How does a kidney dialysis machine filter blood?

Answer 1

The dialysis machine is really a 2-part machine, serving two basic functions. First it acts as a blood pump, and second, it pumps a solution known as dialysate. The machine has a very accurate metering system that combines ultra-purified water, bicarbonate, and a potassium "bath" together. The patient is hooked up to the machine via what is known as the extra-corporeal circuit (meaning outside of the body) via two large-bore needles (or a semi-permanent central catheter). The lines go to the machine, and into a pump. No blood actually goes into the machine, but rather stays in the blood tubing. There is a larger diameter section of the line that fits in the blood pump, and the pump moves the blood by squeezing the larger section of the line at regular intervals. The blood comes from the patient through the pump, and into the artificial kidney (the dialyzer). The dialyzer is made of thousands of microscopic fiber tubes. These tubes can be likened to drinking straws that have small holes punched in the sides of the straws. These holes in the fibers are too small to allow the blood cells to pass through (much like a colander will let water out, but not your spaghetti noodles). The dialyzer is hooked to larger hoses that flow the dialysate through the area around the fibers in the dialyzer (usually in the opposite direction from the blood flow), and by pressure and osmosis, the fluid around the cells in the blood that contains the urea (waste) passes out of the blood and into the dialysate and to the waste system (drain). Dialysis is only about 10% to 15% as efficient as a working kidney, so patients need to dialyze frequently (usually 3 times per week or more, usually for 3 to 4 hours per treatment). Also, because of this, their blood levels of essential electrolytes like potassium, calcium, and sodium, as well as phosphorus, vitamins and other essential minerals must be continually monitored because they are lost during dialysis. Additionally, most patients need a drug to stimulate the production of red blood cells. A drug called Epogen is commonly used. It is very expensive, as much as $1000 USD to $2000 USD per shot, usually at each treatment. Many patients can gain 2 to 4 kilograms of fluid weight (4.4 to 8.8 lbs) in only 2 days. Access to the patient is usually gained through what is known as a fistula. A surgeon ties an artery to a vein, and this makes the vessel grow very large, sometimes as large in diameter as a thumb (or larger). This is done because the patient has to have needles inserted every other day as long as they are on dialysis. The machine monitors many parameters such as the blood flow, dialysate flow, arterial and venous pressures, the conductivity of the dialysate solution, the temperature and pressure in the artificial kidney (dialyzer) and will set off an alarm if anything is out of normal parameters.

Answer 2

A renal dialysis machine is used when a person's kidneys function is no longer efficient enough for them to survive - usually when it drops to 10-15%. It 'filters' blood by flowing it opposite 'dialysis' fluid where wastes and toxins can then pass through a semi-permable membrane because of passive transport.

Answer 3

by taking blood and cleaning it for them then they put it back