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    Estimated/Expected Peak Expiratory Flow (Peak Flow)

    Quantifies asthma exacerbation severity.


    This calculator includes inputs based on race, which may or may not provide better estimates, but cannot be run without inputting race due to how the formulae were developed by the CDC’s Third National Health and Nutrition Examination Survey See here for more on our approach to addressing race and bias on MDCalc.

    When to Use
    Why Use

    Use in patients age 5-80 years with asthma.

    • Useful in patients who do not know their baseline peak expiratory flow rate (peak flow).

    • Comparison of a patient’s current peak flow to a known or expected personal best is only one aspect of the evaluation of a child with an acute asthma exacerbation. Other important factors such as respiratory rate, lung auscultation, mental status, and accessory respiratory muscle use must also be considered.

    • Height and sex have been the factors most strongly correlated with peak flow across multiple studies; however, other differences, including ethnicity and other factors may also play a role in affecting predicted values.

    Asthma exacerbation severity can be quantified by comparing a patient’s current peak expiratory flow rate (PEFR) to their most recent personal best value. In the absence of a known recent personal best, this calculator can be used to estimate an expected “personal best.” The difference between the predicted and actual value can therefore help the clinician determine how severe the current exacerbation is.



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    Creator Insights
    Dr. John L. Hankinson

    About the Creator

    John L. Hankinson, PhD, is a biomedical engineer and consultant. He is also the course director for a National Institute for Occupational Safety and Health approved spirometry course and serves on the ATS Proficiency Standards for Pulmonary Function Laboratories Committee. Dr. Hankinson’s primary research is focused on respiratory diseases and spirometry.

    To view Dr. John L. Hankinson's publications, visit PubMed

    Are you Dr. John L. Hankinson? Send us a message to review your photo and bio, and find out how to submit Creator Insights!
    MDCalc loves calculator creators – researchers who, through intelligent and often complex methods, discover tools that describe scientific facts that can then be applied in practice. These are real scientific discoveries about the nature of the human body, which can be invaluable to physicians taking care of patients.
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