Dialysis: Definition and Overview

Text Size:
What Is Dialysis

What is dialysis?

Dialysis is the process of cleaning and filtering the blood, ridding the body of harmful waste products and extra salts and fluids. It is used in people with kidney failure, including those with advanced diabetic nephropathy.

The major role of the kidneys is to remove waste products and excess fluid from the body through urine. They also regulate the body’s salt, potassium, and acid content, and they produce hormones, including erythropoietin, which stimulates the production of red blood cells.

When the kidneys’ ability to remove and regulate water and chemicals is seriously impaired, waste products and excess fluid build up in the body, causing swelling and other symptoms. According to the National Kidney Foundation, diabetes is the leading cause of chronic kidney failure in the United States, accounting for nearly 45% of all new cases each year. Currently, about 500,000 Americans suffer from chronic kidney failure.

When is dialysis needed?

Kidney failure is treated either with transplantation or dialysis. Treatment is usually initiated once a person’s kidney function drops to 10% or less of normal, or when a person experiences nausea, vomiting, fatigue, or severe anemia from kidney failure. People awaiting kidney transplants and those who are not candidates for transplants are treated with dialysis.

What are the two types of dialysis?

There are two types of dialysis: hemodialysis and peritoneal dialysis. During hemodialysis, a person’s blood flows through tubes into a special filter called a dialyzer, which filters out waste and extra fluids. Another set of tubes carries the newly cleaned blood back into the person’s body. Performed at home or in a dialysis center, hemodialysis is usually done three times a week and lasts two to four hours per session.

Like hemodialysis, peritoneal dialysis filters extra water, waste, and chemicals from the body. The difference is that peritoneal dialysis uses a person’s own peritoneal lining, located in the abdomen, to do the filtering, and the procedure is more likely to be done at home. A cleansing solution called dialysate travels from a plastic bag through a catheter into the abdomen. Fluid, wastes, and chemicals pass from tiny blood vessels in the peritoneal membrane into the dialysate, which is drained from the abdomen back into the plastic bag. This exchange of fluid must be performed several times a day.

The technology for dialysis is constantly improving. Hemodialysis has become much more sophisticated and, with the aid of built-in computers, very precise. Doctors have become better able to evaluate the amount of dialysate and the number of exchanges needed in peritoneal dialysis.

Another improvement is the advent of the drug Epogen, a genetically engineered version of erythropoietin, the hormone the kidneys make to stimulate the production of red blood cells. Replacing erythropoietin helps alleviate the anemia associated with kidney failure. As a result, clinicians say, dialysis patients are looking better and feeling better and may be living longer.

Robert Dinsmoor

A contributing editor at Diabetes Self-Management, Dinsmoor is an award-winning medical journalist who has written hundreds of articles on health and medicine, including dozens related to diabetes.

Learn more about Robert Dinsmoor:

Professional website

Originally Published May 19, 2006

Get Diabetes-Friendly Recipes In Your Inbox

Sign up for Free

Stay Up To Date On News & Advice For Diabetes

Sign up for Free

Get On Track With Daily Lifestyle Tips

Sign up for Free

Save Your Favorites

Save This Article