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Get the Forecast on Your Asthma with a Peak Flow Meter

Asthma image

The colors used with each peak flow zone correspond with those on a traffic light. Green signals good control. Yellow signals caution. And red signals medical alert.

Monitoring your asthma on a regular basis will help you keep it under control. Writing down your symptoms whenever you have them is a good idea. This will provide a good record that will help you and your doctor adjust your treatment over time.

Another way to monitor your symptoms is with a peak flow meter. This handheld device shows how well air moves out of your lungs. Measuring your peak flow can help you tell how well your asthma is controlled. It can also alert you to an oncoming attack hours or even days before you feel symptoms. And during an attack, it can help tell you how bad the attack is and if your medicine is working.

Here are instructions for using a peak flow meter. Don’t forget to ask your doctor to teach you how and when to use it.

Find Your Personal Best Peak Flow Number
The first step is to find your personal best peak flow number. To find your personal best peak flow number, take your peak flow every day for two to three weeks. It is best to do this during a period when your asthma is well controlled – when you feel good and do not have any asthma symptoms.

Your peak flow zones are based on your personal best peak flow number.

Take your peak flow at the same time every day, either right after you take your quick-relief medicine to relieve symptoms or any other time your doctor suggests. Write down the number you get for each peak flow reading. The highest peak flow number you have during the two to three weeks is your personal best. Your personal best can change over time. Ask your doctor when to check for a new personal best.

Use Your Personal Best to Help Make Treatment Decisions
The next step is to mark your peak flow zone. Your peak flow zones are based on your personal best peak flow number. The zones will help you monitor your asthma and take the right actions to keep it under control. The colors used with each zone come from the traffic light.

Green Zone (80 to 100 percent of your personal best) signals good control. If you take daily long-term control medicines, keep taking them. And keep taking them even when you are in the yellow or red zones.

Yellow Zone (50 to 79 percent of your personal best) signals caution: your asthma is getting worse. Add quick-relief medicines as spelled out in your written asthma action plan. You might also need to increase other asthma medicines; ask your doctor.

Red Zone (below 50 percent of your personal best) signals medical alert! Add or increase quick-relief medicines according to instructions in your action plan and call your doctor immediately.

Use Your Peak Flow Meter to Check How Well Your Asthma is Controlled
You can use your peak flow meter in several ways to check how well your asthma is controlled. You should use your peak flow meter

  • every morning when you wake up, before taking your asthma medicine. Make this part of your daily routine. Check this number against the peak flow number on your action plan to make sure your asthma is under control.
  • when you are having asthma symptoms or an attack. First, take your medicine for the attack; then take your peak flow. This will help you see if the medicine is working for you or if you need more treatment.
  • any other time your doctor suggests.

Ask Your Doctor to Include Peak Flow in Your Asthma Action Plan
The action plan should specify

  • the numbers for each of your peak flow zones. Mark the zones on your peak flow meter with colored tape or a marker.
  • the medicines you should take while in each peak flow zone.
  • the steps you should take while in each peak flow zone.
 

Source: National Heart, Lung and Blood Institute, www.nhlbi.nih.gov.

This article was originally published in Coping® with Allergies & Asthma magazine, Winter 2010-2011.