Since the publication of AAMI ST91:2021 National Standards for processing flexible and semi-rigid endoscopes, medical device processing experts continue to observe and address flexible endoscope storage cabinet challenges and confusion.
Common questions asked are, “What kind of endoscope storage cabinet are we supposed to have and where can the cabinet be positioned and why?” Several factors determine the type of endoscope scope cabinet needed. Healthcare facilities have different financial budgets and constraints.
The square footage and footprint of a facility often present challenges that make it nearly impossible to purchase the proper storage cabinet. Most flexible endoscope storage cabinets are large and require a healthy amount of space. Flexible endoscope devices vary in complexity, length and size, and they could change the height, width, depth and space necessary to meet the storage cabinet manufacturer’s specifications. Electrical, filtration, ventilation and compressed-air requirements could affect the cost and space.
With today’s economic challenges, healthcare facilities have tighter equipment capital and operational budgets. Healthcare facilities must creatively find ways to cut costs, work more efficiently by eliminating wasteful processes and unnecessary supplies, and mitigate staffing shortages, while reducing overtime and the excessive use of contracted employees—and this is the tip of the iceberg. Healthcare facilities focus on revenue-generating growth strategies, partnerships, acquisitions or mergers to support long-term success and provide medical services to their communities. Rising equipment costs present difficult budgetary limitations for most facilities now.
Choosing the right storage cabinet is challenging, so assessing and evaluating the current state to identify potential gaps or risks in the process can often support a more cost-effective solution and plan. Most importantly, when making the decision, the outcome should result in the greatest protection for the device and the best prevention for potential recontamination and ensure that every stored endoscope is patient-ready.
Endoscope Storage Considerations
Two types of storage cabinets are outlined in the AAMI ST91:2021 National Standards. According to AAMI, professional organizations have differing views on the best storage cabinet choice. However, published scientific studies show using endoscope drying cabinets will reduce the risk of retained moisture and microbial contamination. Flexible endoscopes processed via liquid chemical sterilization (LCS) or high-level disinfection (HLD) should be stored in a cabinet that is tall enough to prevent the devices from touching the bottom of the cabinet, and has enough space (in width and depth) to allow the endoscopes to hang freely without touching each other or coiling. If using a horizontal scope cabinet, there should be enough space to store the endoscope without obstructing other stored devices.
Option 1: Endoscope Drying Cabinets
Designed to store flexible endoscopes, endoscope drying cabinets circulate HEPA-filtered or instrument air throughout the closed cabinet and through each endoscope channel at continuous positive pressure. The collective evidence shows that drying cabinets provide practical storage of flexible endoscopes to facilitate drying, decrease the potential for contamination, and provide protection from environmental contaminants (AORN, 2018 [367]).
Within the drying cabinet, the internal and external surfaces of the endoscope are intermittently or continuously dried, suppressing microbial growth. Studies related to the efficacy of drying cabinets compared with other methods of storage showed that drying cabinets effectively limited bacterial proliferation during storage of potentially incompletely dried endoscopes (Saliou, 2015 [284]; Perumpail, 2019 [254]).
Drying cabinets tend to be more costly than the conventional type. The cabinet may require routine disinfection or sterilization of the connection tubes and accessories. Compressed air is typically used to open the doors and for continuous air circulation. Reviewing and verifying that the facility can perform all the routine services and maintenance required is essential. Some cabinets have RFID badge access, keypad punch, or a swipe mechanism to open the cabinet, which is excellent for staff accountability and control.
A more popular feature seen with some drying cabinets is the built-in endoscope tracking system (AI technology or smart devices), automatic drying timers, and color-coding systems that visually indicate when an endoscope is completely dry or needs to be reprocessed (e.g., hang time). Although the up-front costs may be higher, there are advantages to using this type of cabinet, such as knowing the endoscopes are stored dry and safe for use. Drying challenges related to endoscope processing and storage continues to be a hot topic and a critical element contributing to elevated infection transmission risks.
Option 2: Conventional Drying Cabinets
Conventional cabinets are closed cabinets that enable the passive circulation of HEPA-filtered or instrument air through the cabinet or via continuous positive pressure. However, they do not include forced air through endoscope channels. When drying cabinets are not available, conventional cabinets may be used. Conventional cabinets should be cleaned following the manufacturer’s instructions for use (IFU) at least weekly, and when visibly soiled. Conventional cabinets with HEPA filtration should be used to store flexible endoscopes.
