurements show?

Spirometry will help determine if a person has any airflow problems and it is indicated for:

• Diagnosing and staging the severity of COPD
• Identifying smokers who are developing COPD
• Diagnosing and categorizing Asthma severity
• Diagnosing Restrictive Lung Disease
• Measuring the effectiveness of treatment with bronchodilators or corticosteroids
• Evaluating the effects of workplace exposure to irritants, among others

Who should be tested?

• Every former or current smoker
• People 40 years of age and older
• Anyone exposed to fumes or irritants in their workplace
• Anyone experiencing:
  • A persistent cough with colored mucus, especially in the morning
  • Difficulty or painful breathing, Wheezing or frequent chest infections
  • Fatigue, shortness of breath at rest or while exercising, walking, climbing stairs, or engaging in everyday activities
  • Snoring, restless sleep, or Sleep apnea
  • Weight loss, heart failure, fever, chills, or Osteoporosis
  • Extreme discomfort with routine activities

Are there any side effects?

Spirometry is a very low risk test. Sometimes if a person used too much effort to blow out it might make him or her feel a little dizzy. However, blowing out hard may also cause an increase in the pressure of the chest, abdomen and eye.

This is why some people are not advised to have a spirometry, including those with:

• unstable Angina
• someone who had a recent Pneumothorax (air trapped beneath the chest wall)
• someone who had a recent heart attack or stoke
• someone who had recent eye or Abdominal surgery

Spirometry should be done with certain precautions if a patient is pregnant, is under 18 years old, has had a recent respiratory or ear infection or has any type of pain that increases with breathing.

Before having a spirometry performed, patients should receive instructions from the healthcare provider who performs the test. If there is something that a patient does not understand, it is important for him or her to ask and not take the test until he or she fully understands the procedure. It is also recommended that patients do not wear tight clothing that may interfere or make it difficult to take a deep breath. Also, patients should not eat a large meal, drink alcohol, or do vigorous exercise for a few hours before the test.

Wouldn’t it be easier to have a peak flow reading?

It would certainly be easier, but it is not accurate enough. A peak flow meter is a small device that measures the fastest rate of air that a person can blow out but not exactly the amount of air that a person can move in and out of their lungs. A peak flow reading is especially useful to monitor asthma but not to diagnose or monitor COPD as it may underestimate the severity of COPD.

What is a Reversibility Test?

A reversibility test is also a Spirometry Test but one that is done after the patient is given a bronchodilator by inhaler or nebulizer. It is done in some cases where the diagnosis is not clear and it is especially important to differentiate between asthma and COPD. A spirometry test will be done. Then the patient will be given a bronchodilator. After thirty minutes pass, another spirometry test is performed to see if there are any improvements. If the patient shows improvement, the bronchodilator was able to widen the airways suggesting a diagnosis of asthma.