Dialysis is a procedure that does some of the activity done by healthy kidneys. It is necessaries when your own kidneys can no work for your body's needs.
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.
Hemodialysis : 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.
Peritoneal Dialysis : 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.
You need dialysis when you the end stage of kidney failure Or you can say when you lose about 85 to 90 percent of your kidney function and have a GFR of < 15.
When your kidneys fail or about to fail, dialysis keeps your body in balance by activities like dialysis keeping a safe level of certain chemicals in your blood such as sodium, potassium and bicarbonate dialysis helping to control blood pressure and removing waste, salt and extra water in the body.