Peritoneal dialysis (PD) is an alternative dialytic modality for the patient with chronic kidney disease (CKD). The U.S. Renal Data System (US RDS, 2008) reports that only 8% of the prevalent CKD patient population is on PD. Despite its safety and effectiveness, PD has been in decline since the mid-1990s. PD is primarily a home dialysis therapy for CKD, but it can also be a treatment option for the patient with acute kidney injury in the hospital setting. The range of home therapies for the CKD patient includes PD and home hemodialysis. Home therapy allows patients to remain somewhat independent in their own care and to have greater control over their schedules. Of all home therapies, PD is the most commonly used.
What is peritoneal dialysis and how does it work?
PD is a process during which the peritoneal cavity acts as the reservoir for the dialysate and the peritoneum serves as the semipermeable membrane across which excess body fluid and solutes, including uremic toxins, are removed (ultrafiltrate). The peritoneal membrane surface area is approximately equal to the body surface area (1.73 m2). The peritoneum consists of the lining of the inner surface of the abdominal and pelvic walls, including the diaphragm (parietal peritoneum) as well as the covering of the abdominal organs (visceral peritoneum). In males the peritoneum is a closed cavity, but in females the fallopian tubes and ovaries open into the peritoneal cavity.
The peritoneal membrane is in contact with the rich blood supply to the abdominal organs. Dialysate is infused into the peritoneal cavity via a catheter, allowed to dwell for a predetermined amount of time, and then drained (effluent). This process is called an exchange. Dextrose is used in the dialysate to create an osmotic gradient that causes water to be moved into the peritoneal cavity. The excess fluid is removed when the effluent is drained. Electrolytes and uremic toxins are removed by diffusion from an area of higher concentration (bloodstream) to an area of lower concentration (peritoneal cavity). Solute removal is further enhanced by “solute drag,” created when hypertonic dialysate is used, which increases ultrafiltration (UF) and causes additional low molecular weight solutes to be “dragged” along with the ultrafiltrate by convective transport.
What solutions are used for peritoneal dialysis?
The solutions used for PD should be biocompatible and preserve peritoneal membrane structure and function as much as possible. Conventional solutions use glucose as the osmotic agent and lactate as the buffer base. Commercially available solutions approximate the composition of extracellular body water except for potassium because many patients tend to be hyperkalemic. Potassium may be added (2 to 4 mEq/L) if necessary to correct hypokalemia. Oral potassium supplementation may also be prescribed. Dextrose provides the osmotic gradient between the plasma and the dialysate that leads to fluid and solute removal. The more hypertonic the dialysate is (i.e., 2.5% and 4.25% dextrose), the greater the UF. After a 2-L exchange has been dwelling for 4 hours, an average of 200 mL of ultrafiltrate will be obtained with a 1.5% exchange and an average of 600 to 1000 mL will be obtained with a 4.25% exchange. Table 19-1 highlights some common compositions of peritoneal dialysis solutions.
Table 19-1 Typical Composition of Common Peritoneal Dialysis Solutions
What is icodextrin?
Newer PD solutions use different osmotic agents for UF and clearance. Icodextrin (Extraneal) is a newer PD solution that differs from standard dialysis solutions in that it does not contain dextrose. In standard PD dialysate, glucose is the osmotic agent. Icodextrin is a starch-derived osmotic agent made from a mixture of glucose polymers (polyglucose). This solution allows for increased fluid removal from the bloodstream during PD as well as reduced net negative UF and increased small solute clearance. Icodextrin is intended to be used for once daily, long dwell exchanges lasting 8 to 16 hours. The dialysate solution should be used for no more than one exchange in a 24-hour period. Icodextrin is contraindicated for those with glycogen storage diseases or an allergy to cornstarch. The most common adverse effect from the use of icodextrin is a skin rash. Sterile peritonitis, hypertension, cold, headache, flulike symptoms, and abdominal pain are other possible side effects.
Are there different ways to perform peritoneal dialysis?
PD can be done either manually or automatically with a cycler. The manual form of PD is called continuous ambulatory peritoneal dialysis (CAPD). In CAPD, four or more exchanges are performed each day, seven days a week. Each exchange takes approximately 30 minutes. The patient connects to a tubing system, drains the effluent, and infuses new dialysate to dwell for a prescribed amount of time, usually four to six hours. The last exchange of the day dwells overnight and is then drained in the morning. Most patients do “bagless” CAPD; they disconnect from the tubing system at the end of each exchange, leaving a short transfer set or the capped catheter. Most CAPD tubing systems involve a Y configuration that enables the patient to “flush” any contaminants that might have been introduced while connecting to the system. Spiking the bag has been eliminated from most systems thus reducing the potential for contamination by as much as 50%.
What is automated peritoneal dialysis?
