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Difficulty: HardCardiovascular System

An 68-year-old woman is brought to the emergency department by ambulance due to sudden, severe chest pain that began 45 minutes ago. She describes the pain as "tearing" and radiating directly to her interscapular region. En route to the hospital, the patient had a brief episode of syncope. Her medical history includes long-standing hypertension and a 40-pack-year smoking history. Upon arrival, she is lethargic and diaphoretic. Vital signs are temperature 36.8°C (98.2°F), heart rate 122/min, blood pressure 78/50 mm Hg in the right arm and 82/54 mm Hg in the left arm, and respiratory rate 24/min. Pulse oximetry shows 95% on room air. Physical examination reveals distended jugular veins while sitting at a 45-degree angle. Lung fields are clear to auscultation bilaterally. Cardiac auscultation reveals a faint early diastolic decrescendo murmur at the right upper sternal border. The peripheral pulses are weak but symmetric. An electrocardiogram demonstrates sinus tachycardia with low-voltage QRS complexes. Which of the following is the most appropriate next step in management?

  1. Bedside transthoracic echocardiographyAnswer
  2. B
    Computed tomography angiography of the chest
  3. C
    Intravenous labetalol administration
  4. D
    Intravenous furosemide administration
  5. E
    Immediate bedside pericardiocentesis

Answer

Bedside transthoracic echocardiography
The correct answer is bedside transthoracic echocardiography. This patient presents with classic signs of an acute Type A aortic dissection (tearing chest pain, new aortic regurgitation murmur). However, her clinical picture is complicated by obstructive shock, evidenced by profound hypotension, jugular venous distention with clear lungs, syncope, and low-voltage QRS complexes. These findings strongly suggest the dissection has ruptured into the pericardial space, causing acute cardiac tamponade. In a hemodynamically unstable patient, the standard diagnostic test of choice (CT angiography) is unsafe. The next best step is bedside transthoracic echocardiography (TTE), which can rapidly confirm the presence of a pericardial effusion and often visualize the dissection flap, facilitating immediate transfer to the operating room for definitive surgical repair.

Step-by-Step Solution

1
Analyze the primary presentation
Sudden, severe tearing chest pain radiating to the back with a new early diastolic murmur (aortic regurgitation) indicates an acute Type A ascending aortic dissection.
Recognizing the classic clinical syndrome of aortic dissection is the first diagnostic step.
2
Evaluate the patient's hemodynamic status and secondary symptoms
The patient has hypotension, tachycardia, jugular venous distention, clear lungs, syncope, and low-voltage QRS complexes on ECG.
These findings point to obstructive shock caused by cardiac tamponade, a known and highly lethal complication of Type A dissection when the aorta ruptures into the pericardial space.
3
Determine the safest diagnostic approach for an unstable patient
Bedside transthoracic echocardiography is selected to immediately visualize the pericardial effusion and potential intimal flap without leaving the resuscitation bay.
Transporting a hemodynamically unstable patient to a CT scanner is contraindicated.

Key Concept

Management of acute Type A aortic dissection complicated by cardiac tamponade in a hemodynamically unstable patient requires immediate bedside echocardiography.
Estimated Time:1m 15s
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Topics

Cardiovascular System

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