Perioperative Antibiotic Prophylaxis

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PAP Basics - Germ Warfare Intro

  • Definition: Perioperative Antibiotic Prophylaxis (PAP): Antibiotics given immediately before, during, or after surgery.
  • Primary Goal: Prevent Surgical Site Infections (SSIs); not for treating active infections.
  • Mechanism: Ensure bactericidal antibiotic levels in tissues by incision time.
  • Critical Timing:
    • Standard agents: Within 60 min pre-incision.
    • Vancomycin/Fluoroquinolones: Within 120 min pre-incision.
  • Duration: Typically single dose; may extend up to 24 hrs post-operatively.
  • Selection: Guided by procedure-specific pathogens & patient allergy profile.

⭐ PAP aims to reduce microbial burden at the surgical site, enabling host defenses to prevent SSI.

Wound Classification - Infection Risk Radar

Wound ClassDescriptionInfection RiskPAP Indication
CleanNon-traumatic, no inflammation; aseptic technique maintained. Respiratory, GI, GU tracts not entered.1-2%Usually not needed; consider for high-risk cases.
Clean-ContaminatedGI/GU/respiratory tract entered under controlled conditions; no unusual contamination. Minor technique break.5-15%Indicated.
ContaminatedOpen, fresh, accidental wounds; major break in technique; gross spillage from GI tract; acute non-purulent inflammation.15-30%Indicated.
Dirty/InfectedOld traumatic wounds, devitalized tissue; existing clinical infection (e.g., pus); perforated viscera.>30%Indicated (therapeutic, not just prophylactic).

Antibiotic Selection - Bug-Drug Matchmaking

Procedure CategoryCommon PathogensPreferred ProphylaxisAlternatives (Allergy/MRSA)
Clean Procedures (Cardiac, Ortho, Neuro, Vascular)S. aureus, CoNS Staphylococcus Aureus bacteria iconCefazolin 2g IV (3g if >120kg)Vancomycin 15mg/kg IV or Clindamycin 600-900mg IV
Clean-Contaminated
- GI (Upper, Biliary)Skin flora, GNRs, EnterococciCefazolin 2g IVClinda + (Gent or FQ)
- Colorectal / AppendectomyGNRs, Anaerobes Shapes of Bacteria Bacteria icon for antibiotic prophylaxisCefoxitin 2g IV / Cefotetan 2g IV
OR Ertapenem 1g IV
OR Amp/Sulbactam 3g IV
Metro + (CTX or FQ or Gent)
- Hysterectomy (Vag/Abd)Skin, Vaginal, Enteric floraCefazolin 2g IVClinda + (Gent or FQ)
- GU (entering tract)Enteric GNRsCiprofloxacin 400mg IV / TMP-SMXGentamicin

Administration & Special Populations - Clock & Complications

  • Administration Timing & Redosing (The Clock):
    • Infuse antibiotics:
      • Most: within 60 minutes before incision.
      • Vancomycin, Fluoroquinolones: within 120 minutes (longer infusion).
    • Intraoperative Redosing:
      • Procedure >2 drug half-lives (e.g., Cefazolin q4h).
      • Major blood loss (>1500 mL or >20 mL/kg).
  • Duration of Prophylaxis:
    • Typically single dose.
    • ⭐ > Discontinue within 24 hours post-surgery, even with indwelling drains.
    • Cardiothoracic surgery: may extend up to 48 hours.
  • Adjustments for Special Populations:
    • Obesity (BMI >30): ↑ dose (e.g., Cefazolin 2g for >80kg; 3g for >120kg).
    • Renal Impairment (CrCl <50mL/min): Adjust dose/interval for Cefazolin, Vancomycin.
    • Known MRSA Colonization/High Risk: Add Vancomycin to standard regimen.
  • Managing Beta-Lactam Allergies:
  • Potential Complications:
    • Allergic reactions (mild rash to anaphylaxis).
    • Antibiotic-associated diarrhea, Clostridioides difficile infection.
    • Emergence of antimicrobial resistance.
    • Surgical Site Infection (SSI) despite prophylaxis.

High‑Yield Points - ⚡ Biggest Takeaways

  • Timing is crucial: administer within 60 minutes prior to incision (120 minutes for vancomycin/fluoroquinolones).
  • Cefazolin is the most common prophylactic antibiotic for clean/clean-contaminated surgeries.
  • For beta-lactam allergy or MRSA risk, use vancomycin or clindamycin.
  • A single dose is generally sufficient; re-dose for surgeries >2 drug half-lives or major blood loss.
  • Post-operative antibiotics are not routinely indicated for prophylaxis.
  • Dirty/infected wounds require therapeutic antibiotics, not just prophylaxis_._

Practice Questions: Perioperative Antibiotic Prophylaxis

Test your understanding with these related questions

In postoperative intensive care unit, five patients developed postoperative wound infection on the same day. The best method to prevent cross infection occurring in other patients in the same ward is to:

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Flashcards: Perioperative Antibiotic Prophylaxis

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Alcoholic patients with cirrhosis require a _____ month abstinence before being considered for liver transplant

TAP TO REVEAL ANSWER

Alcoholic patients with cirrhosis require a _____ month abstinence before being considered for liver transplant

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