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How Do You Disinfect
By Pat Holland, RN, BSN, CGRN
Years ago we would never have heard this question from our endoscopy patients. Today, however, it is not uncommon for endoscopy personnel to be asked this question by their patients. During the past few years, public awareness of infection control issues with flexible endoscopes has been raised through articles in news publications including USA Today and Newsweek and in televised programs.1,2
The incidence of documented infection being transmitted via endoscope is actually very small. In 1993 the American Society for Gastrointestinal Endoscopy (ASGE) reviewed all infections in the literature and found 281 cases of disease transmission from endoscopes, endoscopic accessories, water bottles, and automated endoscope reprocessors (AERs).3 This number represents only one infection in 1.8 million endoscopy procedures. Of those cases, the majority (253) occurred prior to 1988. Several changes were made to endoscope design during 1986-1988: the entire suction channel became brushable, the air and water channels became "flushable" with special adaptors, and the entire endoscope became immersible. Additionally, during this time the first endoscope reprocessing standards were established.
Since 1988 there have been additional incidents of endoscopic disease transmission including the transmission of hepatitis C via colonoscope and tuberculosis via bronchoscope.4,5,6 These and every other documented case since 1988 can be traced to some omission or error in the reprocessing process. Essentially, reprocessing renders a reusable instrument safe enough to be used on another patient. The process includes cleaning and disinfecting or sterilizing.
Endoscopes by design are challenging to clean and reprocess because of their multiple internal channels. These long, narrow lumens must be brushed whenever possible or purged when brushing is not an option.
The Centers for Disease Control and Prevention (CDC) determines how medical equipment is to be reprocessed based on the degree of risk of the device transmitting an infectious organism to the patient. The Spalding classification of medical instruments identifies three categories. Critical instruments, those that penetrate tissue or invade the bloodstream, pose the highest risk for transmission of infections and must be sterilized. Endoscopic accessories such as biopsy forceps and snares are in this category. Semi-critical instruments come in direct contact with intact mucous membranes and must be high-level disinfected (HLD). Flexible endoscopes are semi-critical instruments. Non-critical instruments come in contact with intact skin and must be cleaned. Environmental surfaces, including patient carts, counters, cabinets, as well as blood pressure cuffs, sphygmomanometers, fall into this category.
From 1996 to 1998 three clusters of culture positive bronchoscopy specimens from patients at healthcare facilities in New York7 prompted the Food and Drug Administration (FDA) and the CDC to publish a public health advisories addressing endosocope reprocessing.8 The incidents of patient-to-patient transmission of infections were linked to bronchoscopes having been inadequately reprocessed by Automated Endoscope Reprocessors (AERs) when inappropriate channel connectors were used and instructions by the endoscope manufacturers and the reprocessor manufacturers were inconsistent. The public health advisory makes the following recommendations: determine that each endoscope can be reprocessed in the AER; compare endoscope and AER manufacturers' instructions for consistency; follow manufacturers' instructions for each endoscope, the AER and the chemical germicide; identify device specific instructions for each scope model and reprocessor system; as a final drying step, purge all channels with alcohol followed by air; conduct comprehensive and intensive staff training, and establish a quality control program.
In addition to guidelines published by federal regulatory agencies such as the CDC and FDA, several professional organizations have established guidelines for flexible endoscopes. These are the Society of Gastroenterology Nurses and Associates (SGNA),9 the Association for Practitioners in Infection Control and Epidemiology (APIC),10 the Association of periOperative Registered Nurses (AORN),10 and the American Society for Gastrointentinal Endoscopy (ASGE).10
All of the endoscope reprocessing guidelines published by these organizations are consistent with the standard established in 1994 by the American Society for Testing and Materials (ASTM).13 This organization provides a forum for interested parties to come together and write standards for their industry. The organizations that participated in writing this standard include the CDC and FDC, SGNA, APIC, AORN, and ASGE, as well as representatives from industry (endoscope manufactures, disinfectant manufacturers, etc). The language in this standard is very technical, necessitating that professional organizations write standards that are easy to follow.
SGNA has a three-piece module on reprocessing of flexible endoscopes that is comprehensive and easy to follow. The module includes a wall chart that delineates the eight reprocessing steps, a video that demonstrates the reprocessing steps, as well as provides a detailed written guideline. Because SGNA guidelines are the ones most commonly used, they will be used to describe the steps of reprocessing. Be sure to review the manufacturer-specific guidelines for each endoscope model.
