BACKGROUND: Studies from our group and others demonstrate residual fluid in 42% to 95% of endoscope working channels despite high-level disinfection (HLD) and drying. Additionally, persistent simethicone has been reported in endoscope channels despite reprocessing.METHODS: Endoscopy was performed using water or varied simethicone concentrations (0.5%, 1%, 3%) for flushing. After HLD/drying, we inspected endoscope working channels for retained fluid using the SteriCam borescope. Working channel rinsates were evaluated for adenosine triphosphate (ATP) bioluminescence. Fourier transform infrared spectroscopy was performed on fluid droplets gathered from a colonoscope in which low-concentration simethicone was used.RESULTS: Use of medium/high concentration simethicone resulted in higher mean fluid droplets (13.5/17.3 droplets, respectively) and ATP bioluminescence values (20.6/23 RLUs, respectively) compared with procedures using only water (6.3 droplets/10.9 RLUs, p<0.001). Two automated endoscope reprocessing (AER) cycles resulted in return of fluid droplet and ATP bioluminescence values to ranges similar to procedures using only water (p=0.56). Low-concentration simethicone did not increase mean residual fluid or ATP bioluminescence values compared with procedures using only water (5.8 droplets/15.6 RLUs). FTIR analysis revealed simethicone in the endoscope working channel after use of low-concentration simethicone.CONCLUSIONS: Use of medium/high concentration simethicone is associated with retention of increased fluid droplets and higher ATP bioluminescence values in endoscope working channels, compared with endoscopes in which water or low concentration simethicone was used. However, simethicone is detectable in endoscopes despite reprocessing, even when used in low concentration. Our data suggest that when simethicone is used, it should be used in the lowest concentration possible. Facilities may consider 2 AER cycles for reprocessing of endoscopes when simethicone has been used.
View details for PubMedID 30125574