Water Compliance for Endoscope Cleaners and Disinfectants — Is Reverse Osmosis the Answer?

AS / NZS 4187 is changing and the water quality requirements for both CSSD and endoscopy have been revised in line with ISO 15883 and HTM 01-06. However, the requirements for CSSD and endoscopy are so different that traditional products may not have a versatile solution. Reverse osmosis (RO) is a commonly discussed solution, but how good is it for endoscopy?

Historically, RO systems have been used in CSSD departments with variable success rates. For the endoscopy sector, RO systems can be a problem in maintaining bacterial-free water quality. The RO system requires a ring main. An expensive plumbing system downstream of RO that can supply endoscopic cleaning and disinfecting equipment (EWD) and circulate RO water to the system. If the ring main is not installed by the manufacturer, it may refuse to guarantee the water quality of the system. RO manufacturers guarantee only bacteria-free water in their systems and ring mains. This means that the installation of RO systems may not be able to solve the existing water quality problems that the endoscopy department may face.

If you have an existing ring main, you will need to perform ultrachlorination, replace the filter and assess the source of pollution. The problem remains. If the water sampling gives a positive result, who owns the no man’s land between RO and EWD? The RO system may be suitable for CSSD, but it can be an expensive and incomplete solution for the more stringent EWD rinse water requirements in AS / NZS-4187.

Endoscopy requires a unique solution. Tristel has nearly 30 years of experience in endoscopy and has developed the Tristel RA (Rinse Assure) system, especially for use in EWD. The Tristel RA is a small, streamlined unit that can be installed next to or in an adjacent room to the EWD. During the Tristel RA design and concept phase, Tristel analyzed ISO 15883 and HTM01-06 to design products that fully comply with these standards.

Tristel RA combines 5 micron to 0.2 micron prefiltration, deionization of water, RO, and the addition of non-toxic disinfectants. This is a combination of all methods of water treatment designed to check all boxes for bacteria-free supply and maintenance. Water on your EWD. Other products on the market are not specifically designed for endoscopy and guarantee a bacteria-free rinse water.

A unique feature of Tristel RA is Tristel’s patented chlorine dioxide chemistry. Chlorine dioxide is recognized by the World Health Organization for the safe treatment of drinking water. There are many studies comparing chlorine dioxide, chlorine, and thermal disinfection. In the most famous study conducted by Johns Hopkins University in the United States.This study concluded that chlorine dioxide is effective in removing Legionella, Gram-negative bacteria and biofilms. In comparison, high chlorination failed to achieve this and did not work well as a repair shock treatment. Superheated water also failed to achieve this and did not work well as a repair shock treatment.

Tristel RA automatically administers preset levels of chlorine dioxide at low levels to the inflow water supply used during the EWD cycle. The chemicals are produced by mixing the Tristel Base Solution (citric acid) and the Tristel Activator Solution (sodium chlorite) in use. Chlorine dioxide is compatible with the materials in EWD at the concentrations administered by Tristel RA. Chlorine dioxide administered by Tristel RA does not damage the endoscope and affects the chemical composition and effectiveness of detergents (including enzymes) and disinfectants (including peracetic acid) commonly used in EWD. Does not give.

The following statement was found in HTM01-06 and was used for both the development of Tristel RA and the development of AS / NZS-4187.

  • “Residual chlorine remaining in the reprocessed endoscope may reduce the potential for biofilm formation and pollutant growth” (HTM 01-06 Part B-2.62).
  • “Adding a non-toxic biocide to the final rinse water may help prevent the formation of biofilms” (HTM 01-06 Part B-2.82).

Both are oxidants and share the same language, but “chlorine” and “chlorine dioxide” have very different properties. Chlorine dioxide is a selective (rather than reactive) chemistry that is about 2.5 times more potent on a molecular basis than chlorine on a molecular basis. This is why low concentrations are effective without the negative side effects associated with chlorine.

Tristel RA administers 1.5-2.5 ppm chlorine dioxide. Drinking water ranges from 0.5 to 0.8 ppm, and the standard allows up to 10 ppm for EWD. The constant presence of low levels of chlorine dioxide provides a solution to existing water quality problems and a sense of security to move forward, and water complies with AS / NZS 4187 Table 7.3 and related standards.

Tristel conducted the first case study in the endoscopy department of a hospital in Wales (UK), which is known to have water quality problems. Prior to installation, three laboratories took complete water samples to assess the current water quality supplied to the four EWDs. The results showed high total survival (TVC) after 2 days, some reaching 236. TVC increased to over 900 after 5 days.

Tristel RA was set up to administer two of the four EWDs in the department. The remaining two EWDs continued to operate normally to act as control bays. During the Tristel RA installation, several high dose cycles were performed to purge the EWD. Samples were taken daily by the hospital and sent to three laboratories for testing. Five days after installation, the water sample taken from the machine provided by Tristel RA had zero TVC.

Tristel RA base is rapidly approaching 50 installations worldwide. Since the first Tristel RA was installed in 2015, no site has reported a water sample failure. Tristel RA is approaching 3000 final rinse water samples worldwide without failure.

Are you concerned about compliance with Table 7.3 of AS / NZS-4187? Contact Tristel for more information on Tristel RA.

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