Skip to Main Content

Dialysis Technicians


Chemist Thomas Graham discovered the process of dialysis in 1854. In his early experiments, Graham separated crystalloids from colloids. Crystalloids are chemical salts that dissolve in a solution, and colloids are jellylike materials that remain uniformly suspended in a solution and will not dissolve. Graham passed crystalloids in a solution through a membrane into another solution. He then recovered the crystalloids by evaporating the solution. Graham predicted possible medical uses for his discovery, but did not conduct any experiments involving animals or humans.

In 1913, John J. Abel and Leonard G. Rowntree utilized Graham's principle of dialysis in laboratory experiments using animals. They were able to successfully remove chemicals from the animals' blood. Researchers called the process hemodialysis. "Hemo" comes from the Greek word haima, which means blood.

In the early 1940s, scientists developed artificial kidney machines to perform hemodialysis on patients. Improvements in equipment and the development of heparin, a drug that prevents clotting, made hemodialysis practical for the treatment of people with CRF. Before the invention of the artificial kidney machine, patients with CRF would die of uremic poisoning as toxic products built up in their bloodstream.

Just as Graham predicted, the artificial kidney machine separates crystalloids from colloids in a patient's blood. The machine pumps blood from the body through a dialyzer, and then the blood passes through tubes constructed of artificial membranes. The surfaces of the membranes are bathed with a solution called the dialysate. Normal body waste chemicals act as crystalloids and pass through the membranes. However, the blood cells and other proteins act as colloids, which means that they do not pass through the membranes. The blood cells and proteins return to the body with the blood, but without the harmful waste chemicals. The rate of the waste removal depends on the extent of the individual patient's kidney failure, the concentration of waste products in the patient's blood, and the nature and strength of the dialysate.

By the late 1950s, hemodialysis was available in health care facilities throughout the United States. During the 1960s, further advances made it possible for dialysis to be successfully carried out in the homes of patients.

While home dialysis is more economical than hospital dialysis, it is still an extremely expensive process. For that reason, Medicare funds have paid for dialysis carried out in health facilities since 1973 and now also pay for the equipment patients need for home dialysis.

Whether in the hospital or at home, a patient receiving hemodialysis must be closely monitored by a dialysis professional.

Related Professions