Management of Severe Hypernatremia in Hemorrhagic Stroke: Fluid Selection
Direct Answer
For a 70-kg adult with hemorrhagic stroke and severe hypernatremia (serum sodium ≈160 mmol/L), D5W (5% dextrose in water) is the appropriate initial intravenous fluid, NOT D5 0.3% NaCl. D5 0.3% NaCl contains sodium and will slow the correction of hypernatremia, whereas the priority is to replace the free water deficit with hypotonic fluid 1.
Clinical Rationale
Why D5W is Preferred
D5W is functionally hypotonic because once the glucose is metabolized, it delivers free water without sodium, making it the optimal choice for correcting severe hypernatremia 2, 1.
Severe hypernatremia (≈160 mmol/L) requires free water replacement, not sodium-containing solutions, to correct the hyperosmolar state and prevent further neurological deterioration 1, 3.
The water deficit must be replaced slowly over 48-72 hours to avoid cerebral edema from overly rapid correction; D5W allows precise control of the correction rate 1.
Why D5 0.3% NaCl is Inappropriate
D5 0.3% NaCl contains approximately 51 mmol/L of sodium, which will continue to deliver sodium to a patient who already has severe sodium excess 2.
Adding sodium delays correction of the hypernatremia and prolongs the hyperosmolar state, which is associated with worse neurological outcomes in stroke patients 4, 3.
No guideline recommends sodium-containing hypotonic solutions for severe hypernatremia correction in the acute setting 1.
Treatment Algorithm for Severe Hypernatremia in Hemorrhagic Stroke
Step 1: Assess Volume Status
Determine if the patient is hypovolemic, euvolemic, or hypervolemic through clinical examination (orthostatic vital signs, mucous membranes, skin turgor, jugular venous pressure) 4.
In hemorrhagic stroke with hypernatremia, most patients are hypovolemic due to inadequate water intake from altered consciousness or hypodipsia 3.
Step 2: Calculate Water Deficit
Use the formula: Water deficit (L) = 0.6 × body weight (kg) × [(current Na/140) - 1] 1.
For a 70-kg patient with Na 160 mmol/L: Water deficit = 0.6 × 70 × [(160/140) - 1] = 6 liters 1.
Step 3: Initiate D5W Infusion
Start D5W at a rate that corrects sodium by no more than 0.5 mmol/L per hour (maximum 10-12 mmol/L per 24 hours) to prevent cerebral edema 1.
For this patient: Target correction of 10 mmol/L over 24 hours requires approximately 3 liters of D5W in the first 24 hours, infused at 125 mL/hour 1.
Plan to replace the total water deficit over 48-72 hours, adjusting the rate based on serial sodium measurements every 4-6 hours 1.
Step 4: Avoid Hypotonic Crystalloids in Brain Injury
Do NOT use Ringer's Lactate or other balanced hypotonic solutions in hemorrhagic stroke, as they have osmolarity <280 mOsm/L and can worsen cerebral edema 2, 5.
Isotonic crystalloids (0.9% NaCl) should be avoided for hypernatremia correction because they will not lower sodium levels 2.
Step 5: Monitor for Complications
Check serum sodium every 4-6 hours during active correction to ensure the rate does not exceed 0.5 mmol/L per hour 1.
Watch for signs of cerebral edema (worsening mental status, new focal deficits, seizures) which indicate overly rapid correction 1.
Monitor glucose levels because D5W can cause hyperglycemia, which is detrimental in acute stroke; add insulin if glucose exceeds 180 mg/dL 2.
Critical Pitfalls to Avoid
Pitfall 1: Using Isotonic Saline for Hypernatremia
0.9% NaCl has 154 mmol/L sodium and will NOT correct hypernatremia; it is only appropriate for hypovolemic shock resuscitation before switching to D5W 2.
If the patient is hypotensive from hypovolemia, give a limited bolus of 0.9% NaCl (500-1000 mL) to restore perfusion, then immediately switch to D5W for sodium correction 2.
Pitfall 2: Correcting Sodium Too Rapidly
Rapid correction (>12 mmol/L in 24 hours) causes cerebral edema because brain cells have adapted to the hyperosmolar state by generating idiogenic osmoles 1.
If sodium drops too quickly, STOP D5W temporarily and recheck sodium in 2 hours; consider giving a small bolus of 3% saline (50-100 mL) if symptomatic cerebral edema develops 1.
Pitfall 3: Using Glucose-Containing Fluids Without Monitoring
D5W can cause hyperglycemia, which worsens stroke outcomes through increased lactate production and blood-brain barrier disruption 2.
Check capillary glucose every 2-4 hours and maintain levels between 140-180 mg/dL with insulin as needed 2.
Pitfall 4: Ignoring the Underlying Cause
Hypernatremia in hemorrhagic stroke may be due to hypodipsia (loss of thirst drive from hypothalamic injury), diabetes insipidus, or inadequate water access 3.
Once acute correction is underway, investigate the cause: check urine osmolality and volume; if urine is dilute (osmolality <300 mOsm/kg) despite hypernatremia, consider central diabetes insipidus and desmopressin 3.
Special Considerations for Hemorrhagic Stroke
Intracranial Pressure Management
Avoid hypotonic solutions that worsen cerebral edema, but D5W is acceptable because the correction is slow and controlled 2, 5.
If intracranial hypertension develops, hypertonic saline (3% NaCl) is indicated for acute ICP reduction, but this is a separate indication from hypernatremia correction 6.
Do not confuse hypernatremia correction with ICP management; they require opposite approaches (free water vs. hypertonic saline) 6, 7.
Blood Pressure Management
Maintain adequate cerebral perfusion pressure (CPP 60-70 mmHg) during fluid resuscitation, especially if ICP monitoring is in place 6.
Avoid excessive fluid boluses that could worsen cerebral edema; use vasopressors (norepinephrine) if hypotension persists after modest volume resuscitation 2.
Summary of Fluid Choice
| Clinical Scenario | Fluid of Choice | Rationale | Citation |
|---|---|---|---|
| Severe hypernatremia (Na ≈160) in hemorrhagic stroke | D5W | Provides free water without sodium; corrects hyperosmolarity | [1] |
| Hypovolemic shock with hypernatremia | 0.9% NaCl bolus → switch to D5W | Restore perfusion first, then correct sodium | [2] |
| Intracranial hypertension with hypernatremia | 3% NaCl (for ICP) + D5W (for Na correction) | Separate indications require different fluids | [6] |
| Maintenance fluids during correction | D5W at controlled rate | Avoid sodium-containing fluids | [1] |
D5 0.3% NaCl has no role in the acute management of severe hypernatremia in hemorrhagic stroke 1.