Respiratory acidosis is caused by the retention of carbon dioxide, which leads to an increase in the Pco2; this condition is usually caused by what?

• A. Imbalance in the production of carbon dioxide and its elimination through alveolar ventilation
• B. Increase in alveolar ventilation
• C. Decrease in carbon dioxide production
• D. Imbalance in production and elimination of carbon dioxide

Answer: (D)

Respiratory acidosis happens when carbon dioxide produced by metabolism isn’t removed quickly enough by the lungs, so CO2 levels rise and the blood becomes more acidic. The key idea is an imbalance between CO2 production and CO2 elimination: production is relatively constant, while elimination depends on ventilation. If ventilation falls or is impaired, CO2 accumulates and pH drops. Increasing alveolar ventilation would lower CO2 and alkalinize, while decreasing CO2 production would also reduce acidity. The general principle, therefore, is an imbalance between production and elimination of carbon dioxide.