The study on the advanced methodology and the binding affinity for potential contaminants of endoscope to reduce the infection risk of RMDs

Abstract

Medical devices inserted into the human body can be divided into single use device (SUD) and reusable medical devices (RMDs) depending on the method of use. SUD is a medical device supplied in a sterilized package by the manufacturer and users dispose of it after use it is used once. RMDs is applied to more than one patient and users reprocess (cleaning, disinfection, or sterilization) it before reuse. The use of RMDs has increased along with the development of medical science and technology and as the structures of medical devices become more complicated and finer; therefore, reprocessing such as cleaning and disinfection is getting more difficult and infection related to these issues happens more frequently.Two research methodologies were applied in this study to reduce infection risk related to RMDs. One is the proposal of improvements through GAP analysis and methodology studies in advanced countries in relation to the roles and responsibilities of manufacturers, users (hospital), and governments (FDA) from the perspective of the TPLC (Total Product Life Cycle) of reusable medical devices. The other is the research on the characteristics of surface alterations and the adhesion of potential contaminants (microorganisms and organic substances) caused by repetitive use of flexible endoscopes.The research on improvements from the perspective of the TPLC of reusable medical devices was conducted in three categories as follows: a high level survey of RMDs, research on management in advanced countries, and improvement directions in RMDs 1. The RMDs high level survey focused on the analysis of use status, issues related to infection, a classification system, and domestic and overseas management systems. 2. Research on advanced management systems was divided into three parts. The first part is to apply a risk management mindset (Swiss chess theory. The second part is to assign clear roles and responsibilities to relevant parties (manufacturers, users, and governments) from the perspective of TPLC. And the third part is to conduct continuous research for the creation and utilization of professional expertise 3. Improvement directions in RMDs through gap analysis between domestic and advanced management systems were suggested.The research on the surface alterations caused by the repetitive use of endoscopes and the characteristics of the adhesion of contaminants (microorganisms and organic substances) was divided largely into two categories.Surface alterations were simulated through accelerated aging, and the research was performed to compare the results of the surface alterations between aged samples and clinically used samples. This research confirmed that the pattern of physical surface alternations of samples with accelerated aging and clinically used samples were similar.NA (not aged) samples and AA (accelerated aging) samples were contaminated with potential contaminants (microorganisms and organic substances), exposed to the same cleaning conditions, and residual contaminants were analyzed and the adhesion characteristics were investigated. This research indicates that the AA (accelerated aging) samples have a higher content of potential contaminants (protein, carbohydrate, lipid, hemoglobin) and microorganisms.This research proposes approaches for the improvement in usage by relevant parties based on the framework of the advanced mindset (Swiss cheese theory) to efficiently handle infection related to reusable medical devices, clarify roles and responsibilities from the perspective of TPLC, and introduce core elements to improve infection issues, including continuous support of related research and the fostering of professional expertise.In conclusion, Surface alterations like scratches, crevices, dents, and holes caused by repetitive use were observed in aged samples, and a higher content of potential contaminants was confirmed with the altered surface when the cleaning conditions are the same. The necessity to set the use life scientifically considering the effects of repetitive use and the possibility to apply the simulation model through the accelerated aging were proposed through these results. This type of methodology can be applied to various types of reusable medical devices besides endoscopes. Although worst case scenario analysis is required when assessing contaminants and cleaning conditions while performing endoscope validation (ISO 15883), there is a need to regard the material alterations caused by repetitive use as a worst case scenarios for validation.