What is the ideal fluid for a stroke patient to maintain a euvolemic state and support cerebral perfusion?

Ideal Fluid for Stroke Patients

Use isotonic 0.9% normal saline as the primary intravenous fluid for all acute stroke patients—it is the only appropriate crystalloid based on current American Heart Association guidelines and should be administered at 30 mL/kg/day to maintain euvolemia and cerebral perfusion. 1, 2

Primary Fluid Selection

• Isotonic 0.9% normal saline is the exclusive recommended crystalloid for acute stroke management based on osmolality considerations and evidence from the American Heart Association 1, 2
• Administer at a maintenance rate of 30 mL/kg body weight per day, which translates to approximately 2100 mL/day for a 70 kg patient 1, 2
• Recent research supports this recommendation, showing that 0.9% NaCl at 100 mL/h for 72 hours reduced early neurological deterioration (3.3% vs 15%, p=0.02) compared to no IV fluids 3
• A 2025 retrospective study found that balanced solutions were associated with increased 90-day disability (OR 6.3,95% CI 2.4-17.0) compared to normal saline in thrombolysis patients, further supporting normal saline as the preferred choice 4

Fluids to Absolutely Avoid

Never use the following hypotonic solutions as they worsen cerebral edema: 1, 2

• 5% dextrose in water (becomes hypotonic after glucose metabolism) 1, 2
• 0.45% saline (hypotonic) 1, 2
• Ringer's lactate (hypotonic when measured by real osmolality) 1, 2
• Ringer's acetate (hypotonic) 1, 2
• Colloids including albumin or synthetic colloids (not recommended in early brain injury management and associated with higher pulmonary edema risk—OR 2.34,95% CI 1.28-4.29) 1, 5

Volume Management Strategy

• For euvolemic patients: Start maintenance IV fluids at 30 mL/kg/day 1, 2
• For hypovolemic patients: Rapidly replace depleted intravascular volume with isotonic saline boluses first, then transition to maintenance rate once euvolemia is restored 1, 2
• Monitor volume status continuously, with extra caution in patients with renal or heart failure who are vulnerable to volume overload 1, 2
• Adequate fluid intake (>2000 mL/day) is associated with better secondary stroke prevention outcomes, with lower primary event rates (12.3% vs 16.8%, p<0.013) and reduced platelet reactivity 6

Blood Pressure Management During Fluid Therapy

Maintain systolic blood pressure >140 mmHg in most stroke patients, particularly those with brainstem involvement 1, 2

• For ischemic stroke NOT receiving thrombolysis: Keep systolic BP >110 mmHg and only treat if systolic BP >220 mmHg or diastolic >105 mmHg 1, 2
• For thrombolysis candidates: Maintain BP <185/110 mmHg before thrombolysis 1, 2
• For patients who received IV thrombolysis: Keep BP <185 mmHg systolic 1
• If hypotension occurs despite fluid resuscitation, use vasopressors (metaraminol boluses or noradrenaline infusion) 2
• Use a transduced arterial line for continuous blood pressure monitoring during the acute phase 1

Glucose Management Alongside Fluid Therapy

• Measure blood glucose immediately upon presentation 1, 2
• Maintain blood glucose between 60-180 mg/dL 1, 2
• Treat hypoglycemia (<60 mg/dL) urgently with 25 mL of 50% dextrose IV push 1, 2
• Treat hyperglycemia (>180 mg/dL) promptly to reduce cerebral edema and hemorrhagic transformation risk 1, 2

Monitoring Requirements

• Track serum sodium and osmolality every 2-4 hours during active management 1, 2
• Avoid exceeding 296 mOsm/kg unless using deliberate osmotherapy 1, 2
• Monitor serum sodium and urea to track hydration status 2
• Continuously assess volume status, particularly in patients with comorbid renal or cardiac disease 1, 2

Special Considerations for Brainstem Strokes

• Maintaining optimal perfusion through euvolemic isotonic fluid management is critical for brainstem strokes, as there is minimal margin for error in this anatomical location 2
• Maintain systolic BP >140 mmHg, which is especially important for brainstem perfusion 1, 2
• Insufficient evidence exists for prophylactic mannitol or hypertonic saline for early CT swelling in brainstem strokes 1, 2
• If osmotherapy is needed, mannitol 0.25-0.50 g/kg IV over 20 minutes every 6 hours can be used as a temporizing measure 2

Common Pitfalls to Avoid

• Do not use balanced crystalloid solutions (like Ringer's lactate) despite their popularity in general critical care, as recent stroke-specific data shows worse outcomes 4
• Avoid the temptation to withhold IV fluids in non-dehydrated patients—a randomized trial was stopped early due to excess neurological deterioration (15%) in the no-IV-fluid group 3
• Do not use colloids thinking they provide better volume expansion—they increase pulmonary edema risk without improving death or dependence outcomes 5