What is Hemodialysis?

“Hemo” means blood. When kidneys fail, the body is no longer able to filter waste from that blood (End Stage Renal Disease). Hemodialysis picks up where your kidneys left off by using a machine to clean your blood instead. This machine, called a dialyzer, takes small amount of blood at a time and cleans it while monitoring important vitals like blood pressure.

‘Hemo’ means blood, so hemodialysis means blood dialysis.

Hemodialysis is done using a special filter called a dialyzer which functions as an artificial kidney. Your blood travels though plastic tubing the dialyzer, it cleans the blood, and then the machine returns it back to you.

How Does the Dialyzer Clean My Blood?

The dialyzer uses two main principles to filter the blood.

  • Membrane has little pores
  • Allows small molecules like urea, creatinine and electrolytes
  • Stops proteins and red blood cells
  • Diffuses into LOW concentration of dialysate (fluid used in machine)
  • Waste is ‘trapped’ by the dialysate and removed from blood
  • Dialysis uses flowing fluid
  • This creates ‘drag’ aka convection
  • Waste is naturally washed away with the current

The dialyzer filter has two main sections: one for your blood, and one for a washing fluid called dialysate. A thin membrane separates these two parts of the dialyzer. Important things like blood cells and protein remain in your blood because they are too big to pass through the membrane. But smaller waste products in the blood, such as urea, creatinine, potassium, and extra fluid get filtered through it.

The end result? Filtered blood that comes out the opposite end of the dialyzer is free of waste, has the correct concentration of electrolytes, and excess H2O is removed.

We can set the dialysis machine to remove the water weight you've gained. Water retention is a common issue with dialysis patients, so hemodialysis can come to the rescue!

How is the blood taken from the body for hemodialysis?

In order to get the blood we need to “access” to the bloodstream. This can be done with a fistula, graft or catheter.