ABG with pH 7.52, PaCO2 32, HCO3- 22 indicates what primary disturbance?

• A. Respiratory alkalosis
• B. Metabolic acidosis
• C. Metabolic alkalosis
• D. Respiratory acidosis

Answer: (A)

This ABG shows alkalemia with a low PaCO2, meaning the rise in pH is driven by excessive ventilation reducing carbon dioxide. The bicarbonate is normal, so there’s no metabolic component or compensation yet. Therefore the primary disturbance is respiratory alkalosis. If it were metabolic alkalosis, you'd expect a high bicarbonate; if it were respiratory acidosis, the pH would be low with a high PaCO2; if it were metabolic acidosis, the pH would be low with a low bicarbonate.