Asthma Medicines

Peak Flow Meter

In bronchial asthma it is extremely important to recognize the presence of an attack before it becomes severe and requires emergency measures. Each patient should have a means of assessing the degree of asthma that is present from day to day. In this manner severe episodes and often the use of oral or injectable corticosteroids necessary for such emergencies can be avoided. As an extension of this home monitoring the patient should be instructed how to respond to the presence of increased asthma. In this way a contingency plan can be in place and ready before severe attacks occur and require emergency room care. The cornerstone of this home monitoring is the peak flow meter. In essence it is an “early warning” device for individuals with asthma.

What the Peak Flow Meter Measures

The peak flow meter is a simple and inexpensive device that can be used in and out of the home to monitor bronchial asthma and similar conditions. This compact device determines the maximal expiratory flow rate that the patient is capable of producing. Similar to the office spirometry, the patient inhales fully and then exhales fully and forcefully into the flow meter device. A simple scale registers the peak flow. If done as instructed this flow rate correlates well with other measurement of airflow through the large airways of the lung. With a diary to record readings the patient can maintain an accurate assessment of the degree of asthma from day to day. This is not unlike the diabetic who records blood sugar readings. This information can be invaluable to the physician in managing patients with bronchial asthma since it gives an objective measurement to go by instead of trying to assess asthma by the degree of shortness of breath or wheezing. Communication with the physician can be much more meaningful with a record of the patient’s peak flows, resulting in earlier and better treatment. With earlier recognition of an attack through peak flow measurements, severe and potentially fatal asthma attacks may be avoided.

An electronic peak flow meter is now available in the form of Air-Watch which is made by Enact. This more sophisticated and expensive device is capable of storing several hundred peak flow measurements. Patients may also download their readings by phone to a central computer which then faxes the results to the physician.

Asthma with Normal Peak Flows

Remember that peak flow measurements reflect primarily large airways and therefore do not totally assess the asthmatic condition. Normal peak flows may occur in the presence of significant small airway disease that requires continued and effective treatment. This explains why patients may continue to be symptomatic even with normal peak flow rates.

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