Duodenoscope Reprocessing: Assessing the Need and Value of Monitoring Manual Cleaning Adequacy


Executive Summary

Duodenoscopes are flexible fiberoptic or video gastrointestinal endoscopic devices used for examining the digestive tract from the oral cavity to the duodenum. Typically designed for re-use, the complex design of duodenoscopes makes appropriate cleaning and effective reprocessing difficult. Outbreaks, including multidrug resistant organisms, have occurred despite strictly following manufacturer reprocessing instructions. Thus, respecting current reprocessing guidelines may not be sufficient to prevent transmission. Supplemental measures to enhance efficacy may be required. A crucial concern is manual cleaning to ensure adequacy of high-level disinfection (HLD). Supplementary processes align with CAN/CSA Z314-18, Medical device reprocessing – General requirements, provincial advisory group recommendations and reviews supporting enhanced quality assurance of the cleaning procedure by surveillance testing of bioburden prior to HLD.

The utility and benefit of incorporating recommendations for supplementary processes and procedures related to CSA Z314-18 was evaluated. The study assessed the relevance of monitoring manual cleaning for one hundred patient-used duodenoscopes to determine whether this “should” or “shall” be routinely performed. The cleanliness of the elevator mechanism and the biopsy channel, both difficult to access and see, were measured by:

  1. The required visual assessment when meticulously following reprocessing instructions;
  2. The recommended cleaning verification, using a validated adenosine triphosphate (ATP) test and cleanliness threshold of two hundred relative light units (RLU); and
  3. Microbial culture.

Incorporating cleaning verification tests identified challenges to achieving cleaning adequacy; the quality of cleanliness using the required single manual clean with visual assessment; and cleaning quality inadequacies that could be addressed. Results showed the following:

  • High levels of contamination for the elevator mechanism and biopsy channel, respectively:
    • 92,400 RLU and 7,766 RLU mean ATP levels, prior to manual cleaning; and
    • 635 RLU and 462 RLU, mean ATP levels, in samples that failed the initial cleaning.
  • The extent of inadequacy and potential risk, defined by cleaning failure rates, for the elevator mechanism and biopsy channel, respectively:
    • Ranging from 48% to 12%, after the required single cleaning; and
    • Ranging from 16% to 2% after a second manual cleaning.
  • The impact of repeated cleaning for elevator mechanism and biopsy channel, respectively:
    • A significant reduction in ATP levels before cleaning to the first cleaning (p = .007033 and p = .018858); from first to second cleaning (p = .0029 and p = .046041), (significance p < .05)
    • A significant reduction in failure rates from the first to second cleaning (p < .00001 and p = .0101), (significance p < .05)
  • The elevator mechanism posed the greatest challenge to cleaning, with significantly higher:
    • ATP levels before cleaning (p = .009235), and after cleaning (p = .000455); and
    • failure rates after the first clean (p = .0309) and after the second clean (p = .0003)

This work defined the value and necessity for additional steps to monitor cleaning adequacy as part of an overall quality approach to reprocessing. It formed the basis for pragmatic reprocessing changes that included: a routine double cleaning, particularly for the elevator mechanism; implementation of a scheduled cleaning verification process; and the platform for obtaining robust data to build a practical and beneficial approach to increasing the margins of safety in duodenoscope reprocessing.