types of wound contamination and minimising surgical infections Flashcards
what is the definition/threshold for bacterial infection?
Bacterial infection is defined as having more than 105 bacteria per gram of tissue
what is a surgical site infection (SSI) ?
infections of the tissues, organs, or spaces exposed by surgeons during performance of an invasive procedure
what are the subtypes of SSIs?
Incisional infections
* Superficial (limited to skin and subcutaneous tissue)
* Deep incisional
Organ/space infections
what do SSIs result in?
increased morbidity and mortality in surgical patients
what type of SSI accounts for 50% of SSIs?
incisional superficial
how are surgical wounds clasified?
Surgical wounds are classified by degree of contamination to help predict the likelihood that infection will develop.
- clean
- clean-contaminated
- contaminated
- dirty
what is the definition of a clean wound?
Non-traumatic, non-inflamed operative wounds in which the respiratory, gastrointestinal, genitourinary, and oro-pharyngeal tracts are not entered
what are some exaples of a clean wound?
- exploratory coeliotomy
- elective neuter
- total hip replacement
what are the infections of clean wounds?
Published infection rates vary from 0 – 4.4%
define clean-contaminated wounds?
Operative wounds in which the respiratory, gastrointestinal, or genitourinary tract are entered, but under controlled conditions without unusual contamination; an otherwise clean wound in which a drain is placed
what are some examples of clean-contaminated wounds?
- bronchoscopy
- cholecystectomy - removal of gall bladder
- enterotomy - entering small intestine
what is the infection rate of clean contaminated wounds?
Published infection rates vary from 4.5 – 9.3%
what is the definiton of a contaminated wound?
Open, fresh, accidental wounds; procedures in which gastrointestinal contents or infected urine is spilled or a major break in aseptic technique occurs
what is an example of a contaminated wound?
- cystotomy with spillage of infected urine
- open cardiac massage for CPR
what is the infection rate for contaminated wounds?
Published infection rates vary from 5.8 – 28.6%
what is the definition of dirty wounds?
Old traumatic wounds with purulent discharge, devitalised tissue, or foreign bodies; procedures in which a viscus is perforated or faecal contamination occurs
what are some example of dirty wounds?
- excision or drainage of an abscess
- bullae osteotomy for otitis media
- perforated intestinal tract
what is the infection rate of a dirty wound?
gross infection present
what are the methods of reducing infections during surgery?
- Primary objective of aseptic surgery
- Operating room practice – principles of aseptic technique, sterilisation, disinfection, anaesthesia, atraumatic technique, etc.
- Characteristics of bacterial contaminants (can they be managed with broad spectrum antibiotics)
what host factors have a role in post surgical infection?
- Age
- Physical condition
- Nutritional status
- Diagnostic procedures
- Concurrent metabolic disorders (hyperadrenocortisism)
- Current medication (corticosteroids, chemotherapy)
when should antibiotics be used after surgical oprations?
- Surgery time longer than 90 minutes
- Prosthesis implantation – mesh, pacemaker, bone cement, etc.
- Patients with a pre-existing prosthesis (e.g. hip replacement) undergoing certain surgical procedures (e.g., dental prophylaxis, traumatic wounds, colorectal surgery)
- Severely infected or traumatised wounds
must use rational selection of antibiotics for prophylactic use
* Definitive choice would depend of culture & sensitivity results
what are prophylactic antibiotics for surgical use, administed in small animals and why is this done?
intravenous as this allows for the highest conc to bbe circulating at time of contamination (operation) - however there is only a small amount of chocie
what type of prophylatic antibiotic is used for surgical use for small animals?
2nd generation cephalosporin eg Cefuroxime (zinacef) (gram positive)
or
amoxicillin and clavulanic acid eg augmentin (gram positive)
what type of antibiotic is Zincef? and what does it work against?
Cefuroxime (a cephalosporin) - broad spec - gram positive
wha type of antibiotic is augmentin
amoxicillin and clavulanic acid - broad spec - gram positive
what antibiotic would you use for anaerobic organisms?
eg for prophylatic use if operating on large intestine
metronidazole
what three antibiotics are used prohylaticially for surgery in equines?
- procaine penicillin (IV)
- gentamicin (IV)
- Oxytetracycline (Engeemycin) (SQ)
