How does dialysis work?




How does dialysis work? What are the different types of dialysis?


Dialysis is a form of artificial kidney treatment. It does the job of the kidneys, in terms of clearing the body off waste products - but not quite consistently or efficiently as one’s own kidneys. It has been available as a treatment since the early 60s, but is more widely available and covered by most insurance plans since the late 70s. Roughly half million Americans (500,000) undergo dialysis treatments on a day to day basis across the country now. With advancing technology, availability of medications to address complications, and well trained staff, it is now a safe procedure. The dialysis in itself does not make the kidneys any better - this is important to understand! However, it does take over the job of the kidneys when they are diseased temporarily or permanently.

Dialysis is often used as a bridge to kidney transplantation in patients who would be considered eligible for a transplant. It is not uncommon for people to live on dialysis 8-10 years on an average these days.

Dialysis comes in two forms - hemodialysis and peritoneal dialysis.

Hemodialysis Dialysis (hemo means blood in Latin) involves cleaning the blood directly, usually with a machine and an artificial kidney. Blood from the patient (using a fistula or a catheter) goes into the artificial kidney, where the toxins are removed by the process of osmosis/diffusion, and the cleaned blood returns back to the patient. Excess fluid from the patient’s body can also be removed using the artificial kidney. This type of dialysis is usually performed three times a week at an outpatient dialysis center (can be done at home also if the patient is willing to get trained).


Trained nurses and patient care technicians ensure safe treatments and the well being of patients is monitored on a regular basis by doctors/nurse practitioners. The positive to this treatment is that it is done by trained staff and the patient does not need to do anything other than show up for their treatments. The downside is that they need to show up no matter what the weather is like, and there is not a lot of flexibility given that everyone is assigned a set day and time for their treatment. If they want to travel, they need to make arrangements well in advance so that they don’t miss their treatments and get sick during their travels.

Peritoneal Dialysis or PD (peritoneum refers to the membrane or grocery bag like covering around the organs of the abdomen) is done at home and does not involve any blood contact. A surgeon places a catheter (a piece of plastic tubing) well inside the patient’s abdomen, into the peritoneal cavity, and it stays there. Special fluid solutions containing purified water and some electrolytes are installed into this catheter; it dwells there for a set time and then is drained out. The peritoneal membrane acts as the artificial kidney here and facilitates the process of osmosis/diffusion. The advantage here is that it is performed by the patients themselves at home (after a brief training period), and offers some flexibility in terms of timing, travel etc. The downside is that it has to be performed without the assistance of any medical personnel, and has to be done every day.