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Special Words & All Things New: AAMI ST91 Updated Standard

The 2022 HSPA Conference & Expo in beautiful San Antonio was buzzing with excitement as tenured and new sterile processing (SP) technicians, industry leaders, and incredible educators all absorbed the experience like a sponge, and took their knowledge to soaring new heights.

One education session anxiously awaited by many was entitled “The New AAMI ST91: An Updated Standard for Flexible Endoscope Processing,” presented by Mary Ann Drosnock, MS, CIC, CFER, RM (NRCM), AAMIF, FAPIC Director, Clinical Affairs Healthmark Industries. This brilliant leader has dedicated 12 years to improving processes for endoscope reprocessing.

Mary Ann kicked off her presentation with a clear description of the meaning of particular verbiage used within AAMI documents. Here is the breakdown:

Must – Only describes an “unavoidable” situation, including those mandated by government regulation
Shall – Requirements to be followed strictly to conform to the recommended practice
Should – Indicates that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required
May – Indicates that a course of action is permissible within the limits of the recommended practice
Can – A statement of possibility and capability.

All of these terms are used throughout the standard and are to be duly noted as your facility navigates the changes and how to implement them.

What does ST91 cover exactly?
AAMI ST91 covers flexible and semirigid endoscope reprocessing in healthcare facilities, containing best practices for scope reprocessing in any setting (excluding transesophageal echocardiogram ultrasound probes, dilators, manometry, and rigid scopes). It covers all steps of processing from precleaning through reuse.

The update was published March 3, 2022, and is intended to be a one-stop shop for all scopes in all settings, noting that all surgeries are held to the same standard of care. This is not an amendment, but an entirely new document. Mary Ann recommends that your facility “Put together a multidisciplinary team and start looking through it; identify risk areas, targeting high-risk areas first; and proceed to document a process-improvement plan to implement that change. Start working through it.”

Key updates include an expanded and updated definitions section. An example from Slide 12 in Mary Ann’s presentation regarding Section 3.31 High-risk endoscopes defines them as, “endoscopes that have been associated with infectious outbreaks including those that are difficult to process and have an elevated risk associated with them,” and “includes bronchoscopes, cystoscopes, duodenoscopes, linear ultrasounds, endobronchial ultrasounds, ureteroscope, and others as determined by the facility.”

Design of processing area
This area is to be separate from patient care and procedure rooms and physically designated with signage for processing only. It is to have two separate rooms with unidirectional flow, a minimum of 3′ between decontamination and clean area, with a wall or area 4′ above the sink rim. Adequate space is necessary for two (preferably three) sinks for manual cleaning, height-adjustable surfaces, sink size to accommodate scopes, antifatigue mats, and a pass-through window. Hand hygiene, eyewash shower, and proper PPE for personnel is covered in great detail, as well.

Water quality
The facility should monitor and control the water supply quality to endoscope processing sinks and equipment, and consider periodic testing of the automatic equipment reprocessor (AER) to identify water contaminants which may contribute to recontamination of the device after high-level disinfection. Periodic bacterial testing of the water used for final rinse should be considered. 

Transport of soiled endoscopes
Isolate and transport the endoscope with its components in a closed container or closed transport cart. The transport cart or container must be labeled with a visible fluorescent orange, orange-red, or red label containing a biohazard symbol and must meet OSHA requirements (29 CFR 1910.1030) for transporting hazardous items. The closed container or closed transport cart must be nonporous, leakproof on its sides and bottom, puncture-resistant, and large enough to accommodate a single endoscope without the need to over-coil the insertion or light guide tubes. Keep the endoscope moist, but not submerged, for transport with a pretreatment solution, water-moistened towel, or humidity chamber bag.

Point-of-use treatment (formerly known as precleaning; consistent terminology with ST79)
This segment brought with it two key areas of focus. The first is to note the time of point-of-use treatment completed and convey that info to processing staff, which is needed to determine if delayed reprocessing is required. Second, if there is a delay or failure to perform point-of-use treatment, the endoscope should be processed using delayed processing protocols described in the device manufacturer’s IFU (typically one hour).

Leak testing
If a scope cannot be leak tested, it shouldn’t be used. You should regularly calibrate automated leak testers to verify the correct pressure output. Inspect manual and handheld units for damage, leakage, and correct pressure output, and verify each type of tester each day that endoscopes are used. Document the results and note that wet leak testing should have a minimum observation of 60 seconds (not 30).

Manual cleaning
This remains very much the same. Cleaning starts at the point of use immediately following the procedure. When allowed to dry, soils become more difficult to remove and the risk of biofilm formation increases when cleaning is not performed immediately. Biofilm consists of accumulated biomass of bacteria and extracellular materials that tightly adhere to a surface and are difficult to remove. To help prevent formation of biofilm or endoscope damage, cleaning should occur as soon as possible after the endoscope is used. 

