Introduction
Surgical site infections (SSIs) are a major cause of healthcare-associated infections. The CDC defines an SSI as an infection related to an operative procedure occurring at or near the surgical incision within 30 days, or within 90 days if a prosthesis is implanted.
Despite clear evidence and guidelines, prophylactic antibiotic use remains inconsistent — often involving incorrect choice, timing, or duration.
Fundamental Principles of Surgical Prophylaxis
- Goal: prevent SSIs by reducing bacterial burden during surgery.
- Antibiotics must be present in tissue at time of incision.
- Single-dose prophylaxis is typically sufficient.
- Repeat dosing only if surgery >2 drug half-lives or >1500 mL blood loss.
- Choose antibiotic based on expected pathogens.
- High-risk patients (e.g., diabetics, prosthesis insertions) benefit most.
- Good surgical technique is key.
- First-generation cephalosporins are often preferred.
- Cephalosporins generally safe despite reported penicillin allergies.
Timing of Administration
- Administer 30–60 min before incision.
- Vancomycin and fluoroquinolones require earlier infusion (~2 hrs pre-op).
- Delayed administration increases SSI risk 6-fold.
- Anaesthetist should ideally administer in theatre.
Route of Administration
- All antibiotics unless otherwise stated are given IV.
- Oral agents used only for elective colon or high-risk urological procedures.
Indications for Prophylaxis
Prophylaxis is recommended for:
- Clean-contaminated procedures (e.g., controlled GI tract entry).
- Clean surgeries involving prosthetics or high-risk areas (e.g., breast, hernia).
- Not for contaminated or dirty procedures — these require treatment.
Surgical Prophylaxis Summary
Additional Notes
- For MRSA risk: Vancomycin 15 mg/kg IV or Teicoplanin 400–800 mg.
- For beta-lactam allergy:
- Use Clindamycin 900 mg IV ± Gentamicin or Ciprofloxacin depending on procedure.
- Cefazolin 3 g IV for patients >120 kg.
- No prophylaxis for tonsillectomy, adenoidectomy, or clean head/neck procedures.
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