Sodium Correction Rate in Hyponatremia and Hypernatremia

Sodium Correction Rate Calculator

Initial Sodium

mEq/L

Current Sodium

mEq/L

Time Elapsed

hours

Calculates recommended IV fluid type, rate, and volume to correct hyponatremia or hypernatremia at desired rate depending on clinical scenario.

Why Use

To determine the appropriate rate of IV fluids for treatment of hypo and hypernatremia.

When to Use

When managing patients with hyponatremia or hypernatremia this calculator estimates the rate and type of intravenous fluid to be replaced.

Formula

Fluid rate, mL/hr = (1000 × rate of sodium correction, mmol/L/hr) / change in serum sodium Change in serum sodium = (fluid sodium, mmol/L - serum sodium, mmol/L) / (total body water + 1) Total body water = weight, kg × % body water, defined as follows: % body water: Age Male Female Child 0.6 0.6 Adult 0.6 0.5 Elderly 0.5 0.45 Experts recommend correcting no faster than 12 mmol/L/day (0.5mmol/L/hr) to avoid osmotic demylination syndrome (ODS), previously known as central pontine myelinolysis (CPM), and only correcting it faster — and only using hypertonic (3%) saline — if the patient is seriously symptomatic at a rate of 1-2 mmol/L/hr , and even then, only correcting it at 1-2 mmol/L/hr.

Pearls / Pitfalls

The proper rate of correction of hyponatremia is important and should be determined before using this calculator. This calculator is a starting point for hyponatremia treatment and is in no way a replacement for constant monitoring of serum sodium level to assess impact of treatment. Overly rapid correction of chronic hyponatremia can lead to osmotic demyelination syndrome (ODS), previously known as central pontine myelinolysis (CPM). In most cases, sodium correction for severe hyponatremia should be done in an ICU setting, especially with hypertonic fluids for replacement. This calculator does not account for fluid losses such as in urine and through sweat and respiration.

Critical Actions

Determine appropriate rate of correction of hyponatremia based on clinical scenario. Chronic hyponatremia should be corrected slowly. Rapid correction might be necessary for severe hyponatremia with mental status changes. Monitor serum sodium level frequently and adjust therapy accordingly. Consider ICU monitoring for severe hyponatremia particularly when prescribing hypertonic fluids. This calculator does not account for fluid losses such as in urine and through sweat and respiration.

Advice

Correct chronic hyponatremia carefully. Monitor sodium level frequently particularly when correcting severe hypo or hypernatremia to assess impact of therapy. Do not forget to correct the hyponatremia level in hyperglycemic patients with the Sodium Correction for Hyperglycemia calculator. Typically, hypertonic solutions are reserved for patients who are overly symptomatic, such as those with seizures and severe neurologic deficits and in an ICU setting.