D5W Administration Rate for Hypernatremia (Sodium 154 mEq/L)
For a patient with a sodium level of 154 mEq/L, D5W should be administered at a rate calculated to correct the free water deficit over 48 hours, typically resulting in an infusion rate of approximately 75-150 mL/hour for most adults, with the goal of reducing sodium by no more than 8-10 mEq/L per 24 hours. 1, 2
Calculation Method
Calculate the free water deficit using the formula: Water deficit = Total body water × [(Current Na⁺/Desired Na⁺) - 1], where Total body water = 0.6 × weight in kg for adult males (0.5 × weight for females). 2
For example, in a 70 kg male patient:
- Total body water = 0.6 × 70 kg = 42 liters
- Water deficit = 42 × [(154/145) - 1] = 42 × 0.062 = 2.6 liters
- Rate over 48 hours = 2600 mL ÷ 48 hours = 54 mL/hour 2
Critical Correction Rate Guidelines
The maximum safe correction rate is 8-10 mEq/L per 24 hours, which translates to approximately 0.3-0.4 mEq/L per hour. 1, 2 The induced change in serum osmolality must not exceed 3 mOsm/kg H₂O per hour to prevent cerebral edema. 1, 2
More aggressive correction (>0.5 mEq/L per hour) has not been associated with increased mortality or neurologic complications in critically ill adults, but conservative rates remain the standard of care. 3, 4
Why D5W is the Correct Fluid Choice
D5W delivers pure free water because the dextrose is rapidly metabolized upon infusion, leaving only water behind with effectively zero tonicity after metabolism. 1 This provides no renal osmotic load, which is critical for controlled correction without adding sodium burden. 1
Normal saline (0.9% NaCl) must be avoided as it contains 154 mEq/L of sodium with an osmolarity of 308 mOsm/L, which would worsen hypernatremia rather than correct it. 1 Salt-containing solutions paradoxically exacerbate hypernatremia by providing excessive osmotic load that exceeds the patient's ability to excrete it. 1
Monitoring Protocol
- Check serum sodium every 4-6 hours during initial correction to ensure the rate does not exceed safe limits 2
- Adjust D5W rate based on sodium measurements to maintain correction within 8-10 mEq/L per 24 hours 2
- Monitor for signs of fluid overload through hemodynamic assessment, input/output measurements, and clinical examination 2
- Continue monitoring until osmolality normalizes to <300 mOsm/kg 2
Concurrent Electrolyte Management
Once adequate renal function and urine output are confirmed (≥0.5 mL/kg/hour), add 20-30 mEq/L potassium to D5W (using 2/3 KCl and 1/3 KPO4) as hypernatremia often coexists with potassium depletion. 1, 2 Verify serum potassium is <5.5 mEq/L before adding potassium to avoid life-threatening hyperkalemia. 1
Special Clinical Scenarios
In hyperglycemic crises (DKA/HHS) with hypernatremia, switch to D5W with appropriate electrolytes once glucose reaches 250-300 mg/dL to prevent worsening hypernatremia while continuing necessary electrolyte replacement. 5, 1
For patients with nephrogenic diabetes insipidus and hypernatremic dehydration, D5W is mandatory because these patients cannot concentrate urine and will worsen with isotonic fluids. 1
Common Pitfalls to Avoid
- Never use isotonic saline (0.9% NaCl) as primary fluid for hypernatremia correction - it will worsen the condition 1
- Do not correct too rapidly - exceeding 0.5 mEq/L per hour or 12 mEq/L per 24 hours risks cerebral edema 1, 2
- Do not administer potassium without verifying adequate urine output first to prevent hyperkalemia 1
- Avoid lactated Ringer's solution (sodium 130 mEq/L, osmolarity 273 mOsm/L) as it is hypotonic and not appropriate for hypernatremia correction 6