Surgical Prophylaxis

Question 1

SSI

Answer 1

• Surgical site infections
• 2-5% of procedures are complicated by SSI
• Complex, multifactorial
• Increase risk of death, costs, and LOS

Question 2

SSI Contributing Factor Categories

Answer 2

• Procedural factors
• Microbial factors
• Antimicrobial prophylaxis factors
• Patient Factors

Question 3

Procedural Factors

Answer 3

• Type of surgery
• Length of procedure
• Break in sterile technique
• Preoperative shaving
• Perioperative shaving
• Foreign materials

Question 4

Microbial Factors

Answer 4

• Inoculum size
• Tissue adherence
• Virulence Factors
• Resistance

Question 5

Antimicrobial Prophylaxis Factors

Answer 5

• Drug
• Dose
• Delivery time
• Duration
• Appropriate coverage

Question 6

Patient Factors

Answer 6

• Age
• Immunosuppression
• Endogenous flora
• Nutritional status and BMI
• Presence of diabetes
• Smoking status

Question 7

Sources of Infection

Answer 7

• Operating room environment: surgical instruments, material, clothing
• Patients endogenous flora: skin, mucous membranes, GI tract
• Hematogenous seeding from preexisting infection

Question 8

Major pathogens

Answer 8

• S. aureus
• Enterobacteriacea
• Coag-neg. Staph
• Strept. spp.
• Other/no organism isolated

Question 9

Assessment of Risk

Answer 9

• Done through NRC Wound classification
• Dependent on: microbiology, surgical site, contamination liklihood, presence of preexisting infection, events during/after surgery
• Risk index developed

Question 10

NRC: Clean

Answer 10

• Uninfected wound (no inflammation)
• Infection rate: <5%
• Primary wound closure with no break in technique AND no involvement of GI, biliary, oropharyngeal, tracheobronchial, or GU tracts
• Surgical prophylaxis in high morbidity/mortality cases

Question 11

NRC: Clean-contaminated

Answer 11

• Uninfected wound (no inflammation)
• Infection Rate: 5-10%
• Minor break in technique OR GI, biliary, oropharyngeal, tracheobronchial, or GU tracts are transected under controlled conditions
• Surgical prophylaxis

Question 12

NRC: Contaminated

Answer 12

• Uninfected wound (no inflammation)
• Rate of infection: 15-30%
• Infection discovered OR open traumatic wound OR break in aseptic technique
• Surgical prophylaxis

Question 13

NRC: Dirty

Answer 13

• Rate of infection: >30%
• Existing infection OR perforated viscera
• Surgical prophylaxis if antibiotics aren’t broad enough for prophylaxis

Question 14

Antimicrobial Prophylaxis

Answer 14

• Adjunctive preventive measure to aseptic technique
• Administered before contaminated to prevent SSI from developing (usually only one dose)
• Associated with 5x decrease in SSI rates
• Use in high-risk procedures or in increased morbidity/mortality cases

Question 15

Antimicrobial Choice

Answer 15

• Based on procedure/frequent pathogens, allergy and patient factors, local resistance patterns, cost
• Cephalosporins: commonly used due to spectrum, safety, and cost
• IV prefered due to rapid acting, reliable, predictable
• Extended infusion necessary for certain antibiotics (vanco, cipro)

Question 16

Cephalosporin SE

Answer 16

• Rash
• Pruritis
• Rare anaphylaxis
• C. diff colitis

Question 17

Clean Procedure Prophylaxis

Answer 17

• Recc: Cefazolin 2g

- Alt: Cefuroxime 1.5g

Question 18

Clean-Contaminated Prophylaxis

Answer 18

-Recc: Cefotetan 2g OR Cefoxitin 2g
-Alt: Cefazolin 2g + Metronidazole 500 mg
OR
-Cefuroxime 1.5g + Metronidazole 500 mg
-Added coverage for anaerobes

Question 19

Cefazolin Dosing

Answer 19

• Obesity is risk factor for SSI
• Need to adjust for BW
• <80 kg: 1g
• 80-120 kg: 2g
• > 120 kg: 3g

