Definitions of constipation vary from one reference to another. At M. D. Anderson, we define constipation as the condition in which stool is hard and difficult to eliminate. Even if the frequency of bowel movements decreases, as long as the stool remains soft and formed, the patient is not constipated.
Never Underestimate How Much Stool the Intestines Can Hold
The average length of the colon is 4 to 5 feet, and the colon is 2 inches in diameter, which makes possible a large fecal-mass accumulation. Two cases will be presented here to illustrate the need for a very aggressive approach to cleaning out the colon to normalize the GI tract in patients who are eating well and have not had a bowel movement for 5 or more days.
• Case 1: A 110-pound man with a colostomy had not had a bowel movement for 8 days. His colostomy was irrigated, and he eliminated a whole bucket of stool.
• Case 2: A patient from the emergency room was admitted in a crawling position on a stretcher. He had intense pain that was exacerbated by lying on his back. The patient had been eating normally; he had been taking large doses of opioids and had not had a bowel movement for 10 days. An abdominal x-ray series performed in the emergency room showed that the large bowel was full of stool with no signs of obstruction. The patient was given 2 milk-and-molasses enemas (Table 19-3) and then started on 30 mL lactulose (Cephulac) by mouth. Then enemas and lactulose were given 4 times a day until no more formed stool was eliminated. The large bowel was finally cleared of stool after 3 days of this regimen. The patient was then able to lie on his back without pain.
Most healthy people know simple ways to help alleviate simple constipation (e.g., consuming prunes or prune juice). Patients, however—even those who are very intelligent and highly educated (i.e., college professors and physicians)—often do not know how to prevent bowel dysfunction secondary to cancer treatment. Few health care professionals correctly estimate the noxious effects of the treatments patients receive, and many tend to undertreat constipation in patients with cancer, approaching it as they
Table 19-3. Milk-and-Molasses Enema
8 ounces hot water (it will cool down before use) 3 ounces powdered milk (may be purchased at a grocery store) 4.5 ounces molasses (may be purchased at a grocery store)
Put the water and powdered milk in a jar, and shake it until the water and milk look fully mixed. Add molasses. Shake the jar again until the mixture appears to have an even color throughout. Pour the mixture into an enema bag. Gently introduce the tube into your rectum about 12 inches or until the tube hits stool. Do not push beyond resistance. When the tube has reached the stool, withdraw the tube about half an inch and release the solution.
Modified with permission from Bisanz A. Managing bowel elimination problems in patients with cancer. Oncol Nurs Forum 1997;24:579-687.
would treat constipation in a healthy individual. It simply does not work that way. The more serious the cause of a symptom, the more aggressive the treatment must be.
One common mistake that health care professionals make is to believe that a positive result from 1 enema solves the problem and restores normal bowel function. They fail to realize that about 75% of the stool remains in the colon after a single enema and that if this stool is not removed, the same problem will resurface in a few days. Thus it is important to normalize the bowel. The goal is to get the bowel back to a normal state so that the patient can commence a bowel management program that will prevent the recurrence of severe constipation.
Constipation differs between healthy individuals and patients with cancer. Many cancer patients go through periods when they eat and drink less than healthy individuals do and have decreased ambulation or exercise. This decreases peristalsis, leading to impaction in many patients. The impaction is in many cases in the transverse or descending colon and is not detected by a digital rectal examination.
At M. D. Anderson, health care professionals differentiate low impactions from high impactions (Figure 19-3). A low impaction is a collection of stool in the rectum and sigmoid colon. A high impaction is a collection of stool in the transverse and descending colon with no stool in the sigmoid colon and rectum.
Patients who present with a low impaction may complain of an inability to sit because they feel like they are sitting on something. They may feel the need to have a bowel movement, but the stool, which is packed in the rectum, is too large to expel through the anal opening. They may
Figure 19-3. Distinction between high and low impactions.
Figure 19-3. Distinction between high and low impactions.
also complain of bloating, cramping, and gas. In some cases, the patient's abdomen is distended. Liquid stool may be expelled from the small bowel since it leaks around the impacted stool. Patients with a low impaction should be advised to take the following actions:
• Do NOT drink hot liquid or eat a big meal, since this will increase peristalsis and discomfort.
• Lie down and call for professional help.
• Give a Fleet mineral-oil enema very fast to force it high in the colon to help the stool slide out more easily (optional).
• Manually disimpact the stool.
• Administer an enema to help eliminate the stool higher up (e.g., a tap-water, soapsuds, or milk-and-molasses enema).
Patients with a high impaction present with a history of 5 or more days of not having a bowel movement. Patients show no signs of impaction on digital rectal examination and do not have the sensation of stool in the bowel that cannot be eliminated. They have no appetite, eat very little, and feel nauseated after eating or drinking. In many cases, high impactions occur because patients do not eat or drink properly and peristalsis is impaired. Patients do not feel an urge to have a bowel movement until the stool reaches the rectum, and the decreased peristalsis from not eating hinders that process. When these symptoms are present, an abdominal x-ray series is not indicated unless the patient is vomiting and shows signs of obstruction. Patients with a high impaction should be advised by the physician or nurse to take all of the following actions:
• Take 2 tablespoons of mineral oil by mouth if on abdominal palpation the stool is felt to be hard (optional).
• Administer a milk-and-molasses enema every 4 to 6 hours.
• Take 30 mL of lactulose by mouth every 4 to 6 hours once stool begins to be eliminated after the enema is started.
• Continue the prior 2 steps until no more formed stool is eliminated.
