What is the most appropriate target mean arterial pressure (MAP) value for a patient with severe brain injury?

Target MAP for Severe Traumatic Brain Injury

For a 32-year-old female with severe traumatic brain injury (GCS 8), the most appropriate target MAP is ≥80 mmHg to ensure adequate cerebral perfusion. 1, 2

Rationale for MAP Target in TBI

The management of blood pressure in traumatic brain injury requires careful consideration to maintain adequate cerebral perfusion while avoiding complications. The evidence supports the following approach:

• The World Journal of Emergency Surgery consensus guidelines specifically recommend maintaining MAP > 80 mmHg or SBP > 100 mmHg during interventions for life-threatening hemorrhage or emergency neurosurgery 1
• This recommendation is reinforced by the American College of Critical Care, which recommends maintaining MAP ≥80 mmHg in patients with severe TBI to ensure adequate cerebral perfusion 2
• The patient's current MAP of 75 mmHg is below the recommended target and should be increased

Cerebral Perfusion Pressure (CPP) Considerations

• CPP is calculated as MAP minus intracranial pressure (CPP = MAP - ICP)
• When ICP monitoring becomes available, the guidelines recommend maintaining CPP ≥60 mmHg 1, 2
• To achieve adequate CPP in the setting of potential intracranial hypertension, maintaining a higher MAP is crucial

Implementation Strategy

1. Initial MAP target: Increase MAP from current 75 mmHg to ≥80 mmHg

2. Intervention options:

   • Fluid resuscitation with 0.9% saline (avoid hypotonic solutions)
   • If fluid resuscitation is insufficient, initiate vasopressors (norepinephrine preferred)
   • Continuous arterial pressure monitoring is recommended

3. Avoid:

   • Permissive hypotension (MAP 50-60 mmHg) is contraindicated in TBI patients 2
   • Excessive fluid volumes that could worsen cerebral edema

Additional Management Considerations

• Maintain PaO2 between 60-100 mmHg 1
• Maintain PaCO2 between 35-40 mmHg 1
• Ensure hemoglobin >7 g/dL (higher threshold may be needed in certain patients) 1
• Maintain platelet count >50,000/mm³ (higher values advisable for neurosurgery) 1
• Keep PT/aPTT <1.5 times normal control 1

Common Pitfalls to Avoid

• Inadequate MAP: A MAP target that is too low (such as 50-60 mmHg or ≥65 mmHg) may lead to cerebral ischemia in TBI patients
• Excessive MAP: While higher MAP targets are needed in TBI, excessive elevation (>100 mmHg) may increase the risk of hemorrhage expansion or cerebral edema
• Delayed intervention: Failure to promptly correct hypotension in TBI is associated with increased secondary brain injury and mortality

By maintaining MAP ≥80 mmHg in this patient with severe TBI, you will optimize cerebral perfusion and minimize the risk of secondary brain injury, which directly impacts morbidity, mortality, and long-term quality of life outcomes.