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ABG Mixed acid-base disorder

Discussion in 'Medical Students - MD' started by CYP2D6, May 20, 2014.

  1. CYP2D6


    May 20, 2014
    Hi, I am working on mixed acid-base disorders and ran across this article:
    "Patients with a metabolic acidosis (acidemia plus a low plasma [HC0]), whose calculated Pco2 is less than the measured value, have, in addition, an underlying respiratory alkalosis. Conversely, patients with a calculated value greater than the measured value have a primary respiratory acidosis in addition to the metabolic acidosis (provided the disorder has been present longer than 12h)."

    This paragraph is confusing doesn't seem correct. It seems to be they have the terms calculated and measured reversed (i.e. should be if the measured Pco2 is less than the calculated value, then there is an underlying respiratory alkalosis). Measured is what comes back on the lab report, and calculated is what you estimate it should be based on the formula PCO2 = 1.5 x HCO3 + (8 +/- 2)......right?

    If the article IS correct, could someone please explain it to me?
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  3. Apoplexy__

    Apoplexy__ Blood-and-thunder appearance 5+ Year Member

    Oct 20, 2012
    Up on the Hydra's back
    Seems wrong. Can't think of any way it could be right the way it's written.

    If pCO2 is lower than what was calculated, you have an additional primary respiratory alkalosis.
    If pCO2 is higher than what was calculated, you have an additional primary respiratory acidosis.
    CherryRedDracul likes this.
  4. CherryRedDracul

    CherryRedDracul Resident Sh!tposter Physician 5+ Year Member

    Oct 12, 2012
    North America
    Somebody dun goof'd.
  5. CYP2D6


    May 20, 2014
    Lol thanks guys, that's what I was thinking, but was afraid I was missing something. Thanks!

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