Pawel de Sternberg Stojalowski, MBA, MSc, BSc kindly shared his comprehensive insight to Hospital Hub…
Cleaning, as a process, is fundamentally different from sterilisation. The end goal is not to kill microorganisms but remove them, together with the soil, from the instruments. This process cannot be described by a simple mathematical equation because there are too many variables that affect it – from cleaning chemistry, through design of particular instruments, and loading patterns, to water quality, etc. In this case, the process needs to be challenged in a different way. We can use instruments inoculated with a test soil. However, testing of real instruments with test soils is somewhat troublesome because the methodology is relatively difficult to replicate for the daily monitoring purposes. This is where Process Challenge Devices (PCDs) come into play.
The clue is in the name: PCDs should be a challenge for the cleaning process that is equal or harder to routinely reprocessed loads, that is consistent and repeatable.
Cleaning assesment in a washer disinfector
The critical characteristics of Process Challenge Devices
There are three separate elements that we must take into account if we want to see the true quality of the cleaning process:
The test soil and how it is applied,
Realistic representation of a particular cleaning challenge,
An appropriate method of evaluation of the sample after the process.
Test soil
The test soil directly affects the level of a challenge, which makes it a critical component of a PCD. On one hand, the harder to clean it is, the more challenging it becomes for the process, on the other it is relatively easy to create test soils that are unnaturally difficult to remove, especially when synthetic materials are used. Test soil should be as close as possible the type of natural contamination we find on surgical instruments that are difficult to clean – representing the worst case but realistic scenario.
Physical challenge
Development of a realistic representation of particular challenges is as important as developing a good test soil. At the least, a PCD needs to simulate narrow gaps in instruments and shadowing of portions of instruments from the process. Even better if we have means of testing horizontal and vertical surface cleaning effectiveness, as this addition makes for a more thorough verification of cleaning. The challenge should also be designed to be used in a normally-loaded cycle – so we get as close to the real case scenario as possible.
Identifying worst case scenario location
Evaluation method
Cleaning of instruments with internal channels must also be evaluated – especially when such instruments are a part of a load containing different instruments. However, cleaning of internal channels is an entirely different process to external cleaning. It is because it is driven by a different mechanical process and is often serviced by an independent system (pump and plumbing). Therefore, if a washer has the ability to clean instruments with internal channels it must be evaluated for internal cleaning with the same frequency as the standard instruments.
The evaluation method has the final word. Evaluation should always start from a visual check. It is not only the fastest direct method for larger quantities of contamination, but visually we can identify other types of issues that analytical technologies may not pick up – for example, chemical induced discolouration indicating there may be other issues with the cleaning process.
After visual inspection come solutions like fluorescence or chemical dyes that take the limit of detection far beyond the ability of naked human eye to the levels recommended by local standards.
Carrier loaded with VeriTest PCDs
Summary
PCDs are simple and effective tools that allow for a comprehensive evaluation and monitoring of cleaning processes. It is, however, important to understand that PCDs are only a representation of contaminated surgical instruments and it is critical to understand their characteristics to make the best value of their use. This is the easiest way to maintain high standard of your processes and – when needed – improve them.
More information can be found about PCDs and VeriTest at http://aseptium.com/
Pawel de Sternberg Stojalowski MSc, BSc, MBA – is an R&D engineer with passion for clever solutions. From his background in mechanical engineering, automation, robotics and business stem innovations, interdisciplinary and cooperative approach to projects. He has been involved in R&D of equipment and technologies for decontamination and sterilisation of complex surgical instruments since 2007. Today Pawel leads an expert team researching, designing, prototyping and evaluating innovative solutions aimed at solving challenges in decontamination of complex surgical instruments, contamination detection and identification as well as fluid dynamics and ultrasonic waves in washers.
