Running head: HOW IMPORTANT IS COLON PREPARATION FOR COLONOSCOPY?

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How Important is Colon Preparation for Colonoscopy? Wendi McDonough Western Governor’s University

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How Important is Colon Preparation for Colonoscopy? Gastroenterologists perform screening colonoscopy to exam the colon for precancerous polyps, with the intent of removing them before they have a chance to develop into colon cancer (Cohen, Kastenberg, Mount, & Safdi, 2009), (Lichtenstein, 2009), (Nguyen & Wieland, 2010). Physicians prescribe bowel preparations prior to colonoscopy to cleanse the colon of stool. Colonoscopy has a number of primary risks involved. These include complications from anesthesia, side effects from preparation, perforation, missing a lesion, and being unable to complete the exam (Hendry, Jenkins, & Diament, 2007). Complications that arise because of poor preparation include increased complexity of the exam, decreased detection of colonic lesions, and increased healthcare spending (Roberts-Thomson & Teo, 2009), (Athreya, Owen,
Wong, Douglas, & Newstead, 2011), (Nguyen & Wieland, 2010).

The most important function of the colon is to absorb sodium, water, and some fats from the food we eat (Adamcewicz, Bearelly, Porat & Friedenberg, 2011). Complications arise from colon cleansing for a number of reasons. The patient may experience a suboptimal exam with multiple possible complications from poor preparation. These include more pain, perforation or tearing of the colon, bowel explosion, and complications of anesthesia (Roberts-Thomson and Teo, 2009). The one way a patient can actually assist the physician during the exam, is to prepare well, increasing the physicians ability to visualize the colon and its many folds. Studies show high quality bowel preparation for colonoscopy is one of the most crucial factors in decreasing complications, detecting colon polyps, and decreasing redundant use of health care dollars. Bowel preparations have many physical effects on the body. The effects of preparation,

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such as dehydration and electrolyte imbalances can interfere with daily activities, and make you feel miserable. When patients do not understand the importance of their role in preparation, they may not make the effort to follow the instructions for cleansing, resulting in a sub optimal preparation (Nguyen & Wieland, 2010). Two commonly prescribed preparations include lavage solutions, and sodium phosphate preparations. Lavage solutions, such as Polyethylene glycol (PEG), are one of the safest and more commonly used preparations to cleanse the colon. They are osmotically balanced electrolyte solutions. These solutions pass through the colon without being absorbed, pushing stool through the colon and rinsing the bowel clean. Some adverse reactions associated with these types of preps include dehydration, nausea, vomiting, bloating, chills, perforation, esophageal “Mallory Weise” tears, malabsorption of medications and nutrients, and allergic reactions (Clark & DiPalma, 2004). Most of these outcomes are a result from the large volume of preparation that patients must ingest to cleanse the bowel effectively (Adamcewicz et al., 2011). Scientists developed sodium phosphate preparations to offer a lower volume alternative to the lavage solutions. These solutions are hyperosmotic, having a high concentration of electrolytes. When ingesting hyperosmotic solutions, the body will pull fluid and shift electrolytes into the bowel to try to balance them out. This causes a flushing of the colon contents (Adamcewicz et al., 2011). Some common side effects include electrolyte imbalances, dehydration, renal failure, seizures, and ulcerations in the colon (Clark & DiPalma, 2004). Hyperosmotic solutions and tablets can cause severe dehydration, especially in patients with pre existing conditions, such as cardiac or renal problems (Adamcewicz et al., 2011).

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Inadequate colon preps can intensify the technical complexity of the exam, putting the patient at high risk for perforation (Roberts-Thomson and Teo, 2009). According to Levin et al. (2006), bowel perforation is one of the more serious complications of colonoscopy (p. 884). Inadequate bowel preparation can increase the chance of perforation. When polypectomy is preformed, a poor bowel preparation increases the risk of further complications caused by leaking of the bowel contents into the peritoneal space (Hendry et al., 2007). The longer it takes the endoscopist to complete the exam, the greater the risk for cardiovascular complications related to anesthesia or sedation (Hendry et al., 2007). Combine this well-known fact of anesthesia risk with electrolyte imbalances because of colon preparation, and the risk is further increased. A deeply sedated patient may require assistance to manage their airway, resulting in decreased pulmonary function (Lichtenstein et al., 2008). Risks of aspiration due to decreased throat reflexes are heightened as sedation deepens towards general anesthesia (Cohen et al., 2009). According to researchers, poor colon preps can increase procedure time, causing “over distention of the colon” (Geyer, Guller, & Beglinger, 2011, p.5). This can be quite painful, requiring larger amounts of sedation to complete the exam. In some instances, the gastroenterologist may stop the exam, and reschedule when an anesthesiologist is available to assist with deeper sedation. If dehydration, electrolyte imbalance, and perforations are not enough, there is a chance of bowel explosion during colonoscopy. It is more common with older preparations that contain mannitol, due to the fermentation process by bacteria in the colon (Adamcewicz et al., 2011). This risk is higher with inadequate colon preparation, the use of room air for insufflation, and the

