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How to avoid common pitfalls with bowel preparation agents
THE FELLOWS’ CORNER
How to avoid common pitfalls with bowel preparation agents Colonoscopy is the driving force of our specialty, and gastroenterologists are obliged to perform a high-quality colonoscopy to ensure the future of conventional colonoscopy. In addition, quality colonoscopy protects against colorectal cancer incidence and mortality. The quality of examination during colonoscopy can be impaired by imperfect bowel preparation. Steps to improve patient understanding of and compliance with bowel preparation could significantly improve the outcomes of colonoscopy in clinical practice. In this month’s edition of the Fellows’ Corner, Dr. Freddy Caldera and Dr. Lisbeth Selby shed light on various bowel preparation regimens and on the different steps that gastroenterologists should follow to improve patient compliance and tolerability of different colonic cleansing regimens. Mouen Khashab, MD Fellows’ Corner Editor Interventional Endoscopy Fellow Johns Hopkins Hospital Baltimore, Maryland, USA Bowel preparation is an important facet of a quality colonoscopic examination. The rate of inadequate bowel preparation for colonoscopies in clinical studies is approximately 21%.1 According to the American College of Gastroenterologists/American Society for Gastrointestinal Endoscopy Task Force, inadequate bowel preparation is defined as the inability to visualize polyps smaller than 5 mm in size. Inadequate bowel preparation can lead to longer procedure times, lower polyp detection rates, decreased flat lesion detection, lower cecal intubation rates, and inefficient use of resources.2 Instructing patients on proper colonic preparation methods is crucial. Unfortunately, this important topic may not be formally covered by many training curricula, but gastroenterologists need to be able to assist patients as they prepare for their colonoscopies.
TROUBLESHOOTING WITH POLYETHYLENE GLYCOL/ELECTROLYTE SOLUTIONS Polyethylene glycol (PEG)/electrolyte-based preparations have been the most commonly used bowel prepara-
Copyright © 2011 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 doi:10.1016/j.gie.2010.12.008
346 GASTROINTESTINAL ENDOSCOPY
Volume 73, No. 2 : 2011
tion products since 2008, when the U.S. Food and Drug Administration placed a black box warning on sodium phosphate products because of reports of acute renal failure. To increase compliance with and tolerability of PEG/electrolyte preparations, one should be aware of commonly used techniques that may render the solution more tolerable and palatable. Chilling the solution up to 24 to 48 hours, sucking on lemon slices, drinking lemon sodas, or adding an artificial flavoring agent (eg, Crystal Light) or lemon juice may mask the taste and make the solution more palatable.
Key Points ●
●
●
Knowing common pitfalls of bowel preparation and some simple management techniques is crucial to increase successful colonoscopy rates. Patients should be prescribed bowel preparation in a split-dose fashion to ensure better tolerability and adequate colonic cleansing. Patients should be counseled on the importance of following the instructions to have a successful outcome.
Nausea, vomiting, and bloating caused by the solution are other common complaints, especially with PEG/ electrolyte solutions. One may recommend that the patient slow down intake of the bowel preparation to 1 L/h or 1 L every 2 hours. It is not necessary to finish the preparation within 2 hours as commonly instructed. If nausea is persistent after slowing down intake, promethazine or metoclopramide can be prescribed. Patients can even stop taking the preparation for couple of hours and then restart taking it at slower rate. The preferred way to deal with nausea should be to give the bowel regimen in a split-dose fashion (half the preparation is taken the night before and the other half the morning of the procedure). Split-dose regimens are better tolerated and have been proven to result in better cleansing. If all these efforts fail, an alternative option is to add another agent, such as magnesium www.giejournal.org
Caldera & Selby
citrate, to decrease the volume of the PEG/electrolyte agent.
