Gastric Preparation for Upper Endoscopy

cc This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Rapid technological advancements have been noted in en-doscopy in recent years. 1 Current standard endoscopes can increase magnification up to 30 times and provide excellent images of mucosal surface of bowel wall. Zoom endoscope can optically magnify an image far more, up to 150 times. High-definition endoscopes generate images of more than one million pixels and provide much clearer images than those produced by standard endoscopes. Moreover, endo-scopes with enhanced imaging technology such as narrow-band imaging (NBI) or multiband imaging further assist diagnosis and characterization of gastrointestinal mucosal lesions. Despite these advancements of technological aspects, the unclean mucosal surface of the stomach can make these high-end pieces of equipment virtually useless. The importance of bowel preparation is highlighted in colonoscopy. 2 Poor preparation of the colon leads to prolonged examination time, incomplete procedures, and more importantly, missed significant lesions. Likewise, an unclean gastric mucosal surface may cause similar problems in upper endoscopy. Foams and bubbles are frequently encountered in an unprepared stomach, thus most of the upper endoscopy examinations are preceded by premedication with defoaming agents such as dimethylpolysiloxane (DMPS). Mucus on the gastric surface is another problem in visualization of the target lesion. Pronase is a proteolytic enzyme isolated in 1962 from the culture filtrate of Streptomyces griseus, which has been used as a raw material to prepare anti-inflammatory and digestive enzymes. 3 Initially, this enzyme was used as a pre-medication to remove gastric mucus for roentgenographic examinations of the stomach. 4 Then, the enzyme was suggested to improve visibility during conventional upper endoscopy and chromoendoscopy. It has also been reported that pre-medication for conventional endoscopic ultrasound by using a mixture of pronase and bicarbonate decreases the number of gastric wall and lumenal hyperechoic artifacts mainly caused by mucus of stomach. A recent study assessed whether endoscopic flushes of pronase with bubble-bursting agent (gascon) is as effective as their use as a premedication to decrease inconvenience. 9 The study showed, however, that en-doscopic spraying of these bubble-bursting and mucolytic agents was not able to offer equivalent improvements in en-doscopic mucosal visibility when compared with their standard pre-endoscopic drink of these agents. In a paper published in Clinical Endoscopy, Lee et al. …