From the Guidelines
Hypertonic saline should be administered when serum sodium levels fall below 120 mEq/L, especially in cases of severe symptomatic hyponatremia, as recommended by the most recent and highest quality study 1.
Key Considerations
- The use of hypertonic saline is reserved for short-term treatment of patients with symptomatic or severe hyponatremia or those with imminent liver transplant (LT) 1.
- For patients with neurological symptoms such as seizures or altered mental status, treatment should begin immediately regardless of the exact sodium level.
- The standard approach involves 3% hypertonic saline, administered as a 100-150 mL bolus over 10-20 minutes, which can be repeated if symptoms persist.
- During treatment, sodium levels should be corrected slowly, typically not exceeding 8 mEq/L per 24-hour period to ameliorate the risk of osmotic demyelination syndrome (ODS) 1.
Monitoring and Correction
- Frequent monitoring of serum sodium (every 2-4 hours initially) is essential to guide therapy.
- The goal of hypertonic saline administration is to rapidly raise sodium levels just enough to resolve life-threatening symptoms while avoiding overly rapid correction that could cause permanent neurological damage.
- Severe hyponatremia (<120 mEq/L) at the time of LT increases the risk of ODS with LT, and multidisciplinary coordinated care may mitigate this risk 1.
From the Research
Sodium Level Threshold for Hypertonic Saline Administration
The sodium level threshold for administering hypertonic saline in patients with hyponatremia is a critical consideration in clinical practice. According to the available evidence:
- Severe hyponatremia is generally defined as a serum sodium concentration of less than 125 mEq/L 2, 3.
- Patients with a sodium concentration of less than 125 mEq/L and severe symptoms, such as delirium, confusion, impaired consciousness, ataxia, seizures, or cardiorespiratory distress, require emergency infusions with 3% hypertonic saline 2, 3.
- The goal of treatment is to increase the serum sodium level by 4-6 mEq/L within 1-2 hours, but not to exceed a correction limit of 10 mEq/L within the first 24 hours 3.
- Symptomatic hyponatremia must be treated promptly with 3% hypertonic saline to increase the serum sodium by 1-2 mmol/L per hour until symptoms abate, or a total magnitude of correction of 12 mmol/L in 24 hours or 18 mmol/L in 48 hours is achieved 4.
Key Considerations
Some key considerations when administering hypertonic saline for hyponatremia include:
- The rate of correction, with overly rapid correction potentially causing osmotic demyelination syndrome 2, 5.
- The underlying cause of the hyponatremia, with treatment tailored to the specific etiology 2, 3, 4, 6.
- The patient's fluid volume status, with hypovolemic, euvolemic, and hypervolemic hyponatremia requiring different treatment approaches 2, 3, 4, 6.