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This is carried out to check that if too much air is allowed in the chamber, it should stop the sterilizing itself. This works by the pressure increasing and steam going in the chamber, if any air is within the chamber it will form pockets. Air pockets are a bad thing as it can disturb the sterilization process by preventing the steam from reaching all places on the load of instruments. So, if there are too many air pockets it will stop the sterilization process. The autoclave should be able to perform the test by itself when set by the operator, it itself will indicate whether he cycle has passed or not. Steam Penetration Test This test is done daily at the beginning of the day. The main aim of the test is to prove whether the steam penetration part of the cycle is efficient when processing equipment through the autoclave. It is achieved when it can validate that air or non-condensable gases that stops the sterilization from working efficiently is removed effectively by the vacuum stage. Because when the air or non-condensable gases are removed, the steam can then penetrate the instruments effectively, thus resulting in fully sterilized instruments. We know the cycle has passed when we use the Helix device. A strip with a yellow part is placed within the helix device and screwed back on. Then once the test has been completed the strip should have turned purple to prove it has passed the test. The strip should be logged in a log book. Describe the positioning of all equipment in the decontamination room, what happens at each stage and why is this important also why is it important to clean instruments prior to sterilisation?

The decontamination room should ideally be separate from the clinical rooms. The decon room should consist of a set down area for dirty items, a handwashing sink, an instrument washing sink, ultrasonic bath (if required) rinsing sink/bowl, washer-disinfector, illuminated magnifier for inspection, autoclave/s and a packaging and storage area for clean instruments. If the entire process is followed accordingly then it should be that the dirty/clean instruments are separated and as far from each other as possible. When nurses are handling the instruments at each process, they will change their gloves to stop them from getting contaminated again. The air flow system should ensure that any aerosols or airborne disease are going further away from the clean side. Autoclaves are to be placed away from the dirty zones. The worktops should be sealed and smooth so that it is easily wipeable. Furthermore, the zones should be labelled clean/dirty. Decontamination How should handpieces be decontaminated?

For handpieces the manufacturer’s instructions should always be followed to prolong the life of the handpieces. With the autoclaves available these days, it is accepted that handpieces cannot be fully sterilised, as we can’t fully eliminate the risk, we must therefore try to control the risk of cross-infection and try reducing it as much as possible. All handpieces must undergo cleaning in a suitable cleaning agent, lubrication according to the manufacturer’s instructions and sterilisation. How should dental hand instruments be decontaminated? Firstly, some washers are handpiece friendly, but it depends on the manufacturer’s instructions. Nonetheless, the hand instruments should be placed in the washer disinfector in such a way that the instruments do not overlap each other. This is so they can go through the full effect of the washing and disinfection cycle. They usually go through 5 stages throughout the process which involve cleaning and disinfection. The 5 stages are as follows; flush, wash, rinse, thermal disinfection and then drying. These stages cannot be altered or missed out. The dental nurse’s job throughout this process is to ensure that all the water and detergents required are full and to load the container in the correct manner wearing full PPE. There is another way to decontaminate instruments before being placed in the autoclave although it is not as effective as the washer disinfector. It’s called the ultrasonic bath. If the instrument is covered in visible contaminants and blood, then the instruments should be soiled in a detergent for a while and then rinsed before being placed within the ultrasonic bath. Items that have a hinge must be opened and assembled items should be de-assembled before being placed in the bath.

For debridement to occur effectively, the instruments should be fully immersed in the solution and placed on the bath tray. Like the washer it is ideal for the instruments to not be overlapped as debridement cannot be done effectively. The nurse should then follow the manufacturer’s instructions which usually state to close the lid and begin the process, also setting a timer. The reason why we close the lid is so that it stops aerosols from escaping and contaminating the area. Once the timer has been completed, the basket should be drained and rinsed in a ‘rinsing’ sink either by distilled or R.O water. Lastly, the instruments should be inspected to see if debridement has been effective during the process. Once this has been completed it can then be placed within the autoclave to be sterilised. Debridement cannot occur on handpieces within the bath. The last way to decontaminate instruments is manual cleaning. This is seen as the least effective and most risky way but is still allowed if there is a problem with the other 2 methods. The instruments should be cleaned with a brush that has bristles with a plastic coating and not metal as that can scratch the surface. Making it easier for bacteria to get stuck within the scratches. Suitable P.P.E should be worn during manual cleaning. Things such as heavy-duty gloves, facemask, visor and apron. Once the items have been used it is best to manually clean them as soon as possible.

This is because it is easier to clean instruments when the soiling is wet on the instrument and not dried up. It should be done in a ‘washing; sink with cold water, preferable below 45°C, because hot water causes the contaminants to ‘fix’ on the instrument surface making it harder to remove. In order to stop the spread of aerosols, the instruments should be scrubbed under the surface. Then once the instruments have been cleaned, they should be placed within the ‘rinsing’ sink and rinsed with distilled/ R.O water in order to remove the detergent used for cleaning and any loose contaminants left. The reason why tap water isn’t used is because it contains chemicals which are unwanted and how ‘clean’ it is depends on the provider. Before placing them in to the autoclaves they should be inspected using the magnifying glass and if anything is left over it should go through the same process again. If any items are to be bagged before sterilising should be dried properly first. Sterilisation So, what happens to the instruments after being decontaminated? Once the instruments have gone through either the washer, ultrasonic bath or manual cleaning, it is then considered safe enough to be put in to the autoclaves in order to be fully sterilised. There are 3 types of autoclaves which are used, they are ‘N’, ‘B’ and ‘S’ type autoclaves.

