Plethysmography is done with your child sitting in an enclosed plexiglass chamber that allows your child and therapist to see in and out. Your child will place padded nose clips on his or her nose and place their mouth around a clean filtered mouthpiece.

Your child will place his or her hands on their cheeks, breathe normally and "pant like a puppy." After panting, your child will go back to breathing normally, blow out air and then take a deep breath.

Plethysmography is performed along with a spirometry test. Both tests combined take 40 to 60 minutes.

If at all possible, your child should not use any short-acting asthma medications / bronchodilators for 12 hours prior to testing. If you have any questions about which medications to hold, check with your child's physician or call the pulmonary function lab at 513-636-8049.

There are no side effects. Your child may resume normal activities and medications after testing.