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Flashcards in Sterilisation Deck (32)
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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?

1. Cleaning
2. Packing
3. Appropriate items
4. Loading/ unloading
5. Times and pressures
6. Sterilisation indicators
7. Storage


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
- Cheap
- Quick
- Reliable
- 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?

- Simplicity
- Sealed containers can be used
- Doesn't dull instruments
- Fairly cheap
- No moisture
- Non-corrosive
- 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
- Slow
- Expensive
- Toxic to people


Describe chemical cold sterilisation...

- Must be non-corrosive
- Used for delicate items
- Immersion time is critical
- Normally 15 mins
- No longer than 60 mins