Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm

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    Attention COACH STUDY participants:

    The principal investigators of the study request that you use the official version of the modified score here.
    Log in to copy your patient's results!

    A-a O₂ Gradient

    Assesses for degree of shunting and V/Q mismatch.
    When to Use
    Why Use
    • Patients with unexplained hypoxia.
    • Patients with hypoxia exceeding the degree of their clinical illness.

    The A-a Gradient can help determine the cause of hypoxia; it pinpoints the location of the hypoxia as intra- or extra-pulmonary.

    mm Hg
    mm Hg
    %
    mm Hg
    years
    Confirmed positive
    Suspected
    Unlikely
    Confirmed negative

    Result:

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    Next Steps
    Evidence
    Creator Insights
    Dr. H. Fred Helmholz

    About the Creator

    H. Fred Helmholz, MD, (d. 2012) spent most of his career at the Mayo Graduate School of Medicine. He was active in most aspects of respiratory care which included research and clinical practice in high-altitude medicine, oxygen therapy, pulmonary function testing, and mechanical ventilation.

    To view Dr. H. Fred Helmholz's publications, visit PubMed

    About the Creator
    Dr. H. Fred Helmholz
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