In The Name of Allah

1. In The Name of Allah

2. Guidelines For Surgical Chemoprophylaxis By: Dr. M. Minaiyan Dept. of Pharmacology, IUMS

3. Surgical Site Infection(SSI) Definition • SSI is an infection related to the operation procedure that occur within 30 days of procedure or 1 year if an implant is left in place. • SSIs account for about 38% of nosocomial infections and an average total cost increament of $3380 per patient and 1.5 $ billions annually in USA.

4. FACTS • One out of every 24 patients who have inpatient surgery in the United States has a postoperative SSI • The cost of SSIs are substantial: an increased total cost of more than 300% • SSIs increase the post operative length of hospital stay by 7-14 days

5. Definitions of SSI • Superficial incisional SSI: Infection involves only skin and subcutaneous tissue of incision. • Deep incisional SSI: Infection involves deep tissues, such as fascial and muscle layers. This also includes infection involving both superficial and deep incision sites and organ/space SSI draining through incision. • Organ/space SSI: Infection involves any part of the anatomy in organs and spaces other than the incision, which was opened or manipulated during operation.

6. Risk factors • Decreased host resistance can be due to: • 1- Systemic factors affecting the patient's healing response • 2- Local wound characteristics • 3- Operative characteristics. • Systemic factors include age, malnutrition, hypovolemia, poor tissue perfusion, obesity, diabetes,steroids, and other immunosuppressants.

7. Risk factors • Wound characteristics include nonviable tissue in wound; hematoma; foreign material, including drains and sutures; dead space; poor skin preparation, including shaving; and preexistent sepsis (local or distant). • Operative characteristics include poor surgical technique; lengthy operation (>2 h); intraoperative contamination, including infected theater staff and instruments and inadequate theater ventilation; prolonged preoperative stay in the hospital; and hypothermia

8. The type of procedure is a risk factor too

9. Risk Factors Which Justify Surgical Antimicrobial Prophylaxis • 1. Operation in the abdomen • 2. Operations lasting more than 2 hrs • 3. Contaminated or dirty wounds (expected infection rate >20%) • 4. Presence of at least three medical diagnosis • 5. Immuno -compromised host • 6. Placement of prosthetic material

10. Prophylactic Antibiotics • General agreement exists that prophylactic antibiotics are indicated for clean-contaminated and contaminated wounds • Antibiotics for dirty wounds are part of the treatment because infection is established already. • Clean procedures might be an issue of debate. No doubt exists regarding the use of prophylactic antibiotics in clean procedures in which prosthetic devices are inserted because infection in these cases would be disastrous for the patient.

11. General Principles of Surgical Prophylaxis • 1. The antibiotic should have proved efficacy in clinical trials • 2. The antibiotic should be active against common surgical pathogens; unnecessary broad coverage should be avoided • 3. The antibiotic must achieve concentrations greater than the MIC of suspected pathogen at the time of incision

12. General Principles of Surgical Prophylaxis • 4. The shortest possible course; ideally a single dose of the most effective and least toxic agent should be used(Postoperative administration of preventive systemic antibiotics beyond 24 hours has not been demonstrated to reduce the risk of SSIs ) • 5. The newer broad spectrum antibiotics should be reserved for resistant infections • 6. If all other factors are equal, the least expensive drug should be used

13. Prevention of SSI Main Factors • 1. The general health of the patient • 2. Meticulous operative techniques • 3. Timely administration of effective preoperative antibiotics

14. Useful common Practices • 1. Preoperative showering with antimicrobial soaps • 2. Application of antiseptics to the skin of patients • 3. Washing and gloving of the surgeons' hands • 4. Use of sterile drapers • 5. Use of gowns and masks by operative room personnel

15. Causes • Table 1. Pathogens Commonly Associated with Wound Infections and Frequency of Occurrence*Pathogen Frequency (%)*NNIS System (CDC, 1996)

16. Antibiotic Selection • Cefazolin (1-2g IV) has been effective for most clean procedures because of its activity against many Staphylococci and Streptococci species • Cefuroxime (1.5g IV) can be given instead of cefazolin in thoracic and orthopedic procedures

17. Antibiotic Selection • For procedures that might involve exposure to bowel anaerobes (B. fragilis) choices are: Cefazolin + Metronidazole (0.5g IV) or monotherapy with Ampicillin+ Sulbactam (3g IV) • Two above mentioned therapies are preferred to 2nd generation cephalosporins like: Cefoxitin or Cefotetan

18. Antibiotic Selection • Vancomycin (10-15mg/kg ~1g, IV) or Clindamycin (600-900mg, IV) are useful drugs for patients are highly allergic to pencillins and cephalosporins • In colorectal procedures, hysterectomy and vascular surgery a drug which add a gramΘ coverage e.g.Gentamicin, Ciprofloxacin and Aztreonam is needed.

19. Antibiotic Selection • Vancomycin is the drug of choice for following conditions: 1- Local resistance pattern (MRSA) 2- Patients with a long preoperative hospitalization 3- Patients have recently taken broad spectrum antibiotics 4- Patients with prosthetic graft implantation