Sterilization Processes And Maintenance Procedures

Case study 1

The reprocessing of medical materials for sterilisation seems to be an easy process but if understood properly it is a complicated process that requires serious practices to ensure complete sterilisation.

As per infection prevention principles, biomedical services and occupational health instructions cleaning and disinfecting are reprocessing practices along with some PPE rules for workers that are strictly required before sterilisation.

The personal protective equipment (PPE) rules are very first requirement that workers should follow to carry on a proper reprocessing for sterilisation. The PPE requirement includes: –

• Workers should perform hand hygiene both before and after removing gloves using soap, water, sanitizers and alcohol as per requirement.
• Workers should wear all the PPE equipment’s to avoid the risk of infections for contaminated stuff (blood and body fluid).
• Workers should follow manufacturer’s recommendations for cleaning specific equipment’s.

Further, the cleaning process is performed before disinfection or sterilisation that involves proper sorting of as critical, semi-critical and noncritical items. The sterilisation performed for different categories are always different, for example- critical items undergo steam, chemical or liquid sterilisation, semi-critical involves thermal or chemical sterilisation and noncritical items are cleaned using detergent.

• Workers need to open instruments, remove clips and latches followed by rinsing instruments with warm water to remove dirt.
• The dirt collected contains four categories of wastes that are clinical, cytotoxic, anatomical and sharps waste. All these waste have separate categories of bins where they should be separately and safely disposed off. Further, the harmful waste is disposed of in biohazard waste destruction bin for safe destruction.
• Scrubbing with the brush is performed for proper cleaning further rinsing with water. Further, instruments are dried using the lint-free cloth and individual instruments are inspected before sterilisation.

After cleaning disinfecting is performed where immerse instruments are disinfected as per the manufacturer manual. The instruments are fully covered and kept for disinfection followed by removal of disinfectant with water. Further, they are dried with cloth and disinfectant is completely thrown as waste.

For a newly engaged dental assistant, it is important to know that sterilisation is an essential and imperative part of dental practice. It is required for each and every dental worker to perform sterilisation as per Australian Standard AS4187 in his or her medical practice.

The following steps help to understand the complete sterilisation process in the appropriate manner.

• Firstly, collect the equipment’s required for sterilisation that are steriliser, packages (paper/laminate materials), sterilization trays (metal or plastic tray with holes), permanent marker, clean tongs, indicator tape, recording and monitoring books.
• Pre-clean and dry all the used items
• Put the instruments in the sterilising tray followed by packing the content so that they are clearly visible through the laminate side. Ensure that sharp instrument tips are protected to stop damage to packaging.
• The waiting time between packaging and sterilisation should be kept minimum to avoid contamination.
• Label the packages with the permanent market before sterilisation with identification name or code and date. Try to record these label in monitoring books as well for tracking faults in sterilisation process.
• Seal the packages with indicator tape across its width overlapping on each side.

Loading steam steriliser

• Ensure that air is completely removed from chamber without blocking the air vents
• Further, keep instruments in a proper manner that steam is surely able to reach and saturate all surfaces for sterilisation.
• Assure that all the condensation is completely drained away
• The instruments must not stick out of the tray and even not touch the chamber walls.
• Arrange unpackaged instruments in a single row in the tray.
• Further, assure that all packaged instruments are lying flat on the tray with paper side facing down.
• Put Hollowware on the sides of sterilisation tray to let the air and condensation drain away. Further, let the linen hanging vertically upwards with no further adding to packages material above it.
• Use distilled water in steam steriliser and allow sterilisation following correct time + correct temperature + correct preparation process.

Unloading steam steriliser

• Follow the drying cycle after sterilisation is complete where assure that packages are not open until drying cycle is complete.
• Unload the steriliser using tongs one by one removing single tray or instrument at one time.
• Remember to wear PPE required for unloading sterilizer.
• Check the change in indicator colour to ensure sterilisation without harming seal.
• Record the pressure, temperature, time and then sign off.
• Keep instruments on the non-solid surface to let them dry without using fans.
• However, if instruments are to be used directly without drying then use sterile gloves to remove packaging paper. Single dry instrument using a lint-free cloth.

For proper maintenance of sterilisation, it is essential to record and monitor the complete process. This helps to detect faults, improve loopholes and missing essentials in the process. For record keeping and monitoring an operating manual, commissioning data copy and a log of the ongoing process, maintenance and calibration should be kept while performing sterilisation.

For getting a good quality performance of a steam steriliser it is essential to provide regular maintenance programme that ensures proper functionality. Any kind of malfunction in maintenance process can lead to damage to sterilise. The below provided are details of daily, weekly, monthly and as scheduled maintenance process that is required to maintain a steam steriliser.

Daily maintenance

Clean the steriliser regularly especially the rubber chamber seal, sterile trays and inner surface with mild detergent, warm water and a soft cloth. Further, rinse well before use.

Use nylon scourer to clean the metal surface of chamber seal very gently using mild detergent and water.

Case study 2

Weekly maintenance

Weekly clean the sterilisation chamber, tray racks, trays and outer surfaces using disinfectant, mild detergent and warm water

Water reservoir should be drained and flushed on weekly basis.

Monthly maintenance

Lubricate hinge and closing mechanism of door monthly if required using silicone-lubricating spray. However, try to use the lubricating spray very rarely.

Remove and clean debris from primary filters on monthly basis

As scheduled

Bacterial filters and chamber seals require periodic replacement depending on the brand, rate of usage, age and handling of steriliser. Therefore, this maintenance is required to be scheduled by the operator as per need.

Importance of quality assurance of sterilisation equipment

Quality assurance testing and servicing will ensure lifelong reliability and safety of sterilisation instrument. The regular servicing and validity test are two methods that ensure the quality of steriliser. Regular service via manufacturer or approved service company shall reduce breakdown frequencies ensuring the safe use of steriliser.

Further, below provided four validity tests ensure the validity of steriliser

Heat distribution test- Detect the coldest spot of the chamber

Penetration time test- Measuring the real time taken for challenge pack centre to reach active temperature of sterilisation

Cycle confirmation test – Validation single sterilisation cycle as per Australian standards

Biological test- This test confirms consistency of steriliser for medical functionality.

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