D5 0.45% NaCl Can Be Used for Hypernatremia Correction, But NOT for Hyponatremia Treatment
D5 0.45% NaCl (5% dextrose in half-normal saline) is appropriate for treating hypernatremia in hypovolemic or euvolemic patients, but should NOT be used for hyponatremia correction. This solution provides both free water and some sodium replacement, making it suitable for moderate hypernatremia where gradual correction is needed 1, 2.
For Hypernatremia Treatment: YES, D5 0.45% NaCl Is Appropriate
Primary indication: D5 0.45% NaCl is a hypotonic fluid option for correcting hypernatremia, containing 77 mEq/L of sodium with an osmolarity of approximately 154 mOsm/L 1.
When to Use D5 0.45% NaCl for Hypernatremia:
- Moderate hypernatremia requiring gradual correction with both free water and sodium replacement 1
- Hypovolemic hypernatremia where the patient needs volume repletion alongside free water 1
- Patients with ongoing losses (diarrhea, vomiting) who need replacement of both water and electrolytes 1
Critical Correction Guidelines:
- Maximum correction rate: 0.4 mmol/L/hour or 10 mmol/L per 24 hours to prevent cerebral edema 1
- For severe hypernatremia, consider starting with D5W (pure free water) first, then transition to D5 0.45% NaCl 1
- Avoid isotonic saline (0.9% NaCl) in hypernatremia as it delivers excessive osmotic load and can worsen the condition 1
For Hyponatremia Treatment: NO, D5 0.45% NaCl Should NOT Be Used
D5 0.45% NaCl is hypotonic and will worsen hyponatremia by providing free water that dilutes serum sodium further 1, 2, 3.
Correct Fluid Choices for Hyponatremia Based on Volume Status:
Hypovolemic hyponatremia:
- Use isotonic saline (0.9% NaCl) for volume repletion 1, 2, 3
- Initial infusion rate: 15-20 mL/kg/h, then 4-14 mL/kg/h based on response 1
- Maximum correction: 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 1, 4, 2
Euvolemic hyponatremia (SIADH):
- Fluid restriction to 1 L/day is first-line treatment 1, 4, 2
- Add oral sodium chloride 100 mEq three times daily if no response to fluid restriction 1
- For severe symptoms: 3% hypertonic saline with target correction of 6 mmol/L over 6 hours 1, 4, 2
Hypervolemic hyponatremia (heart failure, cirrhosis):
- Fluid restriction to 1-1.5 L/day for sodium <125 mmol/L 1, 2, 3
- Avoid hypertonic saline unless life-threatening symptoms present 1
- Consider albumin infusion in cirrhotic patients 1
Special Consideration: D5W for Overcorrection Prevention
D5W (5% dextrose in water) WITHOUT saline can be used to prevent or reverse overcorrection of hyponatremia in specific scenarios 1, 5:
- If sodium correction exceeds 8 mmol/L in 24 hours, immediately switch to D5W to relower sodium 1
- In patients on CRRT with severe hyponatremia, calculated amounts of D5W can be infused prefilter to prevent overcorrection 5
- D5W provides pure free water without sodium, allowing controlled decrease in plasma osmolality 1
Critical Safety Points
Never use hypotonic fluids (including D5 0.45% NaCl) for hyponatremia as this worsens the condition by providing excess free water 1, 2, 3. The American Academy of Pediatrics specifically warns against hypotonic fluids like lactated Ringer's in SIADH patients due to risk of hyponatremic encephalopathy 1.
For hypernatremia correction: D5 0.45% NaCl is appropriate but requires careful monitoring to avoid overly rapid correction, which can cause cerebral edema 1, 2. In patients with nephrogenic diabetes insipidus or severe renal concentrating defects, ongoing hypotonic fluid administration is required to match excessive free water losses 1.