- Ca2+ ions competes for binding sites on albumin with H+ ions
- As pH changes the proportion of calcium bound to albumin and freely ionised in the plasma varies
- For every 0.1 unit reduction in plasma pH, the albumin bound calcium decreases by 0.07 mmol/L and ionised calcium increases by 0.07 mmol/L
- Hyperventilation can lead to alkalosis, and thus reduced plasma ionised calcium:
- As ionised calcium determines clinical effects tetany may be precipitated