When conventional cabinets are used, the facility should monitor for indications the endoscope channels are not being dried before placement in the cabinet (drip marks in the bottom of the cabinet, etc.). If indications are noted, additional efforts should be taken to ensure drying (such as a drying time longer than 10 minutes). Storage cabinets, unless modified to provide drying, or upgraded by a third-party drying manufacturer’s IFU and approved by the storage cabinet manufacturer, do not meet the criteria to be a drying cabinet. If manual drying is used, verify the endoscope is dry. Develop and implement policies and procedures to perform quality assurance dryness checks.
Studies performed by reputable scientists and researchers cannot emphasize enough the importance of drying the endoscopes after they have been processed. The concern with conventional drying cabinets is that the air circulates and only touches the external parts of the endoscope, while the channels inside the endoscopes remain wet. If conventional drying cabinets are considered, the facility should also consider how to remove the water from endoscope channels before placing endoscopes into the cabinet.
Numerous studies have demonstrated endoscopes frequently harbor microbes after the endoscopes were high-level disinfected and revealed retained moisture after an alcohol purge followed by 10 minutes of forced air in an automatic endoscopic disinfector (AER) cycle (Cori L. Ofstead et al. 2024). Fluid retention within endoscope channels poses risks for increased transmission of residual bacteria to patients.
According to AAMI, bacteria can double in population every 20 to 30 minutes. An inadequately dried endoscope contaminated with only one or two viable bacteria can end up contaminated with tens of thousands to millions of bacteria after only eight hours of storage, magnifying the risk of transmission of infectious organisms to the next patient (Alfa et al. [54]). The exterior surface and all interior channels of flexible endoscopes should be thoroughly dried before reuse or storage.
Drawbacks to conventional drying cabinets include added operational costs for supplies, testing materials, and additional equipment needed to dry endoscopes before storage. The potential for missed drying steps, errors and inconsistent processes is higher. Mechanical drying aids can be used, but these require frequent accessory and tubing changes. The drying aid needs routine service and verification checks, which adds more steps to the workflow and process. Another way to dry endoscopes after processing is with instrument-grade air. When reviewing both options, be sure to evaluate the cost for all required supplies, additional equipment, contract agreements and quality-assurance materials.
Storage Area
Storage cabinets should be placed in an area designated as a clean space. Staffers need enough space to open cabinet doors, retrieve the scope, and place the scope in a clean trans- port container. Clean work rooms, a clean or sterile storage alcove or closet away from water sources or plumbing, or a clean area near or outside of the procedural room, is ideal. Storage cabinets should not be located inside the endoscopy procedural room (AORN, 2018e, IX.a [39]). The benefit of finding a low-traffic area that is secure and clean is that it helps protect endoscopes and prevents recontamination.
Storage cabinets should have doors and be located at least 3 feet from any sink. Ensuring storage cabinets have doors and are separated from sinks by at least 3 feet provides protection and reduces the potential for processed flexible endoscopes to be contaminated by water droplets (AORN, 2018e [39]). Cabinet doors should remain closed until endoscopes are needed. Staff will be responsible for routine cleaning and maintenance of the storage cabinet. A proper amount of space may be required for staff to clean the cabinet; service technicians need access; space is needed to change the filters periodically; and staff need the capability to process any attachments or accessories that come with the cabinet.
Shop Around and Ask Questions
When shopping for a storage cabinet, it is vital to ask the vendor or manufacturer for specification documents for installation, the technical information report or published white paper of their cabinet (if applicable), the FDA 510K Clearance document, a copy of the user operational manual to review, and a price list of replacement parts or filters that may need periodic replacement. Most equipment companies honor a 1-year warranty for parts and services. After the year ends, the facility is on its own unless there is a service agreement in place for routine and preventative maintenance. For future cost avoidance and to safeguard against common oversights during the review process, the facility should:
- Verify that the proposed price is within the national benchmark range to avoid inflated costs or price-gouging
- Purchase cabinets from reputable vendors or manufacturers that can provide a copy of the FDA 510K premarket clearance for the cabinet.
