From the Guidelines
In the treatment of hypernatremia, D5 half normal saline is generally preferred over plain half normal saline due to its ability to provide free water and glucose, making it more effective at correcting free water deficit and lowering serum sodium levels. The choice between D5 half normal saline and plain half normal saline depends on the patient's volume status, glucose levels, and the severity of hypernatremia 1. D5 half normal saline contains 5% dextrose, which, once metabolized, effectively provides free water in addition to the hypotonic saline solution, making it more suitable for patients with volume depletion. On the other hand, plain 0.45% NaCl is more appropriate for hypernatremic patients who are euvolemic or hypervolemic but still need some sodium replacement.
When administering either fluid, it's crucial to correct sodium levels gradually (typically no faster than 8-10 mEq/L in 24 hours) to prevent cerebral edema and osmotic demyelination syndrome 1. Regular monitoring of serum electrolytes, glucose, and volume status is essential during treatment. The addition of dextrose in D5 half normal saline also provides calories and can help prevent hypoglycemia, which may be beneficial in certain patients, particularly those with poor nutritional status or diabetes. According to the international expert consensus statement on the diagnosis and management of congenital nephrogenic diabetes insipidus, dextrose 5% solutions should not be administered as a bolus due to the risk of rapid decrease in serum sodium, and isotonic fluids are appropriate for acute fluid resuscitation in patients in hypovolaemic shock 1.
Key considerations in the treatment of hypernatremia include:
- Correcting sodium levels gradually to prevent cerebral edema and osmotic demyelination syndrome
- Monitoring serum electrolytes, glucose, and volume status regularly
- Providing free water and glucose to correct free water deficit and prevent hypoglycemia
- Avoiding bolus administration of dextrose 5% solutions
- Using isotonic fluids for acute fluid resuscitation in patients in hypovolaemic shock. As stated in the study 1, a common concern associated with the use of dextrose 5% solutions is a rapid decrease in plasma sodium concentration, which poses the risk of brain oedema, however this concern does not usually apply to patients with NDI.
From the Research
Hypernatremia Treatment
The treatment of hypernatremia involves correcting the sodium imbalance in the body.
- The use of half normal saline (0.45% saline) is a common approach to correct hypernatremia, as it provides free water to help dilute the sodium in the blood 2, 3.
- D5 half normal saline (0.45% saline with 5% dextrose) is also used in some cases, as it provides additional calories and can help to correct hypernatremia more slowly 4.
- However, there is limited evidence to suggest that D5 half normal saline is more effective than half normal saline alone in treating hypernatremia.
Risks of Overcorrection
- Overcorrection of hypernatremia can lead to cerebral edema and other complications, so it is essential to monitor serum sodium levels closely during treatment 5, 6.
- The rate of correction of hypernatremia depends on the severity of the condition and the patient's overall health, with acute symptomatic hypernatremia requiring more rapid correction than chronic hypernatremia 4, 2.
Choice of Fluid
- The choice of fluid for correcting hypernatremia depends on the patient's individual needs and the severity of the condition.
- Half normal saline is often used as a first-line treatment, while D5 half normal saline may be used in patients who require additional calories or have specific nutritional needs 4, 3.