Reusable flexible endoscopes are reprocessed to remove contaminants and prevent device-related infection of patients. It’s an extensive undertaking that can take as long as two hours to complete.
Device-related infections caused by reprocessed flexible endoscopes have been traced back to a number of reprocessing steps, including:
After manual pre-cleaning, AERs are often used during reprocessing because they minimize hospital staff contact with dangerous chemicals and the contaminated instruments. AERs run high-level disinfectants through the instrument that must be manually rinsed afterward with 70 percent alcohol.
But if an AER is damaged, broken, or contaminated, it can become a hazard.
In a review of 14 M. tuberculosis outbreaks caused by contaminated bronchoscopes, the most common causes for the reported reprocessing failures were non-sterile rinse water and an over-reliance on automated reprocessors.
The FDA actually recommends that for duodenoscopes, AER use be purely supplemental, as rigorous and thorough manual cleaning is most effective. Duodenoscopes are very difficult to clean and disinfect due to their intricate design and some recent outbreaks have been traced back to these instruments.
AERs are widely used to reprocess flexible endoscopes and their accessories to decontaminate them between uses, though they should only be used at the flexible endoscope manufacturer’s recommendation. Reprocessing is a multistep procedure that involves manual cleaning and/or the use of an AER for high-level disinfection or low-temperature sterilization.
AERs expose the interior channels of flexible endoscopes to chemical solutions to help kill microorganisms that may be lodged in the channels. This is done by hooking endoscope channels up to the AER using special connectors that allow HLD chemicals to circulate through the channels under pressure. The cycle time is typically 22 to 30 minutes, and then the AER rinses the endoscope channels with water to remove harmful chemicals. Some models—which cost about $50,000 or more—will then flush the channels with forced air or alcohol solutions to aid in the drying process.
Industry guidelines for the use of AERs vary by regulatory group, though most recommend following the manufacturer’s instructions for use.
Studies suggest that contaminated rinse water, broken instruments, and the presence of biofilm in the automated equipment have all contributed to device-related infections from a reprocessed endoscope.
After an imipenem-resistant Pseudomonas aeruginosa (IRPA) outbreak at the New York Hospital Medical Center in Queens, New York in 1998, researchers discovered that peracetic acid—an oxidizing agent that is used for high-level disinfection in AERs—was not reaching the bronchoscope lumen due to an incorrect connector joining the bronchoscope suction channel of the AER. Low concentrations of peracetic acid are required to quickly deactivate pathogenic microorganisms, viruses, and spores inside flexible endoscope channels.
In the 1998 example, no malfunction warning was received, and researchers determined staff needed to be better trained on how to work and maintain AERs.
The risk of bacterial outbreaks following the use of an AER has declined in recent years, according to a recent CHEST article by Dr. Atul Mehta of the Cleveland Clinic and Lawrence Muscarella, president of LFM Healthcare Solutions in Pennsylvania. The study, which highlights the potential risk of MDRO infection transmission through flexible bronchoscopy, notes that the perceived risk from contaminated AERs has reduced since the 1990s. Since then, the authors note, the design of AERs has improved to help mitigate contamination risk.
But while the technology may have improved, the use of an AER is still not a foolproof way to guarantee disinfection of a flexible endoscope. The AER is just one part of the rigorous procedure needed to ensure flexible bronchoscopes are ready for re-use. And, for the AER use to be effective in that stage of the process, the instrument must be cleaned and maintained ready for use so as not to inhibit the cleaning process.
Just as flexible endoscopes undergo regular cleaning, disinfection, and surveillance to mitigate the risk of cross contamination, the same should be done for reprocessing equipment, including AERs.
The table below, from the FDA, represents a list of AER manufacturers who have successfully completed the current high-level disinfection or liquid chemical sterilization validation testing with duodenoscopes.
The FDA now requires AER manufacturers to include validation data in their premarket notification instructions.
If your bronchoscope and AER manufacturers have different cleaning instructions, whose should you follow? Download our step-by-step guide to managing this issue.