Dialysis is a procedure that removes waste products from the body. When the kidneys are not functioning correctly, these waste products build up and remain in the blood. As the quantity of these waste products rise in the blood, the patient becomes sick with symptoms such as progressive nausea and vomiting, lack of appetite, muscle cramps and itching. This is called uremia. Family members may notice that the person with uremia may become sleepy, tired or weak.
Dialysis is a cleansing procedure that removes toxins and excess water from the blood (replacing the job the patient's kidneys were doing before they stopped functioning correctly). This is necessary when the kidneys are no longer able to filter these waste products and remove the extra fluid that accumulates. "When is it needed and where is it done?"
Dialysis is required when your kidneys are no longer performing enough of their function of cleansing the blood of waste and excess fluid (End Stage Renal Disease [ESRD] has set in). A person can lose approximately 80-90% of their kidney function before its the time for dialysis. A person can dialyze (the verb tense of the noun 'dialysis') in several places, depending on the type of dialysis they take: in a hospital, in a dialysis center that is setup specifically for dialyzing patients on a daily basis, or in your home. (Both types of dialysis can be done at home.) You and your doctor will decide which place is best, based on your medical condition and personal wishes. Info on the Two Types of Dialysis There are two types of dialysis: hemodialysis and peritoneal dialysis.
Hemodialysis is done using an artificial kidney machine that directly filters the blood. This occurs by removing the blood from the body via a vein (called a "vascular access," typically in the forearm), running it through the artificial kidney machine (which performs the cleansing step), and reinjecting the blood back into the same vein (but in a slightly different location).
Hemodialysis usually occurs either in a dialysis center or in the home. The dialysis center has televisions for viewing. Most dialyzing patients will either watch TV, read a book or magazine or nap. Most folks who dialyze via hemodialysis are placed on a schedule that includes three days per week of dialyzing for approximately 4-5 hours. This schedule will typically be either Mon.-Wed.-Fri. or Tues.-Thurs.-Sat., and will either occur in the morning or during the afternoon. The procedure is typically considered discomforting or painful sometimes, but that discomfort is primarily only caused by needle insertion at the start of dialysis. Most people describe this as a "burning" or "stinging" sensation that lasts only a couple of seconds. Discomfort can also occur with muscle cramping during dialysis, but this occurs fairly infrequently.
Peritoneal dialysis (PD) is a procedure in which the natural lining of the abdominal cavity is used as a filter. This lining, called the peritoneal
membrane, is richly supplied with small blood vessels. Types of PD include continuous ambulatory peritoneal dialysis (CAPD), intermittent peritoneal dialysis (IPD), and continuous cycling peritoneal dialysis (CCPD).
PD is done by instilling about two quarts of a special fluid (dialysate) through a catheter into the abdominal cavity and periodically draining
and replacing the fluid. PD uses simple physical principles to remove water and waste from the blood. While there are several ways of doing PD, all require that a permanent catheter be placed into the abdominal cavity. This soft plastic tube is about 12 inches long with only 4-5 inches remaining outside the body. It is placed below the level of the umbilicus (belly button) and usually to either side of it. The catheter insertion is performed in the operating room and often with local anesthesia.
The main concern with peritoneal dialysis is the risk of infection. Since the catheter is a direct opening into the abdomen, strict guidelines are used to avoid infection. Patients are examined monthly as outpatients and blood work is done to make sure that the dialysis is adequate.
CAPD requires no external machine. The dialysis is done by connecting the bag of dialysate to the abdominal catheter and allowing the fluid to flow into the abdominal cavity. The empty bag is left attached and rolled up and placed inside clothing (or detached). At this point, the patient can return to their normal activity. After about 4-6 hours, the bag is either removed from the clothing and unrolled or reattached and lowered beneath the abdomen to allow the dialysate to flow back out of the cavity into the bag (via gravity). At this point the full bag of removed fluid is disconnected and a new bag of dialysate is attached. The exchange (draining the accumulated fluid and infusing the new fluid) takes about 45 minutes. CAPD patients perform four exchanges per day, seven days per week. The exchanges are typically done once at wakeup, once at bedtime and two more times during the day.
With IPD, dialysis is done for 8-12 hours 3 times per week. The automatic machine has a timer which controls each cycle. The amount of fluid that flows into the abdomen is measured, as well as the amount that flows out. The fluid is left in the abdomen for about 5-10 minutes and then allowed to drain out over about 15 minutes. This inflow, remain and outflow is called a cycle. Each cycle takes 20-30 minutes to complete and between 16 and 24 cycles complete a treatment. One treatment takes between 8 and 12 hours, for a total of 30-40 hours per week. CCPD is a modification of CAPD and IPD. People who select CCPD dialyze via an automated machine at night.
