Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons why people may need dialysis, but kidney failure is the most common. For kidney failure, many doctors recommend dialysis when urine output is low and certain conditions develop. For acute kidney failure, doctors continue dialysis until the person's blood test results indicate that adequate kidney function has been restored. For people with chronic kidney failure, dialysis may be used as long-term therapy or as a temporary measure until a kidney can be transplanted. Short-term or urgent dialysis can also be used to remove certain drugs or poisons from the body. Making the decision to begin long-term dialysis is not easy because it entails a major change in lifestyle, including a dependency on machines to maintain life. However, for most people, a successful dialysis program results in an acceptable quality of life. Most people undergoing dialysis are able to eat a tolerable diet, have normal blood pressure, and avoid progression of nerve damage, severe anemia, and other severe complications. Dialysis usually requires the effort of a team of people. A doctor completes a dialysis prescription, manages complications, and monitors the medical care. A nurse monitors the person's general well-being and mental health and educates the person about dialysis and what needs to be done to maintain the best possible health. A social worker arranges transportation and home assistance. A dietitian recommends an appropriate diet and monitors the person's response to dietary changes. Doctors decide to place a person on dialysis when kidney failure is causing certain conditions: Types of Dialysis There are two types of dialysis: hemodialysis and peritoneal dialysis. Hemodialysis: In hemodialysis, blood is removed from the body and pumped by a machine outside the body into a dialyzer (artificial kidney). The dialyzer filters metabolic waste products from the blood and then returns the purified blood to the person. The total amount of fluid returned can be adjusted. Hemodialysis requires repeated access to the bloodstream. Doctors can achieve temporary access by inserting a large intravenous catheter in a big vein, usually one near the neck. An artificial connection between an artery and a vein (an arteriovenous fistula) is surgically created to make long-term access easier. In this procedure, typically the radial artery in the forearm is joined with the cephalic vein. As a result, the cephalic vein subsequently enlarges and blood flow through the vein increases, making the vein suitable for repeated puncture with a needle. When a fistula cannot be created, an artery and a vein may be surgically connected to each other using a synthetic connector (graft). In this situation, the synthetic graft is punctured by the needle for hemodialysis. Hemodialysis Heparin, a drug that prevents clotting, is administered during hemodialysis to prevent blood from clotting in the dialyzer. Inside the dialyzer, a porous artificial membrane separates the blood from a fluid (the dialysate). Fluid, waste products, and electrolytes in the blood filter through the membrane into the dialysate. Blood cells and large proteins are unable to filter through the small pores of the membrane and so remain in the blood. The dialyzed (purified) blood is then returned to the person's body. Dialyzers have different sizes and degrees of efficiency. Dialysis treatment time is usually about 3 to 4 hours. Most people who have chronic kidney failure need hemodialysis 3 times a week. Complication Usual Cause Fever Bacteria or fever-causing substances (pyrogens) in the bloodstream Overheated dialysate Life-threatening allergic reaction (anaphylaxis) Allergy to a substance in the dialyzer or blood tubing Low blood pressure Removal of too much fluid or excessive fluid gain between dialysis Abnormal heart rhythms Abnormal levels of potassium and other substances in the blood Low blood pressure Air embolus Air entering blood in the machine Bleeding in the intestine, brain, eyes, or abdomen Use of heparin to prevent clotting in the machine Infection Bacteria entering the bloodstream through a dialysis catheter or through a needle inserted into veins for hemodialysis access Peritoneal Dialysis: In peritoneal dialysis, the peritoneum—a membrane that lines the abdomen and covers the abdominal organs—acts as a filter. This membrane has a large surface area and a rich network of blood vessels. Substances from the blood can easily pass through the peritoneum into the abdominal cavity. A fluid (dialysate) is infused through a catheter inserted through the abdominal wall into the peritoneal space within the abdomen. The dialysate must be left in the abdomen for a sufficient time to allow waste products from the bloodstream to pass slowly into it. Then the dialysate is drained out, discarded, and replaced with fresh dialysate. A soft silicone rubber or porous polyurethane catheter allows the dialysate to flow smoothly and is unlikely to cause damage. A catheter can be put in place temporarily at the person's bedside, or it may be surgically put in place permanently. One type of permanent catheter eventually forms a seal with the skin and can be capped when not in use. Various techniques are used for peritoneal dialysis. Manual intermittent peritoneal dialysisis the simplest technique. In manual intermittent peritoneal dialysis, bags containing dialysate are warmed to body temperature and infused into the peritoneal (abdominal) cavity, which takes about 10 minutes. The dialysate is allowed to remain there (dwell time) for 60 to 90 minutes and then is drained out in about 10 to 20 minutes. This process is then repeated. The entire treatment can take 12 to 24 hours. Automated cycler intermittent peritoneal dialysis is another technique. This technique uses a machine (cycler) to do automated exchanges of dialysate. Use of an automated cycler can reduce the need for nursing attention. Peritoneal Dialysis In continuous ambulatory peritoneal dialysis, the dialysate is kept in the abdomen for much longer intervals. Typically, the dialysate is drained and replenished 4 or 5 times a day. Generally three of these dialysate exchanges are performed during the day, with dwell times of 4 hours or longer. An exchange is performed at night with a long dwell time of 8 to 12 hours during sleep. Continuous cycler-assisted peritoneal dialysis uses an automated cycler to perform short exchanges at night during sleep, whereas longer exchanges are performed manually—without the cycler—during the day. This technique minimizes the