Renal hemodialysis is a recurrent treatment intended to scrub harmful waste products out of the bloodstream and maintain a healthy blood chemistry. The procedure reproduces the natural function of the kidneys, which makes it a routinely prescribed treatment for patients suffering kidney failure, according to WebMD.
Chronic renal disease deprives the body of the ability to filter chemical waste out of the blood and into the urine, which is the main function of the kidneys. When the kidneys lose over 85 percent of their filtering capacity, it is necessary to periodically pass the patient's blood through a filtration system to remove wastes, excess salts and fluid, as the kidneys are no longer able to do this naturally, according to WebMD.
Access to the patient's bloodstream is gained through a shunt, or after a minor surgery to implant an arterial graft, according to the National Kidney Foundation. Once the blood is removed, it passes through the dialyzer, and excess quantities of potassium, sodium and bicarbonate are filtered out. The cleaned blood is then returned to the body. Typically, patients are assigned time on a dialysis machine two or three times a week, as the process must be regularly repeated until a kidney transplant can be done.