FRCA Notes

Infection Post-Cardiac Surgery

This stunted page is included largely for completeness.

Those seeking a curriculum item to hang it on could probably falls use: 'understands & explains the principles of antibiotic prophylaxis in patients with cardiac disease', although I think this largely refers to endocarditis.

Resources

  • The overall rate of infectious complications following cardiac surgery is 5-21%
  • They are associated with higher post-operative mortality and a prolonged duration of stay
  • Account for roughly a quarter of post-operative infections in cardiac surgery
  • Types of surgical site infection include:
    • Saphenous vein graft harvest site infection (1 - 24%)
    • Superficial (down to pectoralis fascia) sternal wound infection (0.5 - 8%)
    • Deep (e.g. mediastinitis) sternal wound infections (1 - 4%)

  • The commonest pathogens are Gram-positive organisms, which account for 80% of infections
    • Staph. aureus (75%)
    • MRSA
    • Staph. epidermidis

Risk factors

Patient risk factor Surgical risk factor
Obesity Emergency surgery
Cardiac disease inc. HF, AF, MI Use of steroids
Smoking Prolonged mechanical ventilation
Diabetes Haemorrhage, transfusion
Advanced age Prolonged perfusion times
Peripheral vascular disease Use of IABP
Renal failure Re-do surgery
Pedicled internal thoracic artery


VAP

  • Respiratory infections account for approximately half of the infectious complications following cardiac surgery
  • Ventilator-associated pneumonia occurs in 5-8% of those undergoing major cardiac surgery
  • It is associated with prolonged ICU and hospital stay, higher mortality and increased healthcare costs

Indwelling devices

  • CVCs remain the main culprit
  • There's a decreasing incidence of CVC-associated infections over time due to implementation of care bundles
  • The presence of CVC-associated bloodstream infection increases risk of surgical site infection (>5x)
  • Typically coag-negative Staph., gram-negative bacteria or S. aureus

  • Arterial lines are rarely infected although ~16% demonstrate bacterial colonisation

  • Patients with urinary catheters have an 8%/day incidence of bacteriuria, but they are less commonly associated with bona fide infection than other indwelling devices

Prevention

  • Standard perioperative methods of preventing infection, although of particular importance in cardiac surgery is:
    • Patient warming and avoidance of hypothermia
    • Glycaemic control
    • Prophylactic antibiotics:
      • Gram-positive cover e.g. penicillin, vancomycin (15mg/kg, esp. if MRSA), third-generation cephalosporin
      • Gram-negative cover e.g. gentamicin, ciprofloxacin
  • Early removal of lines and catheters
  • Implantation of antibiotic-impregnated collagen sponges reduces the rate of surgical site infection

Management of infection

  • Appropriate antibiotics following usual good practice/antimicrobial stewardship principles
  • Prompt removal of indwelling devices if suspect infection
  • Consider VAC dressings or debridement of infected sternal wounds