Both the incidence and associated mortality of

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1 Benjamin Lebwohl, MD Colorectal cancer is currently the third most frequently diagnosed cancer in the United States and the second leading cause of cancer deaths for both men and women. 1 Screening for this disease was introduced in the 1970s, when the feasibility of testing for occult blood in stool was first investigated in clinical trials. Both the incidence and associated mortality of colorectal cancer have been declining, and screening appears to have had a considerable impact on reducing these numbers. 1 Colonoscopy can detect malignant tumors, and it also allows for both identification and removal of adenomatous polyps. 2-4 This provides a greater potential for preventing cancer from developing by removing polyps that could eventually progress to cancer. Joint guidelines issued by the American Cancer Society, the American Gastroenterological Association, and the American College of Radiology note that colon cancer prevention should be the primary goal of screening. 3 The American College of Gastroenterology (ACG) recommends that colonoscopy be the preferred screening strategy, due to its potential for a high level of effectiveness in preventing colorectal cancer. It has also been extensively Faculty Benjamin Lebwohl, MD Assistant Professor of Clinical Medicine Division of Digestive and Liver Diseases College of Physicians and Surgeons Columbia University New York, NY Intended Audience This continuing education (CE) activity has been designated to meet the educational needs of gastroenterology nurses, nurse practitioners in gastroenterology specialties, and other health care professionals with an interest in bowel preparation prior to CRC screening. CE Approval Period: May 1, 2013 through May 31, 2014 Time to complete this activity: 1.6 hours Participants will earn 1.6 contact hours/ 1.6 advanced pharmacology hours. Program Description This continuing education activity will provide nurses, NPs, and other health care professionals in gastroenterology specialties with new insights into, and the consequences of, suboptimal bowel preparation; the role of timing in the efficacy of a bowel-cleansing regimen, and the rationale behind split-dosing; the benefits and risks of the spectrum of bowel-preparation formulations; and the vital role of the gastroenterology nurse who, in collaboration with the gastroenterologist, provides shared decision-making and counsel on the ongoing imperatives of CRC screening, most appropriate bowel preparation for individual patients, and guidance, tools, and techniques that ensure adherence to the bowel preparation and fulfillment of the CRC screening procedure. CE INFORMATION Educational Objectives Following completion of this CE program, participants should be better able to: Identify the consequences of suboptimal bowel preparation Implement procedures to support patient adherence to bowel preparation regimens to minimize the chances that a repeat screening is required Review the updated ACG recommendations for CRC screening and the implications for nursing practice Review the potential advantages of novel bowelpreparation regimens with patients preparing to undergo CRC screening Accreditation Statement Lippincott Williams & Wilkins (LWW) is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center s Commission on Accreditation. LWW is also an approved provider of continuing nursing education by California CEP 11749, District of Columbia # , and Florida # Certificates are valid in all states. Faculty Disclosures Lippincott Williams & Wilkins (LWW) policy requires all faculty to disclose any affiliation or relationship with a commercial interest that may cause a potential, real, or apparent conflict of interest with the content of a CE program. LWW does not imply that the affiliation or relationship will affect the content of the CE program. Disclosure provides participants with information that may be important to their evaluation of an activity. Faculty are also asked to identify any unlabeled/unapproved uses of drugs or devices made in their presentation. Benjamin Lebwohl, MD, has served as a consultant to Ferring Pharmaceuticals. Disclaimer Participating faculty members determine the editorial content of CE activity; this content does not necessarily represent the views of LWW, Ferring Pharmaceuticals, or Haymarket Medical Education. This content has undergone a blinded peer review process for validation of clinical content. Although every effort has been made to ensure that the information is accurate, clinicians are responsible for evaluating this information in relation to generally accepted standards in their own communities and integrating the information in this activity with those of established recommendations of other authorities, national guidelines, FDA-approved package inserts, and individual patient characteristics. Successful Completion of the Activity Successful completion of this activity requires the participant to complete the following activity steps before the deadline of May 31, 2014: (a) read the learning objectives, disclosures, provider accreditation, and disclaimers; (b) take the pre-test; (c) study the material in the learning activity; (d) take the post-test and complete the activity evaluation: (e) to receive CE credit, a score of 70% or better on the post-test is required. Commercial Support This program is supported by an educational grant from Ferring Pharmaceuticals. MAY

