The reprocessing of endoscopes following gastrointestinal endoscopy is highly effective for mitigating the risk of exogenous infections, yet challenges in duodenoscope reprocessing continue to persist. While several enhanced reprocessing measures have been developed to reduce duodenoscope-related infection risks, the effectiveness of these enhanced measures is largely unclear.
Rahul A. Shimpi, MD, and Joshua P. Spaete, MD, from Duke University, Durham, N.C., wrote in a paper in Techniques and Innovations in Gastrointestinal Endoscopy that novel disposable duodenoscope technologies offer promise for reducing infection risk and overcoming current reprocessing challenges. The paper notes that, despite this promise, there is a need to better define the usability, costs, and environmental impact of these disposable technologies.
Current challenges in endoscope reprocessing
According to the authors, the reprocessing of gastrointestinal endoscopes involves several sequential steps that require a “meticulous” attention to detail “to ensure the adequacy of reprocessing.” Human factors/errors are a major contributor to suboptimal reprocessing quality, and these errors are often related to varying adherence to current reprocessing protocols among centers and reprocessing staff members.
Despite these challenges, infectious complications associated with gastrointestinal endoscopy are rare, particularly in relation to end-viewing endoscopes. Many high-profile infectious outbreaks associated with duodenoscopes have been reported in recent years, however, which has heightened the awareness and corresponding concern with endoscope reprocessing. Many of these infectious outbreaks, the authors said, have involved multidrug-resistant organisms.
The complex elevator mechanism, which the authors noted “is relatively inaccessible during the precleaning and manual cleaning steps in reprocessing,” represents a paramount challenge in the reprocessing of duodenoscopes. The challenge related to this mechanism potentially contributes to greater biofilm formation and contamination. Other factors implicated in the transmission of duodenoscope-associated infections from patient to patient include other design issues, human errors in reprocessing, endoscope damage and channel defects, and storage and environmental factors.
“Given the reprocessing challenges posed by duodenoscopes, in 2015 the Food and Drug Administration issued a recommendation that one or more supplemental measures be implemented by facilities as a means to decrease the infectious risk posed by duodenoscopes,” the authors noted, including ethylene oxide (EtO) sterilization, liquid chemical sterilization, and repeat high-level disinfection (HLD). They added, however, that a recent U.S. multisociety reprocessing guideline “does not recommend repeat high-level disinfection over single high-level disinfection, and recommends use of EtO sterilization only for duodenoscopes in infectious outbreak settings.”
New sterilization technologies
Liquid chemical sterilization may be a promising alternative to EtO sterilization because it features a shorter disinfection cycle time and less endoscope wear or damage. However, clinical data for the effectiveness of LCS in endoscope reprocessing remains very limited.
The high costs and toxicities associated with EtO sterilization may be overcome by the plasma-activated gas, another novel low-temperature sterilization technology. This newer sterilization technique also features a shorter reprocessing time, thereby making it an attractive option for duodenoscope reprocessing. The authors noted that, although it showed promise in a proof-of-concept study, “plasma-activated gas has not been assessed in working endoscopes or compared directly to existing HLD and EtO sterilization technologies.”