In pulmonary insufficiency, excessive calorie administration may cause increased blood pCO2 resulting in

• A. metabolic acidosis
• B. metabolic alkalosis
• C. respiratory acidosis
• D. respiratory alkalosis

Answer: (C)

When CO2 production rises from high calorie intake and the lungs can’t remove it adequately in pulmonary insufficiency, the result is respiratory acidosis. The retained CO2 combines with water to form carbonic acid, which dissociates to hydrogen ions and bicarbonate, increasing hydrogen ion concentration and lowering pH. Metabolic disturbances would require changes in bicarbonate or non-CO2 acids, and respiratory alkalosis would come from excessive ventilation (CO2 loss), not retention. So the elevated pCO2 causes respiratory acidosis.