Does Bowel Preparation Alter Diagnostic Yield in Capsule Endoscopy?

Capsule endoscopy (CE) is a safe, proven, non-invasive method of small bowel visualisation whereby a pill-sized video capsule is swallowed and passes through the digestive tract, taking photo images of the bowel. The images are transmitted to a receiving device attached to the patient’s skin for the 8 to 9 hour duration of recording. The capsule is disposable and usually passed from the bowel within 24 to 48 hours. The recorded images are analysed by an expert reader, typically a gastroenterologist, to investigate the cause of obscure gastrointestinal bleeding (OGIB) and obtain a diagnosis where small bowel pathology is suspected. The current standard of care prior to CE does not include use of a bowel cleansing preparation. The yield of CE for detection of sources of OGIB has been estimated to range between 60 and 80%. Given the potential for small bowel contents including food, bilious secretions and blood to obscure visualisation of the small bowel lining, we postulate that the yield for detection of sources may be higher if the bowel is prepared by use of a bowel cleansing preparation. Polyethylene glycol based (PEG) solutions have been extensively used for bowel cleansing prior to colonoscopic procedures and shown to be safe and tolerable. Low volume PEG preparations have been developed with the aim to improve tolerability and have been shown to have equal efficacy to standard preparation regimes in colonoscopy. We have chosen to use half volumes of two types of PEG preparations, ColonLYTELY and Moviprep, to improve visualisation of the small bowel which is not subject to the level of obscuration as the large bowel, and to improve patient tolerability. The difference in findings of CE will be compared between three groups of patients who are randomised to the following preparations for the procedure. Prior to ingestion of the capsule, patients in each group will be required to maintain a clear fluid diet for 18 hours. All patients will receive a standard 200mg dose of simethicone in 150ml of water at the time of capsule ingestion. Simethicone acts as an anti-foaming agent to reduce bubbles in the stomach and thereby improve views of the bowel during the procedure. (Times specified assume procedural commencement time of 8am.) Arm 1 – no bowel preparation used (current standard of practice) Patients randomised to arm 1 will fast for 6 hours before the procedure. Arm 2 – Patients randomised to arm 2 will commence drinking 2L (standard is 4L) of ColonLYTELY 15 hours prior to the procedure (to be completed within 3 hours). Arm 3 –Patient randomised to arm 3 will commence drinking 1L (standard is 2L) of Moviprep 4 hours prior to the procedure (to be completed within 1 hour).