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Difficulty: HardCardiothoracic and Vascular Surgery

A 72-year-old man is evaluated in the surgical step-down unit for sudden-onset shortness of breath, confusion, and decreased urine output. He underwent a coronary artery bypass grafting and aortic valve replacement 6 days ago. His medical history includes chronic obstructive pulmonary disease and ischemic cardiomyopathy with a left ventricular ejection fraction of 35%. His temperature is 37.9°C (100.2°F), blood pressure is 80/55 mm Hg, pulse is 118/min, and respirations are 26/min. Pulse oximetry shows 91% on room air. Physical examination reveals distant heart sounds and distended jugular veins up to the angle of the mandible. The lungs have decreased breath sounds at the bases with scattered end-expiratory wheezes. His extremities are cool and clammy. Chest radiography shows an enlarged cardiac silhouette and small bilateral pleural effusions, unchanged from postoperative day 2. An electrocardiogram demonstrates sinus tachycardia and low-voltage QRS complexes. Arterial blood gas analysis on room air shows:

pH: 7.28
pCO2: 32 mm Hg
pO2: 60 mm Hg
Bicarbonate: 15 mEq/L

Which of the following is the most appropriate next step in management of this patient?

  1. Transthoracic echocardiographyAnswer
  2. B
    Intravenous furosemide and nitroglycerin
  3. C
    Computed tomography angiography of the chest
  4. D
    Intravenous vancomycin and cefepime
  5. E
    Administration of intravenous sodium bicarbonate

Answer

Transthoracic echocardiography
The correct answer is Transthoracic echocardiography. This patient is presenting with obstructive shock due to acute cardiac tamponade, a well-known complication in the days following cardiothoracic surgery. The diagnosis is strongly suggested by his hypotension, elevated jugular venous pressure, distant heart sounds (Beck's triad), and low-voltage QRS complexes on ECG. In hemodynamically unstable patients with suspected tamponade, immediate bedside echocardiography is the most appropriate next step to confirm the presence of pericardial fluid and right-sided chamber collapse before proceeding with emergent pericardiocentesis or surgical re-exploration.

Step-by-Step Solution

1
Analyze the patient's hemodynamic status and vital signs.
The patient is in shock (blood pressure 80/55 mm Hg, tachycardia, cool/clammy extremities, altered mentation, oliguria).
Identifying the presence of shock prioritizes immediate life-saving diagnostic and therapeutic steps.
2
Identify the specific etiology of shock based on physical examination and diagnostic findings.
The presence of Beck's triad (hypotension, jugular venous distention, distant heart sounds) along with low-voltage QRS complexes in a recent postoperative cardiac surgery patient strongly indicates cardiac tamponade (obstructive shock).
Differentiating obstructive shock from cardiogenic shock (heart failure) or distributive shock (sepsis) is critical because treatments are inherently contradictory (e.g., diuretics worsen tamponade).
3
Determine the safest and most effective next step to confirm the diagnosis.
A bedside transthoracic echocardiogram should be performed immediately.
Echocardiography is the gold standard for diagnosing cardiac tamponade, visualizing the pericardial effusion and the resulting diastolic collapse of the right atrium and right ventricle without requiring the unstable patient to leave the unit.

Key Concept

Recognition and acute management of postoperative cardiac tamponade
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Topics

Cardiothoracic and Vascular Surgery

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