Dextrose 5% in Water (D5W) for DKA with Hypernatremia
Yes, you should use dextrose 5% in water (D5W) instead of dextrose-containing normal saline (DNS) when treating DKA with hypernatremia (serum sodium 150 mEq/L), as the patient requires free water replacement to correct the elevated sodium while maintaining glucose levels during insulin therapy. 1
Fluid Selection Algorithm for DKA with Hypernatremia
Initial Resuscitation (First Hour)
- Start with isotonic saline (0.9% NaCl) at 15-20 ml/kg/h to restore intravascular volume and renal perfusion, regardless of sodium level 1, 2
- This initial bolus is critical for hemodynamic stabilization before addressing the hypernatremia 3
After Initial Stabilization
- Calculate corrected sodium: Add 1.6 mEq/L to measured sodium for every 100 mg/dL glucose above 100 mg/dL 1
- With a measured sodium of 150 mEq/L and typical DKA glucose levels, the corrected sodium will be significantly elevated (potentially >190 mEq/L) 4
- Switch to hypotonic fluid (0.45% NaCl) at 4-14 ml/kg/h if corrected sodium is normal or elevated 1
When Glucose Reaches 250 mg/dL
- Transition to D5W with 0.45% NaCl (dextrose 5% in half-normal saline) 1, 5, 3
- This provides free water to correct hypernatremia while maintaining glucose levels to prevent hypoglycemia during continued insulin therapy 1
- Add 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO4) once renal function is assured 1, 6
Free Water Deficit Calculation
Formula: Free water deficit (L) = 0.6 × body weight (kg) × [(serum Na/140) - 1]
Example Calculation
For a 70 kg patient with serum sodium of 150 mEq/L:
- Free water deficit = 0.6 × 70 × [(150/140) - 1]
- Free water deficit = 42 × 0.071 = 3 liters
Critical Correction Parameters
- Do not exceed 3 mOsm/kg/h change in serum osmolality to prevent cerebral edema and osmotic demyelination 1, 2
- Target sodium correction rate: Maximum 8-10 mEq/L per 24 hours 4
- Correct estimated fluid deficits within 24 hours 1, 2
Why D5W is Superior to DNS in This Context
Free Water Content
- D5W provides pure free water once dextrose is metabolized, directly addressing hypernatremia 4, 5
- DNS (dextrose in normal saline) contains 154 mEq/L sodium, which would worsen hypernatremia 3
- Half-normal saline with dextrose (D5-0.45% NaCl) provides partial free water while maintaining some sodium replacement 5, 3
Dual Treatment Goals
- Maintains glucose levels 200-250 mg/dL during continued insulin infusion to clear ketones 1
- Simultaneously corrects free water deficit from hypernatremia 4, 5
Additional Management Strategies for Severe Hypernatremia
When Standard IV Fluids Are Insufficient
- Consider free water via nasogastric tube if corrected sodium exceeds 190 mEq/L 4
- Desmopressin may be beneficial to reduce ongoing free water losses if diabetes insipidus is contributing 4
- These adjunctive measures were successfully used in a case with corrected sodium >190 mEq/L 4
Critical Monitoring Requirements
Laboratory Monitoring
- Check basic metabolic panel every 2-4 hours during active treatment 1
- Monitor glucose hourly 7
- Calculate corrected sodium with each lab draw 1
- Track serum osmolality to ensure change does not exceed 3 mOsm/kg/h 1, 2
Clinical Monitoring
- Assess mental status frequently, as altered sensorium may persist until hypernatremia corrects 4, 3
- Monitor for signs of cerebral edema (headache, altered consciousness, seizures) 1
- Track fluid input/output and hemodynamic parameters 1
Common Pitfalls to Avoid
Fluid Selection Errors
- Never use isotonic saline throughout treatment when corrected sodium is elevated—this will worsen hypernatremia 1
- Do not switch to dextrose-containing fluids before glucose reaches 250 mg/dL—this may interfere with ketone clearance 1
- Avoid DNS (dextrose in normal saline) in hypernatremia—use D5-0.45% NaCl or D5W instead 5, 3
Correction Rate Errors
- Overcorrecting sodium too rapidly (>10 mEq/L per 24 hours) risks osmotic demyelination syndrome 4, 8
- Treating DKA too aggressively without addressing hypernatremia can worsen neurological outcomes 5