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Automated washers today are an essential tool for an SPD to standardize their cleaning process of reusable medical devices and are expected to deliver the same clean result every time. These wash- ers today aren’t considered an expensive replacement for manual cleaning, and they are a mandatory tool for the cleaning of new medical devices that have physi- cal conformities that prevent effective manual cleaning.
Automated washers are complex equip-
ment that require preventive mainte- nance and have the possibility to break, undergoing corrective maintenance. To illustrate the criticalness of releas- ing equipment used in an SPD, a steam sterilizer release after maintenance relies on engineering testing performed by the maintenance technician. This will be confi rmed afterwards by an SPD profes- sional that will run a Bowie & Dick cycle, an empty chamber cycle with a process challenge device that contains a biological indicator, and an assessment of the print- outs from both cycles. If the physical, chemical, and biological indicators show satisfactory results, the steam sterilizer is cleared for use. Unfortunately, automated washers only have cleaning monitoring indicators that are applied on a medical device or are placed in a process challenge artefact, requiring more attention from the SPD professional when assessing the performance of the equipment3
.
As shown above, if a reusable medical device is loaded into a sterilizer with a bioburden above standard, the 12-log reduction that will be obtained at the end of the cycle will not reach SAL of 10-6
.
Therefore, cleaning plays a critical role in the sterility assurance of reusable medical devices and requires monitoring practices as rigorous as, or more than, of what is used for the steam sterilizer. Automated washers use pressurized water and detergent that are sprayed on reusable medical devices, at a high temperature, continuously for a period of time, to mechanically remove all residues and dirtiness. A thermal disinfection phase is normally present in a cleaning cycle program, where hot water with temperatures ranging from 140ºF (60ºC) to 203ºF (95ºC) is sprayed for a period of time, reducing the bioburden load. The last phase is the drying phase, where hot air is blown on the instruments (Figure 2). The cycle confi guration must follow automated washer and reusable medical device manufacturer’s IFU.
The main component used in an auto- mated washer is water. It is essential for the water quality to meet all equipment manufacturer specifications and be evaluated frequently to assure cleaning effectiveness. If the water quality is not specifi ed, a good reference to follow is the Association for the Advancement of Medical Instrumentation (AAMI) Techni- cal Information Report (TIR) 34 – Water for the reprocessing of medical devices4
.
This TIR also suggests the water quality analysis frequency. It is important to know that AAMI is currently working on a new water quality guideline, ST108, that is on the fi nal stages of development. To improve water cleaning, detergents are added during the cleaning process. There are many different detergents
SELF-STUDY SERIES available in the market, and automated
washer’s and detergent manufacturer’s IFUs must be followed, and the correct dosing programmed into the equipment. The correct dose is required on every cycle to assure the desired performance, and a dosing verifi cation device should be used to verify if the dosing system is working correctly. Also, it is important to verify if empty switches are working properly. In the cleaning phase, water is admitted
into the washer chamber at the same time as detergent is dosed. During the washing process, water is continuously circulated and sprayed on medical devices through rotatory arms with holes or injected into lumen devices using specifi c connectors, linking the washer cart rack to the medi- cal device.
These rotatory arm holes and lumen connectors have very small diameters, and any debris can cause clogs (Figure 3), preventing water to pass through, reducing the cleaning effi ciency of the equipment.
Figure 3: Example of debris found inside
washer’s rotatory arm. Tape, plastic markers, human hair, and other.
Washers are fi tted with debris screens to retain all debris, preventing clogging during water recirculation. These screens must be cleaned frequently and correctly installed. If a small space is left, debris will go through and clog the rotatory arms and lumen connectors (Figure 4, next page). Rotatory sprayers have O-rings on their
Figure 2: Example of an automated washer cycle phases
fi xation to the washer cart that allow the rotatory arm to move freely. The rota- tional movement must be verifi ed on each arm, and if the arm shows any resistance to movement or excessive wobbling, these O-rings have to be replaced. The procedure and frequency to per- form these mechanical verifications should be part of the automated washer manufacturer IFU. Monitoring the clean-
hpnonline.com • HEALTHCARE PURCHASING NEWS • February 2023 33
Self-Study Test Answers: 1. C, 2. B, 3. C, 4. D, 5. C, 6. D, 7. D, 8. D, 9. C, 10. A
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