What Is Dialysis Used For?
Kidney dialysis is used for patients who have either suddenly lost kidney function or have chronic kidney disease that gradually robs the kidneys of their functions. The kidneys have two functions in the body. They filter the blood, removing waste products and condensing them into urine. They also secrete various hormones that are important for vitamin processing and blood pressure maintenance. Dialysis machines are able to replace the blood filtration function of the kidneys but not their hormones.
How Do Dialysis Machines Work?
Dialysis machines work on the principle of diffusion of solutes through a semi-permeable membrane. A semi-permeable membrane is one that only lets some solutes through, and the solutes in this case are things that are dissolved in the blood, specifically waste products. The dialysis membrane has two sides. One side faces the blood, which is flowing in one direction. The other side is facing a specially made dialysis liquid flowing in the opposite direction. The membrane has holes that are small enough to let small solutes (like waste products) and fluid flow through them but not bigger things like blood cells and sugars. The flow of the dialysis liquid in the opposite direction helps to ensure that there is maximum diffusion of solutes from the blood to the dialysis fluid. As a result, certain solutes that are abnormally high in the blood, such as urea, potassium and calcium, will be removed, helping the blood to maintain healthy levels of these solutes. The things that are present in the dialysis solution can be altered to fit the individual needs of the patient.
Types of Dialysis
Hemodialysis is a form of dialysis in which the blood is pumped through an artificially created membrane. Once the blood has been cleansed, it is returned to the body. Often these types of machines use alterations in the pressures to even further filter the blood. Hemodialysis treatments are generally performed three times a week. The other main type of dialysis is peritoneal dialysis. In this case, the dialysis liquid is pumped into the abdominal cavity, and the peritoneum, a membrane in the abdomen, serves as the semi-permeable membrane. The liquid absorbs waste products and is then removed. The liquid typically needs to be changed several times a day, but this type of dialysis does not have to be performed in a clinic.
Tags: waste products, dialysis liquid, semi-permeable membrane, Dialysis machines, diffusion solutes