In our experience at M. D. Anderson, the milk-and-molasses enema has proven to be relatively easy for patients to take because it has a low volume (1// cups). It is not a stimulant; instead, it works like an osmotic enema that helps the patient eliminate stool comfortably. In the treatment of patients with high impactions, the enema tube needs to be inserted 12 inches or more until resistance is met or it will not be effective (Figure 19-4). The tube is left in place for 15 minutes after the enema is given to help patients hold the solution.
To self-administer a milk-and-molasses enema for a high impaction, a patient needs an enema bag that will allow the solution to be released close to the impaction. Enema bags sold in drugstores are not made for this type of enema; they usually have about a 3-inch tip, which will deliver the enema solution only about 6 inches into the colon. The correct type of
enema bag has 1 continuous length of tubing that is soft and can be inserted higher in the colon; it is usually available at hospital central supply departments or home-care agencies. It may be helpful for physicians to maintain a supply of these enema bags for oncology patients' use.
Milk-and-molasses enemas administered to clean out the colon should be repeated every 4 to 6 hours (every 6 hours at home and every 4 hours in the hospital). Lactulose should be administered simultaneously (30mL by mouth every 4 to 6 hours) after the patient begins eliminating stool or after 1 or 2 milk-and-molasses enemas. The lactulose draws water into the GI tract, and the increased volume provides pressure to push the stool down through the GI tract. Because lactulose brings more fluid into the bowel, however, patients can become dehydrated and thus must be given sufficient hydration. Patients at home must drink at least 2 quarts of fluid every day.
The goal of the enema and lactulose regimen is to clean out just the large bowel, not the small intestine. Consequently, the enemas and lactu-lose should be discontinued when the patient stops eliminating formed stool and there is just liquid return.
Effectiveness of Milk-and-Molasses Enemas plus Lactulose
Patients typically tolerate the milk-and-molasses-enema-plus-lactulose regimen well. It involves a very low volume enema (1/ cups) and is not uncomfortable. The patient can usually hold the enema because it is low-volume and administered high in the colon. The caregiver does not mind giving the enema because the solution does not run out of the colon immediately. Any gas pains that the patient has subside as soon as the patient begins eliminating stool because the gas is trapped behind the stool.
Once the patient's GI tract is normalized, the patient should be monitored for 1 week to determine the normal bowel pattern and then placed on a bowel management program. It may be possible to treat the patient with just titration of food, fluid, fiber, and medication. If this does not work, then in addition, the bowel may need to be trained to empty at the same time each day, by using the bowel training program described in the next section.
A bowel training program trains the bowel for life to empty at the same time daily with a given stimulus. If patients can eat 3 full meals per day and drink 64 ounces of fluid per day, they are good candidates for bowel training. Patients who cannot eat or drink are not eligible.
Before beginning a bowel-training program, patients must take oral laxatives, enemas, or both to help eliminate the formed stool in the large intestine. Patients start bowel training 3 days later.
Bowel training consists of the following. The patient drinks 4 ounces of prune juice; eats a big meal at the mealtime chosen by the patient; and drinks 1 cup of hot liquid after the meal. Then a bisacodyl suppository is inserted into the rectum and pushed against the mucous membrane of the bowel. These 4 steps are repeated for 14 days. On day 15, a glycerin suppository is substituted for the bisacodyl suppository.
The patient must not take oral stimulant laxatives once the bowel training program has started, although stool softeners may be taken. They will not interfere with the training program because they are not a stimulant cathartic.
If the patient does not respond to the glycerin suppository, the glycerin should be discontinued and the bisacodyl suppository continued for 1 more week before the glycerin is substituted again. If the anal sphincter muscle is tight, the anal opening should be massaged to gently relax the muscle for easy passage of stool. This type of digital stimulation is needed for all patients with spinal cord lesions involving the sacral area. Adjustments to the program should be made 1 at a time and adhered to for 3 days. If there is more than 1 large bowel movement and liquid stool follows, the amount of prune juice should be decreased to 2 ounces, or a half rather than a whole bisacodyl suppository should be inserted into the rectum. If constipation persists, stool softeners should be added to the regimen, and the patient should be directed to eat 5 prunes at bedtime, increase the daily fluid intake, increase the fiber content in the diet, or increase physical activity, of course initiating only 1 change every 3 days.
Bowel Management Program for Constipation
When bowel training is not needed, patients with constipation can be placed on a bowel management program consisting of the following:
• Determine the desired frequency of stooling on the basis of the patient's appetite.
• Prescribe adequate fluid intake, adequate fiber, and at least one good-sized meal for peristaltic pushdown daily, plus medication if needed to counteract side effects of other medicines in the disease process.
• Assess outcome and guide the patient to the program that will be effective, adjusting fluid, fiber, food, and medication.
Patients with advanced disease should be treated using a symptommanagement approach. Never allow patients to go more than 3 days without a bowel movement. Do not fear laxative use and abuse. Your goal is to keep patients comfortable. Suppositories or oral laxatives may be used as needed according to circumstances.
When a patient is receiving opioids, a program to prevent constipation should be initiated immediately. The program consists of treatment with senna, a stimulant cathartic, and docusate sodium, a stool softener; the maximum daily dose is eight senna pills and 500 mg of docusate sodium.
Patients start with a lower dose, which is titrated up as the opioid dose is increased. The pill form of senna and docusate sodium may be ordered in bulk at a better price. Patients need to ask their pharmacist about this. Senokot-S (Purdue Frederick Company, Stamford, CT) combines senna and docusate sodium in 1 pill, and up to 8 Senokot-S tablets per day may be taken. Health care professionals often fail to prescribe these medicines in doses sufficient to offset the side effects of opiates and should be more aggressive to prevent the complications that patients frequently experience. Both senna and docusate sodium are available in liquid form and can be given via gastrostomy or jejunostomy tube.
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