Q: My daughter was given a peak flow meter by her GP, along with several prescriptions, but no instructions on how to use it or interpret the results. While away at college, her asthma was bad, and she was disallowed from playing intramural sports. Can you please provide good instructions and tell us what the results mean?
Dr. Chiaramonte answers:
The most important instruction is that SHE MUST DO IT. It is more important to her health day-to-day than brushing her teeth, so one way to remind her to do it is to combine the two tasks; I would like her to do the toothbrush trick—attach her toothbrush with an elastic band to her peak flow meter as a morning reminder.
–The peak flow meter should read zero to start
–Use the peak flow meter while standing up straight
–Take in as deep a breath as possible
–Place the peak flow meter in the mouth, with the tongue under the mouthpiece
–Close the lips tightly around the mouthpiece
–She must refrain from “cheating” which she can do by putting her tongues near the whole which will give a falsely higher number.
–Blow out as hard and fast as possible; do not throw the head forward while blowing out
She should try to blow just a little bit harder than her normal exhalation on three attempts—it’s not like blowing up a balloon or blowing out a lot of birthday candles where you keep going till you feel lightheaded–and take the best reading of three.
Breathe a few normal breaths and then repeat the process two more times. Write down the highest number obtained. Do NOT average the numbers.
WHERE IS THE STARTING LINE? Unlike blood pressure or body temperature, there is no one “normal” measurement with peak flows. The best baseline is her personal best all-time peak flow, but we are initially forced to use her predicted peak flow without the knowledge of her best score until there’s more of a track record.
After that, 80% and up of the baseline would be a green normal zone. She can just take maintenance dosages if her medication.
60-80% of baseline would be a yellow cautionary zone –medication should be increased.
Below 60% of baseline would be a dangerous red zone-she should seek medical attention.
She should also work with her doctor to create an asthma action plan—see the link “Action Plan” in the upper right corner of this page–or click here.
You should also know that maximal peak flow number will go up as children get old and taller. A peak flow of 250 may be fine for an eight year old, but if it is still 250 at ten, that’s no good. Asthma Action Plans must be re-evaluated in children on a frequent basis.
As for intramural sports, David Beckham and many other elite athletes have asthma. Get it under control and go out and play!