About Vascular Accesses
A vascular access is simply the passageway or opening through which blood will be moved from the body to a dialyzing mechanism. "Vascular" refers to the blood vessels. There are several types of accesses, including a fistula, shunt, subclavian catheter and femoral catheter.
A fistula involves a short operation in surgery and is generally done under local anesthesia. The fistula is made by sewing two of your own blood vessels together. Of the two blood vessels, one is an artery and one is a vein. This new connection will build a vein with a large flow of blood.
Generally the fistula is placed between the wrist and the elbow of the arm which you do not use for writing. That way you can use your free, dominant arm while you dialyze. The fistula is used for hemodialysis by placing two needles in different places into the fistula. The needles have special tubing attachments, and blood will flow through one needle out of the body and to the artificial kidney, and then back into the body through the other needle and tubing. At any one point in time, only about 1.5 cups of blood are out of the body and either en route to or in the artificial kidney.
A fistula has to 'mature,' meaning that it has become strong enough and big enough to have needles placed in it for dialysis. Even before the fistula has matured, you will be able to feel the rush of blood through its new path. It is a 'rippling' or 'superpulse' which you will feel when your fingers are placed over the skin. This rush of blood is also called known by the bruit (pronounced "bru-ee"), which is the roaring sound you will hear when placing a stethoscope over the fistula.
A shunt ("A/V" or "external") is made by sewing a piece of special tubing into an artery and a vein. These two narrow tubes are joined on the outside to form a loop; blood flows from the artery and into the vein just as it does in a fistula.
A subclavian catheter is a means of dialyzing the blood immediately after the catheter has been placed ('installed'). It is placed in the subclavian vein which lies just below the collar bone. It may be used for several weeks until a permanent vascular access is available. Subclavian catheters are covered with a dressing, which is changed with each dialysis treatment. Care must be taken to keep the catheter dressing secure, the ends sealed against the skin and the caps and clamps in place on the catheter.
A femoral catheter is placed into blood vessels in the groin. It is used only when there is no other means of vascular access available and dialysis must be done immediately. Femoral catheters are only placed while the patient is in the hospital, and the catheter is typically only used once or twice at the most. The patient must remain in bed while the catheter is in place.
"How long can a person live on dialysis?"
There are many patients who have been on chronic dialysis since it was first available in the early 1960s. We don't yet know the total life expectancy, but some dialysis patients may approach normal life spans.
Dialysis and Cost
Dialysis is very expensive. Fortunately, the federal government now pays 80% of all dialysis costs, and private health insurance or state medical assistance pays almost everything else. So the cost of dialysis is now no where near the financial drain it was before Medicare coverage was enacted.
Dialysis and Travel
Yes. For hemodialysis patients, there are dialysis centers throughout the United States which will allow prescheduled dialysis by travelers. If
you are planning on traveling and want to find the nearest dialysis center to where you are headed, click here to see a list of National Kidney Foundation affiliates and contact the one nearest your destination. They will be able to provide you with information on the nearest dialysis centers.
For Continuous Ambulatory Peritoneal Dialysis (CAPD) patients, travel is always an option as this type of dialysis is naturally suited for the traveling patient! For Continuous Cycling Peritoneal Dialysis (CCPD) patients, travel is also possible because they can typically switch to CAPD for their trip.
Dialysis and Diet
A person on dialysis needs to take some cautions with their diet as a proper diet can help reduce the wastes that build up in the bloodstream. A dietitian can help you plan meals according to your doctor's orders. When choosing foods, you should remember to:
Eat balanced portions of foods high in protein such as meat, chicken, fish and beans. Animal protein is better used by your body then the protein found in vegetables and grains. Watch the amount of potassium you eat. Potassium is a mineral found in salt substitutes, some fruits, vegetables, milk, chocolate and nuts. Too much or too little potassium can be harmful to your heart. Limit how much you drink. Fluids build up quickly in your body when your kidneys aren't working. Too much fluid makes your tissues swell. It also can cause high blood pressure and heart trouble. Avoid salt. Salty foods make you thirsty and cause your body to hold water.
Limit foods such as milk, cheese, nuts, dried beans, and soft drinks. These foods contain the mineral phosphorus. Too much phosphorus in
your blood causes calcium to be pulled from your bones. Calcium helps keep bones strong and healthy. To prevent bone problems, your doctor may give you special medicines. You must take these medicines everyday as directed.