Automated peritoneal dialysis (APD) is performed with a cycler, usually at night while the patient sleeps. Cyclers are programmed according to the physician’s prescription to perform the following functions automatically: (1) measure the volume of dialysate to be infused, (2) warm the dialysate to body temperature before infusion, (3) time the frequency of exchanges, (4) count the number of exchanges, and (5) measure UF. Cyclers can be programmed for volumes of 50 to 3000 mL per exchange, have a last bag option to accommodate a unique diurnal (day) dwell (volume, percentage, additives), and have the capability to program one or more exchanges during daytime hours. All machines can be programmed to perform tidal PD. APD enables the patient to mix dextrose concentrations to achieve the desired UF (e.g., 2.5% mixed with 4.25% to achieve 3.3%). Patients must be taught to set up and run the machine by a trained professional, such as a self-care home dialysis training registered nurse with at least 12 months of experience in providing care and an additional 3 months of experience in this modality.
What are the different forms of automated peritoneal dialysis?
Continuous cycling peritoneal dialysis (CCPD). Three to five exchanges are performed nightly with a full diurnal dwell. The diurnal dwell improves the clearance of middle molecules.
Nocturnal intermittent peritoneal dialysis (NIPD). Three to five exchanges are performed nightly, but there is a minimal or no diurnal dwell. NIPD is indicated in patients who are unable to tolerate a diurnal dwell (e.g., those with hyperpermeability of the peritoneum to dextrose, resulting in absorption of diurnal dwell) and in those with problems exacerbated by increased intraabdominal pressure, including hernias, low back pain, cardiopulmonary compromise, etc.
Intermittent peritoneal dialysis (IPD). Several frequent exchanges are performed three or four times a week, and the peritoneum is left “dry” between treatments. IPD is appropriate for patients with residual renal function or for institutionalized patients. Also, it is used in economically underdeveloped countries because of the financial constraints imposed by daily PD.
Tidal peritoneal dialysis (TPD). An initial volume of dialysate is infused, followed by partial drainage of effluent at the end of each exchange (leaving a constant reserve volume); finally a “tidal” volume of fresh dialysate is infused. TPD is intended to enhance clearance by maintaining continuous contact of dialysate with the peritoneum and maintaining the dialysate/plasma gradient. TPD may improve clearance by 20% but increases costs because of the need for additional dialysate.
TPD may also be used for patients who experience discomfort or “drain pain” at the end of the drain cycle because of the position of the tip of the PD catheter. By always having a reserve of fluid, the tip is allowed to float, thus alleviating discomfort in sensitive individuals.
What kinds of catheters are used for peritoneal dialysis?
Catheters for both acute and chronic PD must transport fluid into and out of the peritoneal cavity as rapidly as possible and be biocompatible (maintain normal structure and function of the tissues near the catheter tract). Catheters manufactured for both acute and chronic PD come in sizes to accommodate neonates to adults.
Catheters for acute PD are usually placed at the patient’s bedside and include rigid catheters or soft silicone catheters. The patient should have an empty bladder and the rectum should be free of stool at the time of insertion to minimize the risk of organ perforation. Placement may be by direct insertion with a trocar or guidewire or by use of a peritoneoscope. Dialysis may be initiated immediately after insertion. Risks with the rigid catheter include bowel or organ perforation, dialysate leaks, peritonitis, discomfort, and inadvertent catheter loss. Silicone catheters, used for acute dialysis, are more comfortable and may be used for chronic dialysis if necessary. When an acute PD catheter is used immediately, the patient should be kept supine whenever dialysate is in the peritoneal cavity to minimize the occurrence of leaking of dialysate around the catheter.
Catheters used for chronic PD are usually placed surgically during a laparotomy or laparoscopically. The exit site should be directed in a downward or lateral direction and be located in the right or left midquadrant area, avoiding the belt line, scars, and skinfolds. Catheters are made of silicone or polyurethane with a radiopaque stripe for x-ray visualization. Catheters may be straight or coiled and have one or two cuffs. Coiled catheters are believed to minimize catheter migration out of the pelvis and have fewer outflow problems than straight catheters. The coiled catheter is also thought to improve patient comfort by keeping the tip of the catheter away from direct contact with the peritoneal membrane.
Cuffs are made of Dacron polyester or velour and provide for tissue ingrowth to stabilize the catheter. Cuffs are also intended to prevent migration of bacteria along the subcutaneous tunnel into the peritoneum. When placing double-cuffed catheters, the internal cuff is placed in the rectus muscle and the external cuff is placed in the subcutaneous tissue proximal to the exit site. Implanted catheters (Fig. 19-1) consist of an intraperitoneal segment containing side holes and an open tip for fluid flow; a subcutaneous segment that passes through the peritoneal membrane, muscles, and subcutaneous tissues; and an external segment that extends from the external cuff to the exit site. There are several versions of chronic catheters, including the Tenckhoff, column disk, Toronto Western, Swan neck, Cruz, and Moncrieff-Popovich catheters (Fig. 19-2). All versions include features intended to improve dialysate flow and decrease catheter complications.
