We've all spent many hours manually cleaning items in our time. Few would suggest it was truly their method of choice (if they are the one doing the cleaning!), as anyone remembering the experience of the great change-over when a nice new white dishwasher found its home in a 600mm slot in the kitchen or utility room will verify. Before this day, manual cleaning of the spoils of a dinner party was neither enjoyable nor therapeutic. If you consider this manual method and relate it to soiled and contaminated medical instruments with sharp protrusions then it becomes an even less enticing or effective option, particularly to those who are actually doing the cleaning.
As to the differences between the kitchen dishwasher and the modern thermo-washer disinfector, these are less visible on the outside - and even when opening the door the trays and baskets look somewhat familiar. At this point however, the similarities end. The thermo-washer should be manufactured from high grade stainless steel, with the chamber of AISI 316 quality, and the cabinet of a similar standard; this is to prevent corrosion by ensuring it can cope with the strong detergents used in dental /medical practices, as well as withstanding the heavy amount of use within a busy dental or medical practice. Just a simple weight test reveals the kitchen machine can be lifted with ease whilst the medical thermo-washer is a two person with trolley and stair lifter type of load (don't try this, just take our word for it). This additional weight comes from the robust chamber, the external casing, plus far more components, which are tightly packed beneath the casing.
Difference
So why the difference: how does it work and what does it do?
Thermo-washer disinfectors are sophisticated medical devices: thorough cleaning is achieved by very high water flow rates, which are created by a powerful pump at high pressure. Process control is an essential feature that regulates and controls the various stages of the cycle. Temperature is regulated to ensure it is below 45°C during the initial stages to prevent possible coagulation of protein that may be present; it is then raised to above 60°C at which point the detergent or cleaning agent is introduced into the process. This detergent is formulated and validated for the particular machine developed and takes into account both the cleaning efficacy for the cycle profile and the necessity to minimise damage to instruments. Once the cleaning phase is complete the machine is drained to waste to prevent any damage from residual detergent when the important thermal stage starts by further elevating the temperature, typically to just over 90°C, but this may be lower if the manufacturer has selected a longer 'hold' time. Drying is then applied to the instruments by several methods, but to keep cycle times to a minimum, the preferred method is by forcing hot air into the chamber with a built-in condenser which removes most of the moisture with just a minimal ingress into the decontamination room.
Many users, when looking to purchase a thermo-washer disinfector, are unaware of the medical standards and guidance demanded upon the manufacturer, which require the inclusion of many features you will not find on a domestic appliance. These are necessary as the machine has to reliably and reproducibly process contaminated items in a medical environment. A few of the most noticeable things have associated warnings or alarms, such as a door lock that cannot be interrupted without halting the process, a system for administering a precise dose of detergent, dual temperature monitoring, dual processors, and monitors which would identify problems including jammed water distributors and incorrect pump pressure. The machine is monitoring factors that would affect performance and efficacy and may prevent thermal disinfection from occurring. The cycle must be monitored at all stages and a printed or data record stored for the required period.
Many machines also have the facility to process a quantity of handpieces using a special handpiece rack that forces water through the narrow lumens. For dentistry this should be supplied as a standard feature together with a variety of racks and baskets to accommodate clip trays and loose instruments. The debate on reverse osmosis (RO) water has led to some recent changes in recommendations and specific requirements but generally this change only affects England so far. Whilst it may not be current advice in your area we advise you to purchase a machine that has this facility to fully future-proof your practice or to check that it is available as a retro-fit option in the event that guidance changes.
As with any equipment purchase, check the dimensions - both external and chamber size - to ensure it meets with your requirements of being neither too small for the throughput of instruments you require, or equally important not too large as this will invariably push up the cycle times, water, energy and detergent consumption. Check also that it can it be plumbed to a standard water (and RO if available) or waste services and whether it will connect to an adjacent 13 amp supply or will require a dedicated 32amp supply. Feel the quality of the machine and satisfy yourself it is well made and fit for purpose. Ask if it has a service and validation protocol for daily and monthly testing by the user and an annual testing protocol performed by your test or service engineer. Look at the cost of consumables which should be readily available from the supplier or distributor and do not be tempted to use non-recommended detergent or accessories as they may not be validated to be effective in a dental/medical environment or work with the machine.
Unlike 'best practice' (under HTM 01-05), 'essential requirements' does not demand automated cleaning, but by integrating a high quality thermo-washer disinfector into your decontamination process, you will reduce the risk of sharps injuries to your team and you will be introducing a reproducible, validatable, medically effective washing process, that will ensure you are doing the best you possibly can to reduce the risk of cross infection amongst your patients and your team – and that has to be a good thing.