Bowel Preps

Bowel preparation is one of the least favorite elements of gastrointestinal (GI) care — for everyone involved. Patients hate it, physicians despair of getting a clean colon, and nurses educate patients until they are blue in the face. Even so, colons are not as clean as they could be, leading to suboptimal exams and suboptimal results.

The solution for this seems simple — education. However, that is already being provided. So what can nurses do to get the point of a clean colon across?

When educating their patients, nurses first need to consider that the patients may fundamentally be unable to read, see or hear the material provided. If the patient is illiterate, he cannot read written material the nurse gives him. If the patient is deaf or has vision impairment, another set of obstacles crops up. If the patient has Alzheimer’s or another disorder that could cause cognition problems, that is yet another issue.

Nurses must first assess the literacy of the patient, according to Denise Kohler, RN, MSN, and Barbara Darby, RN, BSN, CGRN, nurses from Sharp Grossmont Hospital in San Diego who presented a session on this topic at the 2007 SGNA conference in Baltimore.

Half of all patients have literacy issues, the nurses stress. And even if patients can read, most of them read at an eighth-grade level. Twenty percent read at a fifth-grade level or lower.

For these patients, fancy brochures with complicated medicospeak will do no good, and might even discourage the patient. Written materials are frequently provided at an eighth- to ninthgrade reading level. But patients may not understand such terms as “sedation” or “low residue.” And the information may be crammed together, making it difficult to read or to separate out from other information.

As all GI nurses know, if the prep isn’t adequate, it is impossible for the procedure to fully visualize the large intestine and determine if there are problematic areas. Fecal matter can obstruct polyps or other irregularities.

Kohler and Darby took their facility’s patient instructions and ran them through a software program called Readability Plus, which assessed the language and format of the document and informed the nurses which areas were problematic.

By following the suggestions of the software, the nurses were able to adjust their prep instructions to make it easier for their patients to follow. Instead of providing their patients with three dense pages of text, they reformatted the document to work as a single-page calendar of events, outlining what must happen seven days, four days, two days, and one day before the test. There was also a box of instructions for the day of the test. On the back of the calendar page was a list of food and drink the patients can and cannot have.

When creating the new document, it was important that they keep in mind that many patients were undergoing their first colonoscopy, and knew absolutely nothing about the procedure.

After the revision, the nurses performed a study comparing the efficacy of the new document compared to the old document, with different gastroenterologists consistently using only the new document or only the old document. Patients included in the study were facing their first colonoscopy and therefore had no previous experience with preps; they had to speak and read English, and had to be undergoing the colonoscopy as outpatients.

The physicians rated the bowel preps for quality — based on a scale of one to four:

1 — Poor
2 — Marginal
3 — Good
4 — Excellent

The preps were much better in the group receiving the modified, shorter document. Still, some gastroenterologists scorned the new document and preferred the previous, longer version.

Kohler and Darby suggest that further research should investigate Spanish-speaking patients and the instructions they receive; the endoscopy units could also begin hosting a regular 20- to 30-minute pre-assessment class, to answer patient questions beforehand.

1. As a result of their study and related research, the nurses offered these tips:
2. Write the document in second person, using “You should ...”, rather than “Patients should ...”
3. Run the document by a fifth grader to see if she clearly understands the instructions.
4. Don’t use any medical jargon. Keep the terminology simple.
5. Keep sentences in the instructions short.
6. Use a large font when printing the document, to make it easy for the elderly to read it.
7. Don’t use italics.
8. Don’t use fancy typefaces. Use easy-to-read fonts, not script fonts.
9. Don’t use abbreviations or acronyms.
10. Include plenty of white space.
11. Don’t ever use ALL CAPITAL LETTERS. It makes it look like you are shouting and is difficult to read.
12. Use colors to call out important text.
13. Pictures — but not cartoons — are helpful.

Safety

There are safety issues associated with preps as well. Recently, researchers performed a meta-analysis to determine which bowel preparation agent is most effective.1 When looking at studies published between January 1990 and July 2005, the investigators found that sodium phosphate (NaP) preparations were more effective than polyethylene glycol (PEG) or sodium picosulphate (SPS) preparations, and that patients had more difficulty completing PEG than the other two types. However, all three of the preparations were comparable in terms of side effects. Sodium phosphate resulted in more asymptomatic hypokalemia and hyperphosphatemia than the other two types of preparations; the researchers therefore concluded that because of the effects of a small-volume prep such as NaP, caution was necessary for patients with cardiovascular or renal impairment.