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application of electrocautery (Geyer et al., 2011). Adamcewicz et al. (2011) reports on a more palatable preparation of Miralax, a peg solution, and Gatorade that has caused concern over increased chances of bowel explosion. This is due to the fermentation process of carbohydrate digestion and subsequent methane and hydrogen gas production. It is essential that the colon is clean to avoid this complication. A poorly prepped colon can affect the physician’s ability to see polyps and other abnormalities during the exam. Decreased visualization related to the poor preparation, may cause decreased identification of colon polyps and adenomas argues Athreya et al., (2011). It can increase the complexity of the exam, therefore increasing time to complete the procedure and increasing the risk of perforation. Increased procedure time can result in further dangers related to anesthesia. Geyer et al. (2011) states that, “Better colonic insufflation may be associated with a better diagnostic yield and especially a higher polyp detection rate” (p.2). Poor bowel preparation can limit the visualization field, prohibiting cecal intubation, making the exam more difficult, and decreasing the ability to detect colon polyps. Levin et al. (2006) acknowledges that the majority of polyps are smaller than 10mm. With a poorly prepped colon, it would be easy to miss such a small lesion. When physicians remove precancerous polyps early, it decreases the risk that a patient will develop colorectal cancer (Nguyen & Wieland, 2010). Athreya et al. (2011) argues that physicians may miss abnormalities such as polyps due to insufficient bowel preparation. Lichtenstein (2009) reports that up to 25% of patients do not have adequate bowel preparations and this can cause missed polyps. Nguyen and Wieland (2010) maintain that poor bowel

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preparations diminish the amount of polyps or abnormalities seen during colonoscopy. According to Nguyen and Wieland (2010), “High quality colon cleansing improves detection of colonic lesions, shortens total procedural time, and results in lower rates of complications during colonoscopy evaluation” (p. 370). With a poor bowel preparation, colonoscopy may take longer to perform due to manual washing of the colon (Roberts-Thomson and Teo, 2009). Poor bowel preparation increases the use of healthcare dollars due to missing polyps, prolonged procedures, and repeat or further testing (Enestvedt, Fennerty, & Eisen, 2011). When a polyp goes undetected, it may develop into a cancer. (Nguyen & Wieland, 2010). The cost of treatment for colon cancer is much greater than the cost of finding and removing a colon polyp. Hendry et al., (2007) reports on a study of 10,571 colonoscopies. Of those, 1788 did not have a quality preparation. Only 36% of the poorly prepped colonoscopies were completed. The authors argue that the increased cost associated with inadequate bowel preparation, is due to subsequent studies preformed, such as repeat colonoscopy, barium enema, or virtual colonoscopy. These repeat tests require completion sooner than normally recommended. (Lichtenstein, 2009) Of course, the physician may be unable to complete the exam, due to poor visibility. This can result in increased healthcare dollars spent to repeat the exam (Adamcewicz et al., 2011). Anesthesia services are costly, and insurance companies may refuse to pay for repeat exams (Hawes, Lowry, & Deziel, 2006). Anesthesia complications are directly proportional to amounts of anesthesia used, and the number of times a patient is sedated (Levin et al., 2006).

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This can put a patient at risk for hospitalization, which is another unexpected expense (Hendry et al., 2007). Electrolyte imbalances can be critical, resulting in interventions to correct the imbalance, such as hospitalization. Diabetic ketoacidosis is one such imbalance that preparing for colonoscopy can cause (Levin et al., 2006). Even so, healthy patients also have problems adjusting to the rigorous clean out. Sodium phosphate solutions caused 30% of the more healthy patients in a study of 352 people to develop serious electrolyte imbalances (Bitoun et al., 2006). Enestvedt et al. (2011) maintains that, “adequate bowel cleansing is critical to optimal endoscopic visualization and therefore influences the safety, efficacy, diagnostic accuracy and quality of screening colonoscopy” (p.34). The most advantageous colon prep would be one that effectively cleans out the colon, does not put the patient at risk for electrolyte imbalances, and has a pleasant taste (Adamcewicz et al. 2011) (Lichtenstein 2009). An inadequate colon preparation makes the exam more difficult. This increases the time needed to complete the procedure. More time equals more air insufflation, which increases the risk of pain and perforation. Increased cardiopulmonary complications result from longer procedures. This is due to increased sedation requirements and greater air insufflation. If colon preparation is poor, the complexity of the exam is increased. The physician may miss polyps or adenomas, and necessitate a repeat exam. This increases healthcare costs by requiring the purchase of a second preparation as well as the cost of the exam and anesthesia fees. Missing a polyp can increase the chances of a patient developing colon cancer, and all of the cost associated with treating the disease. It may also place the patient at risk for