2 studied. For persons at average risk, the ACG recommends colonoscopy screening every 10 years beginning at age THE EFFECTS OF POOR BOWEL PREPARATION However, many patients and even their referring clinicians feel that colonoscopy is an invasive procedure that causes a great deal of discomfort to the patient. 5 (Table 1) This distress may well be exacerbated by the need for bowel preparation prior to undergoing a colonoscopy. A complete bowel evacuation is always required before colonoscopy. Proper bowel preparation and cleaning is a critical element in the accuracy of this test, and entails that patients go on a modified diet 1 or more days prior to the procedure. This is then followed by either an oral lavage solution or other laxatives to stimulate bowel movements until the bowel is clean. 3 The preparation is often perceived as the most unpleasant part of the colonoscopy, and thus the procedure is avoided by many individuals because of this requirement. Unfortunately, poor-quality bowel preparation has negative consequences. An inadequate preparation can result in incomplete visualization of the colon, a missed pathologic lesion, and procedural difficulties, as it limits the ability of the endoscopist to visualize the colonic mucosa. 6 Colonoscopy in poorly prepared patients takes longer, is more difficult, and more often incomplete. 5 In addition, this can lead to a substantial economic impact by prolonging the procedure time and increasing the chance that a repeat colonoscopy will be required at an interval sooner than what is currently recommended by evidence-based guidelines. Suboptimal bowel preparation is estimated to increase the cost of colonoscopy by 12% to 22%. 7 In one study of 5832 patients, researchers found that detecting lesions of any size was dependent on the quality of bowel cleansing; odds ratio (OR) 1.73 for intermediatequality compared with low-quality preparation and OR 1.46 for high-quality compared with low-quality preparation. 6 But while inadequate cleansing did affect the detection of polyps, Table 1. Common Reasons That Deter Patients From Undergoing CRC Screening 9 Deterrents to screening colonoscopy Procedure too costly Concerns about modesty/embarrassment Lack of physician recommendation Fear of pain/discomfort Lack of awareness of need for screening Reluctance to take the bowel preparation cancerous lesions were not detected less frequently in the case of poor bowel preparation. The researchers also found that the procedure took longer in patients with inadequate preparation, and that it was also more difficult to perform. In a more recent study, researchers found that of 12,787 colonoscopies performed, the quality of preparation was suboptimal (poor or fair) in nearly a quarter of them (24%). 8 Repeat examination was performed in <3 years in 17% of this group, and lesions detected only during the second examination were considered to be missed lesions. The adenoma miss rate was 42%, and the miss rate for advanced adenomas was 27%. BOWEL PREPARATIONS A large number of bowel preparations are currently available (Table 2), and these regimens continue to evolve. The timing of administration is very important in determining the quality of bowel preparation for colonoscopy. One report found that consumption of the purgative solution shortly before undergoing colonoscopy had superior results than when larger intervals were used. 9 Preparation begins with dietary changes, and these regimens generally incorporate clear liquids and low-residue foods for a period of 1 or more days prior to the procedure. 10 Guidelines emphasize that modifying the diet, such as going on clear liquids, is not adequate preparation by itself. 10 Rather, these modifications have been shown to be an important adjunct to other cleansing strategies in pre paring for a colonoscopy. Colon cleansing preparations ideally should have the following characteristics. 