Bowel preparation: is endoscopic administration worth the extra risk?

Abstract

Bowel preparation before colonoscopy is usually considered worse than the actual procedure. The regimen usually consists of the intake of a large amount of fluid (2–4 L) with an unpalatable taste and smell, which might lead to nausea, vomiting, bloating, and abdominal pain in addition to the required diarrhea. In a meta-analysis comparing the effectiveness of different bowel preparation agents, about 29 % of the subjects were unable to ingest the full volume of polyethylene glycol (PEG) solution [1]. Incomplete consumption of the solution usually affects the quality of bowel cleansing, increasing the probability that the procedure will be aborted and then repeated. One of the conventional ways to overcome the barrier of ingesting a large amount of an unpalatable solution is to instill it directly into the stomach with the use of a nasogastric (NG) tube. Nevertheless, shortcomings including subjects’ discomfort, nasopharyngeal trauma, tube misplacement, and pulmonary aspiration have precluded its general use. It is now used only for subjects with dysphagia or with difficulty of ingesting large volume of fluids. Delivering cathartic solutions such as PEG via an esophagogastroduodenoscope into the duodenum is a novel approach to bowel preparation. Although it is impractical to perform esophagogastroduodenoscopy (EGD) just for the sake of infusing bowel preparation regimen, same-day EGD and colonoscopy (bidirectional endoscopy) are commonly performed for the evaluation of gastrointestinal conditions, such as active gastrointestinal bleeding, iron deficiency anemia, positive fecal occult blood test, and abdominal pain. In addition to these indications, asymptomatic subjects undergo bidirectional endoscopy in the course of routine healthcare evaluation or for cancer screening. A recent US study based on a national endoscopic database showed that over 11 % of subjects had received same-day bidirectional endoscopy [2]. Of the procedures, EGD is usually performed before colonoscopy due to its superior tolerability and the lower dose of sedatives needed [3]. Now, we have another reason to perform EGD before colonoscopy—to deliver the bowel preparation regimen. In this issue of Digestive Diseases and Sciences, Jung et al. [4] evaluated the EGD-assisted administration of bowel purgative for colonoscopy. They reported that subjects who received intraduodenal PEG perfusion suffered less nausea and vomiting, felt more comfortable, and were more willing to repeat the bowel preparation method in the future than the subjects receiving oral PEG solutions. The efficacy, as judged by the Aronchick and Ottawa Scales, was comparable between the two groups. The intraduodenal method appeared safe, although more subjects who received intraduodenal PEG reported dizziness. Their findings are consistent with those reported in a non-randomized study by Maeng et al. [5] and in a randomized study by Barcley et al. [6]. Y.-H. Hsieh (&) Division of Gastroenterology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, 2 Minsheng Road, Dalin, Chiayi 62247, Taiwan e-mail: hsieh.yuhsi@msa.hinet.net