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      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





    Chief Complaint


    Organ System


    Patent Pending

    Cardiac Output (Fick’s Formula)

    Calculates cardiac output, cardiac index, and stroke volume.
    When to Use
    Why Use

    • Inpatients with suspected cardiogenic shock and a pulmonary artery catheter in place.

    • For patients undergoing right or left heart catheterization to determine cardiac output (CO), cardiac index (CI), and stroke volume (SV).

    • The two most widely used ways of calculating CO are Fick’s method and the thermodilution technique. Fick’s method is based on the principle that oxygen consumption is equal to the product of the organ’s blood flow (CO) and the difference in the concentration of the substance in the arterial and venous circulation (arterial-venous oxygen difference).

    • Fick’s method is less reliable in patients with pulmonary hypertension, heart failure, or abnormal body habitus.

    • The thermodilution technique is less reliable in patients with tricuspid regurgitation or intracardiac shunting.

    • Assesses cardiac capacity and aids in hemodynamic assessment.

    • Guides management in cardiogenic shock patients, specifically to assess effectiveness of fluid resuscitation, vasopressors, or inotropic support.

    <70 years
    ≥70 years


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    Next Steps
    Creator Insights


    • If CO or CI is low or decreasing, consider increasing fluid administration.

    • If the patient is not fluid responsive, consider adding vasopressors (norEPINEPHrine, DOPamine) via a central line, and use the CO/CI to guide adjustment of vasopressors as per goals of resuscitation (CI >2.5, MAP >60).

    Content Contributors
    Reviewed By
    • On Chen, MD
    About the Creator
    Dr. Adolf E. Fick
    Are you Dr. Adolf E. Fick?
    Content Contributors
    Reviewed By
    • On Chen, MD