Pulmonary Function Tests: When Your Infant Needs Spirometry

Technician giving baby spirometry test.Your infant’s healthcare provider suggested a test to measure how well your child’s lungs are functioning. This test is called spirometry. Spirometry measures how much air your infant can take into the lungs and how fast he or she can blow it out. Special equipment may be used to do this test with an infant.

Before the test

  • Don’t feed your infant any solid foods for 6 hours before the test and no liquids 2 to 4 hours before the test.

  • Your infant is given medicine to help him or her relax and to prevent pain.

During the test

This test may be done in a variety of settings, such as a lab, treatment room, or intensive care unit (ICU). It takes about 90 minutes. This is what you can expect:

  • Your child is placed on a special bed.

  • A technician places a mask over your child’s mouth and nose and a loose jacket bag around the chest and upper abdomen.

  • Your child takes a few breaths. Then the jacket bag inflates. This gives the chest a gentle squeeze, forcing air out of your child’s lungs.

  • To measure the size of the lungs, the technician closes the top part of the bed and briefly stops the air going through the mask. This changes the air pressure, allowing the computer to measure lung size.

After the test

After the test:

  • You can take your baby home soon after the test.

  • Your baby may be a little weak and sleepy from the medicine used to relax him or her.

  • Your baby will likely nap off and on for a few hours.

  • You will get results within about 7 days.