A patient with a severe traumatic brain injury is undergoing resuscitation.
End-tidal capnography shows a value of 25 mm Hg. Based on current
understanding of cerebral physiology, what is the most immediate risk of this
finding if left uncorrected?
A. Cerebral vasodilation leading to increased intracranial pressure.
B. Cerebral vasoconstriction leading to secondary ischemic injury.
C. Impaired autoregulation leading to systemic hypotension.
D. Increased cerebral metabolic rate leading to hyperthermia.
Correct Answer: B - Cerebral vasoconstriction leading to
secondary ischemic injury.
RATIONALE
Hypocapnia (PaCO2 < 35 mm Hg) induces cerebral vasoconstriction,
which can critically reduce cerebral blood flow and worsen secondary
ischemic injury in the already vulnerable brain. While
hyperventilation was historically used to lower ICP, current guidelines
emphasize avoiding prophylactic hyperventilation. Vasodilation (A)
occurs with hypercapnia, not hypocapnia.
Question 2
A patient arrives after blunt chest trauma with paradoxical chest wall
movement and severe respiratory distress. Which intervention is the immediate
priority according to current trauma resuscitation principles?
A. Application of a chest binder to stabilize the flail segment.
B. Immediate endotracheal intubation and positive pressure ventilation.
C. Administration of intravenous analgesia and observation.
D. Needle decompression of the affected side.
Correct Answer: B - Immediate endotracheal intubation and
positive pressure ventilation.
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, RATIONALE
A flail chest with respiratory distress indicates impending respiratory
failure due to underlying pulmonary contusion and pain. Positive
pressure ventilation provides internal pneumatic stabilization and
addresses hypoxemia. Chest binders (A) are contraindicated as they
restrict ventilation and increase risk of pneumonia.
Question 3
In a patient with suspected neurogenic shock from a high cervical spinal cord
injury, which set of hemodynamic findings is most characteristic and requires
immediate intervention?
A. Hypertension and bradycardia with warm, dry skin.
B. Hypotension and tachycardia with cool, clammy skin.
C. Hypotension and bradycardia with warm, dry skin.
D. Hypertension and tachycardia with cool, clammy skin.
Correct Answer: C - Hypotension and bradycardia with warm,
dry skin.
RATIONALE
Neurogenic shock results from loss of sympathetic tone, causing
vasodilation (hypotension) and unopposed vagal tone (bradycardia),
with warm, dry skin due to peripheral vasodilation. This contrasts with
hypovolemic shock (B), which presents with tachycardia and cool,
clammy skin.
Question 4
A patient with a known history of heart failure presents after a motor vehicle
crash with blunt cardiac injury. Which diagnostic finding is most specific for
cardiac contusion and would alter immediate management?
A. Elevated troponin I level.
B. New-onset atrial fibrillation on ECG.
C. Echocardiographic evidence of regional wall motion abnormality.
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, D. ST-segment elevation on ECG.
Correct Answer: C - Echocardiographic evidence of regional wall
motion abnormality.
RATIONALE
Echocardiography showing regional wall motion abnormalities is the
most specific indicator of myocardial contusion and can guide
hemodynamic support. Troponin elevation (A) is sensitive but not
specific; ECG changes (B, D) may occur but are less specific than
echocardiographic findings.
Question 5
In a trauma patient requiring massive transfusion, which laboratory value is
most critical to monitor for the development of acute traumatic coagulopathy,
and what is the target threshold?
A. Platelet count; target > 100,000/mm³.
B. Ionized calcium; target > 1.1 mmol/L.
C. INR; target < 1.5.
D. Fibrinogen; target > 150 mg/dL.
Correct Answer: B - Ionized calcium; target > 1.1 mmol/L.
RATIONALE
Citrate toxicity from massive transfusion causes hypocalcemia, which
impairs coagulation and cardiac contractility. Ionized calcium must be
monitored and maintained > 1.1 mmol/L. While fibrinogen and
platelets are important, ionized calcium is critical for coagulation
cascade function and is often overlooked.
Question 6
A patient with a traumatic amputation of the right arm is bleeding profusely. A
tourniquet has been applied, but bleeding continues. What is the most
appropriate next step according to current trauma guidelines?
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