Spirometry is a quick and easy test used to assess pulmonary function. It has been the tool of choice for monitoring the progress of most chronic diseases in children. Spirometry alone does not establish the diagnoses of a specific disease but it aids in differentiating pulmonary dysfunction as having obstruction, restrictive, or a mixed case. With automated equipment, it is possible to interpret more than 15 different measurements from spirometry alone.

Doctors use spirometry to diagnose and keep track of asthma in children age 6 and older.  Also, it measures how quickly your child can move air in and out of the lungs and how much air is moved. However, spirometry is not used with babies and small children. In those cases, the doctor usually will listen for wheezing and will ask how often the child wheezes or coughs.

Why Spirometry is Important?

For children with chronic lung diseases, having lung function testing is highly important. In addition to lung function measurements, spirometry indicates whether or not there is airway obstruction or airway restriction.

Lung function and pulmonary function test results differ for obstructive and restrictive lung disease. In fact, spirometry helps the doctor understand how well your child’s lungs and treatment plan are working. Chronic lung diseases are progressive and conditions and will worsen over time.

What Does Spirometry Measure?

Spirometry tells your doctor if your lungs are functioning normally. It does this through different breathing measurements, some of the key spirometry measurements include the following:

  • Forced Vital Capacity (FVC) – The total amount of air you can breathe out after taking the deepest breath possible.
  • Forced Expiratory Volume in One Second (FEV1) – Measures how much air a person can exhale.
  • Peak Expiratory Flow Rate (PEFR) – Measures how fast a person can breathe out, and the estimated value depends on gender, ethnicity, height, weight, and age.
  • Total Lung Capacity (TLC) – Measures the maximum lung volume allowed after a deep breath.
  • Forced Expiratory Volume (FEV) – Measures how much air a person can exhale during a forced breath.
  • Maximum Voluntary Ventilation (MVV) – Measures the maximum amount of air that can be inhaled and exhaled within one minute.
  • Forced Expiratory Flow (FEF) – The flow or volume of air coming out of the lung during a middle portion of a forced expiration.
  • Functional Residual Capacity (FRC) – The volume of air present in the lungs after a normal breath.
  • Tidal Volume (VT) – The amount of air inhaled or exhaled while breathing normally.
  • Minute Volume (MV) – The volume of air exhaled per minute.
  • Vital Capacity (VC) – The maximum amount of air a person can expel from the lungs after inhaling as much as possible.

How Spirometry is Performed?

Depending on the doctor’s recommendations, your child might wear soft nose clips to prevent air from escaping, Your child also may be asked to stand during the test. If seated, your child should not lean forward because this can affect breathing. Removing any clothing is not necessary. In addition, it is important that your child listens closely to the technician’s instructions.

Your child will be asked to breathe normally at first. Then, your child will take a very deep breath while placing the device in the mouth with the lips sealed securely around the mouthpiece, and then exhale as fast and has as possible for as long as possible. These blasting breaths must be repeated at least three times to make sure the results are accurate.

Your child may then be given a dose of asthma medicine called a bronchodilator. Then he or she blows into the tube again. An increase in airflow suggests that asthma medicine may be helpful.

Finally, the provider might ask your child to do some physical activity. However, the test is repeated to see how the activity affects your child’s breathing and symptoms

What is the Purpose of Spirometry?

Spirometry can be used to help diagnose a lung condition your child has symptoms of a problem, or the doctor feels that your child at an increased risk for developing a particular lung condition.

Conditions that can be picked up and monitored using spirometry include:

  • Asthma – A long-term condition in which the airways become periodically inflamed (swollen) and narrowed.
  • Chronic Obstructive Pulmonary Disease (COPD) – A group of lung conditions where the airways become narrowed.
  • Cystic Fibrosis – A genetic condition in which the lungs and digestive system become clogged with thick, sticky mucus.
  • Pulmonary Fibrosis – Scarring of the lung.

If your child already been diagnosed with one of these conditions, spirometry may be carried out to check the severity of the condition or see how your child responding to treatment.


It is important to monitor your child’s lung condition, keep track of how well your child’s treatment plan is working and the progression of the condition.
At Pediatric Associates California we use computerized spirometers to monitor the lung function of our asthmatic patients.
To schedule an appointment with the best pediatricians in Fresno CA, you may call 559-728-4133 (Fresno office) or 559-673-6085 (Madera office).