title: Oolong tea is useful for lens cleansing in transnasal small-caliber esophagogastroduodenoscopy.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  In transnasal small-caliber EGD, oolong tea instead of water as a washing solution for endoscopic lens cleansing is useful to maintain good visibility.
authors.affiliation: Division of Internal Medicine, Izumo City General Medical Center, Izumo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Komazawa
authors.forename: Y
authors.initials: Y
authors.lastname: Amano
authors.forename: M
authors.initials: M
authors.lastname: Yuki
authors.forename: H
authors.initials: H
authors.lastname: Fukuhara
authors.forename: T
authors.initials: T
authors.lastname: Mishiro
authors.forename: T
authors.initials: T
authors.lastname: Mishiro
authors.forename: T
authors.initials: T
authors.lastname: Shizuku
authors.forename: Y
authors.initials: Y
authors.lastname: Kinoshita
mesh_terms: D001628:Beverages; D003902:Detergents / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods*; D020776:Endoscopes, Gastrointestinal; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007909:Lenses; D008297:Male; D008875:Middle Aged; D009666:Nose; D011446:Prospective Studies; D013662:Tea
chemical_list: D003902:Detergents; D013662:Tea