Head Trauma

Essential Emergency Nursing Role in TBI

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in trauma patients, making head trauma one of the highest-yield topics on the Certified Emergency Nurse (CEN) exam.^[1] The emergency nurse plays a critical role in the initial assessment, rapid identification of life-threatening injuries, and prevention of secondary brain injury. Mastery of this content is essential for both clinical practice and exam success.

Pathophysiology and Classification of Head Injuries

Primary vs. Secondary Brain Injury

• Primary Brain Injury: The immediate mechanical damage occurring at the moment of impact (e.g., contusion, laceration, diffuse axonal injury). This is largely irreversible and preventable only through injury prevention efforts.^[3]
• Secondary Brain Injury: The delayed, progressive physiological injury that occurs minutes to days after the initial insult. It is caused by hypoxia, hypotension, cerebral edema, increased intracranial pressure (ICP), and ischemia.^[2] The primary focus of emergency nursing interventions is to prevent secondary brain injury.

Intracranial Dynamics

• Intracranial Pressure (ICP): Normal ICP is 0–10 mmHg. Sustained ICP > 20 mmHg requires immediate intervention.^[2]
• Cerebral Perfusion Pressure (CPP): The pressure needed to perfuse the brain. Calculated as: CPP = MAP – ICP. Target CPP is 60–70 mmHg.^[2]
• Monroe-Kellie Doctrine: The cranial vault is a fixed space containing brain tissue (80%), blood (10%), and CSF (10%). If one component increases, another must compensate, or ICP will rise.^[3]

Types of Head Trauma

Systematic Neurological Assessment and Monitoring

Assessment: Primary and Secondary Survey

1. A – Airway with C-spine Precautions: Assume cervical spine injury in all head trauma patients.^[1]
2. B – Breathing: Maintain oxygenation. Avoid hypercapnia and hypoxia. Target SpO₂ > 90%.^[2]
3. C – Circulation: Maintain SBP > 90 mmHg. Hypotension is a major cause of secondary brain injury.^[2]
4. D – Disability (Neurological Exam): Assess level of consciousness (GCS), pupillary response, and motor function.^[1]
5. E – Exposure: Fully expose the patient while preventing hypothermia.

Glasgow Coma Scale (GCS)

• Eye Opening (1–4): Spontaneous (4), To voice (3), To pain (2), None (1).
• Verbal Response (1–5): Oriented (5), Confused (4), Inappropriate words (3), Incomprehensible sounds (2), None (1).
• Motor Response (1–6): Obeys commands (6), Localizes pain (5), Withdraws from pain (4), Flexion posturing (3), Extension posturing (2), None (1).
• Interpretation: Severe (GCS ≤ 8), Moderate (GCS 9–12), Mild (GCS 13–15). A GCS ≤ 8 usually indicates the need for definitive airway management.^[1]

Herniation Syndromes

• Uncal Herniation: Medial temporal lobe compresses CN III and the brainstem. Classic sign: ipsilateral fixed and dilated pupil with contralateral hemiparesis.^[3]
• Cushing's Triad (Late Sign): Severe hypertension with a widening pulse pressure, bradycardia, and irregular respirations. This is a pre-terminal sign of increasing ICP.^[1]

Diagnostic Tools and Monitoring in Severe TBI

• Diagnostic Imaging: Non-contrast CT scan of the head is the gold standard for acute TBI.^[2]
• Laboratory Tests: Coagulation profile (PT/INR, PTT), platelet count, type and crossmatch, and troponin (cardiac contusion can coexist in high-impact trauma).
• Advanced Neurological Monitoring: ICP monitor, brain tissue oxygen monitoring (PbtO₂), and jugular venous oxygen saturation (SjvO₂) are used in severe TBI.^[2]

