- Replacement fluid is given to replace the fraction of fluid which has been produced as effluent
- The addition of fluid dilutes the concentration of solutes in excess in the plasma
- The addition of solutes in the fluid can increase the concentration of solutes that are deplete in the plasma
- They consist of a balanced salt solution with a molecule used to buffer acid – commonly either lactate or bicarbonate
- Individual components vary but should contain:
- Sodium 140 mmol/l
- Chloride 108–112 mmol/l
- Potassium 0–4 mmol/l
- Calcium 1.5–1.75 mmol/l
- Magnesium 0.5–0.75 mmol/l
