Dialysis works based on the principles of the diffusion of solutes and ultra filtration of fluids across a dialysis bag. Dialysis is a passive process that favors the transport of small molecules across a semipermeable membrane or dialysis bag. When the kidneys fail, dialysis can do their job of removing harmful substances and excess water from the body. This is done with the help of technology that makes use of the physical principles of diffusion, convection and osmotic pressure. The two main types of dialysis are hemodialysis and peritoneal dialysis.
In hemodialysis, the blood is cleaned outside of the body. The treatment usually takes place in a dialysis center. The procedure involves removing blood from a blood vessel, usually in a forearm, passing it through the dialysis device and then transporting it back into the body.
In peritoneal dialysis, the blood isn't cleaned outside the body, but inside the body, in the abdominal cavity. The lining of the abdominal cavity serves as a semipermeable membrane. The peritoneum is well-supplied with blood and covers the organs like the small and large intestines.