The study was conducted at five hospitals across the United States. Researchers from 3M's Infection Prevention Division examined 275 flexible endoscopes. Types examined include ones inserted through the mouth, such as duodenoscopes, which examine the first section of the small intestine, and gastroscopes, which look at the stomach. Researchers also inspected colonoscopies, which are inserted through the anus to examine the colon. They found that 30 percent of duodenoscopes, 24 percent of gastroscopes, and 3 percent of colonoscopies didn't pass a cleanliness rating test.
"Three out of 20 is an unexpectedly high number of endoscopes failing a cleanliness criterion," said Dr. Marco Bommarito, lead investigator and lead research specialist of the 3M Infection Prevention Division. "Clearly, we'd like no endoscopes to fail a cleanliness rating."
To test the endoscopes, the researchers first allowed them to be cleaned manually, which includes using an enzymatic cleaner and flushing by a hospital technician. The second step, the application of a high-level disinfectant, is ineffective if the manual cleaning isn't done properly. The researchers skipped the second step, and flushed the endoscopes with sterile water, using the sample water to test for adenosine triphosphate (ATP), a marker of bio-contamination. They then measured the amount of ATP in relative light units (RLU) with a hand-held luminometer. Any endoscope with more than 200 RLUs of ATP was considered a cleaning failure.
"The cleaning protocols for flexible endoscopes need improvement, such as guidelines tailored to the type of scope or identifying if there is a critical step missing in the manual cleaning process, and documented quality control measures," Bommarito said. "These types of improvements could have a positive impact on patient safety."
In the U.S., there are about five million gastrointestinal endoscopies each year. They're used to screen different parts of a person's GI tract, looking for polyps or colon cancer. While they are responsible for the most healthcare-related outbreaks of infection compared to any other medical instrument, the number of incidences is still very low, at about one out of every 1.8 million procedures, according to the Centers for Disease Control and Prevention.
The findings from this study were presented at the annual conference of the Association for Professionals in Infection Control and Epidemiology, which is held June 8-10.