ICP Reduction and Seizure Prevention Protocols

ICP Management

• Head of Bed (HOB) Elevation: Elevate HOB to 30 degrees to promote venous drainage.^[2]
• Sedation and Analgesia: Propofol, Etomidate, or Fentanyl to reduce cerebral metabolic demand and prevent elevation of ICP from agitation.
• Hyperosmolar Therapy:
  • Mannitol (0.25–1 g/kg IV): Reduces cerebral edema but causes diuresis, which can lead to hypovolemia. Monitor serum osmolality (target < 320 mOsm/L).^[2]
  • Hypertonic Saline (3%): Effective volume expander that reduces cerebral edema. Less risk of hypovolemia than Mannitol.
• Mild Hyperventilation: Reserved for acute neurological deterioration. Target PaCO₂ of 30–35 mmHg. Excessive hyperventilation causes cerebral vasoconstriction and ischemia.^[1]
• Temperature Management: Prevent hyperthermia. Therapeutic hypothermia (targeted temperature management) may be used to reduce ICP.
• Surgical Interventions: Decompressive craniectomy, burr hole evacuation, or hematoma evacuation.^[2]

Seizure Prophylaxis

• Indication: Severe TBI (GCS < 10) with radiographic evidence of intracranial hemorrhage.^[2]
• Medication: Levetiracetam (Keppra) or Phenytoin (Dilantin) for 7 days. Prolonged prophylaxis is not recommended.

Critical Complications and Safety Priorities in TBI

Systemic Complications

• Diabetes Insipidus (DI): Posterior pituitary dysfunction → polyuria, hypernatremia, low urine specific gravity. Treated with Desmopressin (DDAVP).^[3]
• Syndrome of Inappropriate Antidiuretic Hormone (SIADH): Hyponatremia, concentrated urine. Treated with fluid restriction and careful sodium replacement.^[3]
• Cerebral Salt Wasting (CSW): Similar to SIADH but with hypovolemia. Treated with fluid and sodium replacement.
• Coagulopathy: TBI commonly triggers disseminated intravascular coagulation (DIC). Monitor fibrinogen, D-dimer, platelet count.^[2]

Critical Safety Warnings

• Avoid Hypotension: SBP < 90 mmHg correlates with significantly worse outcomes in TBI. Aggressive fluid resuscitation and blood product administration may be required.^[2]
• Avoid Hypoxia: PaO₂ < 60 mmHg is independently associated with increased mortality in severe TBI.
• Avoid Hypoglycemia/Hyperglycemia: Both worsen neurological outcomes. Maintain tight glucose control (140–180 mg/dL).
• Reverse Anticoagulation: Use 4-factor prothrombin complex concentrate (PCC), Vitamin K, and FFP for warfarin reversal. Use idarucizumab (Praxbind) for dabigatran reversal. Use andexanet alfa (Andexxa) for Factor Xa inhibitors.

CEN Exam Preparation: Essential Distinctions

• Know the CPP formula: CPP = MAP – ICP. The target is > 60 mmHg.^[1]
• Differentiate the hematomas: Epidural = biconvex shape, arterial bleed, lucid interval. Subdural = crescent shape, venous bleed, fluctuating LOC.^[3]
• Recognize Cushing's Triad: This is a late sign of impending herniation. Do not wait for this to intervene.
• “Epi-dural = Eye-dural”: Remember that epidural hematomas often present with an ipsilateral fixed and dilated pupil (CN III compression).
• GCS is not static: Serial GCS assessments are always more valuable than a single score for trending neurological status.
• Common Traps:
  • Do NOT perform a lumbar puncture on a patient with suspected increased ICP (risk of herniation).
  • Do NOT oversedate to the point of hypotension. Maintain SBP > 90 mmHg.
  • Do NOT prophylactically hyperventilate. Use it only as a temporizing measure for acute herniation.

References & Sources

1. Emergency Nurses Association. TNCC: Trauma Nursing Core Course Provider Manual. 9th ed. ENA; 2018. View Source
2. Carney N, Totten AM, O'Reilly C, et al. Guidelines for the Management of Severe Traumatic Brain Injury, 4th Edition. Neurosurgery. 2017;80(1):6-15. doi:10.1227/NEU.0000000000001432
3. Lewis SL, Bucher L, Heitkemper MM, Harding MM. Medical-Surgical Nursing: Assessment and Management of Clinical Problems. 11th ed. Elsevier; 2022. View Source
4. American Heart Association. Advanced Cardiovascular Life Support (ACLS) Provider Manual. 2020. View Source