- Ask to see all service agreement options and the costs associated with those options. The end user needs to understand what service is offered if or when the cabinet malfunctions, gets damaged or is defective. Response time and vendor support should weigh heavily in the decision-making process.
- The vendor should share the most reported issues and the average cost for those types of repairs and provide a general lead time for service (especially when parts need to be ordered before repairs or service can be performed).
- If the vendor does not offer preventative maintenance or routine services, consider other options, e.g., third-party repair services. When considering third-party repair ser- vices, proceed with caution, as using a third-party service will often void the original manufacturer’s warranty, liability and service guarantees. It is important to read all contracts and fine print.
- Don’t limit the search to one vendor; shop
- Ask about the cabinet’s average useful lifespan/end-of- Technology is ever-changing and advancing. Equipment will not last forever. Knowing how long the company will support the equipment with parts and services will help significantly with future budget planning. Once the cabinet becomes obsolete, the parts and services for the cabinet will be phased out and will no longer be available. Then the cabinet will need to be replaced or upgraded.
- Find out whether the company offers future trade-ins for upgrades or obsolete All these proactive measures can prevent a lot of unforeseen costs and challenges in the future.
- What do the other customers think about their cabinet? Ask the vendor to provide a customer reference list. Some vendors will offer a site visit to another facility to see how the cabinet is used and to connect with other process users.
- Ask about the cabinet’s capabilities, such as artificial intelligence (AI) or innovative smart capabilities, security features, necessary accessories or adapter hookups, and passive, forced-air or active airflow.
Using ventilated cabinets with continuous, HEPA-filtered, circulating airflow that promotes exterior and internal channel drying is a best practice. Facilities responsible for processing flexible endoscopes (regardless of the device’s complexity) should evaluate and consider cabinets that provide the most ideal and effective way to reduce microbial contamination and biofilm buildup after the device is processed correctly.
Drying cabinets must support continuous air externally and inside the endoscope channels to ensure safe, ready-to-use, flexible endoscopes. Despite the industry inconsistencies regarding the exact type of storage cabinet required, the industry experts’ consensus is when endoscopes are not properly dried (or stored wet), they are most susceptible to microorganism growth and biofilm buildup, and risk transmission of infectious diseases to patients. Endoscope storage cabinets without a drying feature complicate the staff’s processing steps.
New products on the market to test and verify drying effectiveness are available for purchase through various vendors and distributors. Facilities should develop quality assurance (QA) processes to ensure residual moisture inside the channels is absent. The QA process should be incorporated into the facility’s policies and procedures, along with protocols for routine cleaning, inspection and maintenance of the storage cabinet, as well as its hoses, connectors and miscellaneous parts. Test results, cleaning and preventative maintenance should be tracked for trends and opportunities.
If the facility chooses not to purchase endoscope drying cabinets, the staff will need to thoroughly dry endoscopes before placing them in storage cabinets. Endoscopes must be purged with forced air for ten minutes at the correct pounds per square inch (psi) of pressure. This can be achieved using mechanical endoscope drying aids (with HEPA filtration) or with instrument-grade air, an air gun and a pressure regulator. Importantly, complex endoscopes (those with multi-channels, elevators and balloons, differing lengths, diameter of channels or ports) may take longer than ten minutes to dry with drying aids or compressed air. Always follow the endoscope manufacturer’s IFU and evaluate the workday time challenges this may present.
When shopping for endoscope cabinets, facilities must consider how scope drying will delay operational workflow, increase the time it takes to turn over the endoscope for following procedures, and increase the labor needed.
Time is of the essence in high-volume endoscopy facilities. Wet endoscopes should never be stored, as this presents the highest risk for infectious disease transmission between patients caused by microorganism growth and waterborne pathogens; therefore, choosing the best storage cabinet also requires evaluating the operational workflow and impact(s) to current or future volume. Utilizing drying cabinets eliminates the hands-on, laborious, air-drying step and inconsistencies associated with human factors (errors and process step variations). Endoscope storage cabinets are meant to protect endoscopes from becoming contaminated or damaged until they are used. The type of cabinet purchased determines the effects, and the risks associated with the proliferation of organisms. Choose wisely.
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