Automated cleaning
The automated cleaner manufacturer’s written IFU should be followed. Fresh cleaning solution should be used and the tech should verify that the solution flows through each lumen. Use model-specific cleaning adapters that are compatible and validated for use with the endoscope being processed. All connections should be correctly secured to ensure endoscope channels are flushed. Channels should be flushed with water for the length of time specified in the manufacturer’s written IFU.

Identifying high-risk endoscopes
This refers to endoscopes associated with infectious outbreaks that are difficult to process and have increased risk, or those with complex design. This includes duodenoscopes, linear ultrasound (EUS) endoscopes, bronchoscopes, endobronchial ultrasound (EBUS) endoscopes, ureteroscopes, cystoscopes, and high risk as determined by the facility. It’s important to know the inventory and location of high-risk scopes in your facility.

Cleaning verification testing
High-risk scopes shall be monitored with cleaning verification after each cleaning. Scopes that are not high risk should be verified using cleaning verification tests when new endoscopes are purchased and at established intervals (e.g., at a statistically significant frequency based on the number of procedures performed). See Annex F for statistical frequency determination. Consider other factors, such as endoscope type, technician competency, procedural characteristics (e.g., duration, complexity, and heavy soiling), or delayed reprocessing.

Visual inspection
Endoscopes should be inspected with each reprocessing cycle. Lighted magnification should be used to inspect for debris and damage (the FDA recommends 5–10x magnification for duodenoscopes). Please note the use of the word “should” in this segment and refer back to definitions provided at the beginning of this article. Internal channels can be inspected with a borescope. This can be used periodically at a frequency determined by the facility. Make sure the endoscope is dry prior to inspecting. If used on a processed endoscope, process the endoscope again before clinical use. If a scope repeatedly fails cleaning verification, you may want to inspect with a borescope before sending for repair.

HLD or sterilization
Semicritical devices contact mucous membranes or nonintact skin. These devices should be thoroughly cleaned and then sterilized. If sterilization is not possible, high-level disinfection (HLD) is the minimum advised processing method. Sterilization is not required for all scopes. It is advised that flexible and semirigid scopes used in semicritical applications be sterilized prior to use. Transition from HLD to sterilization as the standard of care may be accelerated by identifying and addressing key technical and compatibility obstacles and defining priorities and key steps. Contributions of the reusable medical device manufacturer are essential, and partnerships between the sterilizer and medical device manufacturers are encouraged.

Storage
Ensure the endoscope is dry prior to storage in a cabinet or place into a drying cabinet. Dryness can be checked with an indicator test. The cabinet should have minimum HEPA filtered air. Maximum storage time is based on a risk assessment. Identify patient-ready scopes with a distinct visual cue and ensure they are in a secure location, such as a clean workroom, not a procedure room. Visually inspect cabinet for cleanliness, and clean at least weekly (per IFU).

Handling processed endoscopes
Perform hand hygiene and don new, clean, nonlatex gloves to handle processed endoscopes. Identify the endoscopes as clean to transport to point of use. Protect from contamination and damage by containerizing, unless in a controlled, connected corridor. Reprocess containers between uses per the IFU of the container. Containers for transport should be clean, covered, solid protective containers that are nonporous and leakproof on the sides and bottom.

Personnel training and certification
All personnel shall complete formal training and competency verification in all aspects of endoscope processing prior to their first assignment. All personnel processing endoscopes should be certified in flexible endoscope processing within two years of employment and should maintain that certification throughout their employment.

Finally, new appendices were added that include keeping cool, purchase considerations for AERs, repairs, IFU conflict management, visual inspection, cleaning verification, simethicone, use of HLDs and sterilants, storage risk assessment, and drying.

The purpose of this article is to provide you with a brief recap and key takeaways from the in-person lecture. Proper endoscope processing requires strict adherence to IFUs, national standards, and professional society guidelines. This article simply outlines the latest national standard on flexible endoscope processing, AAMI ST91. That said, your facility should have its own copy, which is now available for purchase electronically at the AAMI store (in print at a later date). Your healthcare facility should be a member of AAMI to verify you don’t miss any updates and documents critical to patient safety. Next up for AAMI will be the new TIR99: Dilators, transesophageal and ultrasound probes processing in health care facilities, hopefully coming in 2023.


Rebecca Kinney is a medical sales representative and small business owner of Cypress, Inc. She is a Certified Central Service Vendor Partner (CCSVP). Rebecca has worked in healthcare for more than 15 years: 7 years as a sterile processing technician and 8 years in medical sales working directly with SP. Focused on a proactive and consultative approach, she takes her experience to share knowledge in the field she wishes she knew when she worked in SP. She actively participates in speaking engagements and uses LinkedIn as an educational tool to reach an audience of almost 30,000 professionals. 

Continual process improvement and education lending to patient safety has always been her primary objective.

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