The following is recent information from the Association for the Advancement of Medical Instrumentation (AAMI) that we think will be of interest to the readers of OR Today magazine.
What’s Left Behind: Assessing Residuals from Medical Device Cleaning
It has long been understood that the manufacturers of cleaning formulations are responsible for demonstrating the inherent risks that come with the intended use of their product. However, according to a team of concerned scientists, lab operations managers, and microbiological quality and sterility assurance specialists, there are no regulations that specify how manufacturers can help users determine the risk of residual chemicals on device surfaces after cleaning.
That’s why the team, hailing from Johnson & Johnson and Nelson Laboratories, recently published a study investigating the impact residual detergent chemistry can have on patient safety. The study “Assessing Detergent Residuals for Reusable Device Cleaning Validations” was published in BI&T, the peer-reviewed journal of AAMI.
The researchers conducted cytotoxicity tests – measuring to what degree a substance can damage a biological cell – in accordance with AAMI TIR30:2011(R)2016 and ISO 10993-5:2009, the established state-of-the-art test for reusable medical device processing. Eight detergents for the cleaning of reusable medical devices were evaluated at 10 different concentrations.
“The cytotoxicity profiles described in this study were clearly tested under worst-case conditions … assuming the lack of any rinsing during use,” the authors wrote.
It was surprising to note then, that many these products “did not show considerable cytotoxicity” at recommended concentrations. This is startling, because the products are designed to break down biological matter, such as proteins and lipids, so that it can wash away.
Only two of the detergents, Enzymatic C and D, posed a cytotoxicity threat all the way down to 0.2% of the maximum recommended concentration, implying that devices cleaned with these formulations will need to be thoroughly rinsed. What could confuse some users is that, in inspecting a manufacturer’s safety data sheet (SDS) alone, the formulation of enzymatic C will appear remarkably similar to enzymatic B. Enzymatic B proved safe even at 6% concentration – which is well above the residual concentration that is expected after a rinsing (0.1-1%).
“Because cleaning solutions consist of a combination of various chemicals … it is not practical to assume that the chemistry reported in the detergent manufacturer’s SDS is sufficient to accurately predict its toxicity profile,” the authors concluded.
They are now calling for manufacturers to better define cleaning chemical performance “to allow for harmonization of safety and efficacy expectations.”
Seeking Harmony in Microbiological Quality Definitions
A team of sterility assurance professionals has released a comprehensive glossary that proposes harmonized terminology commonly used in the design, control, and regulation of microbiologically controlled devices and drugs, such as those used in the clinical setting.
The commentary, “Words Matter: A Commentary and Glossary of Definitions for Microbiological Quality,” helps establish a common lexicon that the authors say will better address challenges associated with “global economic, distribution, and regulatory requirements that are often confounding and evolving.”
The article was published in BI&T, the peer-reviewed journal of AAMI. The glossary uses established definitions for commonly used terms when possible. However, the committee behind the document is proposing that, in specific cases, established definitions may need to be retired or revised if found to be too limited or redundant for modern use.
The team, consisting of professionals from microbiology, sterility assurance, regulatory affairs, engineering, medical device design, pharmaceuticals, and the clinical setting, focused on definitions that are inherently simple and internationally relevant. As such, their proposed definitions avoid phrases or terms that would have an alternative meaning outside of English-speaking countries. To avoid common points of debate between manufacturers, regulators, and scientists, the definitions also prioritize scientific accuracy and “should not be open to individual interpretation.”
The term biofilm, for instance, is a term that is often used incorrectly. This is in-part because scientific knowledge of biofilms has evolved, revealing that biofilms are not restricted to water systems. However, common definitions often continue to perpetuate this limitation, the committee claims.
“A simpler definition in this glossary defines a biofilm as a community of microorganisms,” the authors wrote. The definition’s accompanying commentary delves deeper into describing wet and dry biofilms as well as a detailed description of what to look for when identifying a biofilm structure.
More than 100 terms, ranging from “action level” to ”z value,” are defined in the glossary. The proposed definitions are supported by commentary from the authors and more than two dozen citations of peer-reviewed research.
The glossary was written by Gerald McDonnel, BSc, Ph.D., senior director in microbiological quality and sterility assurance at Johnson & Johnson; Hal Baseman COO and principal at ValSource Inc; and Lena Cordie-Bancroft, the president of Qualities Professional Services LLC. The glossary was designed with the knowledge of the members of the Kilmer Regulatory Innovation Team – borne of the revived Kilmer conferences for sterility assurance professionals – and dedicated to creating opportunities for cooperation and innovation between regulators and medical device manufacturers.
