What are the recommendations for IV fluid management in patients with brain injury?

IV Fluid Management in Brain Injury

Isotonic crystalloids, specifically 0.9% sodium chloride (normal saline), are recommended as the first-line IV fluid for patients with brain injury to reduce mortality and improve neurological prognosis. 1, 2

Fluid Selection Principles

Recommended Fluids

• 0.9% Sodium Chloride (Normal Saline): Currently the crystalloid of choice in brain injury as it is isotonic in terms of osmolality 1
• Buffered isotonic solutions: May be considered as alternatives to avoid hyperchloremic metabolic acidosis 1

Fluids to Avoid

• Hypotonic solutions: Ringer's lactate, Ringer's acetate, and other hypotonic solutions should be strictly avoided as they can increase brain water content and worsen cerebral edema 1
• Albumin: Not recommended in brain injury patients, especially those with traumatic brain injury, due to increased mortality 1, 2
• Synthetic colloids: Not recommended in the early management of brain-injured patients 1

Management Strategies by Brain Injury Type

Traumatic Brain Injury

• Maintain euvolemia with isotonic fluids 1
• Avoid permissive hypotension (except in exceptional circumstances) 1
• Target systolic blood pressure to avoid hypotension, which worsens neurological outcomes 1
• Position patient with 20-30° head-up tilt 1

Spontaneous Intracerebral Hemorrhage

• Rapidly reverse anticoagulation while limiting fluid volumes (e.g., using prothrombin complex concentrate, not FFP) 1
• If presenting within 6 hours with systolic BP >150 mmHg, reduce blood pressure if immediate surgery not planned 1
• Maintain euvolemia with isotonic fluids 1

Acute Ischemic Stroke

• Most patients are euvolemic at the time of their event but require IV maintenance fluids due to reduced oral intake 1
• Keep blood pressure <185/110 mmHg in thrombolysis candidates 1
• Avoid hypotension (systolic <140 mmHg could be detrimental) 1
• Use fluids and vasoconstrictors if necessary to raise blood pressure 1

Subarachnoid Hemorrhage

• Maintain euvolemia during transfer 1
• Keep systolic BP <160 mmHg but avoid hypotension (systolic <110 mmHg) 1
• Monitor for development of diabetes insipidus which may cause dehydration 1

Fluid Volume Management

• Cautious use of isotonic fluids to maintain hydration while preventing volume overload 1
• Maintenance fluid requirements: approximately 30 mL per kilogram of body weight daily 2
• Avoid fluid restriction to excess as it may result in hypotension, which can increase ICP and worsen neurological outcomes 3

Management of Blood Pressure

• Hypotension: Correct hypovolemia first, then use small bolus of α-agonist followed by infusion (e.g., metaraminol or noradrenaline via central line) 1
• Hypertension: Manage with increased sedation and small boluses of labetalol 1

Special Considerations

Raised Intracranial Pressure

• For acute management of raised ICP with impending herniation, consider:
  • Mannitol (0.5 g/kg) or hypertonic saline (2 ml/kg of 3% saline) 1, 4
  • Mannitol dosing for reduction of intracranial pressure: 0.25 to 2 g/kg body weight as a 15% to 25% solution administered over 30-60 minutes 4
  • Short-term hyperventilation (PaCO2 not less than 4 kPa) 1

Ventilation Strategy

• Target PaO2 ≥13 kPa and PaCO2 of 4.5-5.0 kPa 1
• Minimum of 5 cmH2O PEEP to prevent atelectasis; PEEP up to 10 cmH2O does not adversely affect cerebral perfusion 1

Monitoring Recommendations

• Regular assessment of neurological status 2
• Fluid balance monitoring to avoid volume overload 2
• Electrolyte monitoring, particularly sodium and chloride 2
• Arterial blood pressure monitoring with transducer at the level of the tragus when patient is positioned head-up 1

Brain injury patients require careful fluid management to maintain adequate cerebral perfusion while preventing cerebral edema. Isotonic solutions, particularly 0.9% sodium chloride, remain the mainstay of therapy, with avoidance of hypotonic fluids and colloids that may worsen outcomes.