10,11 They should be convenient for the patient, with instructions that are simple to understand and a short period of dietary restrictions. They should be tolerable, have a palatable taste, and be contained in a small volume. They should cause minimal distressing symptoms, if any at all, such as nausea, vomiting, or excessive abdominal cramps. They should be safe, with minimal side effects including fluid shifts that may lead to intravascular volume depletion or electrolyte imbalances and abnormalities. Stimulant laxatives, such as castor oil and senna, were once widely used in bowel preparation but were not very effective and considered to be harsh. Their mechanism of action is to increase peristalsis, which then leads to the secretion of fluid into the intestinal lumen. These products have by and large been abandoned by most endoscopists. 9 Hyperosmotic laxatives prepared with non-absorbable carbohydrates (mannitol, sorbitol, lactulose), were also 2 MAY 2013

3 popular in the past, and work by drawing water into the intestine, which in turn causes bowel distention and stimulates evacuation. The routine use of these agents has also fallen out of favor because of the risk of explosion during electrosurgical procedures. 9 Hydrogen gas is produced by bacterial fermentation of the nonabsorbed carbohydrates in the colon, which in turn causes the risk of explosion. PEG Oral gastrointestinal lavage preparations that use balanced electrolyte solutions with polyethylene glycol (PEG) have become one of the preferred methods of bowel cleansing. PEG is a nonabsorbable solution that will normally pass through the intestines without net absorption or secretion. 10 Thus, large shifts in fluid and electrolytes are avoided, although large volumes of PEG solutions must be consumed to have a cathartic effect. A number of studies have shown that PEG solutions are effective and reasonably tolerated by patients, and several commercial preparations are available with slight differences between them, such as the addition of flavoring. 9 PEG has certain advantages compared with some older methods of bowel preparation. These agents do not cause damage to the colonic mucosa and cause minimal osmotic fluid shifts into the gut lumen. These shifts, which have been observed with other bowel preparation solutions, can create hemodynamic instability in susceptible patients. 10 A major disadvantage of PEG is patient tolerance, as large volumes must be ingested to have an effect. Many individuals also find the taste to be rather unpleasant, even with flavoring added. Adequate bowel preparation can sometimes be achieved, however, without having to consume the entire 4 liters. 9 For some individuals, metoclopramide can help in relieving associated nausea or vomiting and enhance bowel motility. To improve palatability, chilling the solutions and sucking on lemon slices is recommended, as well as adding clear, sugar-free, powdered flavor enhancers or lemon juice to the solution. PEG solutions are also contraindicated in certain patient populations, including those with an ileus, Table 2. Commonly Used Bowel Preparations 9,10 Trade Name Type Dose Description GoLYTELY PEG 4 liters Standard PEG solution NuLYTELY Sulfate-free PEG 4 liters Trilyte Sulfate-free PEG 4 liters Colyte PEG 4 liters Halflytely Sulfate-free PEG plus bisacodyl 2 liters MoviPrep PEG with ascorbate 3 liters Sodium sulfate removed to improve taste and smell Sodium sulfate removed to improve taste and smell Available in different flavors for increased palatability Low-volume PEG, may be better tolerated Reduced volume, comparable to 4 L PEG Viscol NaP tablets 30 g, taken in 2 90-min dosing regimens, 12 hrs apart, for a total of 40 tablets Black box warning for acute kidney injury SuPrep Sodium sulfate 32 oz, plus 64 oz of water Low volume Prepopik Sodium picasulfate Magnisium oxide Citric oxide 10 oz, plus 64 oz of additional water Low volume MAY

4 significant gastric retention, suspected or established mechanical bowel obstruction, and severe colitis. 9 NaP and Sodium Sulfate NaP was previously one of the most commonly used saline laxatives for colonoscopy preparation. 9 Via osmosis, it works by drawing plasma water into the bowel lumen, thus promoting bowel cleansing, but significant fluid and electrolyte shifting can occur. 10 It is necessary to dilute NaP prior to consuming it to prevent vomiting, and patients need to ingest a significant amount of fluid to prevent dehydration. NaP is available in tablet form. NaP preparations are contraindicated in persons with bowel obstruction and other structural intestinal disorders, dysmotility, renal failure, congestive heart failure, or liver failure. 9,10 These agents can cause shifts in fluid, possibly leading to intravascular volume depletion. While these products have been found to be safe and effective in the majority of healthy individuals, there have been increasing reports of serious electrolyte and renal complications in patients with certain risk factors. Reports of renal failure in healthy adults have also been reported, possibly due to hyponatremia. The risk of these serious toxicities has prompted the FDA to require a black box warning on tablet formulations. 