Dialysis Basics
Dialysis Basics
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What Is a Peritoneal Dialysis Machine?

Peritoneal dialysis (PD) works by using your body’s peritoneal membrane and exchanges of dialysate fluid to filter and clean your blood. You can do your exchanges manually throughout the day or by using a peritoneal dialysis machine—also called a cycler—at night. Doing PD using a machine is called continuous cycling peritoneal dialysis (CCPD) or automated peritoneal dialysis (APD).

How does a peritoneal dialysis machine work?

Once you’re hooked up to your PD cycler via your peritoneal catheter and are ready to begin, your cycler will do the number of exchanges you need in 1 session over an 8-to-10-hour period. Most people like to use their cyclers at night while they sleep, so they can have their days free.

Each exchange is a 3-step process: your peritoneal cavity is filled with dialysate solution, it "dwells" there for the time needed to clean your blood and remove excess fluid and then the solution is drained out. Your cycler repeats this process until you’ve completed the number of exchanges prescribed by your nephrologist, which may be 3 to 5 cycles.

Here’s a basic overview of a cycler’s parts and functions:
Parts of a peritoneal dialysis machine: control panel, solution supply, heater tray and scale, heater bag, pump and tubes, drain line to drain bag or direct chain.
  1. The control panel is where you communicate with the machine. It lets you start, stop and pause your dialysis treatment as needed. The control panel provides step-by-step instructions to guide you through the entire treatment process. 
  2. The solution supply is all the bags of dialysate that you’ll need for 1 session. Your care team will decide how much you need and exactly which strength of solution you should use.  
  3. The heater tray is where your dialysate is warmed to the right temperature to go into your body. The scale tells the cycler how much fluid is going in so it’s sure to drain the right amount. It also prevents the machine from pumping when there’s no fluid left. 
  4. The heater bag is filled from your solution supply. The cycler pumps dialysate into the heater bag and keeps it there until it’s warmed to the right temperature and you’re ready for your next fill, though it may feel a little cool to you. 
  5. The pump and tubes connect to the machine, the solution bags, your catheter and a drain line. The machine will open and close the tubes and pump the right fluids in the right direction for each exchange. The tubes are long so that you’ll be able to move around or get up and go to the bathroom while you’re connected. 
  6. The used dialysate solution drains from your body through your catheter and into a drain line. The drain line either connects to a drain bag to be discarded. 

What does peritoneal dialysis solution do?

Peritoneal dialysis solution.
Peritoneal dialysis solution, also called dialysate, is the fluid used to absorb waste products, toxins and extra fluid from your body through the lining of your abdomen, also called the peritoneum. The waste, toxins and fluid are then removed from your body during dialysis, leaving the right amounts of electrolytes and nutrients in your blood for your body to use. There are different strengths of dialysate depending on your body’s needs. Your nephrologist will prescribe the strength that is right for you. 

What is peritoneal dialysis solution made of?

Peritoneal dialysis solution is made of water and electrolytes. The electrolytes are mostly salts and sugar that are naturally found in your body. Your nephrologist will prescribe a dialysate solution with the precise amount of each electrolyte to match your body’s needs. If you have diabetes, your doctor will adjust your medications, if needed, to allow for the extra sugar going into your body from the solution. 

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DID YOU KNOW?

At the start of your session, your cycler will ask if you added dialysate to your body without the machine. Basically, it’s checking to see if you’ve started a manual exchange so it can drain any fluid that’s in your abdomen before your first cycler fill.
Keep your catheter clean and use proper techniques for handwashing or sterilizing to prevent peritonitis.
Learn more

What is dwell time in peritoneal dialysis?

PD dwell time.
Dwell time is the time that the dialysate remains in your abdomen during a dialysis session. This is when your body does the work of filtering and cleaning your blood through your peritoneum—your body’s natural filter. Waste products and excess fluid pass from your blood through your peritoneal membrane and into the dialysate solution, which is then drained from your body.

Your dwell time is determined by your nephrologist, based on the number of exchanges you are doing each day and by the condition of your peritoneal membrane. Shortening your dwell time by even 5 minutes can make dialysis less effective.

What happens if there’s a power failure during dialysis?

PD Support
If the power goes off while your cycler is working, it will automatically close all the lines. The machine will store the information about your session using a backup battery. If the power comes back on soon, that stored information lets the machine continue the session. if not, it’s best to call your home dialysis nurse about what to do next—support is available 24/7 if you ever have questions or concerns. Remember, you can always do your exchanges manually.

TIP: TALK TO YOUR POWER COMPANY 

Register with your local power company to get on their medical priority list. Letting your provider know that you use electricity for home dialysis can help you get your power restored faster.