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complications from completing the prep twice, such as electrolyte imbalances and anesthesia risks, requiring unplanned hospitalization. Researchers consider quality bowel preparation a major factor in influencing successful colonoscopy because it is modifiable (Bitoun et al., 2006). Nguyen and Wieland (2010) suggest that physicians should carefully select patients to ensure they understand the risks and benefits of each preparation. A proper history will help the physician in the selection process. Some preparations are complicated and expensive, further challenging the physician when comparing options for each patient (Hawes et al., 2006). This study validates the claim made that high quality bowel preparation for colonoscopy is one of the most crucial factors in decreasing complications, detecting colon polyps, and decreasing redundant use of health care dollars. More research is needed on preparations offering a pleasant taste, low cost, and effective colon cleansing with minimal side effects. This is the optimum way to ensure high quality bowel preparation prior to colonoscopy.

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References Adamcewicz, M., Bearelly, D., Porat, G., & Friedenberg, F. K. (2011). Mechanism of action and toxicities of purgatives used for colonoscopy preparation. Expert Opinion on Drug Metabolism & Toxicology, 7(1), 89-101.doi:10.1517/17425255.2011.542411 Athreya, P. J., Owen, G. N., Wong, S. W., Douglas, P. R., & Newstead, G. L. (2011). Achieving quality in colonoscopy: bowel preparation timing and colon cleanliness. ANZ Journal of Surgery, 81(4), 261-265. Bitoun, A., Ponchon, T., Barthet, M., Coffin, B., Dugu, C., & Halphen, M., on behalf of the Norcol Group. (2006). Results of a prospective randomized multicentre controlled trial comparing a new 2-L ascorbic acid plus polyethylene glycol and electrolyte solution vs. sodium phosphate solution in patients undergoing elective colonoscopy. Alimentary Pharmacology & Therapeutics, 24(11/12), 1631-1642. Clark, L. E., & DiPalma, J. A. (2004). Safety issues regarding colonic cleansing for diagnostic and surgical procedures. Drug Safety, 27(15), 1235-1242. Cohen, L. B., Kastenberg, D. M., Mount, D. B., & Safdi, A. V. (2009). Current issues in optimal bowel preparation. Gastroenterology and Hepatology, 5(11), Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886377/ Enestvedt, B. K., Fennerty, M. B., & Eisen, G. M. (2011). Randomized clinical trial: Miralax vs. GoLytely - a controlled study of efficacy and patient tolerability in bowel preparation for colonoscopy. Alimentary Pharmacology & Therapeutics, 33(1), 33-40.

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Geyer, M., Guller, U., & Beglinger, C. (2011). Carbon dioxide insufflation in routine colonoscopy is safe and more comfortable: Results of a randomized controlled doubleblinded trial. Diagnostic & Therapeutic Endoscopy, 1-6. Hawes, R. H., Lowry, A., & Deziel, D. (2006). 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). American Society for Gastrointestinal Endoscopy, 63(7), 894-910. doi:10.1016/j.gie.2006.03.919 Hendry, P., Jenkins, J., & Diament, R. (2007). The impact of poor bowel preparation on colonoscopy: a prospective single centre study of 10,571 colonoscopies. Colorectal Disease: The Official Journal of the Association of Coloproctology of Great Britain and Ireland, 9(8), 745-748. Levin, T. R., Wei, Z., Conell, C., Seeff, L. C., Manninen, D. L., Shapiro, J. A., & Schulman, J. (2006). Complications of colonoscopy in an integrated health care delivery system. Annals of Internal Medicine, 145(12), 880-W245. Lichtenstein, G. (2009). Bowel preparations for colonoscopy: A review. American Journal of Health-System Pharmacy, 66(1), 27-37. Lichtenstein, D., Jagannath, S., Baron, T. H., Anderson, M., Banerjee, S., Dominitz, J. A., … & Vargo, J. J. (2008). Sedation and anesthesia in GI endoscopy. Gastrointestinal Endoscopy, 68(5), retrieved from http://www.sages.org/publications/SAGES_ASGE_Sedation_Endoscopy.pdf

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Nguyen, D. L., & Wieland, M. (2010). Risk factors predictive of poor quality preparation during average risk colonoscopy screening: the importance of health literacy. Journal of Gastrointestinal & Liver Diseases, 19(4), 369-372. Roberts-Thomson, I. C., & Teo, E. (2009). Colonoscopy: Art or science? Journal of Gastroenterology & Hepatology, 24(2), 180-184.