What infusion is used for the treatment of hypernatremia?

Treatment of Hypernatremia with Appropriate Infusions

For hypernatremia treatment, hypotonic fluids such as 5% dextrose in water (D5W) or 0.45% NaCl (half-normal saline) should be used as the primary infusion, with the rate calculated to correct sodium levels gradually over 48-72 hours to prevent cerebral edema. 1, 2

Assessment and Classification

Before initiating treatment, assess:

1. Severity of hypernatremia:

   • Mild: Sodium 146-150 mEq/L
   • Moderate: Sodium 151-160 mEq/L
   • Severe: Sodium >160 mEq/L

2. Volume status:

   • Hypovolemic hypernatremia (most common)
   • Euvolemic hypernatremia
   • Hypervolemic hypernatremia (rare)

3. Duration:

   • Acute (<48 hours)
   • Chronic (>48 hours)

Treatment Algorithm

1. Choice of Infusion

• First-line for most cases: 5% Dextrose in Water (D5W) 1, 3

  • Provides free water without sodium
  • Particularly useful in hyperglycemic patients after glucose is metabolized

• Alternative: 0.45% NaCl (half-normal saline) 2, 1

  • Useful when some sodium replacement is also needed
  • Better for hypovolemic hypernatremia

• For severe hypovolemia with hypernatremia:

  • Initial volume resuscitation with normal saline (0.9% NaCl)
  • Then switch to hypotonic solutions once hemodynamically stable

2. Calculation of Water Deficit

Calculate the free water deficit using this formula:

Water deficit (L) = 0.6 × body weight (kg) × [(measured Na⁺/140) - 1]

3. Rate of Correction

• For chronic hypernatremia (>48 hours): 2, 4

  • Maximum correction rate: 8-10 mEq/L/day
  • Target correction over 48-72 hours

• For acute hypernatremia (<48 hours):

  • Can correct more rapidly but still not exceeding 1 mEq/L/hour

4. Monitoring Requirements

• Check serum sodium every 2-4 hours initially 2
• Adjust infusion rate based on sodium measurements
• Monitor for signs of cerebral edema (headache, altered mental status, seizures)
• Monitor fluid status and urine output

Special Considerations

• Avoid overly rapid correction which can lead to cerebral edema, particularly in chronic hypernatremia 2, 4

• Diabetic patients: Use caution with D5W as it may worsen hyperglycemia; monitor glucose closely

• Renal impairment: Reduce infusion rates and monitor more frequently

• Cirrhotic patients: May require careful sodium management; consider consultation with hepatology 2

Common Pitfalls to Avoid

1. Too rapid correction leading to cerebral edema
2. Inadequate monitoring of serum sodium during treatment
3. Using isotonic fluids (0.9% NaCl) as primary treatment, which won't effectively lower sodium
4. Failure to address the underlying cause of hypernatremia
5. Not accounting for ongoing fluid losses when calculating replacement needs

Remember that sterile water should NEVER be given intravenously as a direct infusion as it causes hemolysis. Only use commercially prepared hypotonic solutions like D5W or 0.45% NaCl 3.