Q; 30-year old patient with history of diabetes, presented to the hospital with c/o nausea and vomiting. Patient
sodium was 140meq/l,
potassium was 4meq/l,
chloride was 105meq/l,
HCO3 was 5meq/l.
pCO2 was 16 and
pH was 7.11.
What is the acid base disturbance?
A) Metabolic acidosis
B) Respiratory acidosis
C) Mixed metabolic and respiratory acidosis
D) Triple acid-base disturbance
Rationale: Patient anion gap is high (30) suggestive of metabolic acidosis. Patient CO2 is low, not supporting the notion of respiratory acidosis. Expected CO2 is (pCO2=1.5(HCO3) +8 +/-2; 1.5x5+8+/-2=13.5-17.5) within normal range.