Surgical Wounds and Antimicrobial prophylaxis

1. Surgical Wounds and Antimicrobial prophylaxis Philip G. Murphy Consultant in Medical Microbiology, AMNCH Clinical Professor, TCD philip.murphy@amnch.ie (ext 3919)

2. Humanity has three great enemies: Fever, famine and war, Of these by far the greatest, By far the most terrible is fever. William Osler 1849-1919

3. History • 1862 Pasteur • 1865 Lister • 1866 Semmelweiss • 1940’s Antibiotic era • Today ?? Postantibiotic era <2 %

4. Public Health Importance of Surgical Site Infections • In U.S., >40 million inpatient surgical procedures each year; 2-5% complicated by surgical site infection • SSIs second most common nosocomial infection (24% of all nosocomial infections) • Prolong hospital stay by 7.4 days • Cost $400-$2,600 per infection (TOTAL: $130-$845 million/year)

5. Source of SSI Pathogens • Endogenous flora of the patient • Operating theater environment • Hospital personnel (MDs/RNs/staff) • Seeding of the operative site from distant focus of infection (prosthetic device, implants)

6. Pathogenesis • Skin flora into wound margins / deep sites • Surgical risk factors eg haematoma, ischaemia, prostheses • Host factors, eg diabetes, steroid Rx • Bacterial factors eg., innoculum, virulence eg GNB + anerobes

7. Diagnosis Fever CRP, ESR, WBC Rubour,(Redness) Dolour, (pain, tenderness) Tumour, (swelling)

8. SSI- Wound classifications • Superficial • Deep • Organ/space

9. Merely a flesh wound

10. Wound healing - stages

11. Primary Healing – Occurring when a wound is closed within a few hours of its creation. Wound edges are surgically or mechanically approximated, and collagen metabolism provides long-term strength. • Delayed Primary Healing – Occurs when a poorly delineated wound is left open to protect against wound infection. The open woundallows for the natural host defense to debride the wound before closure. • SecondaryHealing – Occurs when an open full thickness wound is allowed toclose by wound contraction and epithelialization. • Healing of Partial-Thickness Wounds – Occurs when a partial-thicknesswound is closed primarily by epithelialization. This wound healing involves the superficial portion of the dermis. There is minimal collagen deposition, and an absence of wound contraction.

13. Age Obesity Diabetes Malnutrition Prolonged preoperative stay Infection at remote site Systemic steroid use Immunotherapy Nicotine use Hair removal/Shaving Duration of surgery Surgical technique Haematoma Necrosis Foreign body Presence of drains Inappropriate use of antimicrobial prophylaxis SSI Risk Factors

14. SSI - Classification and Rates • Clean - no intrinsic bacterial flora <2 % • Clean / contaminated - involving a viscus with bacterial flora 8% • Contaminated - involves spillage of viscus content 15% • Dirty - involves inflammation or viscus perforation 40% <30 days post-op 1 year orthopaedics

15. Bacterial aetiology CDC – NNIS data

16. Staphylococcus aureus 17% Staphylococcus aureus 20% Pseudomonas aeruginosa 8% Pseudomonas aeruginosa 8% Enterococcus spp. 8% Enterococcus spp. 12% Escherichia coli 10% Escherichia coli 8% Coagulase neg. staphylococci 12% Coagulase neg. staphylococci 14% Microbiology of SSIs 1986-1989 (N=16,727) 1990-1996 (N=17,671)

17. Bacteriology • UK Survey: Staphylococci 40-45 % GNB 40-45 % other aerobes 6 % anaerobes 5 % • Specific surgery types have different rates:

18. Bacteriology • Staphylococci and skin flora in bone and cardiac surgery • GNB in biliary surgery • Streptococci and anaerobes in gynae • Colonic surgery: aerobic GNB 10 6-7 / G Enterococci 10 5-6 / G Bacteroides 10 9-11 /G anaerobic cocci 10 10 / G

19. PREVENTION IS PRIMARY! Protect patients…protect healthcare personnel… promote quality healthcare!

20. Theatre environment

21. Theatre design • Min staff • 20-30 air changes/ hr • Plenum flow • Positive pressure • HEPA filtration • Asepsis: hand hygiene • Clothing • THINK HYGIENE

