The peak flow meter is a device to measure the rate of airflow in the large airways (breathing tubes). The measurement of the peak flow rate is a simple lung test to estimate the degree of airway obstruction (narrowing). To be useful the peak flow rate must be repeated with maximum (best) effort for at least three tries. Peak flow meters are different and the same peak flow meter should be used so peak flow rates can be compared.
Use of peak flow meter can help detect airway narrowing early and identify exposure to triggers of asthma. Peak flow rates can also help determine when asthma medicine or treatment change is necessary and when you or your child’s asthma is not in good control.
The peak flow meter is the most useful tool to monitor asthma at home. Every asthmatic over the age of three can learn to use one. The meter should be used for all patients who require daily medications.
When you first get your peak flow meter, take 2 or 3 readings a day to help establish a baseline. Keep a record with dates, times, and readings on it. Your readings will vary in a twenty-four hour period. Because of natural daily variation, the peak flow readings will usually be highest from 12 noon to 6 p.m. and lowest from 12 midnight to 6 a.m. After your baseline is established you will continue to use your peak flow meter when there is a hint of any asthma problems, when you are sick, come in contact with allergens or when tapering medications. Continue to monitor daily–when on regular medications for moderate severe and severe asthma and if you have mild asthma weekly. If you are constantly in the “green zone” of your asthma crisis management plan, and with the okay from your Asthma & Allergy Center doctor, you may decrease monitoring your airways to 3 times a week when you are feeling well.
Your Asthma & Allergy Center doctor will give instructions on what treatment to start when your peak flow meter measurements begin to drop. These instructions should be filed in your notebook and easily accessible. Bring your peak flow meter measurements with you for your office visits so the doctor can help you to understand them.