Simethicone and Bowel Preparation in Colonoscopy

Evaluation of the lower gastrointestinal (GI) tract by colonoscopy is now considered the gold standard and its use is on the rise in all GI units. Clean bowel preparation is a mandatory part of the procedure in order to visualize the bowel mucosa to determine pathology and provide therapeutic intervention safely if needed.

Colon lavage preparations have been effective in improving visibility of the colon and are well tolerated. Split dose bowel preparation regimens have been developed and adapted in order to optimize patient comfort and provide adequate cleanliness .

These bowel preparations address issues regarding the feculent residual material, however bubbles lining the mucosa remain a problem in attempting to visualize the colon mucosa. About 30% of adequately prepared bowels are now affected with mucosa lined with bubbles . The bubbles limit evaluation of the entire bowel, requiring more time to clean the bowel and possibly missing pathology such as small, flat sessile, serrated polyps, small apthous ulcers for crohns and many other pathologies.

Simethicone is a mixture of polydimethylsiloxane and hydrated silica gel and works by reducing surface tension of air bubbles, allowing small bubbles to coalesce to form larger bubbles allowing the air to pass as belching or flatulence. This makes simethicone an ideal antifoaming agent that has been used in all age groups to reduce bloating, abdominal discomfort, and abdominal pain.

In the past, use of simethicone in the irritant fluid has been used to wash away the bubbles, however there has been recent concern with scope manufacturers advising that simethicone not to be used routinely because of simethicone settling in the irrigation channel. This causes a concerning biofilm in the endoscope.

Use of oral simethicone instead of liquid simethicone through the endoscope as an adjuvant to the bowel preparation to reduce bubbles/foam has not been adopted widely due to lack of knowledge and literature available and the project's ability to secure funding. This project aims to compare the amount of bubbles and colon mucosa visibility between patients who ingested oral simethicone with bowel preparation and those who did not to evaluate the use of oral simethicone in future colonoscopies.

All patients who are referred to undergo colonoscopy are booked centrally in the GI Unit at the Brandon Regional Health Centre (BRHC) and are given instructions regarding bowel preparation and procedure time by the booking department. All patients including those not involved in research are instructed and scheduled in the same manner.

About a month prior to procedure all patients are sent bowel preparation instructions, procedure time and colonoscopy information. A letter explaining the study and requesting participation will be included with this information.

All patients are instructed to call the GI Unit 5 days prior to their procedure to confirm. At this time patients will be asked to participate in the study by the Clinical Resource Nurse (CRN) or CRN delegate.

Treatment group is determined by the number on each consent form. This number will be referenced with the master list to determine if the patient is in Group A or Group B. Participants will all be advised to not speak to the endoscopist about whether they have taken simethicone tablets or not. If participants were allotted to group A but present on the day of the procedure without having taking simethicone they will be excluded from the study.

On the day patients present to the GI unit for their colonoscopy they will undergo the same process as a participant not in the study. Participants will present to the interview desk. The patient will be reminded to not tell any physician or nurse other than the interview nurse. The interviewing nurse will ask the patient if they ingested the simethicone and if so what dosage and what brand of tablets. This will be noted on the simethicone ingestion form that will be placed in an envelope and in the appropriate folder in accordance with the treatment group to which the participant belongs. The interviewing nurse will then proceed with the regular intake form.

The endoscopy room will have the Boston Bowel Preparation Scale and the Bubble Scale labeled with appropriate participant number. The endoscopist will complete these forms once the procedure is finished and will be blinded as to which group the patient belongs. Once completed by the endoscopy nurse a photocopy of the Endoscopy Room Quality Indicators form will be placed with the participant folder with the identifying information blacked out and replaced with the participant number. All the completed forms will be collated and placed in a sealed envelope by the recovery room nurse and placed in the appropriate folder in accordance with the treatment group to which the participant belongs.

The amount of bubbles will be compared between Group A (simethicone) and Group B (no simethicone) using a chi square analysis with a statistical significance value of p=0.5. The same will be done for bowel cleanliness using the Ottawa stool scale.