Flashcards in Sterilisation Deck (32)
What is the definition of Sterilise?
To destroy all living organisms
What is the definition of Disinfect?
To make free from infection by destoying all organisms in the vegetative state (spores not included)
What is the definition of Antisepsis?
Destruction or inhibition of organisms on living tissues
- limiting or preventing the harmful results of infection
What is the definition of Sanitise?
To reduce the total bioburden
- Reference to utensils and equipment
What is the definition of Steriliser?
A piece of equipment by which sterilisation may be achieved
What is the definition of Autoclave?
A piece of equipment by which sterilisation may be achieved using steam under pressure
- Simple, inexpensive, safe and reliable
What is the definition of Sterile supply?
The location where sterile items and equipment are dispensed
- In a small clinic this is usually a bench area with laundry
- In a large clinic it is usually a dedicated room
Should be arranged to separate dirty from the clean
What are the required conditions for steam sterilisation?
1. Sufficient moisture to allow full penetration
2. Complete contact
3. Correct temperature to kill organisms
4. Correct contact time
What are the different types of autoclave?
1. Single shelled autoclaves - no drying cycle
2. Double shell autoclaves - preferable
What are the main components of the sterilisation process?
3. Appropriate items
4. Loading/ unloading
5. Times and pressures
6. Sterilisation indicators
How do you clean instruments for sterilisation?
Sterilisation often ineffective if any organic material present
- Rinse in cold water
- Wash in tepid water with enzymatic cleaner
- Rinse and dry
- Ultrasonic cleaners
How do you pack instruments for sterilisation?
Cloth wraps, kimguard or paper backed plastic pouches
- Trays: wrapped
- Single instruments: packed
- Multiple instruments not in tray: double bagged
- Larger items : wrapped then pouched
What is of most importance of packing material for sterilisation?
What and how you wrap has an effect on whether or not the objects achieve sterility
How do you know what items are appropriate for autoclaving?
- Generally autoclaves can't process delicate instruments
- Follow item instructions or note maximum temperature
-- Many plastics will melt at 134C but survive 121C
How do you Load/ Unload instruments for sterilisation?
- Allow free circulation and penetration of steam
- Enhance air elimination
- Prevent entrapment of air and water
- Leave untouched with autoclave door open for 30 mins before unloading
What is important to remember about warm autoclave packages?
If they are placed on a cold surface they will become damp from condensation and become unsterile
What are the times and pressures for autoclave sterilisation?
15psi @ 121C for 15 minutes
30psi @134C for 3-4 minutes
What different things can be used as sterility indicators?
- Indicator tape
- Indicator strips
- Browne tubes
- Biologic indicators
- Batch controllers
only indicate that cerain conditions have been met
What do browne tubes do?
Test air removal
- Determines time, steam and temperature
What is important about biological indicators?
They are the only way of determining that thermophilic bacteria cannot have survived
What are recommended storage times for items?
- Double wrapped Kimguard: 6 months
- Single paper pouches : 6 months
- Double paper pouches: 6 months
- Drapes/linen/Kim guard : 1 month
- Paper pouches : 6 months
What are the best conditions for equipment storage?
- Correct temperature and humidity
- Low traffic area
- Minimal handling
What are the advantages of autoclaves?
- Steam is readily available
- Sterilises most things
- Equipment can be stored afterwards
What are the disadvantages of autoclaves?
- Requires special equipment
- Requires careful monitoring
- Cannot sterilise delicate or sharp instruments
What are some other methods of sterilisation?
- Dry heat
- Chemical gas sterilisation
- Chemical cold sterilisation
- Ionising gamma radiation
- Plasma sterilisation
What is dry heat sterilisation?
- Oxidative denaturation of proteins
- Bacterial spores show greater resistance
- Longer exposure times are thus needed
What are the advantages of dry heat sterilisation?
- Sealed containers can be used
- Doesn't dull instruments
- Fairly cheap
- No moisture
- Sterilised oils and powders
What are the disadvantages of dry heat sterilisation?
- Long exposure times
- Careful loading technique required to ensure all parts of the load are sterilised
- Requires careful monitoring
- Unsuitable for heat sensitive materials; paper, cloth, plastics etc
Describe chemical gas sterilisation...
- Ethylene oxide ETO
- Flammable, explosive gas which becomes an effective steriliser when mixed with CO2
- Kills by alkylation of DNA
- Was used for equipment that couldn't be autoclaved
- Items have longer shelf life
- Toxic to people