Which pattern describes a dual acid-base disorder?

Which pattern describes a dual acid-base disorder?

• A. Metabolic alkalosis only
• B. Respiratory alkalosis only
• C. A dual acidosis
• D. No acid-base disturbance

Answer: (C)

Dual acid-base disorders occur when two primary disturbances happen at the same time, each pushing the system in its own direction. When both are acidifying the blood, you have a dual acidosis. In this pattern, the pH is low because acidemia is driven by two sources: a metabolic component that lowers bicarbonate (HCO3−) and a respiratory component that raises carbon dioxide (PCO2). The combination creates a stronger acid load than either process alone, and the body’s compensatory responses can’t fully normalize the pH. For example, a patient with lactic acidosis from sepsis (metabolic acidosis) plus CO2 retention from lung disease (respiratory acidosis) would show an acidemic pH with low HCO3− and high PCO2. The other single-pattern disorders involve only one regulatory system changing in one direction (metabolic alkalosis or respiratory alkalosis), so they do not represent two concurrent acid-base problems.

Dual acid-base disorders occur when two primary disturbances happen at the same time, each pushing the system in its own direction. When both are acidifying the blood, you have a dual acidosis. In this pattern, the pH is low because acidemia is driven by two sources: a metabolic component that lowers bicarbonate (HCO3−) and a respiratory component that raises carbon dioxide (PCO2). The combination creates a stronger acid load than either process alone, and the body’s compensatory responses can’t fully normalize the pH. For example, a patient with lactic acidosis from sepsis (metabolic acidosis) plus CO2 retention from lung disease (respiratory acidosis) would show an acidemic pH with low HCO3− and high PCO2. The other single-pattern disorders involve only one regulatory system changing in one direction (metabolic alkalosis or respiratory alkalosis), so they do not represent two concurrent acid-base problems.