Surgical Site Infections Flashcards
What is a surgical site infection ?
Infections occurring in an incision made by an invasive surgical procedure.
What % of HAI’s do surgical site infections account for ?
Roughly 20%
Facts about SSI’s
- Incidence varies depending on how ‘clean’ the surgery is
- Increase length of hospital stay
- Associated with high morbidity
- Prevention is better than a cure
- Since 2005 “Surgical Site Infections” (x3) cited >650 times
Louis Pasteur
Germ theory of disease
Joseph Lister
Father of modern surgery.
He found a way to prevent infection in wounds during and after surgery.
Sir Alexander Ogston
First known germaphobe :)
Wound healing by primary intention
Clean narrow incision
Inflammation and proliferation
Minimal scarring
Remodelling
Wound healing by secondary intention
Broader based wound
Granulates over and heals from the base
Wider more visible scar
Name some signs of infection
- Inflammation
- Erythema
- Discharge
- Fluctuant Collection
- Failure to heal
- Pain
- Systemic symptoms of sepsis
- Pyrexia
Bacteremia
Simple presence of bacteria in the blood.
Septicemia
The presence and multiplication of bacteria in the blood.
Differences between bacteremia and septicemia
Bacteremia - less amounts of bacteria in blood
Septicemia - toxins may be produced by bacteria
- potentially life-threatening
5 symptoms of inflammation
Rubor- redness
Calor - heat
Tumor - swelling
Dolor - pain
Loss of function
Rubor
Erythema/redness
Calor
Increased temperature
Tumor
Swelling
Dolor
Pain
Risk factors of SSI’s
Patient factors
Operation factors
Patient factors increasing chances of SSI’s
Extremes of age
Poor nutritional state
Diabetes mellitus
Renal failure
Immunosuppression
Current smoker
?Ethnicity
Operation factors increasing chances of SSI’s
Preoperative shaving or site of incision
Length of operation
Tissue handling
Foreign material in surgical site
Insertion of surgical drain
Poor closure of wound
How do surgical site infections occur ?
Contamination of incision by normal microbiota
Damage to tissues
Damage to blood vessels - reduced blood supply, reduced immune response
Why do surgical site infections occur ?
Presence of foreign bodies
(e.g. sutures, implants)
Reduced efficacy of inflammatory response
When do surgical site infections occur ?
Contamination can occur before, during and after surgery.
Microbial causes of SSI’s on skin
Staphylococcus aureus
Streptococci spp
Enterococci spp
Microbial causes of SSI’s in bowel
Escherichia coli
Bacteroides fragilis
Clostridium perfringens
Enterococci spp
Anaerobic cocci
Symptoms of SSI’s
Wound discharge
Purulent discharge
Gas gangrene
Early signs of fat necrosis
Wound dehiscence
What is wound dehiscence ?
A surgery complication where the incision, a cut made during a surgical procedure, reopens.
Consequences of SSIs
- Microbial penetration of deeper tissues
- Infection spread to bloodstream (bacteraemia, sepsis)
- Spread of bacteria to other sites (e.g. heart valves, bones, joints, peritoneum, CNS)
Factors influencing development of SSI’s
Pre - operative
Intra - operative
Post - operative
Name 4 preoperative factors to decrease risk of SSI’s
MRSA screening
Preoperative showering
Don’t remove hair until immediately pre-operatively (clippers)
Give antibiotic prophylaxis
MRSA
Methicillin Resistant Staphylococcus Aureus
When should you give antibiotic prophylaxis to decrease the risk of SSI’s ?
Before :
- Clean surgery (prosthesis or implant only)
- Clean-contaminated surgery
- Contaminated surgery
What should be disinfected to prevent SSI’s ?
Hands of hospital staff
Hands of surgical team
Patient’s skin
Describe disinfection of hands of hospital staff
Wash with non-antimicrobial soap and water
Alcohol based hand rub should be used
Describe disinfection of hands of surgical team
Scrub with aqueous antiseptic surgical solution before first & subsequent operation.
If not visibly soiled, subsequently use AB Skin prep
(Chlorhexidine, Betadine)
Describe disinfection of patient’s skin
Alcoholic chlorhexidine (preferred)
Povidone iodine (potency can be reduced in ‘bloody’ wounds)
Name some intraoperative factors to decrease the risk of SSI’s
Sterile field + gown + gloves with good scrubbing technique
Prepare skin immediately before incision
Debridement of dead and necrotic skin
Establish a good blood supply
Maintain patient homeostasis
Intraoperative disinfection or topical antibiotics
Wound closure
Cover incisions with appropriate dressings at the end
-ve pressure dressings in higher risk cases
Debridement
Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue.
Role of the surgical team
- Skill of individual surgeon
- Quality of aseptic technique
- Careful tissue handling
- Adequacy of protective clothing
- Wearing of gloves
- Theatre design
- Local protocol
What creates an ultraclean zone around the operative site ?
Laminar flow
Name the classes of surgical wounds
Class :
- Clean
- Clean/contaminated
- Contaminated
- Dirty
Clean (Class 1)
Elective surgery
No acute inflammation
Doesn’t involve respiratory, GI or GU tracts
Clean/Contaminated (Class 2)
Urgent/emergency case
Clean wound with a higher risk of infection
Uncomplicated respiratory, GI or GU tract surgery
Contaminated (Class 3)
Outside object comes into contact with wound
Large amounts of spillage from GI tract into wound
Dirty (Class 4)
Purulent inflammation
Foreign object lodged in wound
Traumatic or infected wounds
Microbial load at time of surgery
For Class 1-4
- <10 cfu/ml
- 20-40 cfu/ml
- 1000-1500 cfu/ml
- > 3500 cfu/ml
Incidence of SSIs without antibiotic prophylaxis
- 2%
- 6-9%
- 13-20%
- 40%
Incidence of SSIs with antibiotic prophylaxis
- 2%
- 3-4%
- 6-7%
- 7-16%
Types of wound closure methods
- Interrupted suture
- Interrupted Mattress sutures
- Staples
- Continuous/ subcuticular suture
Name some postoperative factors to decrease the risk of SSI’s
Use appropriate dressings
Use aseptic or non-touch technique to change or remove dressings
Minimise dressing changes
Use sterile saline for wound cleansing up to 48hs after surgery
Keep preoperative length of stay in hospital to a minimum
Treat any (con)current infections before surgery
Prevent pressure sores by good nursing care
Enhanced Recovery After Surgery (ERAS)
Conventional dressings
Gauze
Tulle gras
Non-adhesive fabrics
Occlusive dressings
Hydrocollids
Polyurethane films
Foams
Vacuum dressings
Wound healing by second intention
Wounds with high amounts of exudate
Device associated infections
ANY INDWELLING DEVICE
Vascular access devices (cannula to central line)
Endotracheal tubes
Urinary catheter
Risk factors for prosthetic joint infections
Rheumatoid arthritis
Diabetes mellitus
Malnutrition
Obesity
Anaemia
Immunosuppression
Prosthetic joint infection diagnostics
History and examination
Blood culture
Culture bone biopsy
Raised inflammatory markers
Radiological imaging
Joint aspiration for culture and microscopy
What is classed as a SSI ?
Within 30 days of surgery, or within a year if a prsoethic device is left in.
