What Is Dialysis?

Dialysis is intended to remove metabolic products and fluids from your body that your kidneys are unable to excrete. The goal of dialysis is also to maintain the body balance by adjusting the levels of various toxic substances in the blood. All patients with non-functioning kidneys would die from the accumulation of toxins in the body without dialysis.

Dialysis principles

There are two types of dialysis:

  • peritoneal dialysis;
  • hemodialysis.

Whichever treatment option is chosen, the goals of dialysis are very similar: dialysis is intended to replace basic kidney functions. The goals of therapy: removal of metabolic products, removal of excess fluid and maintaining a balanced amount of chemical compounds (electrolytes) and other substances in the body. Effective dialysis requires:

  • a semipermeable membrane;
  • blood supply;
  • dialysis solution;
  • a method for removing excess fluid.

Semipermeable membrane

During dialysis, a semipermeable membrane separates blood from the dialysis solution. This membrane passes only certain substances through itself. It allows you to remove metabolic products, water, electrolytes, and other substances from the blood into the dialysis solution (and sometimes in a different direction) through a process called diffusion. The movement of waste products and other substances depends on the permeability of the membrane, the size and structure of various substances, the composition of the dialysis solution and the blood supply to the membrane.

Blood supply

The more efficient the blood supply to the membrane, the higher the quality of dialysis therapy. With hemodialysis, the blood supply can be controlled by a dialysis machine.

Dialysis solution

If either of the two dialysis options is used, the dialysis solution will remove metabolic products from the blood. In addition, it contains certain substances that help correct the imbalance resulting from renal failure.

Fluid removal

Removal of fluid during hemodialysis is achieved through very different processes (as opposed to peritoneal dialysis). During hemodialysis, the dialysis machine uses a pressure differential to cause the fluid to excrete from the blood through the membrane into the dialysis solution. With peritoneal dialysis, glucose is used in the dialysis solution. This gives the effect of stimulating the movement of excess fluid from the blood into the dialysis solution, which is periodically drained.

Dialysis goal

Whatever the dialysis method is used, it pursues the following goals:

  • removal of metabolic products;
  • removal of excess fluid;
  • correction of electrolyte imbalance;
  • adjustment of the pH body level.