Surgical Infections Flashcards
What is a surgical infection
They are infections that occur as a result of a surgical procedure or those that require surgical intervention as part of their treatment
What characterizes a surgical infection
A breach of mechanical/anatomic defence mechanisms (barriers)
Pathogens of surgical infections are usually ………… and …………..
Mixed, generally originate from patient’s endogenous flora
What are some factors associated with increase in the number of serious surgical infections
Performance of more complicated and longer surgeries
Increase in the number of geriatric patients
Use of implants
Increased use of immunosuppressive drugs
Laxity of aseptic techniques
Unwarranted reliance on prophylactic antibiotics
What are the classifications of a surgical site infection
Superficial
Incision deep
Organ space
A superficial incisional SSI occurs in which parts of the body
Skin
Subcutaneous tissue
A deep incisional SSI occurs in which part of the body
Deep soft tissue (fascia and muscle)
What are some things that could be done to prevent SSIs
Aseptic technique
Proper use of prophylactic antibiotics
Maximizing patients ability to prevent infection
Local wound factors
(i. Good judgement/surgical technique
ii. appropriate tissue handling
iii. debridement
iv. avoiding foreign bodies
v. adequate wound dressing
Patient related managing underlying (DM, uremia, obesity, malnutrition etc)
What are the treatments of SSIs
Source control; drainage of infected area
Deep/organ space – surgical drainage (open or percutaneous) +/- therapeutic antibiotics
Mention some types of specific surgical infections
Non necrotizing soft tissue infections
Necrotizing soft tissue infections
What is a non necrotizing soft tissue infection
It is an infectious process characterized by a necrotic center without supply
What are some characteristics of a non necrotising soft tissue infection
There is an abscess:
Infectious process characterised by a necrotic centre without blood supply
Composed of debris from local tissues, dead and dying WBCs, plasma and bacteria
Cannot resolve on antibiotic therapy
There is cellulitis:
Soft tissue inflammation with intact blood
Marked by an acute inflammatory response, vessel congestion, endothelial leakage and PMN infiltration
Resolves on antibiotics
Some abscesses may present as cellulitis because of their anatomic locations disguised in anatomic locations where fibrous septa join skin and fascia. What are some of these abscesses
Perirectal abscess
Breast abscess
Carbuncles
Felons
What are the characteristics of necrotising soft tissue infections
Gas gangrene/necrotising fasciitis
Involve deep subcutaneous tissue, deep fascia, muscle or a combination
Characterized by absence of clear local boundaries or palpable limits
Overlying skin has a relatively normal appearance in the early stages
Presence of gas on palpation (crepitus) grave sign
Diagnostic challenge in diabetic foot, obese
Overt signs of systemic compromise and septic compromise is seen in advance stages
What is the treatment of necrotizing soft tissue infections
Mainstay is debridement, it may be repeated
Broad spectrum antibiotics
Monitoring
Systemic support
?Hyperbaric O2
Anti toxins
Fungal pathogens have been implicated in NSTI
Typical intraoperative findings consistent with NSTI include
A dishwater-like exudate, dusky tissues, thrombosed vessels, lack of clear boundaries allowing finger dissection to spread through the compromised plane abnormally easily
What is a good predictor of outcome in a retroperitoneal or abdominal infection
APACHE score
What are some characteristics of. Intrabdominal/retroperitoneal infections
Usually require surgical intervention for resolution (except SBP, amoebic liver abscess, salpingitis)
Outcome improved by early diagnosis and treatment
APACHE score good predictor of outcome
Mortality still high 5-50%
Talk about prosthetic device related infection
Increased use of prosthesis
Presence of foreign materials impairs host defences
Allows certain bacteria with specific virulence factors (S. epidermidis) to stick
What are some treatments to prosthetic device related infection
Intensive antibiotic therapy
Removal of prosthetic material
Removal under antibiotic cover and replacement
What is the goal of antibiotics in surgical infections
Goal of antibiotic therapy is to achieve antibiotic levels at site of infection that exceed the MIC for the pathogen. Most antibiotics are started intravenously. Patients must be reviewed daily
When do you change an antibiotic in a surgical infection
If no improvement after 3 days:
Initial operative procedure was not adequate
Initial procedure was adequate but a complication has occurred
A superinfection has developed at a new site
Drug choice is correct but not enough is being given
Another drug or different drug is needed
NB: Choice of antibiotics is the most common cause of treatment failure
When do you stop antibiotics in a surgical infection
For most surgical infections, no specific duration is ideal
Role of ABS is to support local host defenses
3-5 days after I&D, local responses of new capillary formation, inflammatory exudate provide adequate local defense
General rule – continue ABS until clinical improvement and temp is stable for 48hrs
Do not send a patient home on oral antibiotics when the patient does not need it
How do you prevent antibiotic resistance
Definitely multidisciplinary
Guidelines in antibiotic use
-Hospital formulary restriction
-Use of narrow spectrum antibiotics
-Antibiotic cycling
-Use of new antibiotics
Assessment of infection risk and quantitative culture
Area specific antibiotic use (OPD vs Inpatient)
Prevention of hospital transmission (hand washing, barrier nursing)
