From the Research
Peritoneal dialysis filters waste from the blood by using the peritoneal membrane in the abdomen as a natural filter, with the most recent and highest quality study 1 supporting this process. The process begins with the insertion of dialysate fluid into the peritoneal cavity through a permanently implanted catheter. This fluid contains dextrose or icodextrin that creates an osmotic gradient, drawing waste products and excess fluid from the blood vessels surrounding the peritoneum into the dialysate solution. Some key points to consider about peritoneal dialysis include:
