Dialysis can be defined as a process for removal of waste, as well as excess water from the blood. It is applied fundamentally as an artificial substitution for lost function of the kidney in individuals with renal failure (U.S. Department of Health and Human Services, 2014). Dialysis functions on the principles of solutes’ diffusion, as well as a semi-permeable membrane. Diffusion is a feature of substances in water, which tend substances to move from a high concentration region to a low concentration area. Blood flows through one side of a semi-permeable membrane while a special dialysis fluid, dialysate, flows through the opposite side. A semi permeable membrane can be described as a thin layered material that has holes of different sizes. Smaller sized solutes and fluid pass across the membrane, though the membrane blocks off the larger substances, such as red blood cells, from going through (U.S. Department of Health and Human Services, 2014). This replicates the process of filtration, which occurs in the kidneys, as the blood gets into the kidneys while the smaller ones are separated from, the larger substances in the glomerulus.
There are two major forms of dialysis namely, peritoneal dialysis and hemodialysis, which get rid of waste products, as well as excess water from the blood in varied ways (Pendse, Singh, & Zawada, 2008). Hemodialysis gets rid of water and waste products by circulation of blood outside the body by use of an external filter, known as a dialyzer, which has a semi permeable membrane (Rocco, 2007). Peritoneal dialysis, on the other hand, gets rid of wastes and water from the blood within the body through the use peritoneal membrane of the peritoneum that serves as a natural semi permeable membrane. In this type of dialysis excess water and waste products pass from the blood via the peritoneal membrane, into dialysate, a special dialysis solution, within the abdominal cavity that has a similar composition to the blood’s fluid portion (Beathard & Litchfield, 2004).
The effectiveness of dialysis is measured in a number of ways. For instance, it is determined by how well it gets rid of urea from the body by measure of the level of blood urea nitrogen, BUN. The BUN is evaluated prior to and following the patient's treatment session. The two levels are then compared to determine how much the level of urea has reduced in the blood. This difference is referred to as the urea reduction ratio, abbreviated as URR, normally expressed as a percentage. Enough dialysis dose results in an average URR of 65%.
Dialysis effectiveness is also measured by comparison of the amount of fluid, which is cleared of urea in the course of every session of dialysis with the amount of fluid that exists within the body. This is, usually, referred to as Kt/V where Kt is the amount of fluid, which is clear of urea in every session of dialysis while V is the water volume that a person body has. The most precise way to measure the effectiveness of dialysis is the Kt/V since it also evaluates the quantity of urea gotten rid of with excess fluid and considers other factors, for instance loss of weight in the course of dialysis. An efficient dialysis dose of results in an average Kt/V of 1.2.
Reference List
Beathard, G. A., & Litchfield, T. (2004). Effectiveness and safety of dialysis vascular access procedures performed by interventional nephrologists. Kidney international, 66(4), 1622-1632.
Pendse, S., Singh, A., & Zawada, E. (2008). Initiation of Dialysis (4th ed.). New York.
Rocco, M. V. (2007). More Frequent Hemodialysis: Back to the Future? . Advances in chronic kidney disease, 14 (3), e1–9.
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES. (2014). Treatment Methods for Kidney Failure: Hemodialysis. Retrieved October 13, 2014, from http://kidney.niddk.nih.gov/KUDiseases/pubs/hemodialysis/index.aspx
