What is dialysis?

When the kidneys do not work as well as they should, there are certain functions of the kidney that must be replaced by artificial means. If this is not done soon enough, it can be very harmful for the body. Dialysis is a process by which the excess toxins and fluid in the body can be removed. There are two types of dialysis:

  • Hemodialysis
  • Peritoneal Dialysis 

Let us see what these two types of dialysis are.

Hemodialysis is a form of dialysis where dialysis is performed intermittently.  The blood in the body is continuously removed during the hemodialysis process and passed through an artificial kidney which cleans it. The treatment is an intermittent treatment and is performed ranging from three hours thrice weekly to eight or nine hours six to seven times a week.

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There has to be a convenient mechanism to remove the blood from the body and return it to the body after passing through the artificial kidney. For this, an “access” is created. An access can be of different types. An Arteriovenous Fistula is thought to be the best form of access. A small surgery is required for this to be done. The fistula is usually ready within a few weeks of the surgery. Needles connected to tubes are then inserted into a vein in the body using which the blood is drawn and passed through the artificial kidney by a pump.

Temporary accesses such as shunts or jugular catheters are used when dialysis needs to be started immediately or is needed for short periods of time.

Optimal Hemodialysis: The more number of hours of hemodialysis a patient gets, the better it is for him or her. This is because the blood is cleaned better and excess fluid is not allowed to accumulate. The current ‘gold standard’ for hemodialysis is daily nocturnal hemodialysis where hemodialysis is performed for 7-8 hours, 6-7 times a week.

Peritoneal Dialysis

Peritoneal Dialysis is a form of dialysis where a special fluid is infused into a cavity called the peritoneal cavity inside your abdomen and kept there for a few hours. During this period, toxins and excess fluid in your body gets transferred to this fluid through a semi-permeable membrane called the peritoneal membrane enclosing the peritoneal cavity. After the period, the fluid is removed from the body and fresh fluid is infused into the abdomen.

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Peritoneal dialysis can be done in two main ways:

1. Continuous Ambulatory (CAPD): Here the fluid is infused into the peritoneal cavity and left there for about 3 to 6 hours during which time the patient can go about his routine activities such as office work, exercise, watch a movie, travel etc. After this period, the fluid is removed because it has removed a lot of waste from the blood and cannot remove too much more.

Fresh fluid is infused and the process repeats. The removal of old fluid and infusion of fresh fluid is called an ‘exchange’. Most people require about 3 to 4 exchanges. The fluid volume that is infused can vary between 1 to 3 liters depending on the person’s weight and size.

2. Continuous Cyclic (CCPD): Here the exchanges are usually performed by a machine called a Cycler. The patient connects to a machine before sleeping at night. The machine then infuses fresh fluid and removes it after 2-3 hours and infuses fresh fluid. Usually the cycles are shorter than in CAPD.

Some people adopt a mix of both CAPD and CCPD. They hook up to the machine and do a few cycles at night, infuse fresh fluid in the morning before getting off the machine and then do one mid-day exchange. This offers better removal of wastes.

For peritoneal dialysis to be performed, a tube is inserted into the stomach to enable fluid removal and filling. Dialysis can be started 2-4 weeks after the surgery.

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To see which modality among these two suits you, please click here