Figure 19-1 Placement of double-cuffed Tenckhoff catheter.
(From Ash SR, Carr DJ, Diaz-Buxo JA: Peritoneal access devices. In Nissenson AR, Fine RN, Gentile DE, editors: Clinical dialysis, ed 2, Norwalk, Conn, 1990, Appleton & Lange.)
Figure 19-2 Chronic catheters. A, Straight Tenckhoff catheter. B, Curled Tenckhoff catheter. C, Toronto Western catheter. D, Swan neck (Missouri) catheter.
(From Smith T, editor: Renal nursing, Philadelphia, 1998, Harcourt Brace & Co. Ltd. Bailliere Tindall.)
What is meant by catheter break-in?
Catheter break-in is the period after the chronic catheter is placed, during which there is healing and tissue ingrowth into the cuff(s). The goals are to promote healing and prevent complications such as dialysate leaks, infections, and catheter obstruction. Healing may take up to six weeks and includes scab formation, granulation of tissue at the exit site, and epithelialization of the sinus tract. Full-volume dialysis, especially CAPD, should be avoided for at least 10 to 14 days to allow healing to occur. This healing period may necessitate the placement of a temporary hemodialysis access if the patient is severely uremic or is fluid overloaded and in need of immediate dialysis. Postoperatively the patient should remain supine when possible and avoid activities that increase intraabdominal pressure, such as straining to defecate, excessive coughing, crying, and lifting. Treatment options during the postoperative period include the following:
• Infusion of heparinized saline solution (1 to 10 units heparin/mL saline), 25 to 100 mL every 4 to 8 hours for 1 to 3 days postoperatively. This protocol will not detect catheter malposition or outflow problems.
• Low volume in and out exchanges with heparinized saline or dialysate done several times a day until the effluent is no longer bloody, then done daily for one to two weeks and weekly thereafter until the patient is on PD. A small volume of heparinized solution should remain in the peritoneum to inhibit the formation of fibrin (whitish protein formed in response to bleeding, inflammation, or infection) and to prevent the development of adhesions. There is no systemic anticoagulation from the administration of low-dose intraperitoneal heparin.
• Low-volume dialysis in the patient who needs immediate dialysis but who is unable to undergo hemodialysis. Frequent, low-volume exchanges (500 to 1000 mL) are performed using a cycler with the patient in the supine position. The volume is gradually increased to eliminate the signs and symptoms of uremia.
How is exit site care performed?
The goals in the immediate postoperative period are to stabilize the catheter, promote healing, and prevent infection. The exit site dressing should not be changed for five to seven days postoperatively unless there is excessive drainage under the dressing (blood, exudate, dialysate). The first dressing change should be performed by trained dialysis personnel and then may be taught to the patient. It is recommended that masks be worn during dressing changes to avoid contamination with oral or nasal flora. The skin around the exit site may be pink, similar to a healing scar, or it may have a brownish or purplish discoloration. During dressing changes the exit site should be assessed for signs of infection (erythema, exudate, induration, tenderness), the subcutaneous tunnel should be palpated for tenderness, and the catheter and connections should be inspected for integrity. The exit site should be cleansed with an antibacterial soap and water and covered with a sterile nonocclusive dressing, such as gauze and tape, or an air-permeable adhesive sheet. Cytotoxic agents (such as 1% povidone-iodine, 3% hydrogen peroxide, and 0.5% sodium hypochlorite) may interfere with wound epithelialization during the postoperative period. The catheter should be secured to the patient’s skin with tape or an immobilization device to avoid tension on the catheter and trauma to the exit site.
The goal of chronic exit site care is the prevention of infection. Exit site care is usually performed in the shower and consists of daily cleansing with an antibacterial soap with careful rinsing and drying. An antibacterial solution (e.g., 1% povidone-iodine, 3% hydrogen peroxide, and 0.5% sodium hypochlorite) is then applied in a circular motion to the skin around the exit site. The exit site should not be submerged in bathwater or hot tubs. Many programs allow swimming in chlorinated pools and the ocean. After the healing period (four to six weeks) a dressing may or may not be worn, according to patient or unit preference. It is extremely important to secure the catheter to the skin with tape or an immobilizing device to avoid trauma and infection should the catheter be accidentally tugged.
How is the adequacy of peritoneal dialysis determined?
The clinical condition of the patient should be paramount when evaluating the adequacy of PD. An important element of the evaluation is careful attention to both overt signs of uremia (laboratory values, fluid overload) and covert signs (sleep and concentration disturbances, anorexia, nutritional indices). Because PD is primarily a home therapy, patient compliance with the prescribed regimen must also be assessed in the evaluation of dialysis adequacy.
