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Monday, March 15, 2010

Peak Flow Meter Monitoring

Your peak flow meter is often considered THE primary tool for to monitor your asthma. Yet, while most asthmatics have one, few use it. And, those who do use it, few of them use it correctly. I know this because I work with asthmatics and I ask.

Read my recent post from and learn all you need to know about peak flow meters:

Your Peak Flow Meter Is An Important Tool
by Rick Frea Wednesday, December 09, 2009,

If you're an asthmatic, chances are you have a peak flow meter somewhere in your possession. Or, if you don't, you might want to consider requesting one from your asthma doctor. A peak flow meter is one of the best tools ever invented for helping us asthmatics monitor our asthma at home.

The problem with peak flow meters is most asthmatics don't use them, or when they do they use them improperly. When I see these asthmatics in the ER, it's my job to educate them.

So, what is a peak flow meter? Why were you given one? How should it be used? Why do asthma experts think they are so important?

The U.S. Department of Health and Human Services (HHS) recommends in their
asthma guidelines that every asthmatic work with his or her doctor to create an asthma action plan. This is a plan that helps you decide when to use your rescue medicine (like Albuterol), when to call your doctor, and when to have someone take you to the emergency room.

To help you decide what to do, the asthma guidelines recommend you either monitor your asthma symptoms, use your peak flow meter, or both. What you do depends on you, your asthma and your doctor. I wrote about asthma action plans
here, and monitoring asthma signs and symptoms here, so in this post we'll tackle the importance of peak flow monitoring.

When I was a kid with
hardluck asthma, my peak flow meter came in handy quite a few times. I say this because I was short of breath so often that I basically became tolerant to it. So, I had to use my peak flow meter as a tool to help me decide what to do.

As an adult my peak flow meter became less useful. It seems that whether my asthma is acting up or not, my peak flow values neither increase nor decrease. This is something unique to me. Still, I monitor my peak flows daily because you never know when it will come in handy.

The asthma guidelines recommend the following asthmatics use peak flow meters:

Moderate asthmatics: They are at increased risk over mild asthmatics

  • Severe asthmatics: They are at highest risk exacerbations
  • History: Patients who have a history of severe exacerbations
  • Dyspnea intolerant: They poorly perceive airflow obstruction and worsening asthma
  • Children: They have a harder time communicating how they feel, and this provides a good tool for parents to monitor their child's asthma.
  • Personal preference: Some asthmatics prefer this method
  • Doctor preference: Doctors can use this as a monitoring tool

A peak flow meter is a handy, easy-to-use, hand-held device that you blow into as hard as you can. It basically measures your peak expiratory flow rate (PEFR), or how much air you can blow out with maximum exhalation.

Because measurement of PEFR is dependent on your effort and technique, it's important you work with your doctor, nurse or respiratory therapist to make sure you are using it properly. To review proper peak flow technique, click


Ideally, you can use your peak flow meter as part of your asthma action plan. According to
National Jewish Health, the plan would work like this:

1. You blow into your peak flow meter every day for two weeks when you are feeling well. Whatever PEFR was your best, that one is considered your personal best.

2. You use your daily PEFR readings, along with your personal best, to help you decide what to do:

1. If your peak flow is less than 80% of your personal best, you take your rescue medication, then wait 20 to 30 minutes and check your peak flow again.

  • 1 If your peak flow is not back above 80%, report this to your doctor.
  • If your peak flow is back above 80%, re-check your peak flow about every 4 hours for a day or so. Call your doctor if you continue to need rescue medicine

2. If your peak flow is less than 60% consider this an emergency: Take your rescue medicine, and call your doctor or go to the emergency room right away.

It's really quite simple.

You should blow into your peak flow meter every day in the morning, and in the evening. This is important, because your peak flows may be normally lower in the morning. Then, if you notice your peak flows trending down, you can use this as an

early sign of an impending asthma attack, and you can act now to nip it in the bud.

Likewise, if you do need to make a visit to the ER or doctor's office, your doctor can use your personal best as an indicator of how well you are doing, whether you need another breathing treatment, or if you need to be admitted. This can save you a lot of time, and maybe even prevent you from needing to be admitted.

Also, your doctor can use your peak flow readings to monitor how well your treatment regimen is working, and as a "quantitative measurement" of how good or bad your asthma is doing.

So, even when you're feeling well, use your peak flow meter. Get it out of the box, out of the closet, dust it off, and place it next to your bed near your
asthma diary to record the results. Then use it daily like the gallant asthmatic we're sure you are.

Note: The Asthma guidelines recommend all asthmatics either use symptoms monitoring or peak flow monitoring as part of their asthma action plan, or both. The guidelines note that both methods are equally effective.


Anonymous said...

I monitor my peak flow, but I find that it tends to be more of a very rough estimate than anything. I can feel very short of breath and be coughing a lot and still be low green zone. If I'm not sure if I need it, I'll take my peak flow, and if it's good, I'll give it five minutes and re-evaluate... if it's low, I'll take my inhaler, since my peak flow is usually the last thing to decline for me, so if it's yellow, there's no way I don't need medication. On the other hand, if my peak flow says green zone but my lungs are screaming "yellow!" I'll still take my rescue medication.

The big thing I use it for is recognizing the gradual asthma flares that might come on over the course of three days to a week, usually just as I'm getting over a cold. While I have no problem recognizing sudden flares, I'm really bad at recognizing gradual ones (usually, someone else will say something like "You feeling okay? You're sighing a lot." before I realize I'm short of breath, which, when it comes on gradually, I perceive as just a general discomfort unless my attention is drawn to it). I'm sure that it's kept me out of the ED a half-dozen times since a worsening of my asthma forced me out of my goofus asthmatic phase a little over a year ago.

Ed said...

I have a question. What if you have been very bad, have let your asthma go way off the rails, and can't get a baseline?

I know there are averages out there...but can they really give me an idea of where I stand, until I get well enough to do a personal best?

Rick Frea said...

Ed: That's something to discuss with your doctor. Because every person is unique, I'm not a fan of using peak flow averages. You may want to go with the best peak flow considering the state you're in, or you may want to rely on symptom monitoring. It depends on which works best for you.

Anonymous: Actually, that sounds about how it is for me too. A peak flow meter is one of many tools we asthmatics have at our disposal. Which tool to rely on depends on the situation at hand.

Relying on others is yet another tool. It's always good to have observant friends and family like that. Sometimes it's hard to know what to do, and that's where the "friends" tool comes in handy. I've used this tool before too.