Q; Patient with history of hypertension and anxiety presented to the hospital with tachypnea. Patient
sodium was 140meq/l,
potassium was 3meq/l,
chloride was 94meq/l and
HCO3 was 34.
On arterial blood gas,
PH was 7.67 and
pCO2 was 30.
What is the acid base disturbance?
A) Respiratory alkalosis
B) Metabolic alkalosis
C) Respiratory and metabolic alkalosis
D) Hyperchloremic non-anion gap metabolic acidosis
Rationale: Patient HCO3 is high suggestive of metabolic alkalosis. Patient expected CO2 should be (pCO2=HCO3x0.9+9; 34x0.9+9=39.6); CO2 is 30, which is lower than expected pCO2, suggestive of mixed respiratory and metabolic alkalosis.