Oolong Tea from a Jet Nozzle Is a Useful Washing Solution for Lens Cleansing of Transnasal Small-Caliber Esophagogastroduodenoscope

Abstract

Background and Aims: Unsedated transnasal small-caliber esophagogastroduodenoscopy (TN-EGD) has been used to examine the upper gastrointestinal tract, and its feasibility have been shown by comparative studies with conventional transoral EGD. However, one limitation to the use of TN-EGD is a well-known poorer image quality compared to conventional endoscopy due to the small size of the CCD. Further, insufficient lens cleansing for TN-EGD results due to a too small caliber water jet nozzle. Recently, use of oolong tea for lens cleansing during endoscopy has been discussed, as it contains saponin that has surfactant actions on a fat solution. We evaluated the efficacy of oolong tea for transnasal EGD, using a randomized, prospective double blind trial. Patients and Methods: Oolong tea (O), barley tea (B) and distilled water (W) were prepared as washing solutions for endoscopy. Study I: After an endoscopic lens was soiled with lard oil, it was washed using 1 of the 3 washing solutions, and photographs of a test chart were taken. Image quality was judged by 3 experts who had no knowledge of which washing solution was used. Study II: 612 patients who underwent TN-EGD were randomly assigned to O-, B- and W-groups. All TN-EGD procedures were done by 3 expert endoscopists, who judged the level for lens cleansing using a five-grade visual analogue scale after TN-EGD. The washing solution volume and the overall time for the endoscopic examination were also measured. Results: In Study I, the photographic image quality was significantly superior in the group using oolong tea compared to the other groups (P<0.001). In Study II, the level for lens cleansing in the O-group was significantly superior to those of the B- and W-groups (P<0.001). The volume used for lens washing in the O-group was 11.3 ml. This was significantly smaller than for the W-group (14.2ml) (P<0.05). The total times for EGD were 382sec, 384sec and 392sec in the O-, B- and W-groups, respectively. The time was shorter in the O-group than for the B- and W-groups. Conclusions: For EGD with transnasal small-caliber endoscope, the use of oolong tea as a washing solution for lens cleansing may be useful to maintain a good visual condition and to decrease the stress for endoscopists.