MIRALAX
Avoiding common pitfalls with bowel preparation agents
TABLE 1. Constituents of clear liquid diet Clear liquid diet Plain water
PEG 3350 (MiraLAX; Schering-Plough Healthcare Products, Memphis, Tenn) is one of the more common agents used for bowel preparation in the United States, partly because of its better tolerability. It is indicated as an overthe-counter agent for constipation and not yet approved by the US Food and Drug Administration as a bowel preparation agent. The dose is usually 238 g (approximately 14 times the dose used to treat constipation) with 64 oz (2 L) of liquids (eg, a sports drink like Gatorade). It does not contain an electrolyte replacement like other PEG-based agents, which theoretically can lead to volume depletion, hypokalemia, and/or hyponatremia. MiraLAX is best avoided in patients with congestive heart failure, cirrhosis, and chronic kidney disease and the elderly. Even though there are concerns regarding its safety and efficacy, it has been used in a large body of patients with few reported side effects. There seems to be an important role for MiraLAX bowel preparation regimens, especially in patients who cannot tolerate PEG/electrolyte products.
NONADHERENCE TO INSTRUCTIONS Picking up bowel preparation instructions late, often the afternoon or night before the procedure, is another common problem. Patients should be advised about the importance of bowel preparation instructions, which often involve actions that need to be completed several days before the procedure. For instance, instructions usually state that patients should follow a clear liquid diet 1 day before the procedure. Poor comprehension of a clear liquid diet has been shown to be common among patients undergoing colonoscopy.3 Therefore, clear liquid nonadherence might be a significant contributor to suboptimal bowel preparations. Patients should be instructed early on what constitutes a clear liquid diet (Table 1) and the importance of compliance with dietary instructions.
INADEQUATE BOWEL PREPARATION Patients presenting for a colonoscopy need to be screened for inadequate preparation by inquiring about the appearance and time of the last rectal effluent. Patients who still have brown stools after completing their bowel preparation have a substantial chance of having inadequate bowel cleansing and need further bowel preparation before colonoscopy is attempted. They should either receive 2 additional liters of PEG or other agents, such as magnesium citrate, PEG 3350, or bisacodyl with a reattempt at colonoscopy later that day or the following day. Administration of the additional cleansing agent should be provided in a split-dose fashion if the repeat procedure www.giejournal.org
Fruit juices without pulp, such as grape juice, filtered apple juice, and cranberry juice Soup broth (bouillon) Clear sodas, such as ginger ale and Sprite Gelatin (Jell-O) Popsicles that do not have bits of fruit or fruit pulp in them Tea or coffee with no cream or milk added Sports drinks
will be the following day. Patients who are identified with poor colon cleansing intraprocedurally should ideally be managed in a similar fashion to avoid being lost to follow-up. To have a successful outcome with subsequent procedures in patients with a history of inadequate bowel preparation, one must discuss with the patient remediable issues, such as compliance with his or her specific bowel regimen instructions, including clear liquid diet and splitdosing regimens. Noncompliance with bowel preparation regimens and instructions is not the only factor contributing to inadequate bowel preparations. Contributing risk factors include a history of constipation, cirrhosis, diabetes, narcotic use, and immobility.1 If a patient was compliant with the bowel preparation, but still had a poor preparation, consider one of the following regimens: 1. Two days of clear liquids with 4 L of PEG/electrolyte solution in a split-dose fashion. 2. Two days of clear liquids with a total of 8 L of PEG/ electrolyte solution: a. 4 L of PEG/electrolyte solution given the first day in the evening b. 4 L of PEG/electrolyte solution given in a split-dose fashion between the evening of the second day and then 5 hours before the procedure 3. Providing a bottle of magnesium citrate at noon, 10 mg of bisacodyl tablets at 3 PM, 10 mg of metoclopramide while taking the PEG, and 4 L of PEG/electrolyte solution in a split-dose fashion 4. Intensive regimen using several days of preparation steps. Serum electrolytes may need to be monitored during an intensive regimen, especially in patients with risk factors for electrolyte imbalance or potential for serious sequelae of imbalances such as arrhythmias. See the following: Volume 73, No. 2 : 2011 GASTROINTESTINAL ENDOSCOPY
347
Avoiding common pitfalls with bowel preparation agents
a. Stop bulk-forming, fiber supplementation agents (eg, Metamucil) 5 days before the procedure. b. Stop popcorn, corn, legumes, seeds, nuts, multigrain bread, salad, and similar high-residue foods 3 days before the procedure. c. Eat a low-residue meal and drink 4 L of PEG/ electrolyte solution 1 day before the procedure. d. Follow a clear liquid diet and drink an additional 4 L of PEG/electrolyte solution in a split-dose fashion, starting 1 day before the procedure. e. Schedule an early morning appointment. There are potential limitations with many of the options discussed. Two days of a clear liquid diet can be difficult for patients to follow. Eight liters of a PEG product is a large volume to tolerate. A complicated regimen, consisting of several agents and/or steps, might be difficult for patients to understand and follow. Written instructions should be given to patients to improve compliance. Patients should be instructed that adherence with their instructions is crucial to obtain an adequate bowel preparation, improve procedure outcome, and avoid the need for aborted colonoscopies and repeat procedures. Split-dose regimens are indispensable when it comes to improving bowel preparation quality. It has been shown that acceptance of and compliance with splitdose bowel preparations is high and should not be a deterrent to prescribing split-dose preparations for colonoscopy.
