Peritoneal dialysis takes place inside your body without having to circulate your blood through a machine, and you can usually do it at home.
We will give you full training, usually over about a week, showing you how to connect and disconnect from the machine, do the fluid exchanges and identify and cope with any problems. Once you feel happy to start to dialyse at home, we will arrange regular delivery of all necessary supplies.
Peritoneal Dialysis (PD): the process
At least two weeks before you start PD, you will need to visit the clinic to have a catheter inserted through your abdominal wall into your abdominal cavity. This is done by a surgeon or nephrologist under general or local anaesthetic. The catheter stays in place permanently, with a small part exiting the skin for connection to the bags from which fluid will be infused and removed. You will be shown how to keep the catheter and insertion site clean as it is vital to avoid infection.
In each treatment cycle, you will use the catheter to infuse a sterile dialysis solution into your abdomen. The fluid will stay there for 4-12 hours and you will need to repeat this process 3-5 times every day, a process called continuous ambulatory peritoneal dialysis (CAPD), or it can be done overnight with the help of a machine, a process called automated peritoneal dialysis (APD).
The reason that water is removed from your blood in this way is that the dialysis fluid has a high concentration of glucose, and this pulls water out of your blood across your own peritoneal membrane. This process is called 'ultrafiltration'. Once this has occurred, when the fluid is drained, it takes with it waste products and excess water from your body.
What is the difference between CAPD and APD?
CAPD and APD are both done at home, or a place of your choice. Unless you have concerns where you need our help or advice, you will usually visit the clinic only for the initial insertion of the peritoneal catheter and for review.
CAPD involves 3-5 fluid exchanges each day, while APD treatment is done overnight. One advantage of CAPD is that it may help preserve any remaining kidney function that you have better than APD.
In CAPD, about 2 litres of dialysis solution are infused into your abdomen through the catheter. After 4-12 hours ("dwell time"), this fluid, containing waste products and excess water, is drained for disposal and a new sterile solution infused into your abdomen. This "exchange" mainly uses gravity and takes 20-40 minutes, 3-5 times a day. At all other times you can move about normally, allowing you to work, study, exercise or travel.
APD follows the same basic principles as CAPD, but exchanges occur while you are asleep, with the help of a 'cycler' machine. This can be an advantage as it leaves your daytimes free. It will usually take you about 10 days to learn how to use this machine.
The cycler measures the fluid needed for each exchange and times the delivery, dwell and drainage carefully and automatically, removing metabolic waste and excess water from your body over 8-10 hours. Just before you disconnect from the machine in the morning, you can infuse a 'last fill' solution which stays in your abdominal cavity during the day, possibly requiring an extra exchange before your overnight dialysis.
The APD device is the size of a small wheeled suitcase and easily portable. The machine is designed to adapt to your normal sleeping patterns and you can interrupt treatment if you need to get out of bed during the night.
Newer APD machines have programmable data cards containing prescribed treatment details and which can capture data from each dialysis session. Diaverum currently offers these to patients in the UK and Germany.
As with CAPD, some space is needed at home for storage of the APD device and dialysis supplies.