Aseptic technique Flashcards
Define sepsis
presence of pathogens +/- toxic products in tissues (asepsis = opposite of this)
Define antiseptic
chemical agent that kills or inhibits pathogenic microorganisms. ONLY for agents applied to the body
Defien disinfectant
chemical that kills microorganisms on inanimate objects - surgical equipment
Define disinfection
removal of organisms, not necessarily their spores
Define sterilisation
complete elimination of microbial viability including spores, by physical/chemical means
What may infection during surgery lead to?
adverse effect on procedure adverse effect on general health increased morbidity and mortality further treatment needed increased costs increased hospital stay
True/false: almost all surgical wounds get contaminated but not all wounds become infected
True
What are 3 surgical factors
Bacteria
local wound environment
local and systemic defence
What are bacterial factors?
presence and growth of bacteria number of bacteria (> 10^5 bacteria/g = infection) type and virulence duration of exposure timing of exposure
What are surgical factors?
PROCEDURE
Duration (at 90 mins you are twice as likely to get infection than an operation lasting <60 minutes)
patient and surgeon prep
type of surgery
SURGICAL WOUND dead space and seroma foreign material blood clots devitalised tissue
What are patient factors?
patient - age and nutrition
Disease conditions
Therapy (concurrent)
What therapies may increase the likelihood of infection?
anaesthetic agents, corticosteroids, chemotherapy, radiotherapy, blood transfusion, vasoconstrictors, surgery
How does the NRC classify wounds from surgery? 4
Clean
Clean - contaminated
Contaminated
Dirty
When does contamination become infection?
Usually in the ‘decisive period’ = first 2-3 hours after wound exposure/inoculation (thus preventative AB only beneficial during first 3 hours).
What are Halstead’s principles about?
Good surgical technique (e.g. minimal trauma, close all dead space, no tension on sutures)
What are the 4 main components of aseptic technique?
Surgeon prep
Surgical instruments
Patient prep
Operating theatre
What are non-sterile barriers?
e.g. scrub suits, cap, shoe/covers, face mask
What are sterile barriers?
gowns and gloves
What are scrub suits made from?
Loose weave lint-free fabric = a barrier for dander but not microbes. wear only in theatre, tuck top into trousers and trousers into boots.
How to scrub up …
remove all jewellery short and clean nails mask on before scrubbing appropriate antiseptic brush and soap ready water running (correct speed and temp)
What is another name for hibiscrub?
chlorhexidine
What is chlorhexidine active against?
kills broad spectrum of bacteria
variable against viruses
no action against spores
Kills by: precipitation of cellular contents, alteration in cell permeability. Rapid initial kill. Persistent residual activity. Not inactivated by organic material (farm vets1!)
Is toxicity a problem with chlorhexidine?
Note generally but it is ototoxic, neurotoxic and corneal toxic with direct contact
What is iodine/povidone-iodine?
Kills bacteria, viruses, fungi but not spores.Inhibits protein synthesis. requires 2 minutes contact time.
Action decreased by organic matter and hard water.
When to use iodine/povidone-iodine?
Mucosal surfaces and near open wounds
Disadvantages - iodine/povidone-iodine?
Corrodes instruments
Acute contact dermatitis
allergic reaction in sensitive people
What is an alcohol scruv?
Usually either ethyl alcohol 70% or isopropyl alchol 99%
What does alcohol kill?
broad spectrum of bacteria via protein denaturation, inhibition of cell division, rapid initial kill. Enhances action of chlorhexidine and iodine
Disadvantages of an alcohol scrub? 3
corrodes instruments
relatively non-toxic
avoid near open wounds
What is Alcohol-sterilium?
ethanol based 85% (bactericidal, fungicidal, virucidal, tuberculcidal)
How does alcohol-sterilium improve skin health?
moisturising, maintains skin lipids (non-drying), no reported allergies, no scrubbing,
How does gowning give a sterile barrier? 2
tied at back
wrap around 360 degrees
What is the difference between open and closed gloving?
CLOSED= most common for surgery, requires long sleeved gown, gloves must cover cuff of gown OPEN = procedures that require sterile hands only, urinary catheter, central venous line (jugular catheter)
What should you remember about instrument sterilisation?
See previous lectures
METHODS (physical or chemical)
INDICATORS OF STERILISATION (chemical, biological)
Practical points (packaging of instruments, storage of packages)
How is the patient prepared?
CLIPPING (wide area, prep room)
ASEPTIC PREP OF SKIN (chlorhexidine 4% or povidone iodine)
PREPARE ALL CLIPPED AREA
SCRUB INSUDE TO OUT
SCRUB UNTIL NO FURTHER ORGANIC DEBRIS
ASEPTIC PREP IN THEATRE - repeat aseptic prep in theatre, wipe off excess scrub with alcohol, apply final solution)
Why is draping important?
reduces the risk of contamination by surrounding hair/skin
What are the different types of drape?
Disposable (impervious, good condition, labour saving)
Reusable (270 threads/sq inch necessary)
Distinguish primary and secondary draping
PRIMARY - single fenestrated drape or 4 field drape
SECONDARY - skin towels, adhesive drapes
What is the surgical field?
Incision site + sterile drapes + instrument trolley + surgical team (front of body, below neck, above waist, arms and hands)
What is the reality of administering an AB?
Every time an AB is used, you select for resistant bacteria. There is NO negative effect on bacteria for having resistance genes/plasmids etc. Every year, resistant bacteria cause 5000 deaths a year in UK and 25000 deaths a year in EU.
Are ABs generally excreted unchanged from the body?
Yes - adds to environmental load and increases resistance. This will accelerate problem as humans and animals share bacteria.
What is the capitalism of AB development?
They are expensive to Research and develop
New AB will be used as little as possible therefore doesn’t make commercial sense
What are therapeutic ABs?
treating an established bacterial infection. appropriate AB for suitable time period course
reduce infection to level body can deal with - don’t forget drainage
What are prophylactic ABs?
reduces the incidence of post-op infection assuming that contamination will occur. You need AB ONLY during the time of contamination. Inappropriate prophylaxis is the unnecessary use of AB or the continuation of AB beyond the recommended time period.
How should prophylactic ABs be administered?
IV
30-60 minutes before incision
Additional doses: every 1-2 times the half life
The maximum time to give prophylactics for after an operation for them to be effective is 12-24 hours post-op, NO MORE!
What is the result of inappropriate AM use? 5
Increased cost
idiosyncratic drug reactions
suppression of normal bacterial flora (esp. GIT)
development of bacterial drug resistance
increased risk of hospital-acquired infection/ superinfection
According to the NRC classification of wounds, when are prophylactic ABs indicated?
Clean - no (with caveats)
Clean-contaminated - indicated but controversial
Contaminated - indicated
Dirty - therapeutic use indicated
When should you use AM prophylaxis in clean surgery?
Longer surgery (>90 mins; 2 times rate per hour)
Implant placed
If infection would be catastrophic to outcome
Immuno-compromised patients
True/False: oily suspensions given S/C post-op don’t work reliably.
True
What group of bacteria are commonly isolated from the skin? What are appropriate AMs?
Gram + cocci
Use - cefazolin/cefuroxime, amoxicillin-clavulanate
What groups of bacteria are commonly isolated from the skin with GIT contamination? 2 What are appropriate AMs?
Gram + cocci
Gram - bacteria
Use - cefazolin, amoxicillin-clavulanate, cefuroximine
Which groups of bacteria are commonly isolated from the body tract? 2 What are appropriate AMs?
Gram - bacteria
anaerobes
USE = cefuroximine, metronidazole
