Peritoneal Dialysis – Indications, Contraindications

Peritoneal Dialysis – Indications, Contraindications

Peritoneal dialysis is a way to remove waste products from your blood when your kidneys can’t adequately do the job any longer. This procedure filters the blood in a different way than does the more common blood-filtering procedure called hemodialysis.

During peritoneal dialysis, a cleansing fluid flows through a tube (catheter) into part of your abdomen. The lining of your abdomen (peritoneum) acts as a filter and removes waste products from your blood. After a set period of time, the fluid with the filtered waste products flows out of your abdomen and is discarded.

Peritoneal dialysis (PD) accounts for a small percentage (less than 7%) of the prevalent dialysis population in the United States compared to Canada (more than 50%). Better early survival on PD compared to hemodialysis (HD) has also been reported by several observational studies, including national registries from different parts of the world.  The cost of HD per patient per year remains significantly higher than for PD ($87,945 for HD versus $71,630 for PD in 2011). Patients have a choice when initiating dialysis to use HD or PD. Choice should be patient-centered and made after careful considerations of all factors that may alter outcomes. A large US cohort study of over 6000 matched pairs of dialysis patients beginning dialysis in 2003, showed that 1-year patient survival was significantly higher for PD when compared to HD (85.8% versus 80.7% (p < 0.01)). However, 80% of end-stage renal disease (ESRD) patients in the United States start hemodialysis (HD) with a tunneled hemodialysis catheter (TDC), and 60% continue to dialyze using an HDC for 91 days after dialysis initiation.  This initial catheter (modality) choice has had a major impact on the mortality of ESRD patients. Patient mortality in the first 90 days of HD as a result of catheter-associated bacteremia and sepsis from TDC use is higher when compared to patients initiating dialysis on PD.  A significant percentage of deaths in HD occurred within the first the 90 days on dialysis.

Alternative Names

Artificial kidneys – peritoneal dialysis; Renal replacement therapy – peritoneal dialysis; End-stage renal disease – peritoneal dialysis; Kidney failure – peritoneal dialysis; Renal failure – peritoneal dialysis; Chronic kidney disease – peritoneal dialysis

Indications

Medicine is moving to quality-driven models; every clinician needs to weigh the risk of early use TDC to start HD compared to the benefit of starting peritoneal dialysis using a peritoneal dialysis catheter (PDC).

Contraindications

PD is contraindicated in patients with:

  • Uncorrected abdominal wall hernia
  • Pleuroperitoneal shunt
  • Abdominal adhesions

Equipment

PD Catheter Placement

Utilizing several different techniques, the success rate of PDC placement reported in the literature varied from 80% to 100%. Are there any differences in catheter outcomes based on the technique used to place PDC? The answer to this question is difficult, as there are wide variations in inpatient and operator factors that cannot be controlled across populations. Overall, open surgical placement was associated with the highest number of complications, including poor function, leaks, and catheter migrations; there was a trend toward higher catheter survival after laparoscopic insertion. (See Table 1) Randomized control trial comparing fluoroscopic versus laparoscopic PDC placement included 113 patients showed a complication-free catheter survival that was significantly higher at 42.5% (95% CI 29.3 – 55.0) in the percutaneous group compared with 18.1% (95% CI 8.9 – 29.8) in the laparoscopic group (p = 0.03). One-year patient and catheter survival in the 2 groups was no different.

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Both surgical and percutaneous procedures have low complication rates when performed by experienced operators. Obese patients who have had previous abdominal surgery or with previous episodes of PD-related peritonitis can benefit from the advanced laparoscopic placement of the catheter. Surgical PD catheter implantation typically takes longer, including referral and consultation delays to a surgeon, operating room scheduling, and preoperative medical and anesthesia clearance. In contrast, nephrology-guided PD catheter placement can be performed relatively quickly, usually under procedure sedation analgesia in an outpatient setting. This is particularly useful in an acute emergent setting with a relatively short window of notice required before dialysis initiation.

Preparation

Peritoneal Dialysis Benefit

Starting dialysis with a PDC is preferable to an HDC in terms of patient morbidity, mortality, and cost. It has also been shown in large observational retrospective studies that there is a survival advantage for PD over HD in the first 1 to 3 years of dialysis. The 2013 Annual Data Report from the United States Renal Data System also shows a significantly improved adjusted probability of 5-year survival with PD compared to HD. This early survival, for the most part, may be explained by selection bias because healthier patients may be more likely to choose PD as their modality. Patients with comorbid conditions tend to start HD after an acute illness and have high early mortality that is wrongly attributed to their HD modality.

Two recent studies from Canada tried to address the selection bias in PD outcomes. Quinn et al. studied 6573 patients who had at least 4 months of follow-up with nephrologists and had an elective outpatient start of dialysis. There was no difference in 2-year mortality between PD and HD, and in patients without diabetes, PD was associated with a survival benefit that extended beyond 2 years of follow-up. Similarly, Perl et al., comparing incident ESRD patients from a cohort of 40,000 patients in Canada, noted an 80% increased risk of death in patients starting HD using a central venous catheter (CVC) but no difference in mortality between PD and HD using AVF or arteriovenous graft (AVG) for dialysis.

Technique

Peritoneal dialysis is one of the modalities utilized for dialysis. There are several advantages of PD versus HD. Patients using PD will not need to leave home every other day to get dialysis, rather they perform their treatments at home using a very simple principle for removing toxins from their body.

