What is the maintenance dose of hypertonic (high concentration) saline for treating severe, symptomatic hyponatremia (low sodium levels)?

From the Guidelines

The maintenance dose of hypertonic saline for treating severe, symptomatic hyponatremia should be individualized, but typically ranges from 0.5 to 2 mL/kg/hour of 3% sodium chloride solution, with the goal of raising serum sodium by up to 5 mmol/L in the first hour and limiting the increase to 8-10 mmol/L every 24 hours thereafter, as recommended by recent guidelines 1.

Key Considerations

• The initial bolus of 100-150 mL of 3% saline over 10-20 minutes can be repeated 1-2 times if severe symptoms persist, with careful monitoring of serum sodium levels and clinical symptoms.
• Frequent monitoring of serum sodium levels (every 2-4 hours initially) is essential to guide therapy and adjust the infusion rate based on sodium correction rate and symptom improvement.
• Treatment should be slowed or stopped once symptoms improve or when the desired sodium increase has been achieved, to avoid the risk of central pontine myelinolysis.
• Patients require close monitoring for fluid overload, particularly those with heart or kidney disease, and the underlying cause of hyponatremia should be addressed simultaneously for comprehensive management.

Important Guidelines

• According to the guidelines on the management of ascites in cirrhosis, hypertonic sodium chloride (3%) administration should be reserved for those who are severely symptomatic with acute hyponatraemia, and serum sodium should be slowly corrected 1.
• The European Association for the Study of the Liver (EASL) clinical practice guidelines for the management of patients with decompensated cirrhosis also recommend that hypertonic sodium chloride administration be limited to severely symptomatic hyponatremia, with careful monitoring to avoid central pontine myelinolysis 1.

From the Research

Maintenance Dose of Hypertonic Saline for Hyponatremia

The maintenance dose of hypertonic saline for treating severe, symptomatic hyponatremia is not explicitly stated in the provided studies. However, the following information can be gathered:

• The goal of treatment is to increase the serum sodium level by 4-6 mEq/L within 1-2 hours, but by no more than 10 mEq/L within the first 24 hours 2, 3.
• The recommended therapeutic goals are an increase of 6-8 mmol/L in 24 hours, 12-14 mmol/L in 48 hours, and 14-16 mmol/L in 72 hours 3.
• A 3% hypertonic saline solution can be used to correct severe hyponatremia, with a rate of correction of 2.4 +/- 0.5 meq/liter/hr 4.
• The European guidelines recommend a bolus-wise administration of 150 mL of 3% hypertonic saline, but this recommendation is based on a low level of evidence 5.
• Reducing the bolus volume and reevaluating before repeating the bolus infusion may help prevent overcorrection 5.

Key Considerations

• Overly rapid correction of hyponatremia can cause osmotic demyelination, a rare but severe neurological condition 2, 3.
• Frequent monitoring of serum sodium concentration and urine output is mandatory to avoid overcorrection 3.
• Diuresis should be monitored, as it can correlate with the degree of sodium overcorrection 5.
• Care should be taken to avoid acute correction to normonatremia or hypernatremia, as well as the development of hypernatremia in the subsequent days following correction to mild hyponatremia 6.

Treatment Approaches

• Hypertonic saline is typically reserved for patients with severely symptomatic hyponatremia 2.
• Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects 2.
• The approach to managing hyponatremia should consist of treating the underlying cause, and patients should be categorized according to their fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia) 2.