The efficiency of PD depends on the ability of the peritoneal membrane to ultrafiltrate fluid and solutes. Peritoneal clearance of solutes is determined by diffusion, which is driven by the concentration gradient between dialysate and plasma and by the “solute drag” created by hypertonic dialysate. Solutes and fluid may move from the intravascular compartment to the peritoneal cavity or from the peritoneal cavity to the intravascular compartment. Other substances lost in the effluent include protein (8.8 to 12.9 g/day), amino acids, water-soluble vitamins, trace minerals, and certain hormones.
UF and solute clearance in PD are influenced by (1) permeability of the peritoneal membrane, (2) volume of the exchange, (3) dialysate glucose concentration, (4) dwell time, and (5) molecular size of the solute. Clearance of solutes is expressed as the dialysate/plasma (D/P) ratio at a given point in time during the exchange. Equilibration is achieved when the D/P ratio approaches 1. Small solutes, such as urea (molecular weight = 60 Da), are highly diffusible and approach equilibration at four hours. Creatinine (molecular weight = 113 Da) moves more slowly toward equilibration, never reaching it during the typical four-hour CAPD exchange. Table 19-2 demonstrates solute clearances that can be achieved with different types of peritoneal dialysis.
Table 19-2 Solute Clearances with Various Peritoneal Dialysis Modalities
Peritoneal equilibration testing (PET) is a standardized test of peritoneal membrane permeability used to determine solute transport characteristics, glucose absorption, and net UF. PET assists in prescribing therapy and in making changes based on the current transport characteristics of the peritoneum. PET involves giving the patient an exchange of 2.5% dialysate and obtaining a serum sample at hour 2 and dialysate samples at hours 0, 2, and 4. Samples are analyzed for urea, creatinine, and glucose. Urea and creatinine are also analyzed from the long dwell (12 hours) obtained when the patient arrives for PET.
The D/P ratios are calculated and plotted on the graphs (Fig. 19-3). Decisions are made as to the best dialytic therapy according to Table 19-3, based on the solute transport characteristics of the patient.
Figure 19-3 Plotting graphs for PET.
(Redrawn from Twardowski ZJ, et al: Peritoneal equilibration test, Perit Dial Bull 7:138, 1987.)
Table 19-3 Baseline Peritoneal Equilibration Testing Prognostic Value
Although PET helps to determine the transport characteristics of the peritoneum, a 24-hour collection of urine (residual renal function) and effluent (dialysis clearance) must be obtained at regular intervals to determine whether adequacy targets are being met. These collections are analyzed for urea and creatinine, and the weekly Kt/V and creatinine clearance are determined. The current adequacy targets recommended by the Kidney Disease Outcomes Quality Initiative (KDOQI) of the National Kidney Foundation (NKF) are summarized in Table 19-4.
Table 19-4 KDOQI Peritoneal Dialysis Adequacy Weekly Targets
Kt/V |
Creatinine clearance (1/wk/1.73 m2) |
|
CAPD |
2.0 |
60 |
CCPD |
2.1 |
63 |
NIPD |
2.2 |
66 |
CAPD, Continuous ambulatory peritoneal dialysis; CCPD, continuous cycling peritoneal dialysis; KDOQI, Kidney Disease Outcomes Quality Initiative; NIPD, nocturnal intermittent peritoneal dialysis.
From KDOQI: Clinical practice guidelines for peritoneal dialysis adequacy, Madison, Wis, 1997, Medical Education Institute.
What complications are encountered in peritoneal dialysis?
Table 19-5 summarizes the common complications encountered in PD, including their causes, signs, symptoms, and interventions.
Table 19-5 Complications of Peritoneal Dialysis
Can diabetics be treated with peritoneal dialysis?
PD offers many advantages to the diabetic patient. In PD there is a steady physiologic state without the drastic biochemical or fluid fluctuations seen with hemodialysis in the diabetic patient with cardiovascular instability or autonomic neuropathy. There is no need for a vascular access. Blood sugar is well controlled with intraperitoneal administration of regular insulin because the peritoneal cavity containing insulin provides a steady, gradual, and prolonged appearance of insulin in the peripheral circulation. The total daily intraperitoneal dose of insulin may need to be much higher than the previous subcutaneous dose because of any or all of the following factors: (1) its slow absorption from the peritoneal cavity; (2) the effect of dilution in the dialysate on insulin absorption; (3) extra insulin needed because of the dextrose in dialysate; (4) binding of insulin to the plastic bags and tubing (10%); and (5) hepatic degradation of insulin. Although intraperitoneal insulin requires the daily addition of medication to the dialysis bags, the incidence of peritonitis is no higher than in other PD patients. There are numerous protocols for the intraperitoneal administration of insulin.
Home dialysis therapy: peritoneal dialysis
How are patients selected for peritoneal dialysis as a home dialysis therapy?
