Which measure is the single best determinant of asthma severity?
A peak expiratory flow rate (PEF or PEFR) is the single best determinant of asthma severity. A PEF measurement is a quick test to measure air flowing out of the lungs. During the test, you blow forcefully into the mouthpiece of a device, usually a peak flow meter (PFM), which is a portable, light, handheld device made of plastic. If the test is done in a healthcare provider's office or a hospital a much larger device, called a spirometer, is usually used. This device has a handheld mouthpiece that’s attached by a cord to a larger electronic machine.
A peak flow measurement can show the amount and rate of air that can be forcefully breathed out of the lungs after a full lung inhalation. An important part of peak flow measurement is looking at peak flow zones. These are areas of measurement that can help show early symptoms of uncontrolled asthma and are set differently for each person. There are 3 peak flow zones noted by color:
- Green for “go.” This is 80% to 100% of your highest peak flow reading, or personal best, and is the zone you should be in everyday
- Yellow for “caution” or “slow down.” This is 50% to 80% of your personal best and is a sign that your large airways are starting to narrow. You may have mild symptoms, such as coughing, feeling tired, feeling short of breath, or feeling like your chest is tightening.
- Red means “stop.” This is less than 50% of your personal best and shows you have severe narrowing of your large airways. It is considered a medical emergency and you should get help right away. Your symptoms may include coughing, being very short of breath, wheezing while breathing in and out, or retractions (this is when you can see the muscles between the ribs working hard to keep you breathing). Walking and talking may be difficult.
References
- Peak Flow Measurement. John Hopkins Medicine. 2021. https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/peak-flow-measurement
- Camargo C, Rachelefsky, Schatz M. Managing Asthma Exacerbations in the Emergency Department. Summary of the National Asthma Education and Prevention Program Expert Panel Report 3 Guidelines for the Management of Asthma Exacerbations. Department of Emergency Medicine and Division of Rheumatology, Allergy, and Immunology, Department of Medicine https://www.atsjournals.org/doi/pdf/10.1513/pats.P09ST2#:~:text=The%20primary%20determinant%20of%20severity,The%20exacerbation%20severity%20determines%20treatment.
Read next
Related medical questions
- How long does an asthma attack last?
- Why is asthma worse at night?
- Does Cinqair treat all types of asthma?
- Prednisone: What are 12 Things You Should Know?
- Prednisone vs Prednisolone - What's the difference?
- Can vitamin C prevent or treat COVID-19 (coronavirus)?
- What are the side effects of steroids?
- What is Diprospan used for?
- Trelegy vs. Breo: How does their use and cost compare?
- What is Quercetin and what are its health benefits?
- Does coffee help with asthma?
- Can you take Symbicort and prednisone together?
- Is Wixela Inhub the same as Advair Diskus?
- Can you take Trelegy and Symbicort together?
- Does Feverfew interact with any drugs?
- Does Fasenra weaken your immune system?
- How long does Fasenra take to work?
- What are 5 key Tezspire side effects to watch out for?
- How does Dupixent help with asthma?
- How long does it take for Nucala to work?
- What is Fasenra used for and how does it work?
- Is loss of sense of smell a symptom of COVID-19?
- I think I have an allergy to my antibiotic! What can I do to treat my infection?
- How is the new Primatene Mist different to the old formulation?
- What drugs are contained in Trelegy Ellipta?
- What type of asthma is Fasenra used to treat?
- How do I use the Tezspire pen?
- What is Nucala (mepolizumab) used for and how is it given?
- The in's and out's of Proper Inhaler Use
Related support groups
- Asthma (112 questions, 471 members)