How Does a Kidney Machine Work?
A kidney machine filters the poisons from the blood of a person whose kidneys are not operating properly. The machine also known as the dialysis machine mixes and monitors the dialysate. Dialysate is the fluid that helps remove the unwanted waste products from your blood.
It also helps get your electrolytes and minerals to their proper levels in your body. The machine also monitors the flow of your blood while it is outside of your body. You may hear an alarm go off from time to time. This is how the machine lets us know that something needs to be checked.
A human being’s two kidneys are fist-sized, bean-shaped organs, placed beneath the small of the back. Each kidney acts like a tiny chemical factory and contains more than 100 miles of tiny tubes through which the blood circulates. In the kidneys, the blood gives up its poisons which are expelled in the form of urine.
Until the 1940s nothing could be done for patients whose kidneys failed. Poisons built up in the bloodstream, fever and pain increased steadily and death followed. But in German-occupied Holland in 1940 a young doctor named Willem Kolff found a long forgotten medical paper on hemodialysis (blood-washing). The main problems were to find a good material for a filter and a substance to keep the blood from clotting.
After the war, Kolff went to live in America. There he constructed a device which was the engineering prototype of nearly every subsequent artificial kidney. Blood circulated through cellophane tubing and an acid, heparin, was used to prevent clotting. Small clots were trapped in a filter. Around the spiral tubing circulated the dialysis solution. Poisons in the blood filtered through the cellophane into the solution which could be changed frequently.
Artificial kidneys can be used to tide a patient over a critical period or, in chronic cases, to keep people alive for undetermined periods. At regular intervals, usually twice a week, the patient is attached to the machine by tubes inserted into his bloodstream. His blood is then passed through the machine to be purified before returning to his body.
At present, artificial kidneys have to be large machines because the filters used are much less efficient than real kidneys and much larger areas of membrane are required. Medical engineers are at work on a portable kidney, perhaps worn on a belt, which could be part of the patient’s circulatory system. Beyond even this, lies the ultimate hope of an implantable artificial kidney.