Kidney failure causes accumulation of waste products and byproducts of protein metabolism in the blood. This also leads to excessive fluid buildup and electrolyte disturbances, resulting in high blood pressure. Kidney dialysis is the process of cleansing the blood with a dialyzer. Your blood flows in small volumes through the dialysis machine's special filter where excess fluids and waste products are removed. The "clean" blood then returns to your body.
Access for Dialysis
To prepare for dialysis, a procedure is first required to establish a site for vascular access. This is a site on your body where the dialysis machine can be attached, to gain access to your blood. The National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) states there are three basic types of vascular access that should ideally be prepared weeks to months in advance of starting dialysis. These are arteriovenous (AV) fistula, AV graft, or venous catheter. An AV fistula is surgically created by adjoining a large artery and a large vein in your arm. The combination causes the vein to grow large and strong to ease access into the blood stream. Venous catheters can be inserted either into the subclavian vein through the chest, or the femoral vein through the thigh. An AV graft is intended for people with inadequate blood vessels and unable to support a fistula. According to the NKUDIC, the AV fistula is considered the best long-term vascular access point.
Hemodialysis
One type of dialysis procedure is hemodialysis, which can be done at the hospital, a dialysis center or sometimes in your home. The treatments require four hours about three times a week, according to the National Kidney Foundation. A health care professional connects the tubes from the hemodialysis machine to your vascular access site. Inside the machine lies a filter known as a dialyzer, often called the "artificial kidney", which separates into two compartments--one for your blood and the other for the dialysate bath. This "washing fluid" consists of water and major electrolytes. As the machine cycles, your blood filters through and is returned to your body.
Peritoneal Dialysis
Another type of dialysis procedure that has less time restrictions, more flexibility and less associated stress than hemodialysis is peritoneal dialysis. The treatment requires an access site just as hemodialysis, but that site is in the peritoneal cavity through the abdomen. A rubber catheter is surgically placed into the capillary-rich peritoneal cavity for access to the blood. With this type of dialysis, dialysate fluid is instilled through the catheter into the abdomen. After a certain period of "dwelling" time, the fluid needs to be drained along with the waste products it has cleansed out. According to the Merck Manual, peritoneal dialysis has three different types and requires extensive involvement from the patient because the procedure is carried out independently.
