DKA Arterial blood gas?

[person011]

For someone in DKA, what blood gas is more likely?

PH 7.05 PO2 110 PCO2 20
PH 7.10 PO2 90 PCO2 65
PH 7.40 PO2 100 PCO2 20

I am thinking it is the first one, but wanted to make sure

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[ksmi117]

First one. Have to be acidotic so not 3. Since it's a metabolic acidosis, the body will attempt to compensate with a respiratory alkalosis (hyperventilation to breath off CO2) so the pCO2 should be low as well. Since the pH is less than 7.1, it'd be considered severe DKA.

Two is an example of respiratory acidosis, as the patient is retaining CO2 and thus becoming more acidotic.

Three is likely a mixed metabolic acidosis and respiratory alkalosis (not compensatory since the pH is normal here), like aspirin overdose. I suppose this could also be the ABG of someone with DKA and a concurrent primary respiratory alkalosis, though this is not as likely as the first ABG for a patient in DKA.

 

[Top Gun]

The first ABG is most consistent with DKA. The second suggests a primary respiratory acidosis, like in a COPDer, and the third suggests a mixed disorder. Also, another key thing to look for with DKA is an elevated anion gap.