How Do Hemodialysis Machines Work?

​Whether home hemodialysis or in-center hemodialysis, you depend on a hemodialysis machine to filter your blood.  This device purifies the blood in a dialyzer, also known as an artificial kidney, with built-in safety checks to ensure the process is safe and effective.  Home and in-center hemodialysis machines are very similar in function, though the home machine is much smaller.

How Do Hemodialysis Machines Work?
By Pierre Mouchette | Bits-n-Pieces

What does a dialysis machine do?
An overview of a hemodialysis machine's parts and functions are as follows:

• Two tubes are connected via your hemodialysis access.  Blood will flow from your body into the machine through one of the tubes.
• If your doctor prescribes blood thinner as part of the treatment, it is added to help keep your blood from clotting while it is in the machine.
• A pressure monitor and the pump work together to keep flow at the proper rate.
• Your blood flows into the dialyzer, where it is then filtered.
• Dialysate solution enters the dialyzer and draws the waste out of your blood.
• The used dialysate solution is pumped out of the machine and then discarded.
• Your blood goes through another pressure monitor and an air trap to ensure it is safe to be sent back to your body.
• Your cleaned blood returns to your body by the second tube attached to your access site.

 
What is dialysate?
Dialysate is a fluid consisting of water, electrolytes, and salts.  During dialysis, dialysate solution helps to clean your blood inside the dialyzer by removing waste products and balancing electrolytes.  Your nephrologist will prescribe the dialysate right for your body's needs.
 
What does a dialyzer (artificial kidney) do?
A dialyzer is a part of the hemodialysis machine where blood is filtered.

• The core of the dialyzer consists of thousands of tiny mesh tubes.
• Your blood flows inside each tube, and the dialysate stays outside the tubes.
• Tiny tube pores let waste and excess fluids pass from your blood into the dialysate.
• Your cleaned blood then leaves the dialyzer and is returned to your body.

 
How is my dialysis treatment monitored?
The machine's monitoring screen will show in-depth information during your dialysis session.  Every function, including the pump speed, blood pressure, and dialysate temperature, is monitored.  Every check will ensure that your dialysis session is safe and effective.

An alert will sound if anything needs attention.  The warning could indicate that the machine needs to be checked or something has to be adjusted.  If you are doing home hemodialysis, you will be trained about what to do regarding any alert you might hear as part of your overall dialysis and safety training.  Call your nurse 24/7 if you have questions or need assistance.  If you receive in-center hemodialysis, your care team will monitor the machine and make necessary adjustments.
 
What happens if a power failure occurs during dialysis?
If your power goes off while your cycler works, it automatically closes all the lines.  The machine will store information on your session using a backup battery.  If the power returns soon, that held data lets the device continue the session.  If not, it is best to call your home dialysis nurse about what to do.  Support is available 24/7 if you have questions or concerns.