From the Guidelines
Normal saline (0.9% NaCl) is the preferred choice for treating hypovolemic hyponatremia, whereas hypertonic saline (3% NaCl) is recommended for symptomatic or severe hyponatremia. According to the guidelines on the management of ascites in cirrhosis 1, hypovolaemic hyponatraemia during diuretic therapy should be managed by discontinuation of diuretics and expansion of plasma volume with normal saline. Lactated Ringer's solution is generally not recommended for hyponatremia treatment because its sodium concentration (130 mEq/L) is lower than normal plasma sodium levels (135-145 mEq/L), which could potentially worsen hyponatremia 1.
When administering hypertonic saline, the rate of sodium correction should not exceed 8-10 mEq/L in 24 hours (or 6 mEq/L in high-risk patients) to prevent osmotic demyelination syndrome 1. For symptomatic severe hyponatremia, an initial bolus of 100-150 mL of 3% saline over 10-20 minutes may be given, followed by a slower infusion with frequent monitoring of serum sodium levels. The underlying cause of hyponatremia should also be identified and addressed as part of the treatment plan.
Key considerations in the management of hyponatremia include:
- Identifying and addressing the underlying cause of hyponatremia
- Monitoring serum sodium levels closely during treatment
- Avoiding rapid correction of serum sodium to prevent osmotic demyelination syndrome
- Using hypertonic saline for symptomatic or severe hyponatremia, and normal saline for hypovolemic hyponatremia
- Restricting water intake in patients with severe hyponatremia, as recommended by the American Association for the Study of Liver Diseases 1.
From the Research
Treatment of Hyponatremia
The treatment of hyponatremia depends on the underlying cause and severity of the condition.
- For patients with hyponatremia associated with moderate or severe symptoms, hypertonic saline is recommended to prevent neurological complications 2.
- In cases of severe chronic hyponatremia, the rate of correction should not exceed 1 mM/l/h and the corrected serum sodium concentration should not be higher than 130 mM/l 3.
- Hypertonic saline should be used with caution, as there is a risk of inadvertent overcorrection, especially in patients with unrecognized hypovolemia or other reversible causes of water retention 4.
Choice of Fluid
The choice of fluid for initial fluid resuscitation in patients with sepsis-induced hypotension may also impact the treatment of hyponatremia.
- A study comparing lactated Ringer's solution with 0.9% saline for initial fluid resuscitation in sepsis-induced hypotension found that lactated Ringer's solution was associated with improved survival and more hospital-free days 5.
- However, there is limited evidence directly comparing normal saline (NS) and lactated Ringer's (LR) solution for the treatment of hyponatremia.
- A study comparing hypertonic saline with lactated Ringer's solution in children with severe head injury found that hypertonic saline was superior in reducing intracranial pressure and improving outcomes 6.
Key Considerations
When treating hyponatremia, it is essential to consider the following: