Peritoneal Dialysis Management
Dialysis is the process of removing fluid and waste products from the body, a function usually performed by the kidneys, through artificial means. There are two types of dialysis: hemodialysis and peritoneal dialysis. Peritoneal dialysis accomplishes the removal of waste and excess fluid by using the abdominal lining, called the peritoneal membrane, as a filter.
The purpose of peritoneal dialysis is to replace the function of the kidneys in patients who have failing kidneys due to disease. Because peritoneal dialysis can be done continuously, it more closely imitates the function of the kidneys than hemodialysis does. Peritoneal dialysis is also easy to do when away from home, which makes it an appealing choice for patients who do not wish to be tied down to a dialysis infusion site's location or schedule.
Peritoneal dialysis is a relatively slow process compared to hemodialysis. This is especially useful for patients with cardiovascular disease because rapid changes in blood urea (a waste product), glucose, electrolytes, or fluid volume can exacerbate cardiovascular disease. Peritoneal dialysis is a commonly prescribed method of dialysis for diabetic patients because insulin can be added to the dialysate. It also reduces the risk of retinal hemorrhage since, unlike with hemodialysis, heparin (an anticoagulant) is not used. Peritoneal dialysis is the treatment of choice for children as it does not interfere with growth.
Peritoneal dialysis is contraindicated in patients with hypercatabolism because adequate clearance of uremic toxins cannot be achieved with this method of dialysis. Peritoneal adhesions and scarring are also contraindications. Caution should be used when prescribing peritoneal dialysis for patients with a history of ruptured diverticuli, respiratory disease, recurrent peritonitis (infection of the peritoneum), abdominal malignancies, severe vascular disease, back problems, and those who are obese.
Before peritoneal dialysis begins, patients have a catheter surgically inserted into their peritoneal cavity. The catheter is usually placed 1.2–2 in (3–5 cm) below the umbilicus. When dialysis is ready to begin, a bag of fluid (dialysate) containing sterile water, normal plasma, electrolytes, and glucose is infused into the abdominal cavity. The volume of dialysate used can range from1.5–3 qt (1.5–3 l), and the concentration of electrolytes and glucose is altered according to what the physician prescribes. The dialysate is left in the abdominal cavity for anywhere from one hour to 10 hours, depending on the type of dialysis. The period of time that the dialysate is left in the abdominal cavity is called the dwell time. At the end of the prescribed dwell time, the dialysate is drained out of the abdominal cavity through the catheter. The drained dialysate takes waste products with it. This process of instilling a bag of dialysate, dwell time, and emptying the dialysate is called an exchange. The amount and timing of exchanges performed by patients depends on the type of dialysis, the recommendation of the physician, and the lifestyle of the patient.
Peritoneal dialysis works based on the principles of osmotic pressure and diffusion. Osmotic pressure is the moving of fluid toward the solution with a higher solute concentration. Diffusion is the passing of particles from an area of high concentration to an area of lower concentration. The dialysate infused into the abdominal cavity is prepared with specific concentrations of electrolytes and glucose that will draw the waste products and excess fluid across the peritoneal membrane using diffusion and osmotic pressure. The pores in the peritoneal membrane are large enough to allow the waste to pass through into the abdominal cavity, but small enough that blood cells and other protein molecules are unable to pass through.
There are two types of peritoneal dialysis: continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD). Within APD, there are three different scheduling methods, including continuous cyclic peritoneal dialysis (CCPD), intermittent peritoneal dialysis (IPD), and nightly peritoneal dialysis (NPD).
With CAPD, dialysate is instilled into and drawn out of the abdominal cavity by gravity alone. No machine is needed. The dwell time for CAPD ranges from four to 10 hours. The CAPD patient usually performs four exchanges per day, including an eight-hour overnight dwell. This continuous exchange most closely resembles normal renal function, and it is also convenient because the exchanges can be performed anywhere since no equipment is required.
The automated dialysis methods require a peritoneal cycling machine. Patients using CCPD set their cyclers to do three exchanges at night and one eight-hour daytime dwell, which frees up the patient during the day. NPD performs several exchanges at night over an eight- to 12-hour
Strict sterile technique should be used when preparing to do an exchange to prevent infection. Dialysate should be warmed to 98.6°F (37°C) to provide comfort to the patient; this also is the optimal temperature for clearance of uremic metabolites. The catheter tubing should be flushed so that air does not enter the abdominal cavity.
When not in use, the dialysis catheter can be clamped and tucked under clothing for concealment. If a method of peritoneal dialysis is chosen with dwell times during the day, the patient may have to wear larger, loose-fitting clothes to account for the additional fluid in the abdominal cavity.
The major complication that can be encountered by peritoneal dialysis patients is peritonitis, an infection of the peritoneum. Symptoms of peritonitis include fever, rebound tenderness, nausea, malaise, and cloudy dialysate output. Peritonitis is treated with antibiotics placed in the dialysate or taken orally. To avoid peritonitis, patients must be taught to handle the catheter and other dialysis equipment with sterile technique.
Other complications associated with peritoneal dialysis are problems with the catheter such as obstruction, as well as bowel and bladder perforations caused by the insertion of the catheter. Dialysis-related complications include fluid and electrolyte imbalances, hypotension, pain, hyperglycemia (high blood glucose levels), and respiratory difficulties due to the presence of the dialysate fluid and the pressure it puts on the diaphragm.
When the proper type of peritoneal dialysis is prescribed, and the patient complies with the regimen, peritoneal dialysis can be very successful in maintaining the fluid and electrolyte balance and removing waste when the kidneys are unable to perform these tasks. Peritoneal dialysis allows patients to live full and productive lives by providing flexibility of time and place in dialysis treatment.
Automated peritoneal dialysis (APD)—A type of peritoneal dialysis that requires a cyclic machine to complete exchanges.
Continuous ambulatory peritoneal dialysis (CAPD)—A type of peritoneal dialysis that uses gravity to infuse and empty dialysate instead of a machine.
Dialysate—The solution that is used during peritoneal dialysis.
Dialysis—The process of removing fluid and waste products from the body through artificial means.
Dwell time—Stage of a dialysis exchange when the dialysate is inside the abdominal cavity, which is when the filtration takes place.
Exchange—A complete dialysis cycle, starting with infusing the dialysate and ending with the emptying out of the used dialysate solution.
Hypercatabolism—A state in which the body is metabolizing proteins at an exaggerated rate.
Peritoneal dialysis—A removal system for waste products and excess fluid in patients whose kidneys are failing. This system uses the abdominal lining or peritoneal membrane as a filter.
Peritonitis—An infection of the peritoneum.
Uremic toxins—Waste products carried in the blood stream that are usually excreted by the kidneys.
Health care team roles
Peritoneal dialysis is primarily performed at home by patients and their family members. It is the responsibility of health care providers to educate patients in the proper use of peritoneal dialysis so that the patient complies with the regimen and avoids complications. Patient education must include instruction on aseptic measures to prevent infection, timing and number of exchanges to be performed, appropriate dwell times, use of the cycler if automated dialysis is chosen, obtaining the proper dialysate solutions, and storage of solutions and equipment.
Black, Joyce M., and Esther Matassarin-Jacobs. Medical-Surgical Nursing Clinical Management For Continuity of
National Diabetes Information Clearinghouse. 1 Information Way, Bethesda, MD 20892-3560. <http://www.niddk.nih.gov/health/diabetes/pubs/esrd/esrd.htm>.
Jennifer Lee Losey, R.N.