Defecation • Defecation (bowel elimination) is the act of expelling feces (stool) from the body. To do so, all structures of the gastrointestinal tract, especially the components of the large intestine (also referred to as the or ), must function in a coordinated manner (Fig. 31-1). In the large intestine, a remarkable volume of water is removed from the remnants of digestion, causing the bowel's contents to become a consolidated mass of residue before being eliminated.
Peristalsis means the rhythmic contractions of intestinal smooth muscle that facilitate defecation. Peristalsis moves fiber, water, and nutritional wastes along the ascending, transverse, descending, and sigmoid colon toward the rectum. Peristalsis becomes even more active during eating; this increased peristaltic activity is termed the gastrocolic reflex.
The gastrocolic reflex usually precedes defecation. Its accelerated wavelike movements, sometimes perceived as slight abdominal cramping, propel stool forward, packing it within the rectum. As the rectum distends, the person feels the urge to defecate. Stool is eventually released when the anal sphincters (ring-shaped bands of muscles) relax. Performing the Valsalva maneuver (closing the glottis and contracting the pelvic and abdominal muscles to increase abdominal pressure) facilitates this process. Several dietary, physical, social, and emotional factors can influence the bowel's mechanical function (Table 31-1).
Assessment of Bowel Elimination • Elimination Patterns • Because various elimination patterns can be normal, it is essential to determine the client's usual patterns, including frequency of elimination, effort required to expel stool, and what elimination aids, if any, he or she uses.
Assessment of Bowel Elimination • Stool Characteristics • Information that is particularly diagnostic includes stool color, odor, consistency, shape, and unusual components (Table 31-2).
Common Alterations in Bowel Elimination • Constipation • Constipation is an elimination problem characterized by dry, hard stool that is difficult to pass. Various accompanying signs and symptoms include the following: • Complaints of abdominal fullness or bloating • Abdominal distention • Complaints of rectal fullness or pressure • Pain on defecation • Decreased frequency of bowel movements • Inability to pass stool • Changes in stool characteristics such as oozing liquid stool or hard small stool
The incidence of constipation tends to be high among those whose dietary habits lack adequate fiber (such as not eating sufficient raw fruits and vegetables, whole grains, seeds, and nuts). Dietary fiber, which becomes undigested cellulose, is important because it attracts water within the bowel, resulting in bulkier stool that is more quickly and easily eliminated.
Constipation is classified into one of four distinct types (primary, secondary, iatrogenic, and pseudoconstipation), according to the underlying cause.
Primary Constipation • Primary or simple constipation is well within the treatment domain of nurses. It results from lifestyle factors such as inactivity, inadequate intake of fiber, insufficient fluid intake, or ignoring the urge to defecate.
Secondary Constipation • Secondary constipation is a consequence of a pathologic disorder such as a partial bowel obstruction. It usually resolves when the primary cause is treated.
Iatrogenic Constipation • Iatrogenic constipation occurs as a consequence of other medical treatment. For example, prolonged use of narcotic analgesia tends to cause constipation. These and other drugs slow peristalsis, delaying transit time. The longer the stool remains in the colon, the drier it becomes, making it more difficult to pass.
Pseudoconstipation • Pseudoconstipation, also referred to as perceived constipation, is a term used when clients believe themselves to be constipated even though they are not.
Fecal Impaction • Fecal impaction occurs when a large, hardened mass of stool interferes with defecation, making it impossible for the client to pass feces voluntarily. Fecal impactions result from unrelieved constipation, retained barium from an intestinal x-ray, dehydration, and weakness of abdominal muscles. • Some clients with an impaction pass liquid stool, which they may misinterpret as diarrhea.
Flatulence • Flatulence or flatus (excessive accumulation of intestinal gas) results from swallowing air while eating or sluggish peristalsis. Another cause is the gas that forms as a byproduct of bacterial fermentation in the bowel. Vegetables such as cabbage, cucumbers, and onions are commonly known for producing gas. Beans are other gas formers.
Diarrhea • Diarrhea is the urgent passage of watery stool and commonly is accompanied by abdominal cramping. Simple diarrhea usually begins suddenly and lasts for a short period. Other associated signs and symptoms include nausea and vomiting and blood or mucus in the stools.
Usually diarrhea is a means of eliminating an irritating substance such as tainted food or intestinal pathogens. Diarrhea may also result from emotional stress, dietary indiscretions, laxative abuse, or bowel disorders.
Fecal Incontinence • Fecal incontinence is the inability to control the elimination of stool.
Measures to Promote Bowel Elimination • Nurses commonly use two interventions—inserting suppositories and administering enemas—to promote elimination when it does not occur naturally or when the bowel must be cleansed for other purposes, such as preparation for surgery and endoscopic or x-ray examinations.
Inserting a Rectal Suppository • Medications released from the suppository can have local or systemic effects. Depending on the drug, local effects may include softening and lubricating dry stool, irritating the wall of the rectum and anal canal to stimulate smooth muscle contraction, and liberating carbon dioxide, thus increasing rectal distention and the urge to defecate.
Administering an Enema • An enema introduces a solution into the rectum Nurses give enemas to : • Cleanse the lower bowel (most common reason). • Soften feces. • Expel flatus. • Soothe irritated mucous membranes. • Outline the colon during diagnostic x-rays. • Treat worm and parasite infestations.
Cleansing Enemas • Cleansing enemas use different types of solution to remove feces from the rectum (Table 31-3).
Retention Enemas • A retention enema uses a solution held within the large intestine for a specified period, usually at least 30 minutes. Some retention enemas are not expelled at all. One type of retention enema is called an because the fluid instilled is mineral, cottonseed, or olive oil. Oils lubricate and soften the stool, so it can be expelled more easily.
Ostomy Care • A client with an ostomy (surgically created opening to the bowel or other structure; requires additional care for promoting bowel elimination. Two examples of intestinal ostomies are an ileostomy (surgically created opening to the ileum) and a colostomy (surgically created opening to a portion of the colon; Fig. 31-4). Materials enter and exit through a stoma (entrance to the opening).
Most persons with an ostomy, also called ostomates, wear an appliance (bag or collection device over the stoma) to collect stool. Depending on the type and location of the ostomy, client care may involve providing peristomal care, applying an appliance, draining a continent ileostomy, and, for clients with a colostomy, administering irrigations through the stoma.
Providing Peristomal Care • Preventing skin breakdown is a major challenge in ostomy care. Enzymes in stool can quickly cause excoriation (chemical injury of skin). Washing the stoma and surrounding skin with mild soap and water and patting it dry can preserve skin integrity.
Nursing Implications • Constipation • Risk for Constipation • Perceived Constipation • Diarrhea • Bowel Incontinence • Toileting Self-Care Deficit • Situational Low Self-Esteem