Surgical Site Infections

Question 1

What are SSIs?

Answer 1

+ Infections occurring in a wound created by an invasive surgical procedure

+ Responsible for ~20% of HCAIs

+ 5% of patients undergoing surgery develop an SSI

+ Can double length of hospital stay

+ Associated with high morbidity

Question 2

What are some different types of SSIs?

Answer 2

\+ Wound discharge
\+ Dehiscence
\+ Lymphadentitis
\+ Abscesses
\+ Necrosis (tissue or fat)
\+ (Gas) gangrene
\+ Sepsis
\+ Induration
\+ Purulent discharge

Question 3

What are possible consequences of SSIs?

Answer 3

+ Microbial penetration of deeper tissue

+ Invasion of bloodstream (bacteraemia, sepsis)

+ Spread of bacteria to other sides (e.g heart valves, bones, peritoneum)

Question 4

How, why and when do SSIs occur?

Answer 4

+ Contamination of incision by normal microbiota
+ Damage to tissues
+ Damage to blood vessels

+ Presence of foreign bodies (e.g sutures, implants)
+ Reduced efficacy of inflammatory response

+ Before, during and afer surgery

Question 5

What are factors that infuence the development of SSIs?

Answer 5

\+ Type of surgical wound (clean/dirty etc.)
\+ Pre-, intra- and postoperative care
\+ Surgical team
\+ Age and general health of patient
\+ Extent of tissue injury
\+ Infection prevention procedures
\+ Presence of prosthesis or foreign body
\+ Presence or absence of drain
\+ Duration of surgery
\+ Place in operation list

Question 6

What are the classifications of surgical wounds?

Answer 6

\+ Clean (class I)
\+ Clean/contaminated (class II)
\+ Contaminated (class III)
\+ Dirty (class IV)

Question 7

What are the features of class I surgical wounds?

Answer 7

+ Elective surgery
+ No accute inflammation
+ Don’t involve R, GI or GU tracts

Question 8

What are the features of class II surgical wounds?

Answer 8

+ Urgent/emergency case
+ Clean wounds with higher risk of infection
+ Uncomplicated R, GI or GU surgery

Question 9

What are the features of class III surgical wounds?

Answer 9

+ Outside object comes into contact with wound

+ Large amounts of spillage from GI tract into wound

Question 10

What are the features of class IV surgical wounds?

Answer 10

+ Purulent inflammation
+ Foreign object lodged in wound
+ Traumatic or infected wounds

Question 11

What is the incidence of SSIs without antibiotic prophylaxis?

Answer 11

Class I - 2%
Class II - 6-9%
Class III - 13-20%
Class IV - 40%

Question 12

What is the incidence of SSis with antibiotic prophylaxis?

Answer 12

Class I - 2%
Class II - 3-4%
Class III - 6-7%
Class IV - 7-16%

Question 13

What are microbial causes of SSIs of the skin?

Answer 13

+ Staphylococcus aureus
+ Streptococci spp.
+ Enterococci spp.

Question 14

What are microbial causes of SSIs of the bowel?

Answer 14

\+ Escherichia coli
\+ Bacteriodes fragilis
\+ Clostridium perfringens
\+ Enterococci spp.
\+ Anaerobic cocci

Question 15

What are some forms of pre-operative care?

Answer 15

+ Pre-operative showering
+ Do not remove hair
+ Give antiobiotc prophylaxus before:
- clean surgery (prosthesis/implant only)
- clean-contaminated surgery
- contaminated surgey
+ Do not routinely use nasal decontamination
+ Do not routinely use mechanical bowel preparation

Question 16

What are some forms of intra-operative care?

Answer 16

+ Surgical team hand decontamination
+ Do not use non-iodophor-impregnated incise drapes
+ Wear sterile fown and 2 pairs sterile gloves
+ Prepare skin at surgical site immediately before incision
+ Maintain patient homeostasis
+ Do not use wound irrigation or intracavity lavage
+ Do not use intra-operative disinfectant or topical antibiotics
+ Cover incisions with appropriate dressing at the end

Question 17

What should be disinfected to minimise SSIs?

Answer 17

+ Hands of ward staff

• non-antimicrobial soap
• ABHR

+ Hands of surgical team
- scrub with aqueous antiseptic surgical solution before first op.
+ If not visibly soiled, subsequently use ABHR or antiseptic surgical solution

+ Patient’s skin

• alcoholic chlorhexidine
• povidone iodine

Question 18

What are the two types of dressings that can be used to prevent infection?

Answer 18

+ Conventional

+ Occlusive

Question 19

What do conventional dressings include?

Answer 19

+ Gauze
+ Tulle gras
+ Non-adhesive fabrics

Question 20

What do occlusive dressings include?

Answer 20

+ Hydrocolloids
+ Polyurethane films
+ Foams

Question 21

What are examples of good post-operative care?

Answer 21

+ Use appropriate dressings
+ Use aseptic or non-touch technique to change/remove dressings
+ Use sterile saline for wound cleansing up to 48hrs after surgery
+ Do not use topical antimicrobial agents for wound healing by primary intention
+ Follow guidance regarding use of debriding agents

Question 22

How can the risk of post-op infections be reduced?

Answer 22

+ Keep pre-op length of stay in hospital to minimum
+ Treat any current infections before surgery
+ Keep length of surgery as short as possible
+ Maintain good operative technique
+ Debridement of dead/necrotic skin
+ Establish good blood supply
+ Prevent pressure sores
+ Arrange active physiotherapy to minimise risk of URTIs and UTIs

Question 23

What precautions can be taken to prevent catheter-related infections?

Answer 23

+ Always wash hands before procedure
+ Wear gloves when handling catheter
+ Use single use antiseptic wipe
+ Cover insertion site with dressing

Question 24

What are early presentations of prosthetic joint infections?

Answer 24

Early < 1 month:

- fulminant with wound sepsis

Question 25

What are delayed presentations of prosthetic joint infections?

Answer 25

Delayed < 1 year:

- indolent, low grade infection

Question 26

What are late-onset presentations of prosthetic joint infections?

Answer 26

Late-onset > 2 years:

- septic arthritis

Question 27

How can a prosthetic joint infection be diagnosed?

Answer 27

\+ Blood culture
\+ Collection of pus by needle aspiration
\+ Bone biopsy
\+ Raised ESR and CRP
\+ Polymorphonuclear leucocytes
\+ Radiological imaging