A Double Blind Randomized Controlled Trial of High Volume Simethicone to Improve Visualization During Capsule Endoscopy

BACKGROUND:

While VCE has become an important diagnostic tool for clinical practice, optimal preparation for VCE has yet to be determined.(13) The European Society of Gastrointestinal Endoscopy recommends bowel preparation but does not provide further details.(2) The Canadian Association of Gastroenterology, American Society of Gastrointestinal Endoscopy, American College of Gastroenterology, and American Gastroenterological Association make no specific recommendation. Many studies have addressed this knowledge gap, testing various regimens of purgatives.(14-18) A meta-analysis found that polyethylene glycol provided adequate visual quality in 68% of patients compared to 48% with fasting alone, while diagnostic yield climbed from 36% to 46%.(4) In contrast, oral preparation for colonoscopy produces adequate visualization in greater than 90% of patients.(19)

Intraluminal debris, bile, and air bubbles impair the visibility of small bowel mucosa during VCE. Simethicone, an anti-foaming agent, has been used with mixed success to improve image quality. Three studies investigated the addition of simethicone (30 mg, 600 mg, and 800 mg) to overnight fast, PEG, or mannitol demonstrated improvement in visualization with high preparation scores favouring the addition of simethicone.(7-9) In contrast, Wei and colleagues (10) compared simethicone (300 mg) + PEG with PEG alone and found that although simethicone improved visualization, adequate visualization was achieved in only 63% of patients. Similarly, Ge et al. (11) compared simethicone (300 mg) against fasting alone and found improvement in visualization with simethicone but this was limited to the proximal half of the small bowel and adequate visualization was limited to 55% of cases. Lastly, Rosa et al. (12) compared simethicone (100 mg) + PEG with PEG alone and did not find a difference in visualization score.

A potential reason for inconsistent improvement in small bowel visualization may be due to an inadequate volume of simethicone being delivered into the small bowel, especially the distal portions. Prior volumes of simethicone were small (<200 ml) and may have pooled in the stomach and become diluted by gastric juices before being delivered into the duodenum. Our hypothesis is that high volume simethicone may overcome this problem and improve small bowel cleansing to facilitate improved visualization during VCE.

STUDY DESIGN: