The current updates to the AAMI ST91 national standard are intended to reduce outbreaks linked to the use of contaminated endoscopes through quality processing. Key aspects of this updated standard focus on inspection, cleaning verification, drying post processing, and endoscope storage, in addition to physical design and an emphasis on training and certification.
During an April webinar hosted by Becker’s Hospital Review and sponsored by Healthmark Industries — a manufacturer and distributor of medical products to healthcare facilities and professionals — experts from Healthmark offered insights on the latest version of the AAMI standard. The panelists were:
- Mary Ann Drosnock, Director, Clinical Affairs,
- John Whelan, BSN, RN, Clinical Educator
Five key takeaways:
1. The AAMI’s newest standard for flexible endoscope processing is the result of a robust committee consensus process. ST91 is a voluntary standard to assist the healthcare industry by outlining performance and safety requirements. Though ST91 has since attracted controversy from certain GI societies, standard ANSI/AAMI procedures were followed and those societies participated and voted. The standard contains numerous citations to peer reviewed literature and the FDA MAUDE safety database to provide rationale for recommendations made; and to aid those using the standard.
2. The standard’s wording conveys precise directives. The standard-writing group, "put much more emphasis on making sure we get the right words for what we need. Use those in your evaluation of the standard," Ms. Drosnock said. "Must" means mandated by government regulation; "shall" is a requirement of the standard. "Should" is a strong recommendation, for at least evaluating the topic. "May" represents a permissible course of action, and "can'' is a statement of possibility.
3. ST91 details considerations for physical space design and classification of high-risk endoscopes requiring greater care. Practitioners "need enough space, and enough time and the proper equipment to do this right," Ms. Drosnock said. The processing area must separate clean and dirty areas, considering the degree to which aerosols travel. Two-room design is preferred but at a minimum unidirectional flow from dirty to clean is required. Other considerations are a designated drying area, separate storage area, restricted traffic, and separate sinks for cleaning and rinsing.
ST91 introduces a new term, "high-risk endoscopes," Mr. Whelan said, to classify "those [endoscopes] that have been associated with infectious outbreaks and are difficult to process" (including elevator channel endoscopes, bronchoscopes, ureteroscopes, cystoscopes and EBUS scopes). These should undergo cleaning verification testing every cycle and be prioritized in risk assessments.
4. Changes in ST91 are designed to shape quality control in the multi-step endoscopic process. "The term ‘point of use treatment’ [instead of pre-cleaning] is now being used to represent all the tasks that are required immediately after the endoscopy procedure," Mr. Whelan said. Then, in soiled transport, a priority is keeping the scopes moist. In the processing area, leak testing is vital every time.
Manual cleaning is the "most important part of processing," Mr. Whelan said, including a utility water rinse and drying exterior and interior channels prior to the next step of inspection. Visual inspection is the bare minimum. Enhanced (i.e., lighted, magnified) visual inspection is considered best practice.
Then, automated processing (AER) is always promoted; manual disinfection is strongly disfavored except as an emergency backup. Water quality monitoring is key to avoid water borne contamination. Direction is given for active filtered air drying, even post-AER. Clean PPE is needed for removing scopes from AERs. To store clean scopes, cabinets with HEPA air circulating are the minimum, and no storage should be in the procedure or processing rooms.
5. The ST91 update also focuses on ongoing compliance. Certification and training are emphasized. Potential weak points at each step in the process demonstrate the need for standardization and through embedded quality control processes. Although ST91 does not require sterilization, it is the goal even though the industry has historically accepted high level disinfection (HLD) as the standard of care. To transition to sterilization, the industry should address key technical and compatibility obstacles.
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