Oolong tea is useful for lens cleansing in transnasal small-caliber esophagogastroduodenoscopy

Unsedated transnasal small-caliber esophagogastroduodenoscopy (EGD) has been used to examine the upper gastrointestinal tract with proven feasibility and tolerability. However, a limitation of transnasal EGD is the poor lens-cleansing function of the scope due to the small-caliber water-jet nozzle. Therefore, this trial was designed to evaluate the cleansing effect of oolong tea for transnasal small-caliber EGD.

Oolong tea (O), barley tea (B), and distilled water (W) were prepared as washing solutions for endoscopic lenses. Study I: after the lenses were soiled by lard oil, they were washed with one of the three washing solutions, and the image quality of photographs was judged. Study II: 982 patients who were due to undergo transnasal EGD were enrolled and randomly assigned to the O-, B-, or W-groups. The level of lens cleansing, the overall time required for endoscopy, and the volume of washing solution used were measured.

Study I: the image quality of photographs taken with lenses washed with oolong tea was significantly superior to that associated with other solutions. Study II: the level of lens cleansing in the O-group was significantly superior to that of the B- and W-groups ( P < 0.001). The volume of solution used for lens cleansing in the O-group was significantly smaller than that in the W-group ( P < 0.05). Endoscopic examination times in the O-group were shorter than those in the B- and W-groups ( P < 0.05).

In transnasal small-caliber EGD, oolong tea instead of water as a washing solution for endoscopic lens cleansing is useful to maintain good visibility.