Free Water Deficit Calculator

This calculator is indicated for pediatric patients exhibiting acute or chronic dysnatremis (Serum Na > 145 mmol/L or < 135 mmol/L). CRITICAL SAFETY GUARDRAIL: In hypernatremic dehydration, the maximum safe rate of serum sodium correction is 0.5 mEq/L per hour (or a maximum of 10–12 mEq/L in a 24-hour window). Correcting hypernatremia too rapidly risks triggering catastrophic cerebral edema, seizures, and permanent neurological injury. For hyponatremia, cautious replacement is required to mitigate the risk of Central Pontine Myelinolysis (Osmotic Demyelination Syndrome). Always cross-reference hourly infusion guidelines with serial electrolyte monitoring every 2 to 4 hours.