Purgative bowel cleansing combined with simethicone

AORN Journal,  April, 2008  by George Allen

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Journal of Gastroenterology

January 2008

Capsule endoscopy is recognized as an important tool for investigating gastrointestinal diseases and conditions, including obscure gastrointestinal bleeding, suspected small bowel Crohn's disease, polyposis syndromes, and small bowel tumors. It involves a minimally invasive examination of the entire small bowel via an ingested capsule containing a camera. The indwelling camera takes images at a rate of two frames per second as peristalsis carries the capsule through the gastrointestinal tract. The average transit time from ingestion to evacuation is 24 hours. The device uses wireless radio transmission to send the images to a receiving recorder device that the patient wears around his or her waist. Images are then downloaded onto a workstation for viewing and processing.

The diagnostic value of capsule endoscopy, however, has been hampered by two limitations. First, the presence of impure intestinal juice or air bubbles can influence the diagnosis by impairing visualization of the intestinal mucosa. Second, limited battery life span can prevent completion of the small bowel examination. The bowel preparation recommended by the capsule manufacturer is a 12-hour fast, but some studies have found that various other bowel preparations can result in higher quality images. Since these studies are extremely heterogeneous because of the different preparations used and because most are nonrandomized, this prospective, randomized controlled study was designed to define a better preparation method to provide high-quality images of the entire small intestine.

Between October 2005 and September 2006, consecutive patients undergoing capsule endoscopy because of suspected small bowel disease were randomly assigned to one of three study groups. Twelve hours before swallowing the capsule, patients in the control group (n = 30) were instructed to ingest 1 L of clear water; patients in the purgative group (n = 30) were instructed to ingest 1 L of an electrolyte lavage solution; and patients in the purgative combined with simethicone (P-S) group (n = 30) were instructed to ingest I L of the electrolyte solution and then to take 300 mg of simethicone 20 minutes before swallowing the capsule. Patients were excluded if they had undergone previous gastric or small bowel surgery, or were pregnant, or if they had

* intestinal obstruction,

* stricture or fistula,

* a history of diabetes or thyroid disease,

* a history of narcotic drug use, or

* paralysis with impaired mobility.

All patients were allowed to resume a clear fluid diet four hours after swallowing the capsule. After eight hours of recording, the images were downloaded to the workstation and viewed. Patients were monitored for any abdominal discomfort and pain before, during, and after the examination. The intestinal mucosa was defined as clean if, at any time, less than 25% of the mucosal surface was covered by intestinal contents or food debris.

The quality of visibility was assessed by a score that took into account the presence of air bubbles and impure intestinal juice. If there were no air bubbles or very few air bubbles and no intraluminal impure fluid, this was defined as a clean small bowel video. If there were more than a few air bubbles or impure intraluminal juice, this was defined as an unclean small bowel video. All the capsule endoscopy recordings were assessed by a single investigator who was blinded to the type of bowel preparation. Common statistical procedures including analysis of variance, the chi square test, and the Kruskal-Wallis test were used to analyze the data.

FINDINGS. Ninety patients (ie, 44 men and 46 women ages 12 to 83 years) were enrolled in the study. A total of 14 patients (ie, four in the control group, five in the purgative group, and five in the P-S group) were not included in the analysis because the capsule had not reached the cecum before the end of the examination. Gastrointestinal transit time was not different among the three groups, nor was the examination completion rate. The number of patients with adequate cleansing of the entire small intestine was 17 in the P-S group, 12 in the purgative group, and seven in the control group (P = .002). Patients in the P-S group had significantly better image quality for the proximal bowel segment than patients in the control group (P = .0001). Both the P-S group (P = .0001) and the purgative group (P = .0002) had significantly better image quality for the distal ileum than the control group; the P-S group had significantly better image quality than the purgative group as well (P = .0121).

CLINICAL IMPLICATIONS. The authors concluded that purgative bowel cleansing combined with simethicone before capsule endoscopy improved the quality of imaging of the entire small bowel as well as visualization of the mucosa in the proximal and distal small intestine. Perioperative nurses must be prepared to provide clear instructions to patients in whom purgative bowel cleansing combined with simethicone is used for capsule endoscopy. Patients should ingest I L of the electrolyte solution 12 hours before the procedure and 300 mg of simethicone 20 minutes before the examination.