BUBBLE TROUBLE An anti-foaming agent can remain on endoscopes even after reprocessing.

If you use infant gas relief drops to clear away the air bubbles and foam in the GI tract that can obstruct endoscopic visualization, you could be exposing your patients to infection. A study in the American Journal of Infection Control found that injecting an infant formulation of simethicone into scopes' working channels might trigger cross-contamination risks among endoscopy patients.

A team of Minnesota researchers found that simethicone residue can remain in the scope even after reprocessing, and may put patients at risk of infectious outbreaks.

Their discovery was accidental, arising during a 7-month study of scope cleaning techniques at a Minnesota surgical facility. Nine unannounced audits had confirmed that sterile processing technicians were following the scope manufacturers' cleaning instructions to the letter. In the last of 3 inspections of 20 disinfected colonoscopes and gastroscopes, however, they found fluid remaining inside 19. In 8 of those 19, the fluid was white and cloudy, like the over-the-counter antiflatulent simethicone. They captured 3 samples, 2 of which tested positive for the medication.

"Finding residual fluid in scopes that should be dry would be troubling alone," said lead author Cori Ofstead of Ofstead & Associates, a St. Paul, Minn.-based medical research firm that conducted the study with gastroenterologists from the University of Minnesota Medical School. "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."

Simethicone drops, which are not sterile, contain sugar and thickening agents, which can foster bacterial growth. And the silicone in them doesn't dissolve in water or detergents, which can contribute to hard-to-remove biofilms in scope lumens.

While the study notes that no patient infections have yet been linked to the use of simethicone in scopes, it recommends limiting its use as further research is conducted. Scope manufacturers Pentax Medical and Fujifilm have previously warned users of the obstacles that simethicone residue presents to cleaning, and Olympus advises users to keep concentrations low.

The study was funded in part by 3M, automated endoscope reprocessor manufacturer Medivators and cleaning accessory manufacturer Healthmark Industries.

David Bernard