What is dialysis? How does a dialysis machine work?

When patients develop advanced kidney disease, medically called stage 5 CKD, they could begin to develop symptoms or signs of kidney failure, called uremia. Up to a certain point, your nephrologist will try and treat these complications medically as much as possible. However, as kidney disease progresses, the symptoms may no longer be amenable to medical treatment. At this point, you will need either dialysis or a kidney transplant.

Image courtesy NIDDK


Dialysis is the process of artificially replacing the kidney's function. Dialysis could be of different types based on the technology (hemodialysis, or peritoneal dialysis), and could be performed in different settings (home, or in a dialysis center). If your nephrologist anticipates that you could require dialysis in the near future, she or he might ask you to start making preparations for it. This is because the process of getting initiated on dialysis requires establishing an "access" for the dialysis machines to either access your blood (in case of hemodialysis, regardless of whether it is done at home or in-center), or your abdominal cavity (in case of peritoneal dialysis). The access can take time to be ready to use. For instance, in case of you choosing hemodialysis, vascular surgeons will create a connection between an artery and vein in your forearm. This is called a arterio-venous fistula, or AVF, and can take up to 6 months to "mature" or be ready to use. 

Choosing what kind of dialysis modality would work for you is a decision best made after extensive discussion with your nephrologist and your family. For patients who are proactive about their health and appreciate the independence that comes with home dialysis modalities, either home hemodialysis or peritoneal dialysis might be good options. However, if you would rather not be burdened with the personal responsibility and prefer frequent monitored care, in-center hemodialysis might work better. Regardless of what you chose, you will be under the care of a nephrologist, dialysis nurses, technicians, and dietitians. It is just the frequency with which you get seen that could vary. From a medical standpoint, as of now, no specific dialysis modality is proven to be better than the rest. Observational data do suggest that home hemodialysis patients tend to do better. This conclusion however is an association, and not a direct causal link since patients who pick home hemodialysis tend to be less sick and more proactive to begin with. 

For a more in-depth discussion about how dialysis machines work and what are the various issues involved with different kinds of dialysis, I would highly recommend that you read  the National Institute of Health's resources on hemodialysis, peritoneal dialysis, and home hemodialysis. 

Veeraish Chauhan, MD, FACP, FASN
Nephrologist
Sarasota, Bradenton, FL

  

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