Surgical Antibiotic Prophylaxis (SAP)

Clinical assessment

Assessment of procedure type (Clean, Clean-contaminated, Contaminated, Dirty) and patient risk factors to determine need for prophylaxis.

Investigations

• Not applicable for decision, but pre-op screening (e.g., MRSA) may guide choice in some settings.

Diagnostic criteria

Indication based on balancing predicted SSI risk reduction against risks of antibiotic use (resistance, side effects).

Non-pharmacological management

• Optimize patient condition pre-operatively (glucose control, nutrition, smoking cessation).
• Aseptic surgical technique.
• Maintain normothermia.
• Appropriate skin preparation.
• Minimize operating room traffic.

Pharmacological treatment

• General Principles:
• - Timing: Administer IV antibiotic within 60 minutes BEFORE skin incision (allow time for tissue levels). Vancomycin/Fluoroquinolones need longer infusion (start 60-120 min before).
• - Choice: Select antibiotic based on likely pathogens for the specific procedure site and local resistance patterns. Often targets Staph aureus and common flora.
• - Common choices: Cefazolin (1st/2nd gen cephalosporin), Cefuroxime. Alternatives for beta-lactam allergy: Clindamycin or Vancomycin.
• - Add cover for Gram-negatives/anaerobes for colorectal/GU/some Gynae procedures (e.g., add Metronidazole or use broader agent like Cefoxitin, Amp/Sulbactam, Ertapenem).
• - Dose: Use appropriate weight-based or standard adult dose.
• - Duration: Usually a SINGLE pre-operative dose is sufficient. Re-dosing intra-operatively ONLY if procedure is very long (>2 half-lives of drug, e.g., >3-4h for Cefazolin) or major blood loss occurs.
• - Post-operative Prophylaxis: Generally NOT recommended or needed (increases resistance/cost/side effects). Antibiotics given post-op are usually for TREATMENT of established infection, not prophylaxis.
• Indications based on Wound Class:
• - Clean Wounds: Prophylaxis generally NOT needed, UNLESS high-risk procedure (prosthetic implant - joint, valve, mesh; cardiac surgery, neurosurgery) OR high-risk patient (immunocompromised).
• - Clean-Contaminated Wounds: (Entering resp, GI, GU, Gynae tract under controlled conditions without unusual contamination) - Prophylaxis usually INDICATED.
• - Contaminated Wounds: (Open fresh trauma, major sterile technique break, gross spillage from GI tract, infected bile/urine encountered) - Considered TREATMENT, not just prophylaxis. Broader spectrum, may need therapeutic course post-op.
• - Dirty/Infected Wounds: (Old trauma, existing infection, perforated viscus) - Requires therapeutic course of antibiotics, NOT prophylaxis.

Monitoring

• Monitor for SSIs post-operatively.