Overview of Dialysis for Kidney Failure

The Essential Dialysis 101

Kidney Dialysis. Getty Images Credit: Science Photo Library

When your kidneys begin to fail, you will typically go through progressive stages of loss of kidney function. These stages are classified from stage 1 through 5 of chronic kidney disease (CKD). Stage 5 is the worst when many people would require either dialysis or a kidney transplant. Not everyone who starts off with mild kidney disease (stage 1-3), will progress to stage 5.

Kidney disease comes with a long laundry list of complications.

In the early stages of CKD, these complications are typically treatable with medical management. That is, pills should suffice to treat complications like high blood pressure, abnormal electrolytes, swelling or edema (that are expected to occur in CKD). However, eventually, if you do happen to progress to advanced kidney disease, or CKD stage 5, these complications begin harder and harder to treat with medical management alone. At this time, should you not get a kidney transplant (or if you are not eligible for it), you will often need dialysis. So let's talk about a few basic questions that most patients will have about dialysis.

What is dialysis?

Dialysis is an artificial way of replacing some of the kidneys' functions. The kidney performs a lot of essential functions in the body, beyond just "making urine." I have covered these functions in detail elsewhere, but here is a brief summary: 

  • The kidneys regulate and maintain the level of all electrolytes like sodium, potassium, etc within a range that is essential for normal life 
  • They regulate the amount of water in your blood, and hence the concentration of your blood.
  • They produce a hormone that is essential to make red blood cells, called “erythropoietin”
  • They make sure that your bones stay healthy by producing a form of vitamin D
  • They dump excess acid, that is generated from normal metabolism, out from your system
  • Very importantly, they control your blood pressure

Dialysis attempts to replace some, but not all of these functions.

How is dialysis performed? What are the kinds of dialysis?

How dialysis gets performed depends on the kind of dialysis. One technique (which is the commonest one employed in the US) is called hemodialysis. Hemo is the Greek word for blood. Hence "blood dialysis" is when the patient's blood is taken from a "dialysis access" and circulated through a machine which has a filter that mimics the kidney's filtration function. Once the blood goes through this filter (called the dialyzer), the purified blood is returned to the patient. Hemodialysis is typically performed in a "dialysis center" (in-center hemodialysis), where it is usually done about three times every week, for three to four hours (this depends on the patient's size). However, it is also possible to perform hemodialysis at home. This is called home hemodialysis. This technique might be performed as often as five to seven times per week, but each session tends to be shorter at two to four hours each.

Another kind of dialysis that is also performed at home is called peritoneal dialysis. Peritoneum refers to the abdominal cavity. In this modality, a permanent catheter is inserted into the patient's peritoneum through the abdominal wall. Clean dialysis fluid is then instilled into the peritoneum, and this fluid sits there for a few hours where it cleans the blood of toxins. Then, this dirty fluid is drained out, and more clean fluid is instilled. This cycle is repeated a few times (typically at night using a machine called the "cycler"), and in the morning, the patient unhooks himself from the cycler and caps the catheter.

What is a dialysis access?

A dialysis access or shunt is the site where two needles are inserted when someone is receiving hemodialysis (patients on peritoneal dialysis will not have such a shunt, but rather a catheter that sits permanently on their belly). One of the needles in the shunt will channel blood from the body to the dialysis machine, and the other one will carry back the clean blood from the machine to the patient.

The shunt itself is a really a connection between an artery and a vein. It is placed by a surgeon, who might use your own vein to create this connection (this is called a fistula) or might use an artificial tube to make this connection (this is called a graft).

Can dialysis be performed at home?

Yes! Both peritoneal dialysis and home hemodialysis can be performed by the patients themselves at home. Your nephrologist and a dialysis nurse will train you for a few weeks on how to do this. Once you are comfortable doing it, they will let you do it in the comfort of your home.

You will still need to be seen about once a month by your nephrologist, and you will have both the nephrologist and a dialysis nurse available on call for troubleshooting. Dialysis nurses will often schedule a visit to your home in case it is something that cannot be taken care of on the phone.

Which type of dialysis is the "best"?

From a medical standpoint, no study has proven any modality to be necessarily better than the other. It is more of a lifestyle choice. Home dialysis is often preferred by patients who have the ability to take care of themselves, are proactive, do not want to be "tied down" to a dialysis center, or want to travel frequently. The independence that comes with home dialysis is empowering and means a lot to many patients. It also improves the quality of life since you are not making thrice-weekly trips to a dialysis center. However, "with great power comes great responsibility" since you do need to take ownership of your health to a large extent!

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