How to use a peak flow meter  



How to use a Peak Flow Meter

  A peak flow meter for asthma is like a sphygmomanometer (blood pressure instrument) for hypertension or thermometer for a fever.

Peak flow meter is a small hand held device that measures the fastest rate of air that a person can blow out of his lungs. It shows how well the airways are open.

What are the uses of peak flow meter?

Peak flow meter is a valuable tool in the arsenal of patients to monitor asthma and to know before hand is there are any chances of impending asthma attack. The main indications are:

  • Determine the severity of asthma.
  • Check the response to treatment of asthma medication. 
  • Monitor progress in treatment of asthma
  • Provide objective information for any possible adjustments in therapy.
  • Detect worsening in lung function before hand and thereby avoid a possible serious flare-up in asthma with early intervention

One of the most important functions of the peak flow meter is to help you and your physician evaluate asthma severity.

You will see a drop in peak flow readings even before the symptoms of asthma (like coughing or wheezing) get worse.

Decreases in peak flow may indicate that you need to increase your medication. The earlier a warning sign is detected, the sooner the problem can be addressed.

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How to use a Peak Flow Meter?

A peak flow meter helps you check how well your asthma is controlled. Peak flow meters are most helpful for people with moderate or severe asthma.

This article below will tell you:

(1) How to take your peak flow reading.

(2) How to find your personal best peak flow number,

(3) How to use your personal best number to set your peak flow zones, and

(4) When to take your peak flow to check your asthma each day.

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How to take your peak flow reading?

A peak flow meter measures air flow, or peak expiratory flow rate (PEFR). 

To take a peak flow reading you should:

  • First set the pointer at zero.
  • Should stand or sit in a comfortable, upright position.
  • Then hold the peak flow meter level (horizontally) and keep the fingers away from the pointer.
  • Now take a deep breath and close the lips firmly around the mouthpiece. Do not put your tongue inside the hole.
  • Then blow as hard and fast as you can.
  • Look at the pointer and check the reading. But if you cough by mistake then do the test again.
  • Reset the pointer back to zero.
  • The whole procedure is to be done three times and highest reading is to be recorded.

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How to find your personal best Peak Flow number:

The personal best peak flow is the highest peak flow value a patient can achieve over a 2-3 week period when his or her asthma is under good control.

To find your personal best peak flow number, take your peak flow each day for 2 to 3 weeks.

Your asthma should be under good control during this time.

Take your peak flow as close to between noon and 2:00 p.m. each day.  The highest peak flow number you had during the 2 to 3 weeks is your personal best. Personal best can change over time as disease is controlled or when child grows up.

Your physician will periodically readjust your personal best. Ask your doctor when to check for a new personal best.

Note: This time is only for taking the reading only for finding your personal best peak flow. To check your asthma each day, you will take your peak flow in the morning

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How to use your personal best number to set your peak flow zones?

Knowing your personal best peak flow number can be very helpful in the management of asthma.

Your should keep a daily record of your peak flow readings. If your medicine is working you should see an improvement in your peak flow reading.

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Traffic light system
Once you and your pulmonologist have established your personal best peak flow, you should make every effort to maintain values within 80% of this number so you feel your best. The following traffic light system can serve as an easy guide:

Green Zone:

Peak expiratory flow rate (PEFR) 80-100% of personal best. All systems "go." You are relatively symptom-free and can maintain your current asthma management program. If you are on continuous medication and your peak flow is constantly in the green zone with minimal variation, your physician may consider gradually decreasing your daily medication.

Personal best PEFR *80 / 100 is lower limit of Green zone.

Yellow Zone:

PEFR 50-80% of personal best. "Caution," as asthma is worsening. A temporary increase in asthma medication is indicated. If you are on chronic medications, maintenance therapy will probably need to be increased. Contact your physician to fine-tune your therapy.

Personal best PEFR * 50/100 is the lower limit of yellow zone.

Red Zone:

PEFR below 50% of personal best. "Danger," your asthma management and treatment program is failing to control your symptoms. Use your inhaled bronchodilator. If peak flow readings do not return to at least the yellow zone, contact your allergist/immunologist, who will help you employ aggressive therapy. Maintenance therapy will have to be increased.

Personal best PEFR * 50/100 is the highest limit of red zone.

These traffic light zones are broad guidelines designed to simplify asthma management. Successful control of asthma depends upon a partnership between the patient and the physician. This open communication and exchange of information can be improved with peak flow monitoring and reporting. Your physician can use this data to design and adjust your asthma medication to achieve the best asthma control possible for you.

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Last edited 22-08-2010


What are the uses of peak flow meter?

How to use a Peak Flow Meter?
How to take your peak flow reading?
How to find your personal best Peak Flow number:
How to use your personal best number to set your peak flow zones?
Traffic light system