- Prolonged vomiting leads to the loss of gastric acid rich in hydrochloric acid (HCl), resulting in a depletion of hydrogen ions.
- This causes a reduction in acid levels and an increase in blood bicarbonate, producing a state of metabolic alkalosis.
- The kidney attempts to compensate by retaining hydrogen ions and excreting bicarbonate, but ongoing acid loss maintains the alkalosis.
- Additionally, volume depletion from vomiting stimulates aldosterone release, further enhancing hydrogen ion secretion and bicarbonate retention, which perpetuates the alkalosis.

Reference: Davidson’s Principles and Practice of Medicine, 23rd Edition, Chapter: Acid-Base Disorders, Page 517.