In the United States, one in 16 people, or about 17 million, are at risk for kidney disease. More than 300,000 Americans currently live with chronic kidney failure resulting from disease, birth defect or injury. Virtually all these patients would die if not for the aid of ongoing kidney dialysis.

Kidney dialysis artificially filters and removes waste products and excess water from blood, a process normally performed by the kidneys. Although often referred to as an artificial kidney, kidney dialysis is not a cure. The procedure can, however, give damaged kidneys a rest and a chance to recover normal function, or be used until the patient receives a transplant. For many patients, kidney dialysis is a way of life.

Kidney dialysis was first developed by a Dutch physician, Willem Kolff, M.D., Ph.D. In the early 1940s, he began searching for a way to use dialysis, the process by which particles pass through a membrane, to treat patients with kidney failure. A sever shortage of materials due to the war forced Kolff to improvise, especially when it came to a suitable membrane, the key component to the filtering process.

In 1943, a biochemistry teacher at Groningen University in Holland introduced Kolff to cellophane, a remarkably thin membrane that was being used as sausage casing at the time. Experiments showed that if two solutions of differing chemical concentrations were separated by cellophane, an exchange of molecules took place from the area of greater concentration to the area of lower concentration. Kolff knew immediately that cellophane could be just the material he needed to perform dialysis in humans, and used it to build the rotating drum kidney machine.

Constructed essentially of wood slats, orange juice cans and a washing machine, his invention was met with early skepticism in the medical community, even though it had been proven as an effective treatment for a few patients. But Kolff soon found an ally in the engineers at Baxter Laboratories in the United States. By the mid-1950s, biomedical engineers at Baxter had improved Kolff's original construction and built 184 artificial kidney dialysis machines. In 1956, Baxter introduced the first commercially built artificial kidney, making life-saving dialysis possible for people with end-stage kidney disease.

Kolff went on to became a research professor and director of the Institute for Biomedical Engineering at the University of Utah, where he continued work developing artificial organs, and Baxter capitalized on Kolff's invention, helping it become one of the largest medical device manufacturing companies in the world.

Baxter dialysis machines and others like them now help more than 1 million kidney patients worldwide who depend on dialysis to live full and active lives. Today's advanced technology also gives dialysis patients more treatment alternatives.

About 90 percent of patients undergo traditional hemodialysis, which, like Kolff's process, uses an external machine to clean the blood. An alternative to hemodialysis, peritoneal dialysis uses the patient's own peritoneal membrane as a filter. This membrane is a sac around the abdominal organs, and, like the dialysis machine membrane, is semipermeable. Waste particles can get through it, but the larger blood cells cannot.

Peritoneal dialysis is performed by putting dialysis solution, or dialysate, into the abdominal cavity through a catheter. Waste products and excess water from the body pass through the natural peritoneal membrane into the dialysate. After about 45 minutes, this solution is drained out of the abdomen and discarded.

Unlike hemodialysis, which usually must be done three times a week at a supervised clinic, peritoneal dialysis is performed by the patient several times a day in their home or wherever a relatively clean environment can be found. Many patients, when given a choice, feel the newer procedure gives them greater control and independence.

Another alternative treatment developed recently is continuous ambulatory peritoneal dialysis. Every night, a machine warms and meters dialysate in and out of the abdomen for 10 continuous hours, freeing the patient during the day. Also, new technologies are beginning to take advantage of the Internet to automatically monitor and communicate critical therapy data from a patient's home to his or her physician.

As the number of dialysis patients continues to grow at a rate of about 7 percent annually, and because costs for dialysis care are already more than $11 billion in the United States alone, research to find more efficient, low-cost methods of treatment remains a priority for biomedical engineers. Current efforts include not only improving the components of dialysis, such as better dialysates and membranes, but also developing alternatives to dialysis, such as a true artificial kidney, xenotransplantation, and replacement kidneys through tissue engineering.