This version was machine-translated from German and has not been medically reviewed. The authoritative version is the German version.
Free water deficit
In hypernatremia: water deficit from sodium, weight and total body water fraction, with correction limit
Scientific basis
Children
The formulas come mainly from studies in adults and are applied unchanged in children; where total body water is involved (water and sodium deficit), the age-appropriate body water fraction is used. According to the European guideline, the sodium correction limits (10 mmol/l per 24 h) also apply to children.
Calculation aid for healthcare professionals: the calculator reproduces what the sources cited assign to the inputs. Clinical assessment and every treatment decision remain with the treating physician. Inputs and results are not stored.
Frequently asked questions
Free water deficit: What does this calculator compute?
Calculates the free water deficit in hypernatremia (TBW × (Na/140 − 1)) with an age-appropriate body water fraction and shows over what period it should be corrected according to the correction limit of 0.5 mmol/l/h or 10 mmol/l/day (Adrogué & Madias).
Free water deficit: Which sources is this calculator based on?
Adrogué HJ, Madias NE: Hypernatremia (N Engl J Med 342:1493–1499) (2000)