Simethicone residue remains inside gastrointestinal endoscopes despite reprocessing

Cori L. Ofstead, Harry P. Wetzler, Ellen A. Johnson, Otis L. Heymann, Thomas J. Maust, Michael J. Shaw

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Background During a study designed to assess endoscope reprocessing effectiveness, a borescope was used to examine lumens and ports. Cloudy, white, viscous fluid was observed inside fully reprocessed gastroscopes and colonoscopes. This fluid resembled simethicone, which is commonly administered to reduce foam and bubbles that impede visualization during gastrointestinal endoscopy. This article describes methods used to determine whether the observed fluid contained simethicone. Methods Photographs of residual fluid were taken using a borescope. Sterile cotton-tipped swabs were used to collect samples of fluid observed in 3 endoscope ports. Samples were evaluated using Fourier transform infrared spectroscopy (FTIR)–attenuated total reflection analysis. Results Residual fluid was observed inside 19 of 20 endoscopes. Fluid photographed in 8 endoscopes resembled simethicone solutions. FTIR analysis confirmed the presence of simethicone in 2 endoscopes. Conclusions Fluid containing simethicone remained inside endoscopes despite reprocessing. Simethicone is an inert, hydrophobic substance that may reduce reprocessing effectiveness. Simethicone solutions commonly contain sugars and thickeners, which may contribute to microbial growth and biofilm development. Studies are needed to assess the prevalence of residual moisture and simethicone in endoscopes and determine the impact on reprocessing effectiveness. We recommend minimizing the use of simethicone pending further research into its safety.

Original languageEnglish (US)
Pages (from-to)1237-1240
Number of pages4
JournalAmerican journal of infection control
Issue number11
StatePublished - Nov 1 2016

Bibliographical note

Funding Information:
Funding/Support: Supported by 3M Company , Medivators Incorporated , and HealthMark Industries , which provided study materials and funding for this study. The University of Minnesota Health and Ofstead & Associates, Inc, also provided additional research support.

Publisher Copyright:
© 2016 Association for Professionals in Infection Control and Epidemiology, Inc.


  • Endoscope
  • biofilm
  • colonoscope
  • contamination
  • epidemiology
  • gastroscope
  • simethicone


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