Aseptic Technique Flashcards
Define sepsis
presence of pathogens ± toxic products in tissues
Define asepsis
Abscnece of patogencic microbes in tissues
Define antiseptic
Chemical agent that kills or inhibits pathogenic microorganisms - only for agents applied to the body (not into)
Define disinfectant
Chemical that kills microbes on inanimate objects
Define disinfection
Removal of microorganisms but not necessarily spores
Define steralisation
Complete elimination of microbial viability, including spores, by physical or chemical means
Do all surgical wounds become contaminated?
YES but not infected
What are the 3 factors that affect surgical wound infection?
- bacteria
- local wound environment
- local and systemic defence
Give some bacterial factors that affect wound infection
- presence and growth
- no. of bacteria (>10^5/g = “infection”)
- type and virulence (capsules, toxins)
- duration of exposure
- timing of exposure (hot defences lowest within 1st 3 hours wound)
Give some surgical factors that affect wound infection
> surgical procuedure - duration (>90 mins = 2x risk of infection, GA time >60 mins every minute extra = 0.5% ^ risk) - patient and surgeon prep - type of surgery > surgical wound - dead space and seroma - foreign material - blood clots - devilatlised tissue
Give some patient factors that affect wound infection
- age (old >8yrs or young)
- nutrition +/-
- disease conditions (DM, renal failure, endocrinopathy, cancer, hypoalbumenaemia, trauma, inflam, immunodeficiency)
- therapy (anaesthetic agents, corticosteroids, chemo, radiotherapy, blood tranfusion, vasoconstrictors, surgery
How may wounds be contaminated? Give examples of surgeries that fall into each category
- Clean (non-traumatic, elective Sx, no inflam, no break in aseptic technique, NO entering GIT/resp/repro tract)
- cat/dog castrate
- bitch spey
- thyroidectomy
- lump removal - Clean-contaminated (GI/resp tract entered with no spillage, urogen/biliary tract enetered with no infection, minor aseptic technique breach)
- cat castrate
- clean Sx with minor aseptic technique breach
- gastrotomy/eneterotomy
- cystotomy - Contaminated (Gross GIT spillage, entracne to urogen/biliary tract if infected, fresh traumatic wound 4hrs)
- abscess, FB, rtaumatic wound, surgical extraction
What is the decisive period?
2-3hours after wound exposure/innoculation = decisive period
- preventative ABx Tx only beneficial within the 1st 3 hours
- after this time outcome decided
When is the optimum time to give preventative ABx?
1 hour pre surgery
- NO difference in infection rate with 5d course of post surgery ABx
Who came up with the principles of good surgical technique?
Halstead
What are the 4 stages of aseptic technique?
- surgeon prep
- surgical instruments
- patient prep
- op theatre
What are non sterile barriers?
- scrub suits, caps, shoes, facemask
What are sterile barriers?
- gowns, gloves
What must be done before scrubbing in?
Put mask on
Give 4 disinfectants used for scrubbing in to surgery
- Chlorhexidine (broad spec, variable action v virus, no action v spores, rapid initial kill, persistent residual activity, NOT inactivated by organic material, toxcity not usually a problem unless direct contact with nerves, ears or cornea)
- Povidone Iodine (kills bacteria, viruses, funghu, not spores, requires 2 mins contact time, action decreased by organic material and hard water, use on mucosal surfaces and near open wounds, corrodes instruments, acute contact dermatitis and allergies)
- Alcohol (ethyl or isopropyl, kills broad spec, enhances action of chlorhexidine and iodine, corrosive to instruments, non-toxic, avoid near open wounds as dissacates)
- Sterrillium Alcohol (bactericidal, fungicidal, virucidal, TB, better for skin, no allergies, no scrubbing! v use water. do not mix with other hand creams/disinfectants)
What are the 2 forms of gloving?
- Open (sterile hands only eg. urinary catheter, central venous line)
- Closed (surgical procedures, gloves must cover cuffs)
What are the 2 types of indicators of steralisation?
- chemical
- biological (capsule of microbes, attempt to plate and grow after steralisation)
How should the patient be prepped?
- Antiseptic scrub in prep room for min 5 mins or until no more dirt removed
- move to theatre then repeat aseptic preparation and wipe off excess with alcohol
- apply final soluation povidone-iodine, PI + alcohol or chlorhexidine + alcohol
- sterile gloves applied
- sterile single use applicator (chlorhexidine gluconate and isopropyl alcohol)
What are the types of draping?
- Primary draping with single fenestrated or 4 field drapes
- 2* draping including skin towels and ahesive drapes
Where is the sterile field?
below neck, above waist
How are ABx excreted?
unchanged in the urine (hence could be recycled in the war)
Why are new antibiotics not developed?
- based on limited no. of products found in envoironment
- no commercial sense in developing new one as wouldnt be used much
What are the 2 ways in which ABx can be used?
> therapeutic
- treating an estabilshed bacterial infection
- appropriate course
- reduce infection to a levle body can deal with
prophylaxis
- reduce incidence of post-op infection
- need ABx only at time of infection, MIC must be maintained for duration of procedure
When should prophylactic ABx be administered?
- 30-60mins pre-incision IV
- additional doses at ~2*t1/2 (usually ~2hrs)
- continued max 12-24hrs post-op
In which types of surgery are ABx indicated?
- clean contaminated
- contaminated
- dirty
- long surgery (>90mins)
- implant placed
- if infection would be catastrophic
- immunocompromised patients
WHat choices of ABx are appropriate for surgical contamination?
Skin - G+s
Skin and GIT - G+ cocci and G- and anaerobes
Give examples of ABx efefctive against Gram positive cocci
Cefazolin, cefuroxine, amoxicillin-clavulanate
Give examples of ABx efefctive against Gram negatives
Cefuroxine?? look up
Give examples of ABx efefctive against anaerobes
Metronidazole
