Traumatic Brain Injury Flashcards

A 50-year-old male involved in a high-speed motor vehicle collision presents with a decreasing level of consciousness. His vital signs are: BP 180/100 mmHg, HR 52 bpm, and his respirations are irregular and shallow. This constellation of signs is known as Cushing's triad and is indicative of what critical condition?

Answer: Increased intracranial pressure with impending cerebral herniation

Cushing's triad consists of hypertension (with a widening pulse pressure), bradycardia, and irregular respirations. [22, 26, 30] This triad is a late, ominous sign of significantly increased intracranial pressure (ICP), which suggests the brain is under severe pressure and brainstem herniation is imminent. [22, 31, 32] The body's response is to increase systolic blood pressure to try to maintain cerebral perfusion, which in turn causes a reflexive bradycardia, while pressure on the brainstem disrupts the respiratory center.

Which of the following is a primary goal in the prehospital management of a traumatic brain injury (TBI) to prevent or mitigate secondary brain injury?

Answer: Preventing episodes of hypoxia and hypotension

Secondary brain injury refers to the damage that occurs after the initial traumatic impact. This secondary damage is often caused by systemic insults, most critically hypoxia and hypotension. [11, 15, 19] A key focus of prehospital TBI care is to maintain adequate oxygenation (SpO2 > 90%) and blood pressure (SBP > 110 mmHg in adults) to ensure the already-injured brain receives sufficient oxygen and perfusion, thereby preventing the initial injury from worsening. [5, 9, 33]

A 33-year-old male is found unconscious after being struck by a vehicle. He opens his eyes only to a sternal rub, makes incomprehensible sounds, and withdraws his arm from painful stimuli. What is his Glasgow Coma Scale (GCS) score?

Answer: GCS 8

The Glasgow Coma Scale (GCS) score is calculated by summing the scores from three categories: Eye Opening, Verbal Response, and Motor Response. [1, 2] In this scenario, the scores are: Eye Opening to Pain (E2), Incomprehensible Sounds (V2), and Withdraws from Pain (M4). The total score is E2 + V2 + M4 = 8. [1, 6] A GCS of 8 or less indicates a severe brain injury. [2, 3, 6]

In an adult patient with a suspected isolated severe traumatic brain injury, prehospital providers should titrate fluid administration to maintain a minimum systolic blood pressure of at least:

Answer: 110 mmHg

Current PHTLS and Brain Trauma Foundation guidelines emphasize the critical importance of avoiding hypotension in TBI patients. A single episode of hypotension can significantly worsen outcomes. For adult patients (ages 15-49 or ≥70), the target is to maintain a systolic blood pressure (SBP) of at least 110 mmHg to ensure adequate cerebral perfusion pressure. [5, 7, 13, 33]

You are assessing a patient who was assaulted and struck in the head. You note their right pupil is 6mm and non-reactive to light, while the left pupil is 3mm and briskly reactive. This finding is most likely caused by:

Answer: Compression of the third cranial (oculomotor) nerve

A unilaterally dilated and non-reactive pupil (a "blown pupil") is a classic and critical sign of compression of the third cranial nerve (the oculomotor nerve). [17, 18, 23] This compression is typically caused by uncal herniation, where rising intracranial pressure on one side of the brain forces the temporal lobe across the tentorium, compressing the nerve on the same side as the injury and dilated pupil. [17, 23]

For a TBI patient WITHOUT signs of active cerebral herniation, what is the recommended target range for end-tidal carbon dioxide (EtCO2) to avoid secondary brain injury?

Answer: 35-45 mmHg

For TBI patients without signs of herniation, the goal is to maintain a normal ventilation status (normocapnia). Both hypocapnia (from hyperventilation) and hypercapnia (from hypoventilation) are harmful. Hypocapnia causes cerebral vasoconstriction and ischemia, while hypercapnia causes vasodilation and can increase ICP. The recommended target EtCO2 range to maintain normocapnia is 35-45 mmHg. [21, 24, 25, 28]