🧪 Sodium Deficit (Hyponatraemia)
Estimate the sodium deficit to plan correction in hyponatraemia.
Sodium Deficit (Hyponatraemia)
Weight (kg)
Current sodium (mmol/L)
Target sodium (mmol/L)
Total body water factor
When to use
Quantify sodium needed to reach a target in hyponatraemia.
How it works
Na deficit = TBW × (target Na − current Na), TBW = factor × weight (0.6 male, 0.5 female/elderly).
Key points
- Estimates total mmol, not the infusion rate.
- Limit correction to ≤ 8–10 mmol/L per 24 h (less if high risk).
- Over-rapid correction risks osmotic demyelination.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.