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 asthmatics monitor their asthma.
So, what is a peak flow meter? 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 asthmatics work with their asthma doctors 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.
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 of 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.
The procedure goes like this:
- Ideally you'll want to sit up, or stand.
- Set the indicator on the meter to zero
- Take in as deep a breath as you can
- Make a tight seal around the mouthpiece with your mouth
- Exhale as hard and fast as you can.
- The indicator will move showing how much air you exhaled (your PEFR)
- Note this number
- Repeat this procedure three times, recording the best result, along with the date and time, in your asthma journal
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 here.
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 your breathing is good. 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:
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.
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
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. Keep it in a handy locatoin, such as a bedside table with your asthma diary. Then use it daily like the gallant asthmatic we're sure you are.