Is 3% saline (hypertonic saline) indicated to correct mild hyponatremia from a serum sodium level of 116 mmol/L to 120 mmol/L?

From the Guidelines

The use of 3% saline (hypertonic saline) is not indicated for correcting mild hyponatremia from a serum sodium level of 116 mmol/L to 120 mmol/L, as it is typically reserved for short-term treatment of patients with symptomatic or severe hyponatremia. According to the 2021 practice guidance by the American Association for the Study of Liver Diseases 1, the management of hyponatremia depends on its severity and symptoms. For patients with severe hyponatremia (<120 mEq/L), the goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of osmotic demyelination syndrome (ODS).

Key Considerations

• The correction rate should be carefully monitored to avoid overly rapid correction, which can lead to ODS.
• The underlying cause of hyponatremia should be identified and treated simultaneously.
• For patients with cirrhosis, the management of hyponatremia may involve fluid restriction, cessation of diuretics, and albumin infusion, depending on the severity of hyponatremia and the presence of symptoms 1.
• The use of vasopressin receptor antagonists can raise serum sodium during treatment, but they should be used with caution only for a short term (≤30 days) 1.

Management Approach

• For severe symptomatic hyponatremia, a bolus of 100-150 mL of 3% saline over 10-20 minutes can be given, which may be repeated if symptoms persist.
• Alternatively, a continuous infusion of 3% saline at 0.5-2 mL/kg/hr can be used, with frequent monitoring of serum sodium (every 2-4 hours initially) to adjust the infusion rate.
• Once the patient reaches 120 mEq/L and acute symptoms resolve, the correction rate should be slowed.
• However, for a patient with a serum sodium level of 116 mmol/L, which is considered severe hyponatremia, 3% saline may be considered if the patient is symptomatic, but the decision to use it should be made on a case-by-case basis, taking into account the patient's overall clinical condition and the presence of symptoms.

From the Research

Indications for 3% Saline in Hyponatremia

• 3% saline (hypertonic saline) is typically indicated for the correction of severe or symptomatic hyponatremia, particularly when patients exhibit significant neurologic signs and symptoms 2, 3, 4.
• The use of 3% saline is recommended for patients with severe hyponatremia (sodium concentration < 125 mEq/L) and severe symptoms, such as delirium, confusion, impaired consciousness, ataxia, seizures, or cardiorespiratory distress 3, 4.
• For patients with mild hyponatremia (sodium concentration 130-134 mEq/L), treatment usually involves addressing the underlying cause and may include fluid restriction, loop diuretics, or vasopressin receptor antagonists, rather than 3% saline 2, 3, 4.

Correction of Mild Hyponatremia

• The correction of mild hyponatremia, such as from a serum sodium level of 116 mmol/L to 120 mmol/L, is generally not recommended using 3% saline, as this condition is often asymptomatic or mildly symptomatic and can be managed with other treatments 3, 4.
• The goal of treatment in mild hyponatremia is to slowly correct the sodium level, usually by treating the underlying cause, and to avoid overly rapid correction, which can cause osmotic demyelination syndrome 3, 4, 5.

Specific Treatment Approaches

• For patients with severe symptomatic hyponatremia, US and European guidelines recommend treating with bolus hypertonic saline 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 4.
• In cases of hyponatremia accompanied by acute kidney injury, a 3% saline bolus before intermittent hemodialysis may be a feasible treatment strategy 6.