Report generated with Calculate by QxMD at https://www.qxmd.com/calculate
Over 400 decision support tools available • get the app for iOS or Android at qx.md/calculate
Hyponatremia is a common electrolyte disturbance frequently requiring fluid administration for correction to physiologic levels. Rapid correction can be dangerous for patients, leading to cerebral edema and osmotic demyelination among other complications.1 Determining a safe rate of fluid administration to prevent these issues relies on patient and fluid variables. The majority of cases of osmotic demyelination were originally thought to have taken place with daily sodium correction of greater than 12 mmol/L/day (0.5 mmol/L/hr); however, many experts advocate for a more conservative approach to correction, targeting 4-6 mmol/L/day with a maximum of 8 mmol/L/day.2
This calculator specifically addresses the total sodium deficit for a patient considering their total body water (TBW) alongside current and desired serum sodium levels. The calculation used for TBW is simplified, however many more complex equations integrating age and height exist in the literature.
Calculator for Sodium Deficit
Sodium Deficit (mEq) = Total body water (TBW) * (Desired sodium - Serum sodium)
Whereby:
Citations:
Adrogue HJ, Madias NE. Hyponatremia.
NEJM, 2000.
Sterns RH, Nigwekar SU, Hix JK. The treatment of hyponatremia.
Semin Nephrol. 2009;29(3):282.
Contributed by: Riley Golby, MD