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Peak Flow Monitoring

Peak flow meters are portable hand held devices that measure lung function or how well your (or your asthmatic child's) lungs are doing at home. The peak flow meter measures the amount of air you (or your asthmatic child) can quickly push out of the airways in one breath. This lets you know how open or closed your (or your asthmatic child's) airways are at that time. Regular monitoring of your (or your asthmatic child's) peak flows will help you better manage your (or your child's) asthma. Sometimes changes in the airways can be detected even before you (or your child) start to have asthma symptoms! Peak flow meters are recommended for use with adults and children 5 years and older. In addition to using your peak flow meter on a regular basis, you should also check your (or your asthmatic child's) peak flow readings any time you (or your child) start to have asthma symptoms or early warning signs

Measuring peak flow readings correctly is essential to getting the best picture of how your (or your asthmatic child's) lungs are doing. This will help you to keep your (or your child's) asthma under better control! The results you get from the peak flow meter are very "effort" dependent. This means that you (or your asthmatic child) must give the best effort each time when using the peak flow meter. If you do not give your best effort when blowing into the peak flow meter, your (or your asthmatic child's) peak flow readings might be falsely low. Also, if you (or your asthmatic child) are coughing while doing the test, the readings might be falsely high. You should use the same peak flow meter each time you check your readings.

Here are the basic steps on how to use your peak flow meter:

  1. Stand up and if you cannot stand, sit as upright as possible
  2. Inspect your peak flow meter for any foreign objects
  3. Remove any gum or food from your mouth
  4. Move the marker to the starting point or to zero
  5. Take a very deep breath
  6. Place the peak flow meter mouthpiece into your mouth
  7. Close your lips tightly around the mouthpiece
  8. Blow out as hard as fast as possible
  9. Take the peak flow meter out of your mouth
  10. Check results by reading where the marker moved to on the number scale printed on the peak flow meter
  11. Write this number down
  12. Repeat steps 3 to 11 two more times
  13. Record the highest number of the three readings in your peak flow diary and/or asthma diary

When checking your peak flow meter readings to find out your (or your asthmatic child's) best peak flow reading, be sure that you do this for 2 to 3 weeks when you (or your asthmatic child) are not having any asthma symptoms. Check your (or your asthmatic child's) peak flow readings before taking any asthma medications. Check your (or your asthmatic child's) peak flow readings twice a day, in the morning and early evening. Always record the highest of the readings in your peak flow diary and/or asthma diary. After you have completed 2 to 3 weeks of recording your (or your asthmatic child's) highest peak flow readings, follow up with your (or your child's) Healthcare Provider or Asthma Nurse Educator. Your Healthcare Provider or Asthma Nurse Educator can identify your best peak flow reading and set up your (or your asthmatic child's) Asthma Action Plan. Remember that your (or your asthmatic child's) best peak flow reading might be different than other asthmatics that are the same age, sex, height, and weight. This is because everyone's asthma is different.

Once you know what your (or your asthmatic child's) best peak flow reading is, you can then monitor your peak flow readings per direction of your healthcare provider and when you (or your asthmatic child) begins to experience any asthma symptoms. It is recommended that individuals with moderate to severe asthma check their peak flow readings daily, preferably in the morning before taking any asthma medications. If you (or your asthmatic child) begin to experience any asthma symptoms, you should check your (or your asthmatic child's) peak flow reading at that time and then treat as directed in your (or your asthmatic child's) Asthma Action Plan. You should record the symptoms in your (or your asthmatic child's) peak flow diary and/or asthma diary. Also record the treatment(s) you gave yourself (or your asthmatic child) and any repeat readings after treatment(s).

The peak flow meters should be replaced yearly or when they are damaged or become defective. You should clean the peak flow meter weekly. Review the manufacturer's recommendations for the cleaning and maintenance instructions for your specific peak flow meter.

Always bring your peak flow meter and peak flow diary and/or asthma diaries with you to your (or your asthmatic child) to your asthma appointments.