SUMMARY Both the American College of Gastroenterologists and the American Society for Gastrointestinal Endoscopy have
348 GASTROINTESTINAL ENDOSCOPY
Volume 73, No. 2 : 2011
Caldera & Selby
developed quality indicators for colonoscopy. Two of these quality indicators, cecal intubation and adenoma detection rate, are dependent on the quality of bowel preparation.2 Performing a high-quality colonoscopy depends in part on the ability of gastroenterologists to deal with the potential pitfalls to achieving an adequate bowel preparation. As gastroenterology fellows, we should be aware of these pitfalls and the ways to avoid and treat them. DISCLOSURE The author disclosed no financial relationships relevant to this publication. Freddy Caldera, DO Lisbeth Selby, MD Division of Gastroenterology and Hepatology Department of Medicine University of Kentucky Lexington, Kentucky, USA Abbreviation: PEG, polyethylene glycol.
REFERENCES 1. Ness NM, Manam R, Hoen H, et al. Predictors of inadequate bowel preparation for colonoscopy. Am J Gastroenterol 2001;96:1797-802. 2. Rex DX, Petrini JL, Baron TH, et al. Quality indicators for colonoscopy. Gastrointest Endosc 2006;63:S16-28. 3. Paranjape S, Nickl N, Selby LA. Understanding of clear liquid instructions as part of colonoscopy preparation. Am J Gastroenterol 2008;103:A1318.
www.giejournal.org
How to avoid common pitfalls with bowel preparation agents Colonoscopy is the driving force of our specialty, and gastroenterologists are obliged to perform a high-quality colonoscopy to ensure the future of conventional colonoscopy. In addition, quality colonoscopy protects against colorectal cancer incidence and mortality. The quality of examination during colonoscopy can be impaired by imperfect bowel preparation. Steps to improve patient understanding of and compliance with bowel preparation could significantly improve the outcomes of colonoscopy in clinical practice. In this month’s edition of the Fellows’ Corner, Dr. Freddy Caldera and Dr. Lisbeth Selby shed light on various bowel preparation regimens and on the different steps that gastroenterologists should follow to improve patient compliance and tolerability of different colonic cleansing regimens. Mouen Khashab, MD Fellows’ Corner Editor Interventional Endoscopy Fellow Johns Hopkins Hospital Baltimore, Maryland, USA Bowel preparation is an important facet of a quality colonoscopic examination. The rate of inadequate bowel preparation for colonoscopies in clinical studies is approximately 21%.1 According to the American College of Gastroenterologists/American Society for Gastrointestinal Endoscopy Task Force, inadequate bowel preparation is defined as the inability to visualize polyps smaller than 5 mm in size. Inadequate bowel preparation can lead to longer procedure times, lower polyp detection rates, decreased flat lesion detection, lower cecal intubation rates, and inefficient use of resources.2 Instructing patients on proper colonic preparation methods is crucial. Unfortunately, this important topic may not be formally covered by many training curricula, but gastroenterologists need to be able to assist patients as they prepare for their colonoscopies.
TROUBLESHOOTING WITH POLYETHYLENE GLYCOL/ELECTROLYTE SOLUTIONS Polyethylene glycol (PEG)/electrolyte-based preparations have been the most commonly used bowel prepara-
Copyright © 2011 by the American Society for Gastrointestinal Endoscopy 0016-5107/$36.00 doi:10.1016/j.gie.2010.12.008
346 GASTROINTESTINAL ENDOSCOPY
Volume 73, No. 2 : 2011
tion products since 2008, when the U.S. Food and Drug Administration placed a black box warning on sodium phosphate products because of reports of acute renal failure. To increase compliance with and tolerability of PEG/electrolyte preparations, one should be aware of commonly used techniques that may render the solution more tolerable and palatable. Chilling the solution up to 24 to 48 hours, sucking on lemon slices, drinking lemon sodas, or adding an artificial flavoring agent (eg, Crystal Light) or lemon juice may mask the taste and make the solution more palatable.
