Kussmaul breathing is a compensatory mechanism for which condition?

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

Answer: (A)

Kussmaul breathing is the body's way of compensating for metabolic acidosis. When there’s excess hydrogen ions and low bicarbonate, the blood pH falls. To counteract this, the respiratory system increases ventilation to blow off carbon dioxide, which shifts the bicarbonate buffer equilibrium toward a higher pH and helps reduce acidemia. This pattern is classically seen with conditions like diabetic ketoacidosis or lactic acidosis. It’s not the typical response to metabolic alkalosis, where the body would tend to retain CO2, nor is it the usual response to primary respiratory acidosis, which is compensated primarily by kidney bicarbonate retention rather than this breathing pattern. Hypoxemia can cause faster breathing, but it doesn’t produce the deep, regular, labored hyperventilation characteristic of Kussmaul respiration.