ABG shows pH 7.32, PaCO2 54 mmHg, HCO3⁻ 26 mEq/L. What is the most likely acid-base disorder?

• A. Respiratory acidosis with no metabolic compensation.
• B. Metabolic acidosis with respiratory compensation.
• C. Respiratory alkalosis.
• D. Respiratory acidosis with metabolic compensation.

Answer: (D)

This ABG pattern shows respiratory acidosis with metabolic compensation. The pH is acidic (7.32) and the PaCO2 is elevated (54 mmHg), indicating CO2 retention as the primary disturbance. The bicarbonate is 26 mEq/L, which is at the high end of normal and reflects renal compensation trying to buffer the excess CO2. Because the pH remains acidemic despite the elevated bicarbonate, compensation is present but incomplete — i.e., partially compensated respiratory acidosis.

Metabolic acidosis would feature a low bicarbonate with a compensatory drop in CO2, which isn’t the case here. Respiratory alkalosis would show a high pH with low CO2, also not matching. A respiratory acidosis with no metabolic compensation would typically have a lower bicarbonate not yet elevated.