In a patient with respiratory alkalosis, what happens to the excretion of HCO3- by the kidneys?

In respiratory alkalosis, the primary issue is an elevated blood pH due to decreased carbon dioxide levels from hyperventilation. To compensate for this disturbance, the kidneys respond by adjusting the excretion of bicarbonate (HCO3-).

During respiratory alkalosis, the body attempts to restore pH balance by decreasing the bicarbonate concentration. This is accomplished by increasing the excretion of HCO3- through the kidneys. The kidneys will actively transport more bicarbonate out of the body in urine, thereby reducing the overall bicarbonate levels in the blood and helping to lower the pH back to a more normal range.

This compensatory mechanism is critical for maintaining acid-base homeostasis when respiratory function alters CO2 levels. Therefore, the increase in HCO3- excretion is the body's way of countering the alkalotic state caused by the underlying respiratory issue.