Respiratory Alkalosis

- Is caused by an increase in respiratory rate and loss of CO2.
- Decreased arterial PCO2, which is the primary disturbance, causes a decrease in [H+] and [HCO3-] by mass action.
- There is no respiratory compensation for respiratory alkalosis.
- Renal compensation consists of decreased excretion of H+ as titrable acid and NH4+, and decreased reabsorption of "new" HCO3-.  This process is aided by the decreased PCO2, which causes a deficit of H+ in the renal cells for secretion.  The resulting decrease in serum [HCO3-] helps to normalize the pH.
- In acute respiratory alkalosis, renal compensation has not yet occurred.
- In chronic respiratory alkalosis, renal compensation (decreased HCO3- reabsorption) has occurred.  thus, arterial pH is decreased toward normal (i.e., a compensation).