What monitoring modality is indicated for a patient with a severe brain injury and abnormal head Computed Tomography (CT) scan, presenting with a low Glasgow Coma Scale (GCS) score?

Intracranial Pressure (ICP) Monitoring is Indicated

This 22-year-old patient with severe traumatic brain injury (GCS 7) and abnormal head CT requires intracranial pressure (ICP) monitoring. 1, 2

Rationale for ICP Monitoring

This patient meets the clear guideline criteria for invasive ICP monitoring:

• GCS ≤8 with abnormal CT scan is the primary indication for ICP monitoring in severe traumatic brain injury 1, 2
• Comatose patients (GCS ≤8) with radiological signs of intracranial pathology require ICP monitoring regardless of whether they undergo neurosurgery 1
• The abnormal head CT in this context indicates risk for intracranial hypertension that requires continuous monitoring 1, 2

Why Other Options Are Inappropriate

• Central venous pressure monitoring (Option B) addresses hemodynamic status but does not monitor the primary pathology—intracranial hypertension—which is the life-threatening concern in severe TBI 3
• Lumbar drain (Option C) is contraindicated in the acute setting of severe TBI with abnormal CT due to risk of herniation from pressure gradients 1
• Train of four (Option D) monitors neuromuscular blockade depth, not brain injury severity or intracranial pressure 3

Technical Considerations for ICP Monitor Placement

• Intraparenchymal probes are preferred over ventricular catheters due to better risk-benefit profile (infection rate 2.5% vs. 10%, hemorrhage rate 0-1% vs. 2-4%) 1, 2
• Catheter placement failure occurs in approximately 10% of cases 1, 2
• ICP monitoring should be initiated urgently to guide therapeutic interventions 1

Management Goals After ICP Monitor Placement

Once ICP monitoring is established, specific therapeutic targets must be maintained:

• Maintain cerebral perfusion pressure (CPP) between 60-70 mmHg after ICP monitor becomes available 3, 1, 2
• CPP <60 mmHg is associated with worse outcomes 1, 2
• CPP >70 mmHg should be avoided routinely as it may worsen vasogenic cerebral edema 1, 2
• Maintain systolic blood pressure >100 mmHg or mean arterial pressure >80 mmHg during all interventions 3, 1

Supporting Evidence for Mortality Benefit

• Propensity score-matched analysis demonstrated that ICP monitoring was associated with an 8.3 percentage point reduction in risk-adjusted mortality in severe TBI patients with abnormal CT scans 4
• Unadjusted mortality rates were significantly lower in the ICP monitoring group (30.7% vs. 45.7%) 4
• Even patients with initially normal CT scans who are comatose remain at substantial risk of developing significant intracranial hypertension, with 7 of 8 patients developing ICP ≥20 mmHg in one study 5

Common Pitfalls to Avoid

• Do not delay ICP monitor placement while waiting for neurosurgical intervention—monitoring is indicated even during extra-cranial hemorrhage control procedures 3
• Do not rely solely on clinical examination in comatose patients, as neurological assessment is unreliable without objective ICP data 1, 2
• Do not use lumbar puncture or lumbar drain in acute severe TBI with abnormal CT due to herniation risk 1

Answer: A. Intracranial pressure (ICP) monitoring