PHTLS - Prehospital Trauma Life Support Prehospital Trauma Life Support Traumatic Brain Injury 1 — Questions and Answers
Question 1: Under what specific circumstance does PHTLS permit controlled hyperventilation in a TBI patient?
- Routinely for any patient with a GCS below 9
- Only when clinical signs of herniation are present, such as posturing or a blown pupil (Correct answer)
- Whenever SpO2 falls below 92% despite supplemental oxygen
- When systolic blood pressure exceeds 180 mmHg
Correct answer: Only when clinical signs of herniation are present, such as posturing or a blown pupil
PHTLS restricts controlled hyperventilation to a temporizing measure when herniation is suspected (e.g., posturing, fixed dilated pupil, Cushing's triad). Routine hyperventilation causes cerebral vasoconstriction that worsens ischemia in injured brain tissue.
Question 2: What minimum SpO2 value should prehospital providers maintain in a patient with suspected TBI according to PHTLS?
- 88%
- 90%
- 94% (Correct answer)
- 98%
Correct answer: 94%
PHTLS requires SpO2 of 94% or greater in TBI patients. Hypoxia is one of the most damaging causes of secondary brain injury, reducing oxygen delivery to already vulnerable neurons and worsening outcomes.
Question 3: Which set of findings constitutes Cushing's triad and what does it signal in a TBI patient?
- Tachycardia, hypotension, and bradypnea — indicating spinal shock
- Hypertension, bradycardia, and irregular respirations — indicating severely elevated ICP with impending herniation (Correct answer)
- Hypotension, tachycardia, and tachypnea — indicating hemorrhagic shock
- Fever, hypertension, and tachycardia — indicating neurogenic fever
Correct answer: Hypertension, bradycardia, and irregular respirations — indicating severely elevated ICP with impending herniation
Cushing's triad (rising blood pressure, reflex bradycardia, and irregular breathing) is a late, ominous sign that ICP has risen to a level that is compressing the brainstem. It demands immediate airway and hemodynamic intervention.
Question 4: What is the primary mechanism responsible for secondary brain injury following the initial TBI impact?
- Direct axonal shearing forces generated at the moment of impact
- Hypoxia and hypotension causing ischemia in vulnerable, already-injured brain tissue (Correct answer)
- Skull fracture fragments continuing to lacerate brain parenchyma after the event
- Immediate cerebral edema that forms within seconds of the primary injury
Correct answer: Hypoxia and hypotension causing ischemia in vulnerable, already-injured brain tissue
Secondary brain injury develops after the initial trauma and is predominantly driven by hypoxia and hypotension, both of which reduce oxygen delivery to neurons teetering on the edge of viability. Preventing these two insults is the core focus of PHTLS TBI management.
Question 5: A TBI patient has a GCS of 7 and cannot protect their airway. What is the PHTLS-recommended airway approach and ventilation rate for an adult?
- Recovery position with high-flow oxygen via non-rebreather mask only
- Bag-valve-mask ventilation at 20 breaths per minute to ensure adequate oxygenation
- Advanced airway placement with ventilation at approximately 10 breaths per minute (Correct answer)
- Nasopharyngeal airway insertion and allow the patient to breathe spontaneously
Correct answer: Advanced airway placement with ventilation at approximately 10 breaths per minute
A GCS of 7 indicates the patient cannot protect the airway, necessitating an advanced airway (endotracheal tube or supraglottic device). The normal adult ventilation rate of ~10 breaths/min prevents inadvertent hyperventilation, which would cause harmful cerebral vasoconstriction.
Question 6: What does the 'talk and die' phenomenon describe in the context of TBI, and why is it clinically important?
- Patients who are verbal at the scene never develop significant intracranial pathology
- A patient may have a lucid interval after TBI and then deteriorate rapidly as an intracranial hematoma expands (Correct answer)
- Verbal responsiveness on scene confirms that no airway intervention will be required during transport
- A GCS verbal score of 5 reliably predicts survival from severe head trauma
Correct answer: A patient may have a lucid interval after TBI and then deteriorate rapidly as an intracranial hematoma expands
The 'talk and die' pattern — classically associated with epidural hematoma — describes a lucid interval after injury followed by sudden neurological collapse as an expanding intracranial hemorrhage compresses the brain. It underscores that an initially alert TBI patient must still be monitored closely and transported rapidly.
PHTLS - Prehospital Trauma Life Support Prehospital Trauma Life Support Traumatic Brain Injury 1
Under what specific circumstance does PHTLS permit controlled hyperventilation in a TBI patient?