12 In addition, the FDA has advised consumers to only use those oral phosphate preparations for bowel cleansing that are obtained with a prescription from a health care provider. NEWER AGENTS An alternative to sodium phosphate solutions are preparations made with sodium sulfate. These do not tend to cause the same significant fluid and electrolyte shifts as NaP, since sulfate is a poorly absorbed anion. 9 A noninferiority trial that compared a sodium sulfate-based preparation to PEG found that the sodium sulfate regimen was not inferior. Prepopik, the most recently FDA-approved bowel preparation agent, consists of sodium picosulfate (a stimulant) combined with magnesium oxide and citric oxide (osmotic agents). This low-volume preparation has been tested in both a split-dose and non-split dosing schedule. 9 ASSESSING THE QUALITY OF A BOWEL PREPARATION The importance of a high-quality colonoscopy ensures that the patient is adequately prepared for the procedure, and that the correct and clinically relevant diagnoses are made or excluded. The American Society for Gastrointestinal Endoscopy (ASGE)/ACG Taskforce on Quality in Endoscopy notes that effectiveness of colonoscopy in reducing cancer incidence is dependent on adequate visualization of the entire colon, diligence in examining the mucosa, and patient acceptance of the procedure. 13 For each colonoscopy, according to the ASGE/ACG, the colonoscopist needs to document the quality of bowel preparation. Terms used to characterize quality of bowel preparation in clinical trials, such as excellent, good, fair, and poor, do not have standardized definitions in practice. 13 Several instruments have been developed to evaluate the quality of bowel preparation. Bowel preparation scales can be used to evaluate the cleanliness of the gut, and also to document the superiority of 1 preparation regime against another. However, Lai et al note that the validity and reliability of these scales are not routinely stated in reports of studies in which the scales are used. 14 Three commonly used scales, the Aronchick Scale, the Ottawa Scale, and the Boston Bowel Preparation Scale (BBPS), are considered reliable measures for assessing the quality of a bowel preparation. (Table 3) The Aronchick Scale is used to assess overall bowel cleansing. Successful cleansing is defined as bowel preparations with >95% of the mucosa seen and mostly liquid stool, which receive an excellent grade. Table 3. Scales Used to Grade Bowel Preparation 15 Scale Scoring Excellent Good Fair Poor Aronchick Ottawa (0-14) Boston Bowel Preparation Scale (9-0) % mucosal surface seen, amount liquid/solid stool present Right, transverse and rectosigmoid are scored 0-4, 0-2 for quantity of residual fluid and totaled (0=best) Right, transverse and left colon are scored 0-3 and totaled (9=best) >95% >90% >90% <90% MAY 2013

5 Conversely, a poor rating is one with <90% of the surface seen and with semi-solid stool that cannot be suctioned or washed away. 15 The Ottawa Bowel Preparation Scale was developed nearly 10 years ago, and evaluates cleanliness and fluid volume separately. 16 It is able to assess the segments of the colon individually and colonic fluid overall, and can provide a summary score for the entire colon. The researchers who developed the scale report that it has high interobserver reliability, whether it is used globally or for segmental colonic preparation quality. The BBPS was developed recently, and is a 10-point scale designed to evaluate bowel preparation after all cleansing has been completed by the endoscopist. 14 Many of the rating scales that have been previously published are specifically designed to compare the efficacy of 2 or more bowel preparation methods. The BBPS is a novel bowel preparation rating scale that was designed specifically for application during withdrawal of the colonoscope, when all of the cleansing maneuvers are completed. This scale can be used in a number of ways, including both clinical and research settings, controlling for bowel preparation in studies that evaluate the rates of missed lesions, and to help establish guidelines on appropriate screening. FAILURE TO ADHERE TO A COLON CLEANSING REGIMEN Health care providers recognize the need for adequate bowel preparation prior to colonoscopy, but the preparation may be more feared than the procedure itself. The preparation is a rather demanding process, as individuals must change their diet (usually for 1 to 2 days) as well as frequently experience unpleasant gastrointestinal effects that include large-volume diarrhea (necessary to clean the bowel) and accompanying abdominal discomfort, bloating, and nausea. 