Step 1. Precleaning. This step is performed immediately after the endoscopy procedure. This is the only step of the reprocessing process that should be performed in the patient care area. The exterior of the scope is wiped with an enzymatic solution. The channels are purged or aspirated with solution to wet and loosen any debris that may be in the channels. Enzymatic solution should be suctioned through the suction channel and the air and water channels should be purged according to manufacturer's instructions.
Step 2. Leak testing. Test for leaks according to the endoscope manufacturers' instructions; a steady stream of bubbles coming from the scope's interior indicates a leak. Pressurize the scope before immersing it. Observe or palpate the bending rubber at the distal tip for distention. Completely immerse the entire scope ensuring that the control knobs are covered. Angulate the distal tip of the scope fully in all directions to open any small holes. Depress each of the switches to observe for leaks. Observe for leaks at the control body, the insertion tube, the light guide tube, and the connector.
Step 3. Cleaning. Use a fresh enzymatic solution for cleaning each scope. When using an enzymatic product, be careful to accurately measure the amount prescribed. If the enzymatic concentration is too weak it may not be effective; if it is too strong it may have deleterious effects on the equipment. Using appropriate adaptors, fill the channels with the enzymatic solution and soak for the time prescribed on the product label, usually 2-5 minutes. When cleaning a duodenoscope, use a 3cc syringe and fill the elevator channel. This step should be performed even when using an automated reprocessor as most reprocessors do not have a "soak" time. While the scope is soaking, perform the remaining cleaning process:
Step 4. Rinsing Using fresh clear water, thoroughly rinse the exterior of the scope. Enzymatic solutions may not be compatible with the disinfecting/sterilizing chemicals, so it is imperative that thorough rinsing precedes disinfecting. Purge all channels using the appropriate adapters. Purge all channels with air to remove any water left in channels that could dilute the disinfectant. Rinse all valves and attachments. If reprocessing manually, dry the scope exterior to remove water that could dilute the disinfectant.
Step 5. Disinfect/Sterilize. Remember to wear proper PPE when handling disinfectants. Use a high-level disinfectant or sterilant that has been cleared by the FDA for flexible endoscope reprocessing14. Mix the disinfectant according to manufacturer's instructions and label with the expiration date. Keep the disinfectant container covered at all times and label the container as a biohazard. Test the disinfectant with product specific test strips at least daily and every 10 cycles if you have more than 10 cycles per day. Some disinfectants require special ventilation. For detailed information on specific reprocessing chemicals refer to SGNA's guidelines for use of disinfectants and sterilants.15 Fill all channels of the endoscope with a high-level disinfectant using appropriate adaptors until no bubbles are seen exiting the channels. Ensure that the endoscope is completely immersed in the disinfectant solution. Cover the disinfectant and set a timer for the required time of the chemical being used. If an automated reprocessor is used, all channels should be connected using the proper adapters. Make sure the reprocessor's disinfection cycle is set for the required time. For ERCP scopes, fill the elevator channel with disinfectant using a 3cc syringe. Some automated reprocessors have a high-pressure port (minimum 20 psi) that can be used for the elevator channel. If you are reprocessing the elevator channel with an automated reprocessor, include documentation in your reprocessing policy that the process does indeed provide high- level disinfection.
Step 6. Rinsing. Submerge the endoscope completely in a basin of fresh water and purge all channels. Purge all channels with air to remove all water from the channels. If using an automated reprocessor, ensure there is a rinse cycle and that all channels are thoroughly purged with rinse water.
Step 7. Drying and alcohol flush. Purge all channels with 70-80% alcohol. Some automated reprocessors have adapters to perform this step. Even when using a sterilization process, this step should be performed. The alcohol will facilitate drying of the internal channels. Purge all channels with air; forced air will further facilitate drying. Wipe the exterior of the endoscope dry with a lint-free cloth and dry valves and attachments.
Step 8. Storage. The endoscope should be stored with valves and attachments removed, hanging vertically in a well-ventilated cabinet. Dry valves and attachments and store them separate from the scope.
With the aging of the baby boomer generation, we will most certainly see an increase in flexible endoscopic procedures in the next few years. Proper reprocessing of endoscopes is easy to achieve through strict adherence to the standards and guidelines set forth by federal and professional organizations. Endoscopy personnel can comfortably assure patients that their endoscopy equipment is safe by following these well-established guidelines.
Patricia Holland is director of clinical education for GE Medical Systems Clinical Service, Endoscopy Services in Golden, Colo.