Full Pulmonary Function Testing vs. Peak Flow Meter

Jeff: Dr. Kraemer, what is your opinion on the routine use of full pulmonary function testing for all asthma patients regardless of disease severity, versus simple reliance upon peak flow meter readings. And, what potential impact do you think the introduction of an inhaled corticosteroid might have on a patient with less than optimal lung function?

Dr. Kraemer: Full pulmonary function testing is our best and most expensive tool to describe the amount of airways inflammation which we define as asthma. Peak flow readings are our cheapest and most available tool to get an inkling of the same information. Neither one is perfect. You can make a diagnosis of asthma without any form of pulmonary function testing, but you are basing it on a lot of guesswork, and if it is not correct, you will waste a lot of time. Most specialists will perform full pulmonary function testing both before and after a bronchodilator to help establish a new diagnosis of asthma, regardless of severity. Then, most would use home peak flow meter monitoring for the “fine tuning” of the therapy. Occasionally, pulmonary function testing is done in the future if there is difficulty achieving a good remission of symptoms or if there is a question about the peak flow results. I don’t think that either of these tests is better than the other. I view these two tests as complementary.

If, using either measurement, we discover that a patient has a mild degree of airways obstruction, then we may use an inhaled corticosteroid to see if there is a significant improvement in that finding. At mild levels of asthma, the symptoms can be so minimal that the patients don’t even recognize them until after they have improved on the inhaled corticosteroids.