Infection

Question 1

What are the three things required for establishment of a wound infection?

Answer 1

1. Sufficient dose of pathogenic microorganisms
2. A suitable microbial nutrient medium
3. Impairment of natural host defenses

Question 2

What is asepsis?

Answer 2

Prevention of wound contamination

Question 3

What is antisepsis?

Answer 3

Killing bacteria that are already present

Question 4

What harm does surgery do?

Answer 4

• A surgical incision is a wound: tissue trauma

- Surgery must be performed in such a way as to minimise trauma

Question 5

Can can trauma manifest into?

Answer 5

• Haemorrhage
• Infection
• Swelling
• Loss of function

Question 6

What may infection be due to?

Answer 6

• Pre-existing tissue contamination
• Surgical exposure of tissues to contamination
• Relative or absolute immunodeficiency

Question 7

What are some predisposing factors to surgical wound infection?

Answer 7

• Systemically compromised patient
• Tissue hypoxia
• Tissue trauma
• Inadequate debridement
• Prolonged tissue exposure to the environment
• Foreign material in the wound
• Haematoma ( inadequate haemostasis + dead space)
• Presence of resistant organisms in the environment

Question 8

Where can the source of self infection/ cross infection come from?

Answer 8

• Operative area
• Operative personnel
• Airbourne
• Equipment
• Post-op area

Question 9

What factors influence the battle between contaminants and the host’s defences?

Answer 9

• Patient Factors
• Surgeon Factors
• Environmental Factors

Question 10

Describe what patient factors are…

Answer 10

Who we do it to:

• Age
• Health status
• Low body weight - can become hypothermic
• Dermatitis at site
• Propensity to lick and scratch wounds
• Lack of compliance with dressings
• Obesity
• Chemotherapy
• Corticosteroids

Question 11

Describe what surgeon factors are…

Answer 11

How we do it

• Disruption of local blood flow
• Tissue trauma
• Blood clots act as growth medium
• Foreign material e.g. sutures
• Electrocautery
• Creation of dead space
• Wicking of bacteria by multifilament sutures
• Long anaesthetic periods
• Drying of tissues
• Thermal damage from drills etc.

Question 12

Describe what environmental factors are…

Answer 12

Where we do it

• Theatre cleanliness
• Theatre air flow
• Theatre traffic
• Hospital and ward cleanliness
• Skin clipping
• Skin disinfection
• Instrument sterility
• Draping
• Gowning and gloving
• Nosocomial infection
• Sink water sterility

Question 13

When should prophylactic antibiotics be given?

Answer 13

• Long surgeries
• Implant surgeries
• Contaminated/ dirty surgeries

Question 14

How should prophylactic antibiotics be given?

Answer 14

• High dose IV
• First generation cephalosporin or penicillin G
• At induction, blood levels are high at surgery
• Repeat after 90 minutes