Monday, September 1, 2014
Pulmonary test: when sick or healthy?
My dr wants me to get pulmonary function testing because I get frequent chest colds with wheezing and trouble breathing. He thinks I might have asthma. Should I get the test when I am sick, it happens often enough, shouldn`t be hard to schedule, or should I get it when I`m healthy and not coughing or wheezing?
It depends on the test your physician has ordered. If your physician has ordered a methacholine challenge test it is best performed when you are well.
A spirometry measures airflow and can be done when you are well or ill. People with intermittent or mild persistent asthma have normal spirometry at baseline. Therefore, your physician may choose to perform the test when you are ill to see if air flow is being affected.
Spirometry is usually performed with a bronchodilator. A bronchodilator is an inhaled medicine which opens the breathing tubes and is given after the initial breathing tests are performed. The breathing tests are repeated after the bronchodilator to determine response. If the exhaled air improves by 12% or 200 ml after the bronchodilator is given, it indicates "reversible airflow obstruction" which is typical of asthma.
Cathy Benninger, RN, MS, APRN, C-AE
Clinical Assistant Professor
Director, OSU Asthma Center Educational Program
College of Medicine
The Ohio State University