Sterile goods: Legal certainty in reprocessing with new water limit values

Sterile goods: Legal certainty in reprocessing with new water limit values

Does your AEMP work with water quality in accordance with DIN EN 285? Then be careful: the standard limit values are no longer state of the art and the legal certainty of your treatment is at risk. Read this article to find out what damage is at risk and what to do.  

Reprocess legally compliant and save costs

DIN EN 285 still officially dominates water quality in the reprocessing of medical devices. However, it no longer reflects the current state of knowledge: specialist guidelines have been recommending stricter limit values since 2022, which could soon become legally binding. Smart hospital management and AEMP managers are therefore already switching to the legally compliant side and working according to these new limit values for water quality. The icing on the cake: not only do they have legal certainty in treatment, they also benefit immediately through cost savings.  

DIN EN 285: Need to expand to include modern new limit values

DIN EN 285 currently applies to steam sterilizers, but it has long been apparent in practice that its limit values for water quality are unsuitable for modern steam sterilizers. Although steam is sterile, a steam sterilizer is a precision instrument and places high demands on the quality of the water and steam used for sterilization. Facilities that only work in accordance with DIN EN 285 risk damaging instruments and medical devices. This is why the Instrument Reprocessing Working Group (AKI) specified stricter limit values in its Red Brochure back in 2017. The DGSV’s expert committee on hygiene, construction and technology has included these in its free recommendation no. 17 from April 2022 and defines requirements for the construction or conversion of an AEMP. For selected parameters, the committee recommends  

Parameters	DIN EN 285, Table B 1 for clean steam generators	DGSV Technical Committee 2022
Conductivity at 25 °C	≤ 5 µS/cm	≤ 0.1 µS/cm
Silicate	≤ 1 mg/l	≤ 0.4 mg/l

  The conductivity shows how many ions are still dissolved in the water. The higher the conductivity, the further away the water quality is from the goal of fully demineralized water (demineralized water). Among other things, sodium, calcium, magnesium and chlorine ions contribute to the conductivity of the water. They can all damage instruments and jeopardize reliable treatment. However, conductivity measurements do not detect silicates, so the silicate content of the water must also be measured. Silicates are salts of silicic acid and damage instruments through glaze-like deposits, which are time-consuming and expensive to remove. Silicates also accumulate in the membranes of water treatment systems, and if their load is too great, the membrane ruptures. Although many facilities check conductivity, they ignore silicate measurement as a safety check – and risk damage to instruments, medical devices and equipment.  

Instrument damage in concrete terms

How do your instruments actually suffer from undesirable substances in the supposed deionized water? The three most important types of damage:

• Scale deposits
• Pitting corrosion
• Silicate deposits

  Limescale deposits Calcium and magnesium salts cause limescale stains and deposits. Although this is not a hygiene problem, it is a sensitive additional expense for the AEMP team, who have to remove these stains manually from each individual instrument. To prevent limescale deposits, it also makes sense to measure the water hardness, because limescale is water hardness.   Pitting corrosion Chlorides and other halogen salts cause pitting corrosion. It is rightly feared, as the small “pinholes” often conceal a larger hole in which germs can colonize. And that’s not all: if the instruments are not sorted out and repaired immediately, there is a risk of irreparable consequential damage and, in the worst case, breakage of the instrument during the operation. Pitting corrosion is therefore a hygiene risk, a cost factor and a danger to the safety of surgical staff and patients.   Silicate deposits Silicates are deposited as brownish or bluish discolorations and coatings – not only on the instruments, but also in the chambers of the washer-disinfector and sterilizer. Silicate deposits make visual inspection difficult, they are as hard as glass and can therefore only be removed with great effort. Acidic cleaners are used for this purpose, in stubborn cases hydrofluoric acid. However, acids can fade laser markings, which in turn damages the traceability of the instruments. In the long term, silicate coatings can lead to corrosion.  

