What are the guidelines for managing traumatic brain injuries (TBI) in the Intensive Care Unit (ICU)?

Management of Traumatic Brain Injury in the ICU

The management of severe TBI in the ICU requires immediate neurological assessment, urgent CT imaging, aggressive prevention of secondary brain injury through maintenance of adequate cerebral perfusion pressure (≥60 mmHg), and a tiered approach to controlling intracranial hypertension when present. 1, 2, 3

Initial Assessment and Severity Classification

• Classify TBI severity using the Glasgow Coma Scale (GCS): severe TBI is GCS ≤8, moderate TBI is GCS 9-13, and mild TBI is GCS 14-15. 1, 2, 3
• Perform serial neurological examinations to detect secondary deterioration—the motor component remains the most robust indicator in sedated patients. 1
• Obtain non-contrast CT scan immediately for all moderate to severe TBI patients to identify mass lesions, hemorrhage, midline shift, and signs of elevated intracranial pressure. 1, 2
• Repeat CT scanning is mandatory if there is neurological deterioration (decrease of ≥2 points in GCS) or new focal deficits. 1, 2

Prevention of Secondary Brain Injury

Arterial hypotension and hypoxemia are the most critical preventable causes of secondary brain injury and must be aggressively corrected. 1

Hemodynamic Management

• Maintain mean arterial pressure ≥80 mmHg in severe TBI patients to ensure adequate cerebral perfusion. 1
• Systolic blood pressure <90 mmHg for even 5 minutes significantly increases mortality and poor neurological outcomes. 1
• Never use permissive hypotension strategies in TBI patients, even with concomitant hemorrhagic injuries, as arterial hypotension exacerbates cerebral secondary damage. 3

Oxygenation and Ventilation

• Maintain PaO2 between 60-100 mmHg to prevent cerebral hypoxia. 2, 3, 4
• Control ventilation to maintain PaCO2 between 35-40 mmHg during routine management—avoid both hypercapnia (which increases ICP) and routine hyperventilation (which causes cerebral ischemia). 1, 2, 3, 4
• Monitor end-tidal CO2 continuously, even in the prehospital setting, to guide ventilation. 1
• Temporary hyperventilation (PaCO2 30-35 mmHg) should be reserved only for acute herniation syndromes while awaiting definitive intervention. 4

Intracranial Pressure Monitoring

ICP monitoring is strongly indicated in severe TBI patients (GCS ≤8) with abnormal CT findings, as more than 50% will develop intracranial hypertension. 1, 2, 3, 4

Indications for ICP Monitoring

• Severe TBI with abnormal CT scan showing compressed basal cisterns, midline shift >5mm, or non-evacuated mass lesion. 1, 3
• Severe TBI with normal CT scan if two or more of the following are present: age >40 years, motor posturing, or systolic BP <90 mmHg. 1

ICP Thresholds and Outcomes

• ICP of 20-40 mmHg increases mortality risk 3.95-fold, while ICP >40 mmHg increases mortality risk 6.9-fold. 1, 2, 3, 4
• Compression of basal cisterns on CT is the best radiological predictor of intracranial hypertension. 1
• Maintain cerebral perfusion pressure (CPP) ≥60 mmHg when ICP monitoring is available. 2, 3, 4

Tiered Management of Intracranial Hypertension

First-Tier Interventions

• Elevate head of bed to 20-30 degrees to facilitate venous drainage and minimize edema. 2, 4
• Provide adequate sedation and analgesia—no single agent is superior, but avoid bolus administration of midazolam or opioids that can cause hypotension. 1
• Do not perform daily sedation interruption in TBI patients with signs of elevated ICP, as this may be deleterious to cerebral hemodynamics. 1, 4
• Maintain normothermia and treat fever aggressively. 1

Second-Tier Interventions for Refractory ICP

• Osmotherapy with hypertonic saline or mannitol for persistent intracranial hypertension despite first-tier measures. 2, 3, 4
• Avoid hypo-osmolar fluids that worsen cerebral edema. 3, 4
• External ventricular drainage (EVD) can be performed to drain cerebrospinal fluid, even from small ventricles, and may dramatically reduce ICP with removal of small CSF volumes. 1

Third-Tier Interventions for Refractory ICP

Decompressive craniectomy should be considered for refractory intracranial hypertension in a multidisciplinary discussion, recognizing it reduces mortality but may increase severe disability. 1

• The RESCUE-ICP trial demonstrated that decompressive craniectomy reduced mortality from 48.9% to 26.9% compared to barbiturate coma, but increased severe disability (8.5% vs 2.1%). 1
• Favorable outcomes at 6 months were similar between surgical and medical groups (27.4% vs 26.6%). 1
• Large unilateral temporal craniectomy (>100 cm²) with duraplasty is the preferred technique for focal lesions, with good outcomes (GOS 4-5) in 40-57% versus 28-32% in controls. 1
• Avoid bifrontal craniectomy for diffuse injury—the DECRA study showed worse outcomes (70% poor outcome vs 51% in controls). 1, 4

Neurosurgical Indications

Immediate neurosurgical consultation is required for: 1

• Symptomatic epidural hematoma (any location)
• Acute subdural hematoma with thickness >5mm and midline shift >5mm
• Acute hydrocephalus requiring drainage
• Open displaced skull fracture requiring closure
• Closed displaced skull fracture with brain compression (thickness >5mm, midline shift >5mm)

Coagulation Management

• Maintain platelet count >50,000/mm³ for life-threatening hemorrhage and higher thresholds for neurosurgical interventions. 3, 4
• Keep PT/aPTT <1.5 times normal control during interventions. 3, 4
• Utilize point-of-care coagulation tests (TEG, ROTEM) when available to guide management. 3, 4

Management of Polytrauma with TBI

In patients with both TBI and life-threatening extracranial hemorrhage, prioritize maintaining adequate cerebral perfusion pressure while controlling hemorrhage—never accept hypotension. 3, 4

• Establish protocols for simultaneous multisystem surgery when both neurosurgical intervention and hemorrhage control are urgently needed. 4
• Balance aggressive resuscitation with avoidance of hypo-osmolar fluids that worsen cerebral edema. 3, 4

Adjunctive Monitoring

• Transcranial Doppler (TCD) can estimate cerebral perfusion through pulsatility index calculation—mean flow velocity <28 cm/s or combination of low velocity and high pulsatility index predicts higher mortality. 1
• Consider multimodal monitoring including brain tissue oxygen (PbtO2) monitoring, as there is weak correlation between ICP and brain oxygenation. 5, 6

Critical Pitfalls to Avoid

• Corticosteroids have no role in TBI management and are not recommended for ICP control. 4
• Avoid routine repeat CT scanning in mild TBI with initially normal CT. 2
• Do not use prophylactic hyperventilation—reserve for acute herniation only. 1, 4
• Recognize that hypoxemia combined with hypotension carries 75% mortality. 1