From the Research
The treatment of hypernatremia should focus on addressing the underlying cause while safely lowering serum sodium levels, with the cornerstone of management being administration of hypotonic fluids, typically 0.45% saline or 5% dextrose in water, calculated to lower sodium at a safe rate of 0.5 mEq/L/hour or 10-12 mEq/L/day to prevent cerebral edema, as recommended by the most recent study 1.
Key Considerations
- The formula to calculate free water deficit is: Free water deficit = Total body water × [(measured Na⁺/desired Na⁺) - 1], where total body water is approximately 60% of body weight in men and 50% in women 2.
- For acute hypernatremia (developing within 48 hours), correction can be more rapid, while chronic cases require slower correction to avoid neurological complications 2.
- In cases of diabetes insipidus causing hypernatremia, desmopressin (DDAVP) may be administered at 1-2 μg subcutaneously or intravenously, or 10-20 μg intranasally every 12 hours 2.
- For hypervolemic hypernatremia, loop diuretics like furosemide (20-40 mg IV) may be needed alongside fluid replacement 3.
Monitoring and Adjustments
- Frequent monitoring of serum sodium, fluid status, and neurological signs is essential, with adjustments to the infusion rate based on sodium measurements every 2-4 hours initially 4.
- Addressing the underlying cause, whether it's excessive sodium intake, water loss, or hormonal imbalance, is crucial for successful management and prevention of recurrence 5.
Prevention of Hypernatremia
- High sodium input by 0.9% saline used to dilute drugs and keep catheters open is a modifiable risk factor for ICU-acquired hypernatremia, and dissolving drugs in dextrose 5% may partially prevent potentially harmful sodium overloading and hypernatremia 5.