Key Points ●
●
●
Knowing common pitfalls of bowel preparation and some simple management techniques is crucial to increase successful colonoscopy rates. Patients should be prescribed bowel preparation in a split-dose fashion to ensure better tolerability and adequate colonic cleansing. Patients should be counseled on the importance of following the instructions to have a successful outcome.
Nausea, vomiting, and bloating caused by the solution are other common complaints, especially with PEG/ electrolyte solutions. One may recommend that the patient slow down intake of the bowel preparation to 1 L/h or 1 L every 2 hours. It is not necessary to finish the preparation within 2 hours as commonly instructed. If nausea is persistent after slowing down intake, promethazine or metoclopramide can be prescribed. Patients can even stop taking the preparation for couple of hours and then restart taking it at slower rate. The preferred way to deal with nausea should be to give the bowel regimen in a split-dose fashion (half the preparation is taken the night before and the other half the morning of the procedure). Split-dose regimens are better tolerated and have been proven to result in better cleansing. If all these efforts fail, an alternative option is to add another agent, such as magnesium www.giejournal.org
Caldera & Selby
citrate, to decrease the volume of the PEG/electrolyte agent.
MIRALAX
Avoiding common pitfalls with bowel preparation agents
TABLE 1. Constituents of clear liquid diet Clear liquid diet Plain water
PEG 3350 (MiraLAX; Schering-Plough Healthcare Products, Memphis, Tenn) is one of the more common agents used for bowel preparation in the United States, partly because of its better tolerability. It is indicated as an overthe-counter agent for constipation and not yet approved by the US Food and Drug Administration as a bowel preparation agent. The dose is usually 238 g (approximately 14 times the dose used to treat constipation) with 64 oz (2 L) of liquids (eg, a sports drink like Gatorade). It does not contain an electrolyte replacement like other PEG-based agents, which theoretically can lead to volume depletion, hypokalemia, and/or hyponatremia. MiraLAX is best avoided in patients with congestive heart failure, cirrhosis, and chronic kidney disease and the elderly. Even though there are concerns regarding its safety and efficacy, it has been used in a large body of patients with few reported side effects. There seems to be an important role for MiraLAX bowel preparation regimens, especially in patients who cannot tolerate PEG/electrolyte products.
NONADHERENCE TO INSTRUCTIONS Picking up bowel preparation instructions late, often the afternoon or night before the procedure, is another common problem. Patients should be advised about the importance of bowel preparation instructions, which often involve actions that need to be completed several days before the procedure. For instance, instructions usually state that patients should follow a clear liquid diet 1 day before the procedure. Poor comprehension of a clear liquid diet has been shown to be common among patients undergoing colonoscopy.3 Therefore, clear liquid nonadherence might be a significant contributor to suboptimal bowel preparations. Patients should be instructed early on what constitutes a clear liquid diet (Table 1) and the importance of compliance with dietary instructions.
