- On November 8, 2017 /
- By davita /
- In Treatment Options
The kidneys are a pair of organs that are extremely important to maintain a healthy body. Rightly functioning kidneys help in the removal of metabolic waste from the body, regulate blood pressure, and keep your bones strong. Kidneys also maintain the right amount of chemicals like sodium and potassium in the blood and produce a hormone called erythropoietin that is responsible for the production of red blood cells.
In case of kidney failure, the kidneys do not function optimally, and dialysis is a treatment used to take over the functions of the failed kidneys. There are 2 types of dialysis used in the treatment of kidney failure, hemodialysis and peritoneal dialysis. In hemodialysis, the blood is passed through a filter outside the body, cleansed, and returned to the body. Hemodialysis can be done at a dialysis center or even at home. In peritoneal dialysis, the blood is cleansed within the body. A special fluid is infused into the abdomen to absorb the waste from the blood that passes through the small vessels in the abdominal cavity, and finally the fluid is drained away. Peritoneal dialysis can be performed by the patient itself and is typically done at home.
How does hemodialysis work?
Preparing for hemodialysis
A minor surgery is conducted by a vascular surgeon to join a vein and an artery together and make the blood vessel larger and stronger. This will make it easier to transfer your blood into the dialysis machine and back again. This surgery is done about 4 to 8 weeks before you begin dialysis. In some cases, when the blood vessels are too narrow to create an AV fistula, an alternative procedure called an AV graft is done, in which a piece of synthetic tubing, i.e., a graft is used to connect the artery to the vein.
The hemodialysis procedure
During hemodialysis, two thin needles are inserted into the AV fistula or graft, and one needle will pass the blood into the dialyzer or the dialyzing machine. The dialyzer is made of a series of membranes which act as filters and contains a special liquid called the dialysate. The membranes filter the waste products from the blood, and pass it into the dialysate. The used dialysate fluid is then pumped out of the dialyzer, and the cleansed or filtered blood is passed back into the body through the second needle.
Hemodialysis is needed 3 times a week in most cases, and each session will last for about 4 hours.
Peritoneal dialysis is of two types:
Continuous Ambulatory Peritoneal Dialysis (CAPD)- in this type of dialysis, the blood is filtered several times in the day.
Automated Peritoneal Dialysis (APD)- this type of dialysis uses a machine to filter your blood during the nights when you’re asleep.
Preparing for the treatment
As in hemodialysis, the patient has to undergo a small surgery to make an opening in the abdomen before beginning CAPD or APD, to allow the dialysate to be pumped into the space inside the abdomen. An incision is made just below the belly button to insert a catheter that will stay permanently attached to the abdomen, and the dialysis team will train you to carry out the treatment yourself.
CAPD is begun 2 to 3 weeks after the insertion of the catheter. In CAPD, 1 to 3 litres of the dialysate are run into the abdominal cavity via the catheter, and the dialysate remains in the cavity for several hours before it is drained out into an empty bag by gravity. The waste products which are normally removed by the kidney, pass into the dialysate which is then disposed on into the toilet. A new bag of dialysate is then drained into the abdominal cavity and the exchange process is usually carried out 4 to 5 times in a day, every day. Each exchange process lasts for about 30 to 45 minutes.
APD is another type of peritoneal dialysis which uses the same peritoneal catheter as CAPD. The only difference between the two methods is that with APD a machine is programed to control how much fluid goes in and out and how often this is done.
In APD, firstly, the machine is prepared with lines and these lines are connected to about 10 to 15 litres of fluid. The end of the line from the machine is connected to the patient’s catheter at bedtime and remains connected all night, for eight hours on average. The machine is programmed to control the fluid movement in and out of the body, using a number of clamps and pumps and when the fluid should drain out and when new fluid should be put in.
As every patient’s need for the amount of dialysis is different, the machine is set up to suit individual requirements.