Before a person is selected as a home PD patient, there must be a thorough evaluation by the interdisciplinary dialysis team. The following areas need to be assessed:
1. Relative medical contraindications for PD, such as:
• Abdominal adhesions
• Concurrent abdominal disease, such as neoplasms
• History of ruptured diverticulum
• History of recurrent hernias
• Documented inability of peritoneal membrane to ultrafiltrate or diffuse solutes (PET results)
• Opening between the peritoneal and pleural cavities
• Patients weighing more than 70 kg without residual renal function
• Severe liver disease or polycystic kidney disease
• Severe respiratory illness
2. Psychosocial evaluation, including:
• Patient motivation for self-care
• Lifestyle (job, school)
• Educational background
• Health beliefs
• Support system within the family and community
• Patient’s decision-making abilities
• History of compliance with medical treatment
• Distance from a dialysis center
• Characteristics of the home (cleanliness; availability of water, electricity, and telephone; space for storage of supplies; etc.)
• Availability of alternate caregiver (spouse, sibling, parent, friend, etc.)
3. Physical characteristics and limitations of the patient, including:
• Vision
• Strength
• Dexterity
• Fine motor coordination
• Cognitive functioning
PD may be medically indicated in the patient with cardiovascular difficulties.
Home PD is particularly well suited to the pediatric patient because it allows for the “normalization” of both the child’s and the family’s life (normal school attendance, fewer dietary restrictions than hemodialysis, fewer needlesticks, steady state of body fluid and electrolyte status, independence, etc.).
How is a patient trained for home peritoneal dialysis?
If possible, training is delayed for at least two weeks after the catheter is inserted to allow time for healing to occur and for the patient to recover physically and psychologically from surgery. Another family member should train with the patient for support and backup. It is important that the patient be trained by a primary nurse who establishes a trusting relationship with the patient and family and subsequently acts as the liaison between the patient and the dialysis team. Training is performed primarily on an outpatient basis. Medicare will fund 15 outpatient training sessions and up to 18 sessions with written medical justification.
Content and method of presentation must be individualized to the patient’s learning abilities. Content of training includes normal kidney function and the effects that renal failure has on body homeostasis; mechanism of PD; performance of aseptic technique; catheter and exit site care; monitoring of weight and blood pressure (BP); dialysis record keeping with weight, BP, and dialysis treatments performed; CAPD exchange procedure; use of cycler if on APD; decision making regarding dialysate to be used to maintain dry weight and normalize BP; recognition of the signs and symptoms of infections (e.g., exit site, tunnel, peritonitis); importance of adequate PD treatment of peritonitis; medications; dietary counseling by the dietitian; ordering dialysis supplies; and management of complications. There must be ample time for return demonstration of dialysis techniques and attainment of all training objectives before the patient is allowed to perform PD independently at home. At the completion of training, a home visit should be made by the primary nurse. Additional support is provided by having a PD nurse on call to assist the patient with problems encountered during the off hours.
How is quality of care monitored in peritoneal dialysis?
Quality assurance programs are required by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) and by the Centers for Medicare & Medicaid Services (CMS), whose mandates are administered by the regional end-stage renal disease (ESRD) networks (see Chapter 24). The focus of quality assurance should be continuous improvement in the quality of care that patients receive.
The following are examples of quality assurance indicators:
• Incidence of infections, such as peritonitis and exit site or tunnel infections
• Incidence of catheter complications, such as pericatheter leaks, migration, obstruction necessitating catheter replacement, holes or cracks in the catheter, etc.
• Patient morbidity (number of hospital days per year and causes for hospitalization) and mortality
• Attainment of adequacy targets
• Revision of policies and procedures to improve patient care
PD is a viable dialytic modality for both the acute patient and the chronic patient. Acute PD is appropriate in the patient who cannot tolerate hemodialysis. Care must be taken in the selection of patients for chronic home PD to optimize the chances for success. Ongoing evaluation of patient satisfaction and compliance with the treatment, incidence of complications, and adequacy of PD in removing uremic toxins and excess fluid must be undertaken and adjustments made to ensure quality patient care.
What are the drawbacks to peritoneal dialysis?
Recently, concern has grown about the frequency of malnutrition and inadequate dialysis in PD patients. Protein malnutrition is frequent as a result of the loss of amino acids and protein in the dialysate, and because of appetite suppression resulting from inadequate dialysis and the glucose load absorbed from the dialysate. The latter often causes hypertriglyceridemia, and the increased caloric intake results in weight gain, especially in patients who are overweight when they start on PD. The other major concern is adequacy of dialysis. In the past, most CAPD patients used four exchanges of 2 to 2.5 L daily, but it has become clear that many PD patients are getting inadequate dialysis after they lose their residual renal function.
The number of hospital days has declined 17% and 21% for patients on hemodialysis and PD, respectively, although patients on hemodialysis have lower overall hospitalization rates as compared to peritoneal patients (USRDS, 2009). Peritonitis continues to be the major complication of PD, and approximately 18% of the infection-related mortality is the result of peritonitis (Kam-Tao et. al, 2010). Admissions for peritonitis in the PD population have decreased 35% since 1993 (USRDS, 2008) (Fig. 19-4). The International Society for Peritoneal Dialysis (ISPD) has recently updated its recommendations for peritoneal dialysis–related infections and treatment, which can be found on the ISPD website.
