Dialysis

Definition of Dialysis

Dialysis is a procedure that cleans and filters the blood when the kidneys are not working properly in their role of removing wastes and fluid from the body. Healthy kidneys clean the blood by filtering out extra fluids and waste products. When the kidneys fail, the body holds on to fluid and harmful wastes can build up.

Who is a candidate for the procedure?

Dialysis is used to treat people with kidney failure, which can be either acute renal failure (is usually reversible and dialysis is only temporary) or chronic renal failure (called ESRD or End Stage Renal Disease which is not reversible).

Treatment is needed to replace the work of the failed kidneys. Once both kidneys fail, a person would die as a result of not having the filtering process normally supplied by the kidneys .

Dialysis is way to keep a person with kidney failure alive. A person waiting for a kidney transplant also would be a candidate for dialysis.

How is the procedure performed?

There are two main ways to filter the blood:

• In hemodialysis, blood is filtered using a special dialysis machine and an artificial kidney. Blood removed from the body travels through tubes into the dialysis machine. The machine has a special, custom made filter or artificial kidney that filters out wastes and extra fluids by diffusion, osmosis, and convection.

The machine can be adjusted to remove exactly the amount of fluid that is necessary. Fluid and medicine can also be given on dialysis. The newly cleaned blood flows through another set of tubes and back into the body.

Ideally only wastes and fluids are removed, no blood cells are lost.

• In peritoneal dialysis, a special tube is put into the abdomen through the skin. A cleansing solution called dialysate travels through the tube into the abdomen.

The peritoneum (the lining around the entire abdomen inside including all the intestines) has as much area as a person's skin surface and lots of blood vessels to exchange materials.

After several hours, the fluid gets drained from the abdomen. It takes wastes from the blood with it by diffusion, osmosis, and convection. This process may be repeated several times a day. Or it can be done during the night while the person sleeps by a machine.

Both types of dialysis require surgery to prepare the person's body:

• For hemodialysis, a surgeon will create a new access to the bloodstream called a fistula. This provides a way for blood to be carried from the body to the dialysis machine at a brisk rate (200cc/min or faster). The access may be either inside the body, usually in the arm, or outside the body, usually in the neck.
• For peritoneal dialysis, a surgeon places a small, soft tube called a catheter into the abdomen. This tube stays in place.

What happens right after the procedure?

Usually, repeated dialysis is needed for survival. Most people who need dialysis have kidneys that are permanently damaged.

Peritoneal dialysis may be done at home or in a healthcare facility. After each time the equipment is used, it must be carefully cleaned. It is important to follow instructions to prevent infection which can occur in peritoneal dialysis especially.

Hemodialysis usually requires a person to go to a dialysis center three times a week for 3-4 hours per treatment.

People may feel tired, weak, and even confused after the first few sessions because of the rapid shifts of wastes and fluids. . Most of the time these sensations go away in a few weeks as the body adjusts.

What happens later at home?

People who use hemodialysis must take care of the fistula. The overlying skin should be kept clean. Any harm to the area should be avoided. Blood pressure should not be taken in arms with a fistula. If the fistula is disturbed, further surgery may be needed to fix it (called a revision).

Peritoneal fluid exchanges must be performed with special training and careful technique. Patients or their helpers wash or scrub, gown, and glove just like surgeons do.

Dialysis patients have to follow careful diets while at home (limited in waste product material, salts, and fluids)

What are the potential complications after the procedure?

With peritoneal dialysis, the main complication is infection. Equipment and technique should be kept clean or sterile to avoid this problem. The dialysis catheter may also stop working or a hernia may develop. These situations may require surgery to correct them.

Hemodialysis patients often develop problems with the fistula, such as the following:

• Blockage by a clot or an overgrowth of tissue.
• abnormal swelling of the site
• blood clots
• infection
• Excessive bleeding after the needles are removed after it is used

During either type of dialysis, people may develop the following problems:

• abnormal swelling of the site
• confusion
• irregular heartbeats
• low blood pressure
• seizures