Question 20

Prophylaxis + Beta Lactam Allergies

Answer 20

• Clean procedures: Vanco 15 mg/kg OR Clinda 900 mg

- Clean-contaminated: Clinda + Aminoglycoside/aztreonam2g/FQ

Question 21

AMG/FQ

Answer 21

• AMG: Genta 5mg/kg OR Tobra 5mg/kg

- FQ: Cipro 400 mg OR Levo 500 mg

Question 22

Administration Timing

Answer 22

• Give 0-60 minutes before incision for most abx

- 60-120 minutes beforehand if extended infusion times are required (FQ, vancos)

Question 23

Prophylaxis Duration

Answer 23

• Typically just one dose
• Long procedures may need additional administration
• Recommend <24 hours
• Lack of evidence for longer duration in cardiothoracic surgery

Question 24

Readministration Times

Answer 24

• From initial dosing
• Varies by abx
• Cefazolin/Cefuroxime: q4h
• Cefoxitin: q2h
• Cefotetan: q6h
• Clinda: q6h
• All others NA

Question 25

Continuous Infusion

Answer 25

- Limited data - Dosen't have better outcomes when compared to intermittent - Benefit may be decreased readministration error for cephs

Question 26

Vanco Use

Answer 26

- Routine use isn't recommended for any procedure - Lack of proven efficacy - Narrow spectrum, poor tissue perforation, long infusion times, SE, concern for resistance

Question 27

Vanco Restrictions

Answer 27

- Appropriate use: MRSA documentations, life-threatening Beta-lactam allergy, surgeries involving foreign material placement - Use with B-lactams whenever possibly over solely - Screen in high-risk patients and procedures

Question 28

Cardiac Procedures

Answer 28

- Clean - Routine implementation of prosthetics increases risk - Pathogens: Skin flora (S. aureus, CoNS) - Recc Prophylaxis: Cefazolin 2g x 1 (up to 24-48 hours) - Vanco additionally can be considered in high-risk MRSA - Mupirocin in MRSA nasal carriers - Routine use of topical abx not established

Question 29

Neurosurgery

Answer 29

- Clean procedures - Low SSI but high mortality - Pathogens: Skin flora (S. aureus, CoNS) - Recc Prophylaxis: Cefazolin 2g x 1 - Routine topical abx use isn't established

Question 30

Orthopedic Procedures

Answer 30

- Clean procedures - Prophylaxis ONLY in spinal and knee/hypreplacement/fracture procedures - Pathogens: Skin flora, Gram "-" bacilli, beta-hemolytic strept - Recc Prophylaxis: Cefazolin 2g x1

Question 31

Gastroduodenal Procedures

Answer 31

- Recommended for high risk cases like obstruction, perforation, malignancy, avid suppression therapy - Pathogens: Gram '-" and "+", less frequently anaerobes - Recc prophylaxis: Cefazolin 2g x 1

Question 32

Colorectal/Uncomplicated Appendectomy Procedures

Answer 32

- Clean-contaminated or contaminated - Pathogens: Enteric Gram "-" and anaerobes - Prophylaxis divided by oral and IV - IV Prophylaxis: Cefotetan 2g x1 OR Cefoxitin 2g x1

Question 33

Colorectal/Appendectomy Oral Prophylaxis

Answer 33

- Added for ELECTIVE colorectal surgery - NEomycin 1g + Erythromycin 1g at 1 PM, 2PM, and 11PM preop day - NOT for bowel obstruction, colostomy reversal, or rectal resection - Mechanical bowel prep should be given BEFORE oral abx

Question 34

C-section Procedures

Answer 34

- Clean or clean-contaminated - Endometritis is most common and usually polymicrobial - Prophylaxis BEFORE initial incision - Pathogens: Strept, entero, enteric Gram "-", peptostrept - Recc Prophylaxis: Cefazolin 2g x1

Question 35

Urologic Procedures

Answer 35

- Clean or clean-contaminated - Pathogen: E. Coli - Therapeutic antibiotics warranted if peroperative UA and use prophylaxis in high-risk circumstances - Recc prophylaxis: Cefazolin 2g IV x1 (add AMG if clean-contaminated)

Question 36

Urologic High-Risk Circumstances

Answer 36

- Positive UA but no therapeutic abx - High-risk procedures: prostatectomy, tumor resection, transrectal prostate biopsy - Prolonged indwelling catheter - Urinary stone/obstruction - Anatomic abnormalities - Neutropenia