subject: How Does A Kidney Dialysis Machine Work? [print this page] A kidney dialysis machine is a life-saving device. Its role in purifying the blood helps to preserve the life of patients whose kidneys no longer perform their original function. How does this amazing machine actually work? Here is a quick overview of the dialysis process so you can have a basic understanding.
The Big Idea -- Clean the Blood
Essentially, all a dialysis machine does is what the kidneys can no longer do. A healthy human kidney cleans blood by removing urea, salt, and other waste products. The dialysis machine does basically the same thing by filtering the blood to remove the waste.
Blood Removal - The Dialyzer
As the blood is filtered from the body, it is transferred through special blood tubing, into the machine, and through the dialyzer. This is the part of the machine where the filtering occurs. To facilitate the filtering process the blood is mixed with dialysate which is a liquid designed to clean the blood with purified water, bicarbonate and an acidified solution with minerals and electrolytes to optimize healthy blood. As the dialysate enters the machine through a tube, it is mixed with the blood so the waste can be extracted. The dialysate solution, which is continually refreshed throughout the dialysis process, absorbs the waste from the blood, and drains it away.
Blood Pumping - The Blood Pump
Meanwhile, the blood must continue being pumped the entire time. The tubing through which blood travels is connected to a pump. In some dialysis machines, the blood pump can be seen turning in a circular motion, keeping the blood constantly flowing. The pump brings the blood outside the body, through the dialysis machine, and back into the body.
Blood Fluidity - Heparin
Since blood is supposed to naturally clot, the dialysis process has to make sure it doesn't in order to keep the blood flowing properly through the machine. Dialysis machines are equipped with a syringe containing heparin. Heparin, which prevents clotting of the blood, is pumped into the blood at precisely programmed intervals.
Blood and Air - Air Filters
Blood must never mix with air, even as it exits the body and moves through the dialysis machine. This means that a dialysis machine has air traps on both sides of the dialyzer to prevent any air from being introduced into the blood at any time.
Finally, dialysis machines are equipped with alarms. If anything goes wrong at any point in the dialysis process, an alarm will sound. From blood pressure, to air entry, to heparin replacement, to dialysate mixture, the dialysis machine monitors everything. A kidney dialysis machine is a marvelous invention that serves a necessary purpose, and sustains the lives of thousands of people.
