Interpreting an arterial blood gas
An arterial blood gas shows pH 7.30, PaCO2 30 mmHg, and HCO3− 14 mEq/L. What is the disturbance?
Answer A: explanation for every choice
A
Correct. Low pH with low bicarbonate is metabolic acidosis. The low PaCO2 shows hyperventilation compensating for it.
B
Respiratory acidosis would have a high PaCO2.
C
The pH is acidic, so alkalosis is excluded.
D
Metabolic alkalosis has a high pH and high bicarbonate.
TakeawayCheck pH, then decide whether CO2 or HCO3− explains it. The other value shows compensation.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb177.