Work out sodium deficit instantly with clear inputs, formula shown and shareable results.
Multiplies total body water by the gap between target and current sodium to give the millimoles of sodium required, then converts that to a volume of 3% saline.
Sodium deficit
Deficit (mmol) = total body water (L) x (target Na - current Na); 3% saline contains 513 mmol/L of sodium
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
Chronic hyponatraemia is usually corrected by no more than 8 to 10 mmol/L in 24 hours to avoid osmotic demyelination.
Lean body water falls with age and is lower in women, so the same weight holds less total body water.