By Susan Klacik, BS, CRCST, CIS, CHL, ACE, FCS
Multidrug-resistant organism (MDRO) infection outbreaks have been associated with flexible endoscopes, and review of processes and procedures used to reprocess these complex devices has revealed failures in reprocessing steps. Mitigating these risks requires proper care and handling – from point of use through all reprocessing steps to safe transport for patient use.
At the end of 2021, the Association for the Advancement of Medical Instrumentation (AAMI) released its updated ANSI/AAMI ST91:2021, Flexible and semi-rigid endoscope processing in health care facilities, which reflects current research and advancements in flexible endoscope processing. What follows is a brief summary of some of the key changes.
Point-of-use treatment, cleaning, inspection
Point-of-use treatment now includes hand-off communication from point of use to the decontamination area (this should include, at minimum, the patient identifier, date of procedure, time point-of-use treatment was completed, and employee contact). It is recommended that endoscopes and their accessories be kept moist following patient use and before transport to the decontamination area by applying a detergent designed to retain moisture, placing a towel moistened with water over the items, or placing items inside a package designed to maintain humid conditions.
The revised ST91 states that three decontamination sinks are ideal (one sink used for leak testing, another for manual cleaning and the third for critical rinsing); at this time, however, two sinks or one sink with two separate basins may be used. Sink size and location(s), flushing accessories and ergonomics are important considerations to facilitate effective cleaning as well as employee safety. Ergonomic, height-adjustable sinks help prevent personnel from bending over to perform cleaning tasks (sinks positioned too high or low increase injury risks). If a delay in endoscope processing exceeds the manufacturer’s recommended time, the endoscope should be cleaned following the manufacturer’s written IFU for delayed processing. If no timeframe is given, manual cleaning should begin within one hour or as determined by the facility’s own risk assessment.
Cleaning verification (CV) used after endoscope cleaning and before disinfection or sterilization may detect residual organic soil and microbial contamination present on a surface, even if a device appears clean. The updated version recommends CV tests be performed after each use of high-risk endoscopes. Additionally, the use of a borescope to visualize interior working channels is recommended in the revised ST91.
Training, competency, certification
It is recommended that all who perform endoscope processing duties complete formal training and competency verification in all aspects of endoscope processing prior to their first solo assignment. All personnel performing endoscope processing should also be certified in flexible endoscope processing within two years of employment.
Transitioning to sterilization
High-level disinfection (HLD) may not reliably inactivate certain types of microorganisms (i.e., bacterial spores). Evidence supports sterilization (instead of HLD) of all flexible endoscopes, including those used in both semi-critical and critical procedures. Sterilization offers a greater margin of safety in the overkill process and provides a sterile packaged endoscope. Transitioning from HLD to sterilization will take time in terms of the endoscope and sterilizer manufacturers implementing necessary technological advances and for health care facilities to provide the budgetary and site accommodations to implement this change. Health care facilities should begin taking steps toward sterilization for flexible endoscopes, when possible.
Environment, HVAC parameters, water quality
It is recommended that heating, ventilation and air conditioning (HVAC) operating parameters in the endoscope processing area comply with the specifications of ANSI/ASHRAE/ASHE Standard 170-2017, Ventilation of Health Care Facilities that were in effect when the HVAC system was first installed or last upgraded. The standard recommends that health care facilities establish processes to monitor HVAC performance parameters and identify, document and resolve variances within the rooms where processing occurs. If a variance in the HVAC parameters occurs, a risk assessment should be conducted.
A new section has been added to ST91 (Section 4.3.11, Water quality). To ensure that the correct water quality is used in each stage of processing, the manufacturers’ written instructions for use (IFU) for all equipment and supplies should be used. The health care facility should monitor and control the water supply to endoscope processing sinks and processing equipment. Whenever major repairs occur or changes to the water utility system occur, equipment qualification testing should be performed before use. Note: More information on water quality can be found in AAMI TIR34:2014/(R)2021.
A multidisciplinary team should be established to select cleaning chemicals, materials, tools and equipment for use in the endoscope processing setting. Cleaning frequencies should be established for high-touch objects and surfaces as well as for storage shelves, endoscope storage cabinets and similar objects. Terminal cleaning frequency should also be established for endoscope processing areas (at a minimum daily and more often as needed).
Leak testing
Significant revisions were made regarding leak testing, including having automated leak testers placed on a calibration schedule to verify that each leak tester is producing the correct pressure. Manual handheld leak testers and leak tester tubing should be inspected for damage, leakage and pressure output. Pressure verification should be performed for each type of leak tester in the facility each day endoscopes are used. Documentation of leak testing results should be recorded. Some AERs include mechanical leak testing, and the updated ST91 recommends that when using this type of AER, the endoscope and AER manufacturers’ written IFU must be followed (with the outcome of the leak test documented). Note: Conducting mechanical leak testing using an AER is not a substitute for the leak testing recommended in the endoscope manufacturer’s IFU.
Drying
It is recommended that endoscope channels be dried for a minimum of 10 minutes with pressure-regulated forced instrument air or, at minimum, HEPA-filtered air. If moisture remains, drying should be extended until no moisture is visible. The use of alcohol has historically been recommended in the drying process after disinfection is completed; however, some studies have shown that alcohol can be a fixative agent. ST91 now recommends that a multidisciplinary team conduct a risk assessment to determine whether endoscope lumens should be flushed with 70-90% ethyl or isopropyl alcohol.
Storage
Two types of storage cabinets are being recommended for HLD- and liquid chemical sterilization-processed endoscopes: drying cabinets and conventional cabinets. There is no clear consensus at this time among professional organizations regarding which type of cabinet is best; drying cabinets, however, have been shown in scientific studies to reduce the risk of retained moisture and microbial contamination. Endoscopes hung in HEPA-filtered storage cabinets that do not have drying capabilities should be dried prior to storage. Cabinets should be located in a secure location, such as in the clean workroom, and not within the endoscopy procedure room. Storage cabinet doors should be kept closed, and the cabinets should be located at least three feet from any sink to prevent endoscopes from becoming contaminated by water.
The updated ST91 is available at the AAMI store (www.aami.org); those with an electronic subscription have immediate access to the revised standard. The standard is also available to HSPA members at a reduced rate; visit www.myhspa.org.
– Susan Klacik, BS, CRCST, CIS, CHL, ACE, FCS, serves as a clinical educator for HSPA.
