Surgery Abx Prophylaxis

Question 1

What is a clean procedure?

Answer 1

Elective operative procedure does not enter:

• normally colonized viscus or
• lumen of the body.

Question 2

Risk of infection of clean wound

Answer 2

• <2%
• Environmental contaminants
• Contaminants for surgical team
• Skin colonists; commonly Staph, aureus

Question 3

What is a clean-contaminated procedure?

Answer 3

Elective operative procedure does enter:

• normally colonized viscus or
• lumen of the body.

Question 4

Examples of clean-contaminated procedures

Answer 4

• Elective intestinal resection
  
  • Pulmonary resection
  • Gynecological
  • Head-neck cancer operations that involve the oropharynx

Question 5

Risk of infection of clean-contaminated wound

Answer 5

• <10%
• endogenous bacteria from site of surgery e.g. bowel - ecoli and mouth - anaerobes
• Can be optimized with specific preventive strategies.

Question 6

What is a contaminated procedure?

Answer 6

When gross contamination is present at the surgical site in the absence of obvious infection.

Question 7

Examples of contamined wound procedure

Answer 7

• Laparotomy for penetrating injury with intestinal spillage
• Elective intestinal procedures with gross contamination of the surgical site.

Question 8

Risk of infection of contaminated wounds

Answer 8

• 20% even with preventative Abx
• Contaminants are the bacteria that are introduced by gross soilage of the surgical field.

Question 9

What is a dirty wound procedure?

Answer 9

• Surgical procedures performed when active infection is already present
• Open injury
• Existing clinical infection

Question 10

Examples of dirty wound procedures

Answer 10

• Abdominal exploration for acute bacterial peritonitis
• Intra-abdominal abscess

Question 11

Risk of infection for dirty wounds

Answer 11

• 40%

Question 12

Risk factors for surgical site infections

Answer 12

• Diabetes
• Corticosteroid use
• Obesity
• Extremes of age: with age healing takes longer
• Malnutrition
• Recent surgery
• Smoking
• Massive transfusion
• Immune deficiency states
• Renal/ liver impairment
• > 3 preop co-morbidities
• ASA class 3, 4 or 5
• Bacterial colonisation

Presence of 2 or more risk factors increases risk of infection for clean procedures 4-fold

Question 13

Procedure risk factors

Answer 13

• Length of surgical scrub
• Lack of haemostasis
• Skin antisepsis
• Shaving
• Length of surgery
• Op theatre ventilation
• Surgical drains/ technique

Question 14

Abx Prophylaxis

Answer 14

• 1st dose before skin incision is performed
• Ideally within 60 mins of time of incision
• When administered antibiotics within 2 hours of starting, operation infection rates have been shown to be 0.6% compared to 3.3% when given postoperatively
• Choice of regimen should be active against organisms most likely to cause infection

Question 15

Deciding which Abx prophylaxis to give

Answer 15

Each NHS trust should have their own protocols for different surgery types based on:
- usual pathogens for the surgery type
- clinical trial comparison of different regimens
- local resistance patterns

Question 16

Benefits of Abx prophylaxis

Answer 16

• Can prevent onset or reduce severity of infection due to surgery
• Reduce MRSA
• Reduce sepsis at site of surgical wound

Question 17

Risks vs benefits of giving Abx

Answer 17

• Consider likelihood of infection without Abx
• Morbidity and cost of infectious complications.
• Pt potentially exposed to dose related toxicity, drug interactions and idiosyncratic toxic reactions (e.g. anaphylaxis).