23. Prevention 1 • Pre-op: avoid antibiotics, minimise hospitalisation, treat remote infection, decolonise Staph, avoid/delay shaving, chlorhexidine bath, resolve obesity/malnutrition, control smoking or diabetes • Intra-op: Skin prep, aseptic technique, filtered air, antibiotic wound irrigation, isolate clean / dirty surgical fields - trays, reglove & new instruments from donor vein to CABG, minimise drains, separate drain wound minimise dead space haematomas and devitalised tissue • Post-op: minimise catheters & IV lines, maintain oxygenation hydration & nutrition

24. Prevention 2 • Bowel preparation: No irrigation, diets, or non- absorbable antibiotics Theatre design & technique: workflow zoning, air flow, CSSD, restricted staffing, aseptic technique etc. Wound management Dressing - no touch technique, Drainage – none or closed or vacuum drains if pus

25. Antibiotic prophylaxis - principles • First dose immediately pre-op • maximum of 3 doses or 24h period • Rarely > 24h • parenteral, PR • No non-absorbables • Rarely required in clean or clean/contaminated

26. Perioperative Antibiotics- Prophylactic • Prophylactic antibiotics should exist at time of contamination. Clean- contaminated and Contaminated showed reduction • In clean only when Foreign Body is inserted • Preoperative, close to cutting time, long half- life, selected against specific pathogens, 4-6 hours later, and for 2 postoperative doses • Colon surgery: Oral antibiotics, poorly absorbed; neomycin- erythromycin along with mechanical preparation, and IV systemic • Dirty: fascial closure, wet-to-dry dressing and delayed primary closure in 4-5 days

27. Importance of Timing of Surgical Antimicrobial Prophylaxis (AP) • Prospective study of 2,847 elective clean and clean-contaminated procedures • Early AP (2-24 hrs before incision): 3.8% Postop AP (3-24 hrs after incision): 3.3% Periop AP (< 3 hrs after incision): 1.4% Preop AP (<2 hrs before incision): 0.6% Classen, 1992 (NEJM 326:281-286)

28. Antibiotic prophylaxis dynamics Time of administration Bacterial load

29. Prophylaxis - specific Indication Antibiotic Duration above knee amputation benzyl penicillin 1 dose Cholecystectomy cefuroxime 1 dose Appendicectomy metronidazole 3 doses Colectomy Cefuroxime + 3 doses metronidazole vaginal hysterectomy as above as above or augmentin Prosthetic hip replacement cefuroxime 2 doses Prosthetic heart valve cefuroxime or fluclox tid <48h Vascular prosthesis as above as above

30. Supplemental Perioperative O2 • DESIGN: Randomized controlled trial, double blind • POPULATION: Colorectal surgery (N=500) • INTERVENTION: 30% vs 80% inspired oxygen during and up to hours after surgery • RESULTS: SSI incidence 5.2% (80% O2) vs 11.2% (30% O2), p=0.01 Greif, R, et al , NEJM, 2000

31. Pre-operative Shaving/Hair Removal Seropian, 1971 Method of hair removal Razor = 5.6% SSI rates Depilatory = 0.6% SSI rates No hair removal = 0.6% SSI rates Timing of hair removal Shaving immediately before = 3.1% SSI rates Shaving  24 hours before = 7.1% SSI rates Shaving >24 hours before = 20% SSI rates

32. Surgical Attire • Scrub suits • Cap/hoods • Shoe covers • Masks • Gloves • Gowns

33. Instruments and infection control CSSD

34. Parameters for Operating Room Ventilation • Temperature: 68o-73oF, depending on normal ambient temp • Relative humidity: 30%-60% • Air movement: from “clean to less clean” areas • Air changes: >15 total per hour, (20 routine, 30 orthopaedic) >3 outdoor air per hour

35. Surgical Technique • Removing devitalized tissue • Maintaining effective hemostasis • Gently handling tissues • Eradicating dead space • Avoiding inadvertent entries into a viscus • Using drains and suture material appropriately

36. Treatment • Most infection are superficial – no antibiotics • If complicated - open, drain, debride, micro & Abx • Topical Vs systemic • Saline Vs disinfectant Vs antibiotic • Target organisms Vs culture • empirical Vs culture targeted • one drug Vs two • Remove all prostheses / implants • pus collection drainage

40. Surveillance • Infection Control Team • Link nurses • Databases • Early discharge, day surgery • Post discharge

41. Reading reference The CDC NNIS 1999 guidance document is the comprehensive reference,(23 pages) : http://www.cdc.gov/ncidod/dhqp/pdf/guidelines/SSI.pdf