The making of process challenge devices

In recent years, there has been a shift in the gravity of importance in decontamination of surgical instruments towards physical removal of contamination – i.e. cleaning. On top of that, cleaning verification looks towards the assessment of the result rather than the process itself (the author wrote about this unfulfilled need in ‘Process versus the result’ in February-April 2014, Vol. 18, No.3 release of the Journal). This shift in focus still leaves a lot of ambiguity about the methods involved, and leaves sterile services professionals with almost as many questions as answers. That is mostly due to the emphasis on protein detection in the guidance but not the overall methodology of verification, optimisation and monitoring of cleaning process effectiveness. 

A Process Challenge Device (PCD) is a device used to assess the effective performance of a process by providing a challenge to the process that is equal to, or greater than, the challenge posed by the most difficult item routinely processed. We have been successfully using PCDs to assess sterilisation processes for many years now and we have been using them to verify cleaning processes as well. In both cases, PCDs can be a powerful tool provided they realistically represent the challenges posed by the process. The problem is that, while for sterilisation the performance of the PCDs is well documented, when it comes to cleaning we do not benefit from much information. We have synthetic test soils, natural test soils and a number of designs that promise to represent regularly cleaned load. As a result they perform differently in different circumstances and that only adds to the overall confusion.

At the same time, a lot has been said about the need for optimisation of cleaning processes. Optimisation, by definition, is the action of making the best or most effective use of a situation or resource – in our case, the entire decontamination process including pre-cleaning, chemicals, equipment and the way we use it. The only way we can perform optimisation is to somehow assess the current state and introduce changes that improve it. Our aim was, and still is, to create a PCD that provides the most realistic feedback from the process and allowing improvement.