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Difficulty: MediumCardiothoracic and Vascular Surgery

A 62-year-old man is evaluated in the intensive care unit due to fever and lethargy. He underwent a coronary artery bypass grafting procedure 5 days ago. Yesterday, he developed a fever, and blood cultures were drawn which are currently growing methicillin-susceptible Staphylococcus aureus (MSSA). Today, his temperature is 39.2°C (102.6°F), blood pressure is 85/50 mm Hg, and heart rate is 128/min. Physical examination reveals a sternal wound with copious purulent discharge and palpable clicking of the sternal halves during respiration. Lung auscultation reveals clear breath sounds bilaterally. Electrocardiogram shows sinus tachycardia. Which of the following is the most appropriate next step in management?

  1. A
    Initiation of intravenous vancomycin and cefepime
  2. B
    Computed tomography of the chest
  3. Immediate surgical exploration and debridementAnswer
  4. D
    Intravenous furosemide therapy
  5. E
    Lower extremity venous duplex ultrasonography

Answer

The most appropriate next step is immediate surgical exploration and debridement.
The correct answer is immediate surgical exploration and debridement. This patient is presenting with acute mediastinitis, a catastrophic deep space infection following median sternotomy. The clinical triad of postoperative fever, purulent sternal drainage, and sternal instability (manifesting as a palpable 'click' or rocking during respiration) is highly specific for this diagnosis. Because the patient is hypotensive and in septic shock, he requires emergent operative intervention. Definitive management includes reopening the incision, aggressively debriding necrotic bone and soft tissue, irrigating the mediastinal space, rewiring the sternum, and tailoring antibiotic therapy to the culture results (e.g., intravenous cefazolin or nafcillin for MSSA).

Step-by-Step Solution

1
Analyze the postoperative timeline and vital signs.
The patient is on postoperative day 5 and is exhibiting signs of septic shock (fever, hypotension, marked tachycardia).
Identifying the severity of the patient's hemodynamic instability is crucial for prioritizing interventions.
2
Evaluate the physical examination findings.
Purulent discharge from the incision and palpable sternal clicking denote deep sternal wound infection (acute mediastinitis) and sternal dehiscence.
Physical signs localize the source of sepsis to the deep surgical space rather than a superficial infection or alternative source like pneumonia.
3
Determine the definitive treatment based on the diagnosis and patient stability.
Immediate surgical exploration, debridement of necrotic tissue, and sternal rewiring are required.
Antibiotics alone cannot penetrate the infected necrotic tissue and hardware; mechanical source control in the operating room is mandatory and life-saving.

Key Concept

Acute mediastinitis after cardiac surgery presents with fever, tachycardia, chest pain, and sternal wound instability. It requires immediate surgical exploration, debridement, and targeted antibiotic therapy.
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Topics

Cardiothoracic and Vascular Surgery

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