2 Thus, the preparation is unpleasant and can be difficult to adhere to, and roughly one-quarter of all patients are inadequately prepared for their procedure. Maximizing patient compliance will therefore enhance even the most effective bowel regimens. This can be accomplished by making the regimen more palatable and manageable for the patient, along with addressing patient knowledge, attitude, and belief barriers to preparation for a colonoscopy. 2 The ACG issued new colorectal cancer screening guidelines that reiterate the importance of adequate bowel preparation. The updated guidelines point out that while there are a number of commercial bowel cleansing preparations on the market, there are ways to enhance their effectiveness. 2 The best established method is split-dose bowel preparation regimens, which appear to be the most well-supported and plausible intervention for meaningful change in efforts to enhance bowel preparation. The ACG lists split dosing (half of the dose is given on the day of the procedure) as one of the key measures for improving the quality and cost effectiveness of colonoscopy. Splitting the dose can improve the efficacy of the bowel preparation, as a number of studies have shown that splitdose bowel preparations result in significantly better bowel cleansing than the traditional day-before preparation. The split dose can also enhance both the safety and patient tolerability of the preparation, which may increase patient compliance. 2,17 An appropriate time interval needs to elapse between the 2 doses, and this is particularly important when NaP is used. The 2 doses need to be spaced at 10 to 12 hours apart in order to minimize the risk of hyperphosphatemia and acute kidney injury. 17 Another method of improving tolerability has been the introduction of reduced volume bowel preparations. Studies have found that these preparations are as effective as the higher volume traditional products. For example, regimens of PEG 2 L combined with bisacodyl (10 mg to 20 mg) appear to be as effective as standard PEG 4 L regimens. 18 However, they have the bonus of superior tolerability. 18 Overall, optimal bowel preparation is a combination of adherence to all of the steps, and not just compliance with the purgative. In one study, Seo et al reported that in addition to the split-dose bowel preparation, improving compliance with instructions for the dietary regimen, plus ensuring an optimal preparation-to-colonoscopy interval, all will contribute to improved bowel preparation. 19 In their analysis, they found that the amount of PEG consumed and compliance with dietary instructions were the 2 factors that significantly led to adequate bowel preparation. 19 Bowel preparation regimens also need to be customized to the unique needs of each individual. Of great importance is proper patient screening and adequate hydration before, during, and after administration of any bowel purgative. For example, PEG solutions have been shown to be safe and effective for the general population, including those with cardiac, renal, or hepatic dysfunction. 20 Phosphate preparations also appear to be safe and effective for preparing the bowel for colonoscopy, but there are some safety concerns for some individuals with cardiac, renal, and hepatic dysfunctions. Both PEG and NaP preparations have been associated with diarrhea, nausea, and vomiting, and with that, the potential for dehydration. Loss of gastrointestinal fluid may cause the patient to be excessively thirsty and to increase their fluid intake. If the patient is unable to adequately MAY

6 excrete water, hyponatremia can be the result of increased levels of plasma antidiuretic hormone. 21 Conversely, if the patient is unable to experience thirst, the excessive loss of fluid can cause the opposite hypernatremia. In the hospitalized elderly population, both acute hypernatremia and hyponatremia can be lethal. 21 FOSTERING PATIENT ADHERENCE It is well established that individuals need to adhere to a bowel preparation program to achieve the best colonoscopy results, but improving adherence has proven to be difficult. It is essential, however, that all individuals who are about to undergo a bowel-preparation regimen understand the importance of following the instructions exactly, and that they received detailed guidance on how to do so. Making the preparation more palatable and tolerable is important, but improved compliance must also include addressing patient knowledge and belief barriers, as well as alleviating fears and misperceptions. The impact that proper bowel preparation has on the success of colonoscopy needs to be emphasized, along with clear instructions on how to prepare for the procedure. In one prospective randomized trial that looked at the effect of a pre-endoscopy patient education program in improving patient compliance, the results were encouraging. 