Patients selected for PD will undergo PD catheter placement using one of the several techniques described above. Once the catheter has healed, they undergo technique training at a dialysis unit for 2 to 3 weeks, learning the proper aseptic technique to use the catheter for dialysis. The basis of toxin removal in PD is diffusion of uremic toxins out of the blood through the peritoneal membrane into the peritoneal fluid, that is then discarded after a specified amount of time in the peritoneal cavity.

The process of PD can be automated using a simple machine attached to peritoneal dialysis fluid bags. The machine is programmed to infuse the predetermined volume of fluid into the peritoneal cavity, dwell fluid in the peritoneal cavity for a specified time, and automatically drain the fluid. Cycles are repeated several times based on patients needs and peritoneal membrane diffusion characteristics. Manual exchanges require the installation and draining of fluid to be performed by the patient, repeating the process several times during the day to achieve the required clearance of toxins.

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What you can expect

During peritoneal dialysis:

  • The dialysate flows into your abdomen and stays there for a prescribed period of time (dwell time) — usually four to six hours
  • Dextrose in the dialysate helps filter waste, chemicals and extra fluid in your blood from tiny blood vessels in the lining of your abdominal cavity
  • When the dwell time is over, the solution — along with waste products drawn from your blood — drains into a sterile collection bag

The process of filling and then draining your abdomen is called an exchange. Different methods of peritoneal dialysis have different schedules of exchange. The two main schedules are:

  • Continuous ambulatory peritoneal dialysis (CAPD)
  • Continuous cycling peritoneal dialysis (CCPD)

Continuous ambulatory peritoneal dialysis (CAPD)

You fill your abdomen with dialysate, let it remain there for a prescribed dwell time, then drain the fluid. Gravity moves the fluid through the catheter and into and out of your abdomen.

With CAPD:

  • You may need three to five exchanges during the day and one with a longer dwell time while you sleep
  • You can do the exchanges at home, work or any clean place
  • You’re free to go about your normal activities while the dialysate dwells in your abdomen

Continuous cycling peritoneal dialysis (CCPD)

Also known as automated peritoneal dialysis (APD), this method uses a machine (automated cycler) that performs multiple exchanges at night while you sleep. The cycler automatically fills your abdomen with dialysate, allows it to dwell there and then drains it to a sterile bag that you empty in the morning.

With CCPD:

  • You must remain attached to the machine for about 10 to 12 hours at night.
  • You aren’t connected to the machine during the day. But in the morning you begin one exchange with a dwell time that lasts the entire day.
  • You might have a lower risk of peritonitis because you connect and disconnect to the dialysis equipment less frequently than you do with CAPD.

To determine the method of exchange that’s best for you, your doctor will consider your medical condition, lifestyle and personal preferences. Your doctor might suggest certain modifications to individualize your program.

Results

Many factors affect how well peritoneal dialysis works in removing wastes and extra fluid from your blood. These factors include:

  • Your size
  • How quickly your peritoneum filters waste
  • How much dialysis solution you use
  • The number of daily exchanges
  • Length of dwell times
  • The concentration of sugar in the dialysis solution

To check if your dialysis is removing enough waste products, your doctor is likely to recommend tests, such as:

  • Peritoneal equilibration test (PET). This test compares samples of your blood and your dialysis solution during an exchange. The results indicate whether waste toxins pass quickly or slowly from your blood into the dialysate. That information helps determine whether your dialysis would be improved if the solution stayed in your abdomen for a shorter or longer time.
  • Clearance test. A blood sample and a sample of used dialysis solution are analyzed to determine how much of a certain waste product (urea) is being removed from your blood during dialysis. If you still produce urine, your doctor may also take a urine sample to measure its urea concentration.
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If the test results show that your dialysis schedule is not removing enough wastes, your doctor might change your dialysis routine to:

  • Increase the number of exchanges
  • Increase the amount of dialysate you use for each exchange
  • Use a dialysate with a higher concentration of dextrose

You can improve your dialysis results and your overall health by eating the right foods, including foods low in sodium and phosphorus. A dietitian can help you develop an individualized meal plan. Your diet will be based on your weight, your personal preferences, and your remaining kidney function and other medical conditions, such as diabetes or high blood pressure.

Taking your medications as prescribed also is important for getting the best possible results. While receiving peritoneal dialysis, you’ll likely need various medications to control your blood pressure, stimulate the production of red blood cells, control the levels of certain nutrients in your blood and prevent the buildup of phosphorus in your blood.

After the Procedure

Call your provider right away if you notice:

  • Signs of infection, such as redness, swelling, soreness, pain, warmth, or pus around the catheter
  • Fever
  • Nausea or vomiting
  • Unusual color or cloudiness in used dialysis solution
  • You are not able to pass gas or have a bowel movement

Also call your provider if you experience any of the following symptoms severely, or they last more than 2 days:

  • Itching
  • Trouble sleeping
  • Diarrhea or constipation
  • Drowsiness, confusion, or problems concentrating

Complications

Infection of the peritoneal cavity is the most important complication that will not only increase the risk of PD failure but also potentially be life-threatening to the patient. The rate of PD infections can be lowered by proper technique and constant patient education to emphasize proper aseptic technique while using the PDC. Most infections will present with abdominal pain and cloudy peritoneal fluid and are diagnosed by looking for white blood cells (WBCs) in the PD fluid. A cell count of more than 100 WBCs per mL of the fluid suggests infection and should be promptly addressed per guidelines.

 

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