Sternal Wound Infection and Mediastinitis: Early Recognition, Sternal Instability and Wound Care
In short
Deep sternal wound infection (mediastinitis) carries up to 30 percent mortality after heart surgery. Learn early warning signs, sternal clicking, and wound care safety.
In this guide (5 sections)
The Surgical Spectrum of Sternal Wound Complications
Median sternotomy remains the standard surgical approach for coronary artery bypass grafting and valve repairs, involving longitudinal division and wire re-approximation of the sternum.
Sternal wound complications range from superficial incisional surgical site infections (SSIs) involving only the skin and subcutaneous fat, to catastrophic Deep Sternal Wound Infections (DSWI) or acute mediastinitis, involving retrosternal tissues, pericardium, and bone osteomyelitis.
While superficial infections occur in 2 to 5 percent of cases, acute mediastinitis occurs in 1 to 2 percent and carries a devastating hospital mortality rate of 15 to 30 percent if debridement and antibiotic therapy are delayed.
Early Clinical Signs: Superficial SSI vs Deep Mediastinitis
Visiting physiotherapists are often the first clinicians to inspect the sternotomy incision during home-visit rehabilitation, placing them at the front line of early detection.
| Diagnostic Feature | Superficial Incisional SSI | Deep Sternal Wound Infection / Mediastinitis | Immediate Clinical Urgency | |
|---|---|---|---|---|
| 1. Sternal Stability | Firm, rigid sternal union with no motion | Palpable sternal separation, clicking, rocking motion | Sternal non-union confirms deep bone involvement. | |
| 2. Wound Drainage | Serous or slight crusting along incision | Copious purulent, cloudy, or foul-smelling discharge | Wound dehiscence with exposed sternal wire loops. | |
| 3. Pain Characteristics | Localized, mild incisional surface tenderness | Deep, throbbing, unrelenting retrosternal chest pain | Pain disproportionate to post-operative timeline. | |
| 4. Systemic Manifestations | Usually afebrile; normal white blood cell count | High fever, chills, diaphoresis, tachycardia, leukocytosis | Impending systemic sepsis; requires emergency hospital admission. |
High-Risk Patient Profiles in India
In Indian cardiac populations, specific co-morbidities drastically elevate sternal wound breakdown risks: poorly controlled type 2 diabetes mellitus (HbA1c > 8.0%), bilateral internal mammary artery (BIMA) harvesting which devascularizes the sternum, severe obesity (BMI > 30), and chronic obstructive pulmonary disease with paroxysmal coughing.
- The Golden Rule of Sternal Inspection: Carefully examine the entire length of the incision, particularly the inferior pole near the xiphoid process where perspiration and abdominal fat folds accumulate moisture.
- Immediate Activity Suspension: If sternal instability, clicking, or purulent drainage is detected, immediately suspend all upper limb exercises and active push-up transfers.
- Sternal Support Vest or Binder: Fit a rigid or semi-rigid sternal support vest to immobilize the chest wall while emergency surgical transport is arranged.
- Urgent Cardiothoracic Contact: Immediately contact the operating cardiac surgeon with exact photographic and clinical documentation for urgent surgical debridement or vacuum-assisted closure (VAC) therapy.
Indian Climate and Dressing Precautions
In hot, humid Indian months, sweat accumulation beneath surgical dressings fosters rapid bacterial colonization (Staphylococcus aureus and Klebsiella pneumoniae).
Physiotherapists instruct patients and family caregivers to keep the sternal area completely dry, avoid applying home herbal remedies, turmeric pastes, or talcum powders on the incision, and bathe using sponge washes until complete re-epithelialization is confirmed.
Frequently Asked Questions
What should a patient do if they feel their chest bone clicking?
Stop all pushing, pulling, and overhead arm reaching immediately. Hug a heart pillow or cross arms across the chest when standing or coughing, and contact the cardiac surgical team for urgent physical examination and chest X-ray.
Can a superficial sternal infection turn into mediastinitis?
Yes. If superficial cellulitis or skin edge necrosis is neglected, bacterial infection can travel along sternal wire tracks into the mediastinum and bone marrow within days.
How is mediastinitis treated once diagnosed?
Mediastinitis requires emergency surgical revision: reopening the incision, thorough debridement of necrotic bone and tissue, sternal rewiring or pectoral muscle flap reconstruction, and prolonged targeted intravenous antibiotics.
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