In the plasma, an excess in the concentration of bicarbonate without a change in PCO2 from normal will result in what physiological state?

In the plasma, an excess in the concentration of bicarbonate without a change in PCO2 from normal will result in what physiological state?

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

Answer: (D)

An excess of bicarbonate raises the base component of the blood, and with PCO2 remaining normal, the ratio of bicarbonate to CO2 increases. According to the Henderson-Hasselbalch relationship, this higher ratio pushes pH toward alkaline values, producing metabolic alkalosis. The respiratory system would normally compensate by adjusting CO2 levels (hypoventilation to raise CO2), but since CO2 is unchanged, this is a metabolic disturbance without respiratory compensation. The other states involve changes in CO2 driving the pH in the opposite direction (high CO2 for respiratory acidosis, low CO2 for respiratory alkalosis) or a decrease in bicarbonate for metabolic acidosis, which don’t fit the scenario.

An excess of bicarbonate raises the base component of the blood, and with PCO2 remaining normal, the ratio of bicarbonate to CO2 increases. According to the Henderson-Hasselbalch relationship, this higher ratio pushes pH toward alkaline values, producing metabolic alkalosis. The respiratory system would normally compensate by adjusting CO2 levels (hypoventilation to raise CO2), but since CO2 is unchanged, this is a metabolic disturbance without respiratory compensation. The other states involve changes in CO2 driving the pH in the opposite direction (high CO2 for respiratory acidosis, low CO2 for respiratory alkalosis) or a decrease in bicarbonate for metabolic acidosis, which don’t fit the scenario.