Colon Cleansing for Colonoscopy: New Guidelines for Optimizing Outcomes

David A. Johnson, MD


October 15, 2014

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I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia. The US Multi-Society Task Force on Colorectal Cancer has just released new evidence-based guidelines on how to improve and perform colon cleansing before a colonoscopy. This is a joint publication, and it is published in the October 2014 issues of The American Journal of Gastroenterology,[1]Gastrointestinal Endoscopy,[2] and Gastroenterology.[3]

I will give you an overview of this guideline and drill down on a couple of salient points. I encourage all of you who deal with bowel preparation ("prep"), including your nurses and schedulers, to read this document because it has some very important information. The committee reviewed the literature from 1980 to 2013 and, using an evidence-based approach, extracted all of the relevant articles and then graded the recommendations using the standard grading strategy.

Colon cleansing/bowel preps are inadequate in 20%-25% of patients presenting for colonoscopy. This has tremendous consequences, including inadequate detection of adenomas and other neoplasia and the need to repeat the colonoscopy earlier than would otherwise be required.

Split-Prep Is Best

The recommendation with the strongest evidence to support it is that split-dose prep is the standard of care. A split-dosing regimen means that part is given the evening before, and part is given the morning of the procedure. The committee overwhelmingly weighed in on this point. The split-dose prep should be routine; the exception is the same-day prep (the patient does the entire prep on the day of the examination). The split-dose prep has multiple advantages. It clearly leads to better bowel cleansing. Use of the split-dose prep also increases patient willingness to return for another colonoscopy. The committee recommended that the second dose be given on the morning of the colonoscopy, 4-6 hours before the start time of the exam, and completed within 2 hours of the exam. This meets the Anesthesia Society of America's guideline[4] of allowing clear liquids up to 2 hours before the procedure.

Measuring the Success of Bowel Cleansing

The second recommendation relates to how we define the success of bowel cleansing. If 20%-25% are inadequate, that means we have a success rate of 75%-80%. The committee said that we need to raise that bar in a more formative way. They set the minimum benchmark for physician evaluation at 85%. This is a very important idea. It's not just the patient's problem. When a patient comes in with an inadequate prep, the physician says, "The patient didn't do the prep." But the committee felt that 85% should be the benchmark that is used to evaluate the quality of that physician and that practice. This will gain some traction as we start to look at new benchmarking technology and thresholds and as national societies start to accept ways to evaluate and measure quality.

Improving Practice Procedures

The committee said that it's not just about the physician and the practice giving recommendations, but they need to give oral and written instructions. They encouraged the use of patient navigators, including patient notification tools. These may be staff personnel who call the patients or automated notification to reinforce instructions. Each practice needs to evaluate how they are currently doing business. If they are not hitting the new benchmark of 85%, they should be improving their procedures. Everyone is going to be accountable to this benchmark, so be prepared.

The committee also said in this document that you should be importing this information into national registries that assess colonoscopy quality. This is part of the quality assessment of such strategies as the GI Quality Improvement Consortium (GIQuIC) or the national endoscopic reporting registries. There are levels of performance in quality exams being done by physicians in your locale and across the country.

Adjuncts to Enhance the Prep

The next area that the committee looked at was adjunctive measures that might enhance the prep. They couldn't identify anything that was supported by the evidence. They looked at promotility agents, olive oil, and simethicone. They evaluated articles on probiotic administration. None of the studies provided enough evidence to support these adjunctive measures. It is left to the physician to find what works for each individual patient.

Prep Products

The next area that they looked at was the dynamics of the preps—prescription preps and the over-the-counter preps.

GoLYTELY® is the standard 4-L propylene glycol-electrolyte lavage solution (PEG-ELS) prep. This was not superior to such lower-volume preps as oral sulfate solution (Suprep®), sodium picosulfate/magnesium citrate (Prepopik®), or a combination of PEG-ELS and oral sulfate solution (Suclear®). These are newer preps, but these lower-volume preps seem to be on par with the 4-L prep. HalfLytely®, the 2-L prep, has been removed from the market, so that's not an option. It didn't work as well anyway. The committee felt that the lower-volume preps were of value in terms of patient acceptability and willingness to repeat.

An assessment also was made for the bariatric patient who has had restrictive surgery (the gastric sleeve or the Roux-en-Y standard gastrojejunal bypass), and these lower-volume preps would be preferable. Although there is very little evidence to support that, it makes sense intuitively.

The next area they looked at was the over-the-counter products, of which PEG powder (MiraLAX®) is the product that many people use. Although there have been a few reports of electrolyte disturbances with MiraLAX (in particular hyponatremia), this has not been reported when MiraLAX is used in a split-dose prep.

Special Populations

The committee also looked at certain populations (older age, diabetes, inflammatory bowel disease, gastrointestinal surgery in the pediatric population) in whom the prep may not be adequate. They found no evidence for strong recommendations in these populations, other than to avoid the sodium phosphate prep in elderly patients and in patients with renal disease. In patients with inflammatory bowel disease, they cautioned that the inflammatory changes prompted by the prep can be mistaken for inflammatory bowel disease activity.

Key Take-Aways

In terms of new evidence, the guideline committee gives us a few take-home points.

The split-dose prep is the standard of care.

You need to look at your patient informatics, navigation strategies, and patient handouts and how well the patients understand them. Address barriers related to certain ethnicities. All patients have to understand the importance of an adequate prep.

The degree of cleansing dictates the quality of the exam.

You should determine the adequacy of the prep quickly as you enter the rectosigmoid colon, and if you encounter an inadequate prep, abort the exam and reschedule unless a salvage strategy is used to cleanse the bowel and attempt the exam again on the same day. If the colonoscopy is complete to the cecum and then the prep is deemed inadequate, the patient should repeat the colonoscopy within a year.

The threshold of 85% should be your new minimum standard, and these rates should be recorded and reported. You will be accountable to these benchmarks as we move forward.

I encourage you to read the document and take it out to great detail. There are appendices that discuss the risk factors for inadequate preparation and also bowel preparation adequacy scales. The committee felt that the easiest scale to use was the standard definition of an adequate prep, meaning the ability to exclude polyps that were 6 mm in size or larger. The recommendation to repeat the colonoscopy within a year if the prep is inadequate is new. Depending on the indication for doing the exam, you may want to err on the side of doing it sooner. So, the new minimum strategy is to repeat in a year, look at your 85% rule, and use the split dose. This is a very good document and will be helpful in guiding your practice. I'm Dr David Johnson. Thanks for listening.


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