This means that everything occurring before in the decontamination cycle is still yet to happen. No doubt, all steps within this reprocessing loop must be completed correctly and in accordance with all manufacturer IFUs which includes the medical device itself, cleaning chemistries, sterile barrier systems (SBS), washer- disinfectors, ultrasonic washers and sterilisers, and any other use instructions provided for any item utilised in the process. Just like every sterilisation process, VH2O2 sterilisation depends on the successful completion of the steps leading up to the sterilisation cycle. In the VH2O2 journey, however, certain steps can have a direct impact on the success of the sterilisation outcome and thus require greater attention. We’re going to break down the importance of these steps, while providing recommendations to aid in successful implementation.

Cleaning and rinsing One of the critical steps in preparing a device for reprocessing is cleaning. This becomes an important step for all methods of sterilisation, including VH2O2 sterilisation. Efficient cleaning aims at removal of all soil to ensure that the sterilising agent can reach all parts of the device. Residual procedural soil, detergents and water residue deposits due to poor water quality used in the facility can create a protective barrier on the medical device surface, which can further be considered as either a physical barrier, or a chemical barrier. Physical barriers directly prevent the vaporised hydrogen peroxide from contacting and destroying the microorganisms, whereas chemical barriers react with and deplete the hydrogen peroxide molecules.

One of the critical steps in preparing a device for reprocessing is cleaning. This becomes an important step for all methods of sterilisation, including VH2O2 sterilisation. Efficient cleaning aims at removal of all soil to ensure that the sterilising agent can reach all parts of the device.

Residual cleaning chemistries may

interfere with the VH2O2 sterilisation process when not completely removed due to improper rinsing – an integral step to the cleaning process. In such circumstances, these may appear after processing as a light-coloured residue on devices. In a situation like this, the entire load should be reprocessed and, equally, an investigation of the entire cleaning process be conducted to eliminate the process risk, for example a washer-disinfector malfunctioning, use of detergent incorrectly dosed in high volume, poor rinsing, etc. Poor water quality often also contributes

negatively, as it is associated with a range of ionic contaminants that may be deposited on the load surfaces, building up a chemical barrier on the device surface. These ions can come from a variety of sources and be present when facilities don’t use treated water across the entire cleaning process. When ionic deposition is high, a chemical reaction with hydrogen peroxide may occur. Unlike residual soil and detergents that cause problems immediately, ionic deposits can take months before the deposited quantity reaches critical mass and become visible to users. Establishing good water

quality and conducting regular water testing is recommended.

Thorough drying

Cleaning and rinsing are followed by thorough drying. The presence of moisture on a single instrument, a set or the whole load is not acceptable whether this is a steam or a VH2O2 sterilisation process. Presence of moisture in a VH2O2 pack is considered a barrier for successful sterilisation and may have two effects; it is likely to lead to aborted cycles but also often associated with a hazard for the user. When the VH2O2 cycle starts and the initial vacuum is drawn, a small amount of residual water can (and will) evaporate. As it does, the pressure in the steriliser chamber rises. If there is an excessive amount of moisture, this will cause a relatively high pressure change in the chamber, triggering the fault response of the steriliser, in the same way as if air is leaking into the chamber, aborting the cycle. Typically, all VH2O2 sterilisers are intolerant of significant moisture, but some are more susceptible to failure than others at this stage. Considering a VH2O2 steriliser that incorporates a conditioning phase that aids in removing residual moisture prior to the sterilisation phase is important. If the steriliser does make it past this stage of the cycle without failure and moisture is present within the load, the area moisture is evaporating from will become extremely cold and can condense and freeze sterilant. These cold spots may further cause hydrogen peroxide vapour to condense into liquid form, which is less effective and resulting in reduced concentration of the gas inside the chamber, leading the steriliser cycle to fail. In addition, in rare cases, this liquid can remain on devices and may pose a chemical burn hazard to users, causing a stinging sensation where hydrogen peroxide has contacted the skin, giving the appearance of white patches. It is important to immediately rinse the affected area in cold water to reduce these effects.

Figure 2 – Examples of packaging options for a VH2O2 steriliser 36 l WWW.CLINICALSERVICESJOURNAL.COM

The white patches and stinging will lessen over a short period until they are no longer visible. Guidance in Safety Data Sheet (SDS) and local policy should be


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