How to Keep Your Endoscope Channels Dry

You can manually clean an endoscope until it shines and examine every millimeter of its insertion tube for pinhole leaks, but none of that matters if fluid remains in the scope's interior channels. The challenge, of course, is that endoscope channels aren't visible to the naked eye, so any retained moisture is hidden from reprocessing staff. And a little fluid can cause big problems.

"Residual moisture allows for bacteria and biofilm growth — both of which put patients at risk of cross contamination," says John Whelan, BSN, RN, who recently retired from his position as system project manager for high-level disinfection at Michigan Medicine in Ann Arbor.

How concerned should you be? In 2018, Cori L. Ofstead, MSPH, co-authored a study of endoscope reprocessing, drying and storage practices at 3 hospitals. Her research team found residual fluid in 22 of 45 endoscopes tested and detected microbial growth in 71% of endoscopes stored for 24 hours (osmag.net/HMr6Fc). Retained fluid was associated with significantly higher microbial growth within the endoscopes, notes the study.

Hanging an endoscope and relying on gravity's pull to dry its inner channels is a common, yet ineffective practice. "The fluid doesn't completely drain out, because the channels are too narrow," says Dr. Ofstead, president and CEO of Ofstead & Associates, a firm that designs and conducts real-world studies to validate healthcare guidelines, treatments and product claims.

Flushing channels with 70% isopropyl alcohol — this step is incorporated into the cycles of some automatic endoscope reprocessors — at the end of high-level disinfection is thought to prevent moisture from forming in channels, but that, too, poses problems.

"A lot of facilities think it helps to dry the scope, and unfortunately we just don't see evidence that it works," says Dr. Ofstead. "Relying on vertical hanging and alcohol is not supported [by clinical research]."

So how can you ensure an endoscope's channels are free of fluid before you store them? Experts suggest wiping down the scope's exterior with a lint-free cloth and using one or both of these drying technologies to remove moisture from its channels:

• Forced-air drying. Compact units mounted on walls or hung on IV poles are connected to the various ports on endoscopes to push filtered air through the interior channels and dry them out. You can use these systems before hanging endoscopes in a conventional storage cabinet.
• Endoscope drying cabinets. These specially designed units let you hook up endoscope ports to a manifold that pushes HEPA-filtered air through the scope's channels and circulates the air around the scope's exterior.

Dr. Ofstead says applying forced air for at least 10 minutes or placing scopes in a drying cabinet for at least an hour ensures channels are properly dried.

Nobody wants to extend the time it takes to reprocess scopes, but drying technology might be worthwhile, says S. Dwayne Taylor, PA-s, CST, CFA, CRCST, CIS, CHL, CFER, ACE, surgical services manager at Sunrise Hospital and Medical Center in Las Vegas, Nev.

Mr. Taylor's staff used to hang-dry endoscopes in a conventional storage unit, but recently added an endoscope drying cabinet. Typically, scopes are left in the cabinet for up to an hour. When the scopes are dry, they're moved to a storage cabinet that continuously circulates filtered air around the chamber.

"Considering the [cross-contamination] problems we've seen throughout the nation, I support using a HEPA-filtered drying cabinet to decrease the likelihood of channels becoming contaminated," says Mr. Taylor.

There's no clear consensus on how long a scope can be stored before it must again undergo high-level disinfection, but the Society of Gastroenterology Nurses and Associates recommends a maximum storage time of 7 days — that's how long scopes are permitted to hang at Sunrise Hospital. Mr. Whelan suggests basing your facility's hang time on such factors as the types of endoscopes you use and procedures you perform, case volume, and scope inventory.

"Until research provides clearer results, you should perform your own risk assessment," he adds.

Drying double-checks

To test the effectiveness of Sunrise Hospital's scope-drying protocols, clinical managers conduct weekly "wet checks" of 20% of the facility's scope inventory. They flush sterile water down the channels of randomly selected scopes and swab residual water in the channels to check for microbial growth.

Borescopes let you visually inspect the scope's inner workings and detect retained fluid in interior channels. Reprocessing techs who use a borescope "should look inside channels to see if droplets are present," says Dr. Ofstead. "When performing the exam, they should move the borescope through the channels slowly. Moving too quickly will flatten droplets, making them harder to spot."

Though there are plenty of new technologies on the market to help dry endoscope channels and confirm that complete drying takes place, many facilities have been slow to incorporate them into their reprocessing practices. Efforts to ensure scopes are properly dried after reprocessing is made more challenging by the constant pressure to turn over scopes as quickly as possible and by endoscope inventories that are often "just enough" to meet case volumes. Unfortunately, because of those factors, it's not uncommon for drying times to be abbreviated or for drying to be skipped altogether, says Mr. Whelan.

Dr. Ofstead says the results of her study not only suggest that the drying and storage of scopes is a significant issue that needs to be addressed, but also that high-level disinfection ultimately may not be enough to eliminate cross-contamination risks and additional steps might need to be taken to protect patients from harm.

"The bottom line is that disinfection is not eliminating all of the microbes, and residual moisture fosters the growth of bacteria and fungi," says Dr. Ofstead. "Because of that, I don't know if there is a safe hang time for endoscopes. Instead, we should be heading toward sterilization." OSM