number of exchanges during the day but prevents mobility at night because of cumbersome equipment. Choice of Method: Many factors, including lifestyle, must be considered in determining which type of dialysis is best for a person. People typically undergo hemodialysis at a dialysis center, usually outside of a hospital. Peritoneal dialysis can be performed at home, eliminating the need for travel to a hemodialysis center. Doctors recommend hemodialysis for people with recent abdominal wounds or abdominal surgery or defects in the abdominal wall that make peritoneal dialysis difficult. Peritoneal dialysis is better tolerated in people whose blood pressure fluctuates frequently between periods of high or normal pressure and periods of low blood pressure. Complication Cause Bleeding Unintentional perforation of an internal organ during placement of the catheter Removal of the catheter from the body Irritation and inflammation of the internal lining of the abdomen (peritoneum) or the area around the insertion site (when the catheter does not seal to the abdominal wall) Infection Unsterile techniques during dialysis Low level of albumin (a protein) in the blood Loss of protein in fluid removed during dialysis along with inadequate protein in diet Scarring of the peritoneum Inflammation and infection Electrolytes in the dialysis fluid Use of certain drugs A high sugar (glucose) level in the blood Use of a peritoneal dialysate that has a high concentration of glucose (used to remove water and sodium during dialysis) Hernias in the abdomen or groin Increased pressure within the abdomen caused by continued exposure to high fluid levels, which weaken the barriers that normally prevent excessive movement of organs and other structures Constipation Intake of inadequate fiber or use of calcium salts to treat high phosphate levels in the blood, causing the intestine to widen, which possibly interferes with dialysate flow in and out of the abdomen Comparing Hemodialysis With Peritoneal Dialysis When the kidneys fail, waste products and excess water can be removed from the blood by hemodialysis or peritoneal dialysis. In hemodialysis, blood is removed from the body into a dialyzer (called an artificial kidney), which filters the blood. An artificial connection between an artery and a vein (arteriovenous fistula) is made to facilitate the removal of blood. In peritoneal dialysis, the peritoneum is used as a filter. The peritoneum is a membrane that lines the abdomen and covers the abdominal organs, creating a space within the abdomen called the peritoneal space or abdominal cavity. Special Considerations Diet: People undergoing dialysis need a special diet. In people undergoing peritoneal dialysis, appetite is generally poor, and protein is lost during dialysis. The diet should be relatively high in protein, roughly ½ gram of protein per pound of ideal body weight a day. (The American Association of Kidney Patients has a food guide.) Salt, both the usual salt containing sodium and the salt containing potassium, is restricted. For those undergoing hemodialysis, daily consumption of sodium and potassium is even more restricted. Foods high in phosphorus also may have to be limited. Daily fluid intake is limited for people who have very little urine output or a persistently low or decreasing sodium concentration in the blood. Daily weighing is important to monitor weight gain. Excessive weight gain between hemodialysis treatments indicates that the person is consuming excessive fluid. Usually, excessive fluid intake is the result of excessive sodium intake, which makes a person thirsty. Multivitamin supplements are needed to replace the nutrients lost through hemodialysis or peritoneal dialysis. Medical Considerations: Erythropoietin Normally, the body's bone tissue is continually replaced, helping bones remains strong and dense. The kidneys secrete hormones that help regulate the production of bone tissue. In people with kidney failure, the kidneys are not able to regulate hormone production, so parathyroid hormone levels may increase. The active form of vitamin D Psychosocial Considerations: People undergoing dialysis may experience losses in every aspect of their lives. The potential loss of independence can be especially distressing. Coping with disruptions in lifestyle can be difficult. Many people undergoing dialysis become depressed and anxious. Psychologic and social counseling is often helpful to families as well as to those undergoing dialysis. Many dialysis centers provide psychologic and social support. Dealing with a loss of independence is helped when people are encouraged to pursue their previous interests. People undergoing hemodialysis need to arrange for transportation to and from dialysis centers on a regular basis. Dialysis sessions may interfere with work, school, or leisure activities. More than half of the people on long-term dialysis are 60 years of age or older. Older people often are better able to adapt to long-term dialysis and the loss of independence than are younger people. However, older people undergoing dialysis may become more dependent on their grown children or may not be able to continue living alone. Older people are more likely to experience fatigue from treatments. Often, family roles and responsibilities must be modified to fit the dialysis routine, creating stress and feelings of guilt and inadequacy. Considerations in Children: Children whose growth has been stunted may feel isolated and different from their peers (see Social Issues Affecting Children and Their Families: Illness in Children). Young adults and adolescents coping with identity, independence, and body image issues may find these issues further complicated by dialysis. Diet is an important issue for children undergoing dialysis because children must receive enough nutrients to support their growth.
Reasons for Dialysis in Kidney Failure 
Possible Complications of Hemodialysis 
Possible Complications of Peritoneal Dialysis 
or darbepoietin may be given to stimulate the production of red blood cells. Iron may also be needed to help the body produce new red blood cells. Phosphate binders, most often those such as calcium carbonate
or calcium acetate, are used to remove excess dietary phosphate.
(calcitriol
) or a similar substance is given to control high parathyroid hormone levels because high parathyroid hormone levels can weaken bones by decreasing their density, a bone condition called renal osteodystrophy.
Saturday, April 3, 2010
Labels: Dialysis
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