Which statement best defines respiratory acidosis?

Which statement best defines respiratory acidosis?

• A. Increase in CO2 content and PCO2 with a decreased pH
• B. Decrease in CO2 content with an increased pH
• C. Increase in CO2 content with an increased pH
• D. Decrease in CO2 content and PCO2 with a decreased pH

Answer: (A)

Respiratory acidosis happens when ventilation fails to remove enough CO2, so CO2 builds up in the blood and drives acidification. CO2 combines with water to form carbonic acid, which dissociates to hydrogen ions and bicarbonate, increasing hydrogen ion concentration and lowering pH. The defining pattern is higher CO2 content with a higher arterial PCO2 and a decreased pH. The body may compensate over time by increasing bicarbonate via the kidneys, but the primary feature remains elevated CO2 with acidemia.

Respiratory acidosis happens when ventilation fails to remove enough CO2, so CO2 builds up in the blood and drives acidification. CO2 combines with water to form carbonic acid, which dissociates to hydrogen ions and bicarbonate, increasing hydrogen ion concentration and lowering pH. The defining pattern is higher CO2 content with a higher arterial PCO2 and a decreased pH. The body may compensate over time by increasing bicarbonate via the kidneys, but the primary feature remains elevated CO2 with acidemia.