There are risks associated with bowel preps if patients have certain pre-existing conditions — for example, calcium and magnesium changes are greater in patients who receive phosphate salts for bowel preparation.2 Not only that, but acute renal failure and nephrocalcinosis are rare but can develop after a NaP preparation is used.3

Currently, C.B. Fleet is the target of a lawsuit that involves sodium phosphate-based bowel preps. There is patient-based furor over acute renal failure in healthy people with hypertension who underwent screening colonoscopies, even though they had no baseline kidney problems.

But studies about sodium phosphate-induced renal failure are controversial — recent research offers evidence for both sides of the argument.

An article in the November 2005 Journal of the American Society of Nephrology focused on this acute phosphate nephropathy, which occurred after patients took an oral sodium phosphate bowel prep.4

According to the article, between the year 2000 and 2004, there were 31 cases of nephrocalcinosis among 7,349 native renal biopsies processed at Columbia University. Twenty-one of those patients had acute renal failure, and had recently undergone colonoscopy with a bowel prep of oral sodium phosphate solution (OSPS) or Visicol. Most of the patients (81 percent) were female and Caucasian (also 81 percent), and 16 of the 21 had a history of hypertension.

After 16 months, four of the patients required permanent hemodialysis, and the remainder had developed chronic renal insufficiency.

“Acute phosphate nephropathy is an under-recognized cause of acute and chronic renal failure,” the authors of the study write. “Potential etiologic factors include inadequate hydration (while receiving OSPS), increased patient age, a history of hypertension, and concurrent use of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker.”

However, another, more recent study from the Canadian Journal of Gastroenterology (April 2007) showed that OSPS did not cause frequent renal damage.5

This study — held from 1995 to 2004 — focused on 767 patients, 55 of whom developed chronic renal failure (CRF), and compared patients receiving OSPS to those receiving large-volume polyethylene glycol (PEG) solution, to see if the sodium phosphate led to frequent renal damage that had gone clinically undetected.

According to study results, 42 patients who used OSPS developed renal failure, compared to 13 who used PEG, but logistic regression analysis showed that only age and blood pressure were predictive of renal failure. “The ingestion of oral NaP for colon cleansing before colonoscopy did not result in frequent renal damage that went clinically undetected,” the authors conclude.

Innovations

At the 2006 annual conference of the Radiological Society of North America (RSNA), researchers showed that computed tomography colonography (CTC) is a breakthrough technology that can improve patient compliance and reduce reliance on traditional bowel preps. An article by Sarah Jersild for the journal Diagnostic Imaging focused on this concept — non-cathartic bowel preps to ready patients for their CTCs.6

Radiologists can incorporate fecal tagging — giving patients a radioactive material that clings to any fecal matter in the GI tract — so that when it’s time to do the CTC, the radiologists simply click a button and the fecal matter “disappears.”

In a study presented at the meeting by C. Daniel Johnson, a radiologist at the Mayo Clinic in Rochester, Minn., patients received barium with their meals for two full days before the exam. They did not have to alter their diets or undergo the traditional bowel prep.

The researcher found that the sensitivity of exam was 81 percent to 89 percent, and specificity was 88 percent to 100 percent.

Someday, perhaps, there will be a bowel prep that will be safe for all patient groups, will not require patients to sacrifice comfort and time, and will be easy to understand and not require the dietary restrictions of today’s preps. Although you currently can’t offer patients the “perfect prep,” you can offer them critical instructions in a palatable format. Giving them simple, legible instructions won’t make your patients feel like idiots; instead, it will make them equal partners in the pursuit of health.

References

1. Tan JJ, Tjandra JJ. Which is the optimal bowel preparation for colonoscopy - a meta-analysis. Colorectal Dis. 2006 May;8(4):247-58.
2. Ezri T, et. Al. Phosphate salt bowel preparation regimens alter perioperative acid-base and electrolyte balance. Can J Anaesth. 2006 Feb;53(2):153-8.
3. Gonlusen G, et. Al. Renal failure and nephrocalcinosis associated with oral sodium phosphate bowel cleansing: clinical patterns and renal biopsy findings. Arch Pathol Lab Med. 2006 Jan;130(1):101-6.
4. Markowitz GS, Stokes MB, Radhakrishnan J, D’Agati VD. Acute phosphate nephropathy following oral sodium phosphate bowel purgative: an under-recognized cause of chronic renal failure. J Am Soc Nephrol. 2005 Nov;16(11):3389- 96. Epub 2005 Sep 28.
5. Abaskharoun R, Depew W, Vanner S. Changes in renal function following administration of oral sodium phosphate or polyethylene glycol for colon cleansing before colonoscopy. Can J Gastroenterol. 2007 Apr;21(4):227-31.
6. www.diagnosticimaging.com/webcast06/showArticle.jhtml?articleID=196513426 48