22 Of the 142 patients in the cohort, 64% participated in a targeted educational session conducted by a dedicated departmental nurse (group 1), 27% did not (group 2), and 9% received telephonic instruction (group 3). Patient cooperation and success/failure of the procedure were documented by the attending nurse. The authors found a significant association between attendance in the education program and success of the endoscopy. Poor preparation caused procedure cancellations in 4.39% of group 1, as compared to 26.31% and 15.38% of groups 2 and 3, respectively. In addition, the overall costs were decreased by 8.6%, 8.9%, and 5.5% for gastroscopy, colonoscopy, and sigmoidoscopy, respectively. The gastroenterology nurse and nurse practitioner can play a vital role within the gastroenterology care team by helping to ensure adherence to the bowel preparation protocol and fulfillment of the CRC screening procedure. As demonstrated by this study, nurses can effectively counsel patients undergoing colonoscopy on the importance of following the recommended bowel preparation protocol as well as advising them on what to expect during and after bowel preparation. Another educational method that proved effective was the use of a novel educational booklet. 4 Interviews were conducted with patients to identify knowledge and belief barriers to colonoscopy preparation, and thus what would be important to include in this educational tool. The booklet focused on the nonpharmacological factors that could help optimize the quality of bowel preparation and it was aimed at addressing patient knowledge, attitudes, and belief barriers to colonoscopy preparation. At a VA Medical Center, patients were then prospectively randomized to receive usual instructions or the booklet before undergoing colonoscopy. The mean Ottawa scores were superior in patients who were given the booklet vs controls, and a good preparation was observed in 68% of those who received the booklet compared to 46% of the control group. SPECIAL POPULATIONS While the bowel cleansing preparations are generally safe, some populations are at a higher risk of complications. The ASGE indicates that certain groups, such as the elderly, patients with underlying inflammatory or bowel disease, and diabetes mellitus, are special situations. 9 They recommend that if the potential benefits of undergoing colonoscopy outweigh the small but potential associated risks, individuals falling into these categories may be prepped with PEG solutions or, in select patients, a NaP preparation. Bowel Conditions PEG has an advantage over other preparations, in that it does not affect the mucosa of the colon. Thus, it can be used in patients with active lower gastrointestinal bleeding, as well as those suspected of having inflammatory bowel disease. 9,10 Some studies have found that whole gut lavage followed by colonoscopy has often allowed for the identification of the bleeding lesions and facilitated endoscopic therapy. Conversely, the use of NaP preparations might cause abnormalities in the colon muscosa that mimic Crohn s disease. 10 The frequency of this complication is rare and does not necessarily warrant against using NaP, but it may not be suitable for patients being evaluated for suspected colitis. In cases of active bleeding, bowel preparation can be completed in a much shorter amount of time, and with a smaller amount of solution. In most cases, only 2 to 3 hours are needed using 0.5 L to 2 L of a PEG solution. 17 PEG can also be administered via a nasogastric tube for patients unable to take fluids orally. However, oral lavage is contraindicated in patients with other types of bowel conditions, including an ileus, significant gastric retention, suspected or established mechanical bowel obstruction, and severe colitis. 9 6 MAY 2013

7 Elderly Bowel preparation may be poorer among elderly individuals. 10 Bowel preparation solutions can cause electrolyte changes, and the elderly may be at higher risk for serious electrolyte disorders, particularly hypokalemia. Magnesium toxicity can also be a problem. Magnesium citrate is excreted via the kidneys, and should be used with caution in those with renal impairment. 9 Hypermagnesemia has been reported in individuals with both known and suspected renal impairment or who are elderly. Chronic Constipation There have not been any studies that specifically address the patient with chronic constipation or with a history of inadequate preparation. However, clinicians have employed several measures to provide adequate bowel cleansing in this population. 