Coatings are a burden on the budget

Limescale deposits, corrosion, silicate deposits – your instruments, washer-disinfectors and sterilizers literally suffer the consequences of poor process water quality. And that is expensive: HeylNeomeris has analyzed the figures of a clinic from 2019. The necessary repairs and replacement purchases of instruments had already consumed 87.55% of the entire annual budget after the first six months. For the year as a whole, there was a budget overrun of 75.11%, or €87,500 in additional costs expressed in euros. Can you rule out such a scenario for your facility? Clinics with such high losses of instruments and frequent new purchases also jeopardize their sustainability goals. This is a bitter pill to swallow at a time when more and more facilities are attaching importance to the economical use of resources. Poor quality deionized water therefore damages the instruments, harms sustainability and incurs considerable costs. But there is an even greater danger.  

Also a building block for patient safety!

More serious than the costs of inconsistent processes is the hygiene risk: germ contamination and soiling jeopardize successful sterilization and therefore patient safety. Every medical facility should put patient safety first, far ahead of economic considerations. According to the RKI, nosocomial infections cause around 15,000 to 20,000 deaths every year – meaning that a town like Mölln or Bad Pyrmont disappears every year. Such hospital infections can have various causes, one of which is the condition of the instruments.   According to the Medical Devices Operator Ordinance (MPBetreibV), the operator of the facility is liable for proper reprocessing. Everyone who bears legal responsibility for patient safety and processes has a duty here: management, purchasing, building services, hygiene officers, AEMP management. Anyone who violates these obligations risks penalties under the Medical Devices Implementation Act (MPDG), which are also imposed in practice. It is clearly in the interests of those responsible to ensure legal certainty before an incident occurs – and is also extremely reassuring for all those responsible. You are a big step ahead in terms of the legal certainty of your treatment processes if you can prove that your water treatment system is state-of-the-art in the event of an incident. However, as explained above, the current state of knowledge is no longer just DIN EN 285, but is further defined in the recommendations of AKI and DGSV.  

How water treatment works

A system for the production of demineralized water, which is used as process water in treatment, is a combination of several components. In its recommendation no. 17, the DGSV expert committee describes the individual stages for optimum water treatment in detail. Here are just a few keywords: filter – ion exchanger – reverse osmosis system – membrane degassing – electro-deionization system (EDI) – mixed bed exchanger – tank for the finished deionized water. Measure the relevant water parameters at various stages of the treatment process. This means you always have an overview of whether the important measured values meet the correct limit values. If the values are too high, you can intervene quickly and correct the error, for example by replacing an exhausted cartridge with replacement resin. You make your system fail-safe by designing it redundantly: If one system fails, the second one steps in and keeps your operation running without interruption. An additional bypass system for emergencies bridges faults for a shorter period of time and provides the water required for a work shift. This gives you time for repairs.  

With HeylNeomeris for optimum water quality

But how can an existing water treatment system be brought up to this new level of knowledge? Cost-effectively and sustainably by retaining as many existing components as possible? Without disrupting ongoing operations? To do this, you first need a thorough and expert analysis of the current situation. This is a complex task, as many different factors, components and departments interact when it comes to water quality, from the municipal water to the equipment technology to the AEMP staff. Only an analysis that takes a close look at the entire process can reveal weaknesses and opportunities for improvement. An independent and competent company such as HeylNeomeris is ideal for stocktaking and optimization: we analyse, evaluate and document the condition of your water and steam treatment and the processes for sterile processing. In doing so, we act neutrally. We optimize the processes, if possible with the existing systems. Where appropriate, we recommend specialist companies. Of course, we also use our own sustainable technology for process monitoring and water treatment. And if you have special requirements, we can develop completely new solutions for you. Not only large hospitals benefit from our expertise, but also smaller clinics. This is demonstrated by our successful reference project with an eye clinic in Hanover.  

Legal certainty in reprocessing? Only with up-to-date water treatment!

Let’s summarize: The limit values specified in the DIN EN 285 standard are not up-to-date for water treatment for steam sterilization. They allow instrument damage, high operating costs and jeopardize process reliability – and thus also the legal certainty of the medical facility. The nine limit values are defined by the DGSV expert committee on hygiene, construction and technology. This is the new state of knowledge.