Steps for sterilising flexible endoscopes

When flexible endoscopes were first developed, their use was initially envisioned for inspection and diagnosis of disease via natural orifices. Today, flexible endoscopes are routinely used for biopsies, and are increasingly used in other minimally invasive surgery; these invasive uses significantly change the risks involved, and the requirement for these devices to be sterile at the point of use. Not only do these new applications pose particular challenges for terminal disinfection or sterilisation of endoscopes, they also raise the question of how we can adequately and correctly decontaminate these devices because of their increasing complexity, construction and inability to withstand the high temperatures traditionally associated with terminal sterilisation. 

It is generally accepted that the first step of endoscope decontamination is an initial bedside clean; this serves to remove significant soiling, but perhaps and arguably more importantly, it minimises the risk of the soiling drying onto the device. It has long been recognised that one of the factors that significantly affect the outcome of cleaning processes is the presence of dried soils; by ensuring that these soils are removed eliminates this problem quite literally at source. This bedside clean involves wiping all external surfaces of the endoscope that have come into patient contact, brushing channels that can actually be brushed, followed by irrigation of these channels. Another important part of facilitating proper cleaning of flexible endoscopes is keeping the device moist until further subsequent processing; this ensures that device soiling can be readily removed in the validated cleaning process that is to follow.

Processing systems The second step of decontaminating the device ready for subsequent and safe patient use is the main wash; this may still be a manual process, or preferably be an automated process within an Automated Endoscope Reprocessor (AER), similarly also termed an Endoscope Washer-Disinfector (EWD).These endoscope processing systems have been adopted across most of the world, and are designed to thoroughly wash and then chemically disinfect one or more such flexible endoscopes. These Endoscope Washer-Disinfectors have two processes which are independently validated – the first stage is the washing stage, validated using recognised test soils to simulate worst-case soiling, followed by the second stage, which is chemical disinfection, validated as part of type testing using a range of challenging micro-organisms. There is clearly a preference to use Endoscope Washer-Disinfectors to wash and disinfect endoscopes, as these automated processes lend themselves better to validation, ensuring that each cycle performs reliably and to specification.