17 These include extending the period of dietary modification from 24 to 48 hours, or to add senna or bisacodyl to a standard regimen. Another intervention is to increase the volume of PEG from 4 L to 6 L, and then to split this dose over a 48-hour period. Emphasizing adequate hydration can also enhance cleansing in this population. Conclusion Colonoscopy is the most commonly used technique for visualizing the colon, but its safety and effectiveness are impacted by the quality of the bowel preparation. 10 Optimal patient compliance with the preparation regimen will achieved the best results. Improvements in bowel preparations, or measures to improve patient compliance with bowel preparation, could significantly improve adherence. In addition, educational interventions to enhance compliance as well as dispel misconceptions and barriers to bowel preparation have been shown to be effective. 4 Nurses and nurse practitioners are key providers of counseling and education prior to colonoscopies, and therefore, it is crucial that they understand the importance of strict adherence to a selected bowel preparatory regimen, as well as be able to effectively convey this information to their patients. In addition, these clinicians must be able to counsel their patients on strategies to ensure the protocols are performed as directed. REFERENCES 1. Edwards BK, Ward E, Kohler BA, et al. Annual report to the nation on the status of cancer, , featuring colorectal cancer trends and impact of interventions (risk factors, screening, and treatment) to reduce future rates. Cancer. 2010;116: Rex DK, Johnson DA, Anderson JC, et al. American College of Gastroenterology guidelines for colorectal cancer screening. Am J Gastroenterol. 2009;104: Levin B, Lieberman DA, McFarland B, et al. Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. Gastroenterology. 2008;134: Spiegel BM, Talley J, Shekelle P, et al. Development and validation of a novel patient educational booklet to enhance colonoscopy preparation. Am J Gastroenterol. 2011;106: Kim WH, Cho YJ, Park JY. Factors affecting insertion time and patient discomfort during colonoscopy. Gastrointest Endosc. 2000;52: Froehlich F, Wietlisbach V, Gonvers JJ, Burnand B, Vader JP. Impact of colonic cleansing on quality and diagnostic yield of colonoscopy: the European Panel of Appropriateness of Gastrointestinal Endoscopy European multicenter study. Gastrointest Endosc. 2005;61: Rex D, Imperiale T, Latinovich D, Bratcher L. Impact of bowel preparation on efficiency and cost of colonoscopy. Am J Gastroenterol. 2002;97: Lebwohl B, Kastrinos F, Glick M, et al. The impact of suboptimal bowel preparation on adenoma miss rates and the factors associated with early repeat colonoscopy. Gastrointest Endosc. 2011;73: A-Rahim YI, Falchuk M. Bowel preparation for flexible sigmoidoscopy and colonoscopy. UpToDate, updated: Nov 13, Wexner SD, Beck DE, Baron TH, et al. A consensus document on bowel preparation before colonoscopy: prepared by a task force from the American Society of Colon and Rectal Surgeons (ASCRS), the American Society for Gastrointestinal Endoscopy (ASGE), and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES). Dis Colon Rectum. 2006;49: Hsu CW, Imperiale TF. Meta-analysis and cost comparison of polyethylene glycol lavage versus sodium phosphate for colonoscopy preparation. Gastrointest Endosc 1998;48: FDA ALERT [12/11/2008] Rex DK, Petrini JL, Baron TH, et al. Quality indicators for colonoscopy. Am J Gastroenterol. 2006;101: Lai, E, Calderwood AH, Doros, G et al. The Boston Bowel Preparation Scale: A valid and reliable instrument for colonoscopy-oriented research. Gastrointest Endosc. 2009; 69(3 pt 2): Cohen LB, Rex DK. Bowel Preparation for Colonoscopy: Achieving a Clear View. From Medscape Education Gastroenterology. Released: 04/23/ org/viewarticle/762172_transcript. 16. Rostum, A, Jolicoeur E. Validation of a new scale for the assessment of bowel preparation quality. Gastrointest Endosc 2004;60: Cohen LB, Tennyson C. Bowel preparation for colonoscopy. Gastroenterology & Endoscopy News. Special Edition 2010: Barkun A, Chiba N, Enns R, et al. Commonly used preparations for colonoscopy: efficacy, tolerability, and safety a Canadian Association of Gastroenterology position paper. Can J Gastroenterol. 2006;20: Seo EH, Kim TO, Park MJ, et al. Optimal preparation-to-colonoscopy interval in split-dose PEG bowel preparation determines satisfactory bowel preparation quality: an observational prospective study. Gastrointest Endosc. 2012;75: Clark LE, DiPalma JA. Safety issues regarding colonic cleansing for diagnostic and surgical procedures. Drug Saf. 2004;27: Ayus JC, Levine R, Arieff AI. Fatal dysnatraemia caused by elective colonoscopy. BMJ. 2003; 326: Abuksis G, Mor M, Segal N, et al. A patient education program is cost-effective for preventing failure of endoscopic procedures in a gastroenterology department. Am J Gastroenterol. 2001;96: MAY