Disposable materials used in the sterilisation process
Sterile barrier systems (packaging)
The purpose of sterile barrier systems is to provide an effective barrier against sources of potential contamination during storage, and permit aseptic removal of the contents of the sterile barrier system at the time of subsequent use.
Sterile barrier systems need to allow for air removal, steam penetration, removal of steam and drying of the contents. Using the correct sterile barrier system ensures that reusable medical devices are sterilised and remain sterile. Sterile barrier systems standardised for quality.
Types of barrier systems include:
- bags made of paper that require tape for sealing
- self-sealing pouches made of paper backed with clear plastic (laminate)
- rolls of paper with laminate, which must be cut to size and sealed at both ends using tape or heat sealing
- sheets of low-lint single-use nonwoven material made from spunbond-meltblown-spunbond polypropylene and/or cellulose
- rigid reusable sterilisation containers and cassettes.
Reusable linen wraps are no longer used in general practices and other office- and community-based practices.
Sterile barrier systems need to be suitable to their purpose. The type of sterile barrier system chosen depends on:
- the size and contents of the sterile barrier system (eg laminate pouches come in a limited range of sizes, while nonwoven purpose-designed fabric is suitable for large packs.)
- the type of reusable medical devices/equipment to be placed in the sterile barrier system.
Most practices use pre-made bags or pouches, which are suitable and convenient for most small-to-medium items or sets of items.
Larger items (such as surgical instruments on a tray) require wrapping using specific approved techniques, which require specialist training to perform correctly. The Sterilizing Research Advisory Council of Australia provides a list of sterilising courses available in all states and territories.
Whichever type of barrier system is used, an external Class 1 chemical indicator must be incorporated into the pack. Pouches and bags are made of material that incorporates a Class 1 indicator. When using rolls or sheets, the wrapped package is secured and sealed with adhesive tape that contains a Class 1 indicator.
Pouches and bags must be correctly sealed to reduce risk of contamination. Laminate rolls require a heat sealer (spare elements should be kept as they can burn out) or tape to seal the ends.
Annual validation confirms the suitability of the sterile barrier system.
Packs of pouches or rolls of barrier system materials must not be exposed to dust and contamination. They must be stored in cupboards or drawers, not on open shelves or benches.
Class 1 chemical indicators
All items placed in a sterile barrier system must incorporate a Class 1 chemical indicator on the bag or pouch, or on the tape used to seal the item.
Class 1 chemical indicators are designed to demonstrate that the sterile barrier system has been exposed to the physical conditions of the sterilisation process, but do not guarantee sterility. They are designed to react to one or more of the critical variables (eg change colour when the correct temperature is reached).
Most new sterilisers capable of Class S or B cycles require a large amount of demineralised (distilled or deionised) water, which can be purchased in containers of 5–20 litres from a commercial supplier or produced on site using a demineraliser. The steriliser draws the water through a tube placed in the water supply under the bench.
Installation of small reverse osmosis water filtration systems to supply small sterilisers and washer-disinfectors avoids the inefficiency and high costs of purchasing demineralised bottled water.
Most modern sterilisers employ inbuilt water recycling. With some older sterilisers, water must be to be added to the chamber and the reservoir must be topped up.
Water that is discharged from any steriliser is not suitable for reuse.