However, ‘S’ type autoclaves are commonly used in a hospital environment. Our duty as a dental nurse is to make sure that the water reservoirs are full and to load instruments in a single layer once it has been decontaminated. ‘N’ type autoclaves heat up to 134°C and stays at that temperature for 3 minutes at a pressure of 2.25bar. Then steam is injected downwards in the chamber so that it touches all the instruments. The entire cycle lasts for about 15-20 minutes, depending on how much it has been used that day, this is because if it was used just recently then it will reuse that heat and not need to warm back up again as much. The instruments should be placed on perforated trays, evenly spread out and not overlapped. This type of autoclave is good for unwrapped and solid instruments. As it can hold usually 4 or more trays at a time it can then reduce the number of cycles needed in a day. Cycles can also be set so that they dry instruments before coming out, however this takes almost double the time for the cycle to be complete. Lastly the door cannot be opened during the cycle. ‘B’ type autoclaves also heat up to 134°C and stays at that temperature for 3 minutes at a pressure of 2.25bar. However, this autoclave tries to create a vacuum so that steam reaches all parts of the instrument, particularly good for hollow instruments. There are more cycles to choose from which is dependent upon the load itself. If a vacuum cycle is set, it can last up to 45 minutes.

The vacuum cycle is preferred for wrapped items and those instruments that are hollow such as handpieces or syringes. These autoclaves usually contain a device which logs the data coming out of it so that the operating parameters are checked and recorded. Similarly, like the ‘N’ type autoclave it can hold 4 or more trays which reduces the amount of cycles needed and neither can the door be opened whilst the cycle is taking place. One con about this autoclave is that it is usually more expensive than the ‘N’ type autoclave. Storage What happens to instruments after sterilisation? In order to make sure that the instruments coming out of the autoclave are still sterilised before they enter the pouches, nurses must ensure that they are wearing full, clean P.P.E, dry the instruments using a lint-free cloth/towel and lastly once sealed they should be placed within something which acts as a barrier between the general atmosphere to avoid aerosol and microorganism recontamination such as a lidded tray. Instruments should be pouched once they are dry as they can be re-contaminated with microorganisms whilst wet/damp.

They should either be dried using the cycle in the autoclaves or dried manually using a single use cloth as opposed to a reusable one. This is because the reusable cloth is more likely to get contaminated by aerosols and such over the period of the day. For autoclaves that have a downward displacement, the items must be dried and wrapped after the sterilisation process. As the pouches are date stamped, it is said to re-sterilise them after 1 year. However, recently it was set at 21 days for downward displacement autoclaves and 60 days for vacuum autoclaves. In vacuum autoclaves, if the instruments were wrapped before being sterilised and then placed within a lidded tray, it can then be date stamped to 1 year. After pouching they should immediately be placed within a cupboard or draws. Within the surgery, it is hard to stop them from being contaminated with aerosols so they should be placed within drawers and brought out only when it is needed. The general public should not have access to the decontamination room. Instruments should be collected from the clean zone in the de-con room when needed. How is the maintenance of equipment and instruments recorded? Ultrasonic baths should be maintained regularly by a service engineer or by a delegated person who is competent enough in de-con which is recommended by manufacturers as a bare minimum. It is recorded in a log book or the sides of the bath could be stamped by the manufacturer to ensure that they were the ones to check this. The washer disinfector usually has automatic logging systems within it to ensure that it is working accordingly. This is then recorded by nurses in a log book to keep a backup record of the cycle and to prove that nurses are constantly checking up on it to prove it is working. The autoclaves test cycles are recorded within a log book.

Tests are carried out daily and weekly which must be recorded. The automatic control test should be carried out daily in vacuum autoclaves along with the steam penetration test. R.O/ distilled water should only be used for the autoclaves to help maintain them and keep it working correctly. An authorised engineer should check the autoclaves are working accordingly and issue a certificate to prove this. This should be done annually. What are the potential risks of failing to decontaminate equipment and instruments? If we fail to decontaminate equipment and instruments properly then they won’t be sterilised when put into the autoclave. It can also increase the chances of cross infection between patients as blood and other debris will still be on the instruments. Autoclaves are only used to kill microorganisms as well as spores but not visible debris. It could also result in a cross-infection risk for the autoclaves because if the debris falls within it, and more instruments are placed within the autoclaves. It could just keep spreading. What are the potential long-term effects of using damaged or pre-used sterile goods? If we use damaged dental instruments it may not work properly on the patient. It could possibly cause more harm. If we use pre-used sterile goods it could increase the risk of cross infection. This is because the instrument or bur has already been used, it may not have been decontaminated properly and may not even be penetrated properly by the steam during the sterilisation process, especially with burs as they are very hard to check if they have been cleaned properly or not.