What is the fluid of choice for initial resuscitation of a patient with suspected brain injury in the emergency department?

Fluid of Choice for Resuscitation in Suspected Brain Injury

0.9% normal saline is the fluid of choice for initial resuscitation in patients with suspected brain injury in the emergency department. 1, 2

Primary Fluid Selection

Use isotonic 0.9% sodium chloride as the first-line crystalloid for all brain-injured patients requiring fluid resuscitation. 1, 2 This is the only commonly available crystalloid that is truly isotonic when measured by real osmolality (mosmol/kg rather than theoretical osmolality), preventing fluid shifts into damaged cerebral tissue. 1

Alternative Isotonic Options

• Balanced isotonic solutions (Plasma-Lyte, Isofundine) with osmolarity 280-310 mOsm/L are acceptable alternatives and may avoid hyperchloremic metabolic acidosis seen with prolonged saline use. 2
• If using 0.9% saline, limit to 1-1.5 L maximum to minimize hyperchloremia and acidosis. 1

Critical Fluids to AVOID

Absolutely avoid hypotonic solutions in any patient with suspected brain injury:

• Ringer's lactate and Ringer's acetate are hypotonic when real osmolality is measured and will increase brain water content and worsen cerebral edema. 1, 2
• Gelatins are also hypotonic and contraindicated. 1
• A multicenter study demonstrated higher mortality in traumatic brain injury patients treated with Ringer's lactate compared to 0.9% saline. 2

Do not use colloids or albumin:

• Synthetic colloids (HES, gelatins) are associated with worse neurological prognosis and should be restricted. 1, 2
• Albumin is specifically contraindicated in traumatic brain injury, with the SAFE study showing increased mortality (relative risk 1.63, p=0.003). 2

Resuscitation Strategy

Volume and Rate

• Reverse hypovolemia aggressively to prevent hypotension, which adversely affects neurological outcome. 1
• Administer fluid boluses of 500-1000 mL rapidly, reassessing after each bolus. 1
• Hypotensive brain-injured patients do not tolerate inadequate resuscitation, and maintaining cerebral perfusion pressure is the top priority. 1, 3

Critical Pitfall: Permissive Hypotension is CONTRAINDICATED

Never use permissive hypotension strategies in brain injury patients. 1, 4 Adequate perfusion pressure is crucial to prevent secondary ischemic injury to the damaged central nervous system. 1 Hypotension should be assumed due to hemorrhage in trauma patients, and bleeding must be controlled before transfer. 1

Blood Pressure Targets

• Maintain systolic blood pressure >110 mmHg to ensure adequate cerebral perfusion. 4
• If hypotension persists after 2-3 L of fluid, initiate vasopressors (norepinephrine) targeting mean arterial pressure ≥65 mmHg. 5

Maintenance Fluid Management

Once euvolemia is achieved, use cautious isotonic fluid administration to maintain hydration while preventing volume overload. 1, 2 Both hypovolemia and hypervolemia are detrimental in brain injury—the CENTER-TBI study showed higher mortality with positive fluid balance. 2

Special Considerations

Hypertonic Saline

• Hypertonic saline is NOT recommended for initial resuscitation in the emergency department. 6, 3
• Meta-analysis of prehospital studies showed no survival benefit for hypertonic saline versus isotonic crystalloids (RR 1.04,95% CI 0.97-1.12). 6
• May be considered later for mannitol-refractory intracranial hypertension, but this is not an initial resuscitation decision. 7

Monitoring During Resuscitation

• Assess response by blood pressure improvement, heart rate reduction, mental status, and urine output. 5
• Monitor for signs of fluid overload (pulmonary rales, respiratory distress, rising JVP). 5
• Watch for hyperchloremic metabolic acidosis with prolonged 0.9% saline use. 2