Treatment of Hypernatremia: D5W is Preferred Over D5 1/2 NS
For hypernatremia (elevated sodium), D5W (5% dextrose in water) is the preferred initial treatment, not D5 1/2 NS (dextrose 5% in half normal saline). D5 1/2 NS contains sodium (77 mEq/L) and will not effectively lower serum sodium, whereas D5W provides free water without additional sodium, making it the appropriate choice for correcting hypernatremia 1, 2.
Treatment Algorithm for Hypernatremia
Initial Assessment and Fluid Selection
Determine volume status first - the priority is correcting dehydration before focusing solely on sodium correction 2.
For unstable patients with hypernatremia and severe hypovolemia, administer isotonic saline (0.9% NaCl) initially to restore hemodynamic stability and intravascular volume 2.
Once the patient is euvolemic or hemodynamically stable, switch to hypotonic fluid replacement with D5W to correct the elevated sodium 1, 2.
D5W is the primary fluid for free water replacement in patients with hypernatremia because it provides water without additional sodium 3.
Correction Rate Guidelines
Target correction rate: 10-15 mEq/L per 24 hours for patients with hypernatremia 3.
Maximum change in serum sodium should be 8-12 mEq/L over the first 24 hours in stable patients to decrease the risk of cerebral edema 2.
Correction rates faster than 48-72 hours for severe hypernatremia have been associated with increased risk of pontine myelinolysis 3.
Why D5 1/2 NS is Inappropriate
D5 1/2 NS contains 77 mEq/L of sodium, which will not effectively lower serum sodium and may even worsen hypernatremia 1.
The goal is to provide free water without additional sodium - D5W accomplishes this while D5 1/2 NS does not 1, 4.
In hypervolemic hypernatremia, treatment requires achieving negative sodium and potassium balance in excess of negative water balance, which is accomplished with D5W plus diuretics, not D5 1/2 NS 5.
Special Considerations
Hypervolemic Hypernatremia
Administer D5W with furosemide to achieve negative sodium balance exceeding negative water balance 5.
Monitor for fluid overload while correcting the sodium - the goal is to reduce both total body sodium and excess water 5.
Monitoring During Correction
Check sodium levels every 4-6 hours initially during active correction to ensure the rate does not exceed safe limits 1.
Watch for signs of cerebral edema if correction occurs too rapidly, including altered mental status, seizures, or neurological deterioration 2.
Adjust D5W infusion rate based on serial sodium measurements to maintain the target correction rate of 10-15 mEq/L per 24 hours 3.
Common Pitfalls to Avoid
Using isotonic or hypertonic fluids (including D5 1/2 NS) when the patient is euvolemic - this will not correct hypernatremia and may worsen it 1, 4.
Correcting too rapidly - exceeding 12 mEq/L in 24 hours increases the risk of osmotic demyelination syndrome and cerebral edema 2.
Failing to address the underlying cause - identify and treat diabetes insipidus, impaired thirst mechanism, or excessive sodium administration while correcting the sodium level 1, 4.
Inadequate monitoring - hypernatremia correction requires frequent sodium checks to avoid overcorrection or undercorrection 4.