INADEQUATE BOWEL PREPARATION Patients presenting for a colonoscopy need to be screened for inadequate preparation by inquiring about the appearance and time of the last rectal effluent. Patients who still have brown stools after completing their bowel preparation have a substantial chance of having inadequate bowel cleansing and need further bowel preparation before colonoscopy is attempted. They should either receive 2 additional liters of PEG or other agents, such as magnesium citrate, PEG 3350, or bisacodyl with a reattempt at colonoscopy later that day or the following day. Administration of the additional cleansing agent should be provided in a split-dose fashion if the repeat procedure www.giejournal.org
Fruit juices without pulp, such as grape juice, filtered apple juice, and cranberry juice Soup broth (bouillon) Clear sodas, such as ginger ale and Sprite Gelatin (Jell-O) Popsicles that do not have bits of fruit or fruit pulp in them Tea or coffee with no cream or milk added Sports drinks
will be the following day. Patients who are identified with poor colon cleansing intraprocedurally should ideally be managed in a similar fashion to avoid being lost to follow-up. To have a successful outcome with subsequent procedures in patients with a history of inadequate bowel preparation, one must discuss with the patient remediable issues, such as compliance with his or her specific bowel regimen instructions, including clear liquid diet and splitdosing regimens. Noncompliance with bowel preparation regimens and instructions is not the only factor contributing to inadequate bowel preparations. Contributing risk factors include a history of constipation, cirrhosis, diabetes, narcotic use, and immobility.1 If a patient was compliant with the bowel preparation, but still had a poor preparation, consider one of the following regimens: 1. Two days of clear liquids with 4 L of PEG/electrolyte solution in a split-dose fashion. 2. Two days of clear liquids with a total of 8 L of PEG/ electrolyte solution: a. 4 L of PEG/electrolyte solution given the first day in the evening b. 4 L of PEG/electrolyte solution given in a split-dose fashion between the evening of the second day and then 5 hours before the procedure 3. Providing a bottle of magnesium citrate at noon, 10 mg of bisacodyl tablets at 3 PM, 10 mg of metoclopramide while taking the PEG, and 4 L of PEG/electrolyte solution in a split-dose fashion 4. Intensive regimen using several days of preparation steps. Serum electrolytes may need to be monitored during an intensive regimen, especially in patients with risk factors for electrolyte imbalance or potential for serious sequelae of imbalances such as arrhythmias. See the following: Volume 73, No. 2 : 2011 GASTROINTESTINAL ENDOSCOPY
347
Avoiding common pitfalls with bowel preparation agents
a. Stop bulk-forming, fiber supplementation agents (eg, Metamucil) 5 days before the procedure. b. Stop popcorn, corn, legumes, seeds, nuts, multigrain bread, salad, and similar high-residue foods 3 days before the procedure. c. Eat a low-residue meal and drink 4 L of PEG/ electrolyte solution 1 day before the procedure. d. Follow a clear liquid diet and drink an additional 4 L of PEG/electrolyte solution in a split-dose fashion, starting 1 day before the procedure. e. Schedule an early morning appointment. There are potential limitations with many of the options discussed. Two days of a clear liquid diet can be difficult for patients to follow. Eight liters of a PEG product is a large volume to tolerate. A complicated regimen, consisting of several agents and/or steps, might be difficult for patients to understand and follow. Written instructions should be given to patients to improve compliance. Patients should be instructed that adherence with their instructions is crucial to obtain an adequate bowel preparation, improve procedure outcome, and avoid the need for aborted colonoscopies and repeat procedures. Split-dose regimens are indispensable when it comes to improving bowel preparation quality. It has been shown that acceptance of and compliance with splitdose bowel preparations is high and should not be a deterrent to prescribing split-dose preparations for colonoscopy.
SUMMARY Both the American College of Gastroenterologists and the American Society for Gastrointestinal Endoscopy have
348 GASTROINTESTINAL ENDOSCOPY
Volume 73, No. 2 : 2011
Caldera & Selby
developed quality indicators for colonoscopy. Two of these quality indicators, cecal intubation and adenoma detection rate, are dependent on the quality of bowel preparation.2 Performing a high-quality colonoscopy depends in part on the ability of gastroenterologists to deal with the potential pitfalls to achieving an adequate bowel preparation. As gastroenterology fellows, we should be aware of these pitfalls and the ways to avoid and treat them. DISCLOSURE The author disclosed no financial relationships relevant to this publication. Freddy Caldera, DO Lisbeth Selby, MD Division of Gastroenterology and Hepatology Department of Medicine University of Kentucky Lexington, Kentucky, USA Abbreviation: PEG, polyethylene glycol.
REFERENCES 1. Ness NM, Manam R, Hoen H, et al. Predictors of inadequate bowel preparation for colonoscopy. Am J Gastroenterol 2001;96:1797-802. 2. Rex DX, Petrini JL, Baron TH, et al. Quality indicators for colonoscopy. Gastrointest Endosc 2006;63:S16-28. 3. Paranjape S, Nickl N, Selby LA. Understanding of clear liquid instructions as part of colonoscopy preparation. Am J Gastroenterol 2008;103:A1318.
www.giejournal.org