11 Nov Design for Cleaning

An outbreak at UCLA’s Ronald Reagan Medical Center in 2015 got the FDA’s attention when several patients died after being exposed to carbapenem-resistant Enterobacteriaceae (CRE)—a bacteria commonly found in the intestines alongside E. coli and other intestinal flora—as part of routine endoscopies.

The culprit: insufficient reprocessing of the duodenoscopes after use led to cross-infection from one patient to the next.

Now, over four years later, the FDA continues to urge facilities that use duodenoscopes to follow manufacturers’ reprocessing instructions. But while it’s easy to point the finger at reprocessing technicians and blame them for this terrible outcome, as designers, let’s take a moment to think about other ways this could have been avoided. It’s important to remember that as developers and manufacturers, we form a team alongside caregivers, healthcare practitioners, and even patients in ensuring safety. Our job as designers is to develop our products to make their use and maintenance as simple and error-free as possible. While there are many aspects of this we could discuss, this article will focus on designing for cleanliness.

In the report linked above, one of the causes of the failure to adequately clean the duodenoscopes was the presence of tiny geometries, too small to clean with a brush, in which debris and therefore bacteria could become trapped. This highlights the most important facet of design for cleanliness: if the user can’t make physical contact with a surface, debris can get trapped. Autoclaving and other sterilization techniques cannot be effective when there are physical particles of debris remaining: the debris acts as a shelter for microorganisms and can allow them to survive conditions that would typically destroy exposed microorganisms. Therefore, it is imperative that the user is able to reach all surfaces to be cleaned. This applies not only to part geometry but also to the types of materials used: porous materials such as sponges, some rubbers, and pumice all contain tiny and even microscopic holes that can harbor bacteria. Maintaining a small aspect ratio (having crevices be wider than they are deep), ensuring that voids are wider at the surface than at their deepest part, avoiding blind corners, and selecting materials and surface textures with low porosity are all ways to help facilitate cleaning. Where tiny geometries cannot be avoided, ensure the device can be disassembled to grant access, and ensure that the device design is such that reassembly is as free of use error as possible. As with any other user task, cleaning should be validated when failure to adequately clean the device could lead to infection or other unacceptable risks.

The holistic and end-user-centric view taken at Realtime enables us to put ourselves in the end-user’s shoes and design our products to make their lives easier. If you think about your favorite products, there’s a fair chance they’re straightforward to understand and easy to use and maintain. As developers, we set that as our goal and challenge ourselves to reach it. The end result is a better, safer product that people are happy to use. Let us use our expertise to help you design your next medical device. Give us a call at 972 985-9100 today!