Figure 19-4 Peritonitis treatment decision tree.
(From Keane WF et al: Peritoneal dialysis-related peritonitis treatment recommendation: 1996 update, Perit Dial Int 16(6):557–573, 1996.)
The Clinical Practice Guidelines for Peritoneal Dialysis Adequacy, developed by the NKF KDOQI, state that adequate dialysis with CAPD requires a Kt/V of at least 1.7 per week and a creatinine clearance of at least 60 L/1.73 m2per week (see Appendix A for additional information on KDOQI). Corresponding figures for CCPD are a Kt/V of 2.1 and a weekly creatinine clearance of 63 L/1.73 m2. For patients who are malnourished, even more dialysis is recommended. As a result, more CAPD patients are now using five exchanges daily, often with larger volumes of up to 3 L, and supplementing this with cycler dialysis overnight. This may increase the patient time required for carrying out the procedure, as well as increase discomfort.
What are the implications of these findings?
One implication of these findings is that the use of PD in the U.S. may have peaked. CAPD and cycler dialysis are good initial treatments for many patients because they allow them to experience the advantages of home dialysis after only a few days of training. However, as their residual renal function declines, many patients will become inadequately dialyzed on PD. They will then need to change to hemodialysis and unfortunately, at present, home hemodialysis is not likely to be available to many of them.
After peaking in 1995, the PD population continues to decline (US RDS, 2007). A significant proportion of PD patients have always transferred to hemodialysis each year. There are many reasons for this, including inadequate dialysis or inadequate UF after residual renal function has been lost, repeated episodes of peritonitis, and inability to do the dialysis. Some patients who are put on hemodialysis while a catheter infection or peritonitis is treated may elect to stay on this treatment permanently.
Home dialysis therapy: hemodialysis
Home hemodialysis is an excellent but underused alternative to dialysis in a center for many patients with CKD. Of the 287,494 patients in the U.S. with CKD receiving dialysis, only 2999 are on home hemodialysis (US RDS, 2007). This section briefly recounts the history of home dialysis in the U.S., describes the use of home hemodialysis today, and discusses its advantages in comparison with PD.
What is the history of home hemodialysis?
Dialysis for the treatment of patients with CKD became possible with the development of the Teflon arteriovenous shunt by Belding Scribner and co-workers at the University of Washington in 1960. For the first time it was possible to get repeated access to the bloodstream for long-term hemodialysis. Clyde Shields, the first patient so treated, lived for 11 years on home hemodialysis. He died from a myocardial infarction.
In 1963 home hemodialysis programs were started in Boston, London, and Seattle, the prime reason for this being financial. At that time there was no funding for long-term dialysis from insurance or government sources other than research funds, so this expensive treatment was paid for by patients themselves or through public donations. It soon became obvious that suitably trained and supported patients could safely do hemodialysis themselves at home for a fraction of the cost of staff-assisted dialysis in a hospital or dialysis unit. Furthermore, these patients were better rehabilitated and had a better quality of life than those treated as outpatients in a dialysis center. For the next 10 years, until the introduction of the Medicare ESRD program in 1973, funds for dialysis in the U.S. remained in very short supply. As a consequence, in 1973 some 42% of the 10,000 or so dialysis patients in the U.S. were on home dialysis, almost all of them on home hemodialysis for 6 to 8 hours, 3 times weekly.
IPD for the treatment of patients with CKD also was developed in the 1960s and early 1970s. This was usually done at home, overnight for 12 hours, 3 nights weekly, using sterile dialysate from plastic bags or bottles or prepared by a machine. However, this was a time-consuming and inconvenient treatment and, because survival was not as good as with hemodialysis, it did not become widely used.
What was the effect of the medicare end-stage renal disease program on home dialysis?
The introduction of the Medicare ESRD program in 1973 provided almost universal entitlement to dialysis and transplantation for CKD patients, and as a result the picture changed radically. Funding was readily available for outpatient hemodialysis, resulting in rapid proliferation of dialysis units across the U.S. Many of these were for-profit units that were often reluctant to present home hemodialysis as a treatment option, and most were directed by nephrologists who lacked personal experience with a home hemodialysis program. At the same time, the patient population treated changed rapidly to include many more diabetics, minorities, and elderly patients. As a result, the use of home hemodialysis declined rapidly. By 1995 less than 1% of all dialysis patients in the U.S. were treated by home hemodialysis, although a few programs still persist in providing this. In contrast, in 1995 in Australia, 14% of patients were on home hemodialysis.
The next innovation in home dialysis occurred in the late 1970s with the development of CAPD by Moncrieff and Popovich. This simple technique, coming at a time when access to home hemodialysis training programs was declining rapidly, gave more patients the opportunity to experience the benefits of self-care dialysis at home. Following the success of CAPD, other varieties of PD were developed, and two of these now account for about 15% of PD patients in the United States. CCPD uses a cycler for treatment overnight with one or more exchanges during the day, and NIPD uses a cycler for nightly overnight PD. In the U.S. in 2007, about 27,000 patients (9.3% of all dialysis patients) used some form of PD, which remains the principal mode of home dialysis.
Recently, interest in home hemodialysis has revived. New dialysis machines are being developed to allow patients to dialyze themselves at home without the need for an assistant. At the same time, there have been reports from Toronto and elsewhere of very impressive results with daily home hemodialysis.
What is daily nocturnal hemodialysis?
Daily nocturnal hemodialysis (DNHD) is an alternate home dialysis therapy in which the patient dialyzes at home, at night, while sleeping. The patient on DNHD generally dialyzes for 7 to 10 hours, 6 or 7 times a week. DNHD allows patients to dialyze for longer periods and with greater frequency. Because of this, the blood flows are usually reduced to about 200 mL/min and dialysate flows are reduced to 300 mL/min. Some patients are monitored via an Internet connection by trained staff at a remote location. This live monitoring allows the dialysis staff to be alerted via the Internet when a machine alarm occurs. If the patient does not respond to the alarm within the established protocol time frame, the staff monitoring the patient will call the patient’s home. If no response is received from the home, the staff will call the emergency medical service. A benefit of monitoring by trained dialysis staff is that the patient and caregiver have a greater sense of comfort and confidence in performing the nocturnal dialysis treatment. Patients dialyzing daily reportedly have an increased sense of well-being, are hospitalized less, and take fewer medications. Of all treatment options, nightly nocturnal dialysis is the best at removing larger molecular weight particles. This is related to the long amount of time that it takes these larger molecules to move from the intracellular space into the plasma (Curtis, 2004). Because there are fewer hours between dialysis treatments, the removal of fluid and waste products more closely resembles normal kidney function.
What is short daily dialysis?
Short daily dialysis is performed over 2 hours in a highly efficient manner, 6 or 7 times a week. This method of treatment resembles in-center hemodialysis in that it is intense and rapid. Patients on this modality report taking fewer medications and feeling better than in-center patients. Short daily dialysis allows patients to have fewer dietary and fluid restrictions, and helps to reduce the number of medications they must take.
Why is frequent dialysis desirable?
Changes in the fluid and biochemical state of the body affect total body function by the extent of such changes and by the rate of change. A large accumulation of wastes or fluid makes the patient ill. However, rapid reduction of the accumulation can also make the patient ill because of the shifts between intracellular and extracellular compartments. Frequent hemodialysis reduces the interval for accumulation of metabolic wastes and fluid. Total accumulation is less, and rate of reduction during dialysis is less.
Why not dialyze every day?
Dialysis is not done every day because equipment and supplies are expensive. As well, the dialysis procedure takes time, which the patient would prefer to spend elsewhere. The duration and frequency of most dialysis prescriptions are a compromise between what is best for the patient’s health and the practical limitations of money and time.
What is intermittent nocturnal dialysis?
Intermittent nocturnal dialysis is another option for the CKD patient. Nocturnal in-center dialysis allows the patient to dialyze at an in-center facility 3 nights a week. The patient runs on lower blood and dialysate flow rates for approximately eight hours each treatment. Fewer hypotensive episodes and other dialytic complications are seen, as the patient is dialyzed more gently. This is becoming a popular modality for some patients because they can sleep at night and carry on normal daytime activities. Better clearances are observed, and these patients report a better sense of well-being because of the less intensive treatment.
How does home hemodialysis compare with in-center hemodialysis?
Home hemodialysis does not differ essentially from outpatient hemodialysis in a facility, except that it is done by the patient, aided by a family member or other helper. There are fewer than 2000 home hemodialysis patients in the U.S.; nevertheless, this is an important treatment because of its advantages for patients. Also, with the promise of new technology and growing concern about the long-term adequacy of PD, home hemodialysis could be poised for a comeback in the not-too-distant future. Another option for home hemodialysis is the NxStage system, which is a compact and portable unit consisting of a control unit (cycler), blood filter and tubing set (cartridge), and dialysate. Patients on the NxStage system typically dialyze 6 days a week for 2½ to 3½ hours. The cycler is easy to set up, and its compact size provides the patient the opportunity to travel with this modality.
What is the patient selection process for home hemodialysis?
Suitably trained and supported patients of all ages, including children and the elderly, can do hemodialysis at home. Contraindications include serious cardiovascular or other problems during dialysis; lack of good blood access; documented noncompliance; lack of an assistant; lack of a suitable home; inability to learn; excessive anxiety on the part of the patient or family; and lack of patient motivation and willingness to undertake treatment at home. All other patients should be regarded as potential candidates for self-care and should be given information on the advantages of home dialysis, both home hemodialysis and PD, when they are selecting a modality of treatment. A multidisciplinary team, working with the patient and family and the patient’s nephrologist, should assess the patient’s suitability for home hemodialysis, looking at medical, psychosocial, and vocational factors that might affect choice of treatment modality.
Inspection of the home itself is important. There must be suitable plumbing, water and electricity, and space to store the equipment and supplies. Many homes and apartments require only minor modifications to allow for home hemodialysis.
How would you train a home hemodialysis patient?
Home hemodialysis training is best done in a separate area using specialized staff. Because of its specialized nature, consideration should be given to establishing regional training units. Training should begin as soon as possible once a patient has made the decision to be treated at home and is well enough to absorb information. The most difficult task for most patients is learning needle insertion, but this is something that patients do best for themselves. From the beginning they must be reassured that home hemodialysis is a relatively simple and safe procedure and that, when any problems occur at home, support and advice are always available from the training staff by telephone. In addition to the technique of dialysis, the patient must learn about diet, the disease and its complications, and the medical regimen. He or she should meet with a social worker, a financial counselor, a nutritionist, an exercise coach, and, when appropriate, a vocational counselor.
Training usually takes between 3 and 8 weeks after the patient becomes proficient with fistula puncture, and progress should be assessed at regular intervals. The training schedule should be arranged to allow the patient maximum opportunity to continue to work or to have access to vocational and other rehabilitation services as required.
What are the qualifications of home hemodialysis training staff?
Selection of home hemodialysis training staff is most important. Staff should be experienced in dialysis, have good teaching skills, be committed to encouraging independence and self-care, and be willing to allow patients to learn by making mistakes. Written materials, videotapes, films, posters, models, and other educational aids can facilitate training. The Centers for Medicare and Medicaid Services Conditions for Coverage require the registered nurse responsible for home dialysis training to have at least 12 months of clinical experience, plus 3 months experience in the specific modality for which she will be training patients (hemodialysis and/or peritoneal dialysis).
What patient support services are required?
Provision of support services for home hemodialysis patients is very important. These services should include follow-up visits to the physician’s office at least once a month; monthly routine laboratory testing; review of dialysis records; provision of supplies; equipment maintenance and repair; 24-hour availability of on-call advice from a training nurse; regular follow-up visits to the home by a training nurse; and access to social, nutritional, and other services as required. Patients can take their own blood samples for laboratory tests and mail these to the laboratory. The results of these are shared with the nephrologist, the patient, and the home dialysis training program.
Backup dialysis in a facility must be available for when a patient develops medical, technical, or social problems that make dialysis at home difficult. Patients are able to take vacations, either by arranging to dialyze at a center elsewhere or by using portable equipment. Backup dialysis should also be available to provide the opportunity for family members or other helpers to take vacations.
What are the advantages of home hemodialysis?
Although home dialysis was first introduced for financial reasons, its other advantages for patients soon became obvious. These include increased patient independence, a feeling of accomplishment, the opportunity to schedule dialysis into the patient’s daily life, better quality of life, greater opportunity for rehabilitation, and a reduced risk of exposure to hepatitis and other infections. In contrast, patients treated in a dialysis unit have a fixed schedule and very easily become dependent on nursing and technical staff. Interestingly, very similar advantages have been reported with other treatment technologies that have been moved into the home. As Scribner pointed out many years ago, with any chronic disease, the more patients understand about the illness and the more responsibility and control they take for their own care, the greater the opportunity for adjustment and rehabilitation. A major aim in treating CKD patients should be to maximize quality of life and encourage rehabilitation to the greatest extent possible. Studies have shown that the quality of life of home hemodialysis patients is better than that of CAPD patients and, in turn, that the quality of life of CAPD patients is better than that of patients dialyzing at a center.
Recently revived interest in more frequent hemodialysis also has implications for home hemodialysis, because it is much easier for patients to treat themselves 6 times per week at home than to have to travel to a center with such frequency. Reports from Canada, Italy, and elsewhere have shown that with such a regimen, much more dialysis can be provided. This results in remarkable improvements in blood chemistry, patient well-being, quality of life, and rehabilitation. As a result, knowledgeable patients are likely to demand home dialysis in the future.
In summary, CAPD and CCPD are relatively short-term but very effective initial treatments for many CKD patients. When treatment becomes inadequate, these patients usually transfer to outpatient hemodialysis because they do not have access to home hemodialysis. Fortunately, attention is again being paid to improving home hemodialysis. With the advent of safe, effective, and easily used equipment, patients will have the opportunity for better and more frequent dialysis and improved quality of life. Those patients, physicians, and nurses with experience of home hemodialysis continue to believe that this modality provides, by far, the greatest benefits for patients who can undertake it. Consequently, now is the time to pursue home hemodialysis again as a readily available treatment option for all CKD patients.