Peritoneal Dialysis Cassette and Tubing

How does one APD machine work?

Automated peritoneal dialysis (APD) is done using a machine that fills patient’s peritoneal cavity with fresh dialysis solution, also called PD fluid or PD solution, and after a specified dwell time, drains the solution with waste out of patient’s body and then fills patient’s peritoneal cavity with new dialysis solution. The average treatment time for automated peritoneal dialysis is 9 hours at night while you sleep, but the doctor will prescribe what is best for patients.

Necessary supplies for APD
  • Large bags of PD fluid (PD solution) – Each PD fluid bag is filled with about 6 liters of PD fluid. Two or three bags are generally used through the night. The PD fluid bags are hooked up to a cassette in front of the cycler machine, which has a tube that is connected to the person’s peritoneal catheter. The catheter leads into the abdomen (peritoneal cavity), and during each exchange some of the fluid will flow from the bags into the abdomen and then later be drained out of the body. The PD solution dwells inside the peritoneal cavity, collecting the wastes and extra fluid from the body which is then drained out after each cycle is completed

  • Drain bag – The drain bag is one of two options used to remove the PD fluid from the peritoneal cavity. The drain bag is attached to a cassette that warms the fluid, sending it through tubes connected to the cassette into a person’s peritoneal cavity. The bag is clear so that the person may examine the waste and fluid that has been drained from the body. The used PD fluid should be clear, like urine. If it is cloudy, that can be an early sign of infection. Peritoneal dialysis patients who see this are recommended to call their PD nurse so they can receive treatment right away
  • Drain line –The second option for draining PD solution is a drain line. The drain line can be from 12 to 24 feet long in order to reach the bathroom for disposal in either the toilet, sink or shower area.
  • Cassette and tubing – The various tubes used to perform APD are gathered into one area of the cycler that keeps everything organized called the cassette or organizer. There are tubes that lead from the cassette to each dialysis solution bag (there can be from one to four bags used for each treatment depending on the patient’s prescription). The PD catheter is attached to a tube on the cassette as well. There is another tube that attaches from the cassette to the drain bag or drain line.

    The APD machine is programmed to drain the solution through the PD catheter to the drain tube (or drain line). Once the draining is finished, new dialysis solution is released from a dialysis solution bag to the peritoneal catheter that leads to the peritoneal cavity where the solution will dwell for a certain time based on the patient's prescription. This process will repeat until the APD treatment is completed for the night.