Effectiveness of oolong tea and simethicone solution for lens cleansing during colonoscopy: A double-blinded randomized study

BACKGROUND AND AIMS: water is an imperfect agent for lens cleansing during endoscopy due to its incompetence to clean hydrophobic dirt, whereas amphiphilic surfactants have the potential to overcome the limitation of water. The trial was aimed to evaluate the cleansing effectiveness of 2 typical surfactants (simethicone solution and oolong tea) for colonoscopic lens. METHODS: Oolong tea (O-), low concentration simethicone solution (S1-), high concentration simethicone solution (S2-) and distilled water (D-) were used as washing solutions for colonoscopic lens. Study I: The tip of the colonoscope was immersed in lard oil in order to simulate the blur, and photographs were taken toward a standard colonoscopy image in-vitro pre- and post- each cleansing procedure. The blurred areas of each image were quantified and compared. Study II: 395 consecutive patients who were due to colonoscopy examination were enrolled and randomized into O-, S2-, D-group. The volume of washing solution used and cleansing level during the examination procedure, adenoma and polyp detected per colonoscopy, insertion time and withdraw time were analyzed. RESULTS: Study I: There were no differences in 4 groups for the blurred areas on images before lens cleansing. The blurred areas after lens cleansing were significantly smaller in 3 groups (O- 8.47 ± 20.91 vs S1- 13.06 ± 10.71 vs S2- 6.76 ± 8.49 vs D- 38.24 ± 29.69, P < .05) than water. The decline range of blurred areas after lens cleansing in oolong tea, low concentration simethicone solution, high concentration simethicone solution groups were significantly higher than that in distilled water group (O- 87.35 ± 20.81 vs S1- 78.12 ± 19.24 vs S2- 89.57 ± 8.50 vs D- 53.39 ± 28.45, P < .05). Study II: The volume of washing solution used in S2-group was significantly smaller than that in O-group and D-group. The cleansing level of the colonoscopic lens of O-group was significantly superior than that of S2-group and D-group. CONCLUSIONS: The in-vitro test showed oolong tea and simethicone solution can effectively cleans the colonoscopic lens. The clinical trial demonstrated that oolong tea instead of water is effective to provide better visualization during colonoscopy. Registration: Chictr.org.cn No: ChiCTR1900025606.