CONTINENT URINARY DIVERSIONS
The most common continent urinary diversion is the Indiana pouch, created for patients whose bladder is removed or can no longer function (neurogenic bladder). The Indiana pouch uses a segment of the ileum and cecum to form the reservoir for urine (see Fig. 45-10A). The ureters are tunneled through the muscu-lar bands of the intestinal pouch and anastomosed. The reservoir is made continent by narrowing the efferent portion of the ileum and sewing the terminal ileum to the subcutaneous tissue, form-ing a continent stoma flush with the skin. The pouch is sewn to the anterior abdominal wall around a cecostomy tube. Urine can collect in the pouch until a catheter is inserted and the urine is drained.
The pouch must be drained at regular intervals by a catheter to prevent absorption of metabolic waste products from the urine, reflux of urine to the ureters, and UTI. Postoperative nurs-ing care of the patient with a continent ileal urinary pouch is sim-ilar to nursing care of the patient with an ileal conduit. However, these patients usually have additional drainage tubes (cecostomy catheter from the pouch, stoma catheter exiting from the stoma, ureteral stents, Penrose drain, as well as a urethral catheter), as depicted in Figure 45-11. All drainage tubes must be carefully monitored for patency and amount and type of drainage. The ce-costomy tube is irrigated two or three times daily to remove mucus from the pouch and prevent blockage.
Other variations of continent urinary reservoirs include the Kock pouch (U-shaped pouch constructed of ileum, with a nipple-like one-way valve; see Fig. 45-10B and C ) and the Charleston pouch (uses the ileum and ascending colon as the pouch, with the appendix and colon junction serving as the one-way valve mech-anism). With both of these methods, the pouch must be drained at regular intervals by a catheter.
Ureterosigmoidostomy, another form of continent urinary di-version, is an implantation of the ureters into the sigmoid colon (see Fig. 45-10D). It is usually performed in patients who have had extensive pelvic irradiation, previous small bowel resection, or coexisting small bowel disease.
After surgery, voiding occurs from the rectum (for life), and an adjustment in lifestyle will be necessary because of urinary fre-quency (as often as every 2 hours). Drainage has a consistency equivalent to watery diarrhea, and the patient has some degree of nocturia. Patients usually need to plan activities around the fre-quent need to urinate, which in turn may affect the patient’s so-cial life. Patients have the advantage, however, of urinary control without having to wear an external appliance.
In addition to the usual preoperative regimen, the patient may be placed on a liquid diet for several days preoperatively to reduce residue in the colon. Antibiotic agents (neomycin, kanamycin) are administered to disinfect the bowel. Ureterosigmoidostomy requires a competent anal sphincter, adequate renal function, and active renal peristalsis. The degree of anal sphincter control may be determined by assessing the patient’s ability to retain enemas.
The postoperative regimen initially includes placing a catheter in the rectum to drain the urine and prevent reflux of urine into the ureters and kidneys. The tube is taped to the buttocks, and special skin care is given around the anus to prevent excoriation. Irrigations of the rectal tube may be prescribed, but force is never used because of the danger of introducing bacteria into the newly implanted ureters.
In ureterosigmoidostomy, larger areas of the bowel mucosa are exposed to urine and electrolyte reabsorption. As a result, elec-trolyte imbalance and acidosis may occur. Potassium and mag-nesium in the urine may cause diarrhea. Fluid and electrolyte balance is maintained in the immediate postoperative period by closely monitoring the serum electrolyte levels and administering appropriate intravenous infusions. Acidosis may be prevented by placing the patient on a low-chloride diet supplemented with sodium potassium citrate.
The patient should be instructed never to wait longer than 2 to 3 hours before emptying urine from the intestine. This keeps rectal pressure low and minimizes the absorption of urinary con-stituents from the colon. It is essential to teach the patient about the symptoms of UTI: fever, flank pain, and frequency.
After the rectal catheter is removed, the patient learns to control the anal sphincter through special sphincter exercises. At first, uri-nation is frequent. With reassurance and encouragement and the passage of time, the patient gains greater control and learns to dif-ferentiate between the need to void and the need to defecate.
Specific dietary instructions include avoidance of gas-forming foods (flatus can cause stress incontinence and offensive odors). Other ways to avoid gas are to avoid chewing gum, smoking, and any other activity that involves swallowing air. Salt intake may be restricted to prevent hyperchloremic acidosis. Potassium intake is increased through foods and medication because potassium may be lost in acidosis.
Pyelonephritis (upper UTI) due to reflux of bacteria from the colon is fairly common. Long-term antibiotic therapy may be prescribed to prevent infection. A late complication is adenocar-cinoma of the sigmoid colon, possibly from cellular changes due to exposure of the colonic mucosa to urine.
Urinary carcinogens promote late malignant transformation of the colon after a ureterosigmoidostomy. Therefore, diligent patient teaching regarding the need for life-long medical follow-up is essential (Guy et al, 2001; Huang & McPherson, 2000).