A common drop added to gastrointestinal scopes to enhance image clarity could actually increase infection risk for patients, according to a study in the American Journal of Infection Control.
Physicians from Minnesota noticed a cloudy, white, viscous fluid in gastroscopes and colonoscopes after they had been fully reprocessed. The clinicians took samples from three endoscopes and, through analysis, found the fluid to be simethicone.
Simethicone is the main ingredient in anti-gas medication sold over the counter at pharmacies and grocery stores, according to Kaiser Health News. Many physicians put these drops inside of scopes, because the concoction can reduce the number of bubbles inside of people's bodies that can affect visibility.
But because the gas relief substance can contain sugar to make it more palatable, it "could provide the perfect habitat for the growth of bacteria," Cori Ofstead, the study's lead author, told KHN. Mr. Ofstead is an epidemiologist and chief executive of Ofstead & Associates, a medical research firm. The drops also contain silicon, which makes cleaning the scopes more difficult.
"Finding residual fluid in scopes that should be dry would be troubling enough," Mr. Ofstead said. "The finding of fluid containing simethicone suggests we have more serious problems. It could explain why we are having more trouble getting these scopes clean."
Pentax Medical and Fujifilm recommend against use of the anti-gas drops because they "cling tenaciously to surfaces," as Pentax put it in its scope-cleaning directions.
Michael Shaw, MD, a gastroenterologist and a co-author of the study, said the findings shouldn't scare physicians away from using the gas relief drops, however, because not using the products at all could make endoscopies less effective.
"I don't want to see the public alarmed, but this study did raise a large number of questions," Dr. Shaw told KHN.
"Studies are needed to assess the prevalence of residual moisture and simethicone in endoscopes and determine the impact on reprocessing effectiveness," the study concludes. "We recommend minimizing the use of simethicone pending further research into its safety."