A decrease in CO2 with a normal HCO3 results in which acid-base disorder?

A decrease in CO2 with a normal HCO3 results in which acid-base disorder?

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

Answer: (A)

A decrease in CO2 lowers the amount of carbonic acid in blood, raising the pH. When bicarbonate (HCO3–) is still normal, this points to a primary respiratory disturbance without metabolic compensation yet, which is respiratory alkalosis. It commonly results from hyperventilation, where excessive ventilation blows off CO2 and the pH increases. Metabolic acidosis would feature a low bicarbonate, metabolic alkalosis would have elevated bicarbonate, and respiratory acidosis would involve an elevated CO2.

A decrease in CO2 lowers the amount of carbonic acid in blood, raising the pH. When bicarbonate (HCO3–) is still normal, this points to a primary respiratory disturbance without metabolic compensation yet, which is respiratory alkalosis. It commonly results from hyperventilation, where excessive ventilation blows off CO2 and the pH increases.

Metabolic acidosis would feature a low bicarbonate, metabolic alkalosis would have elevated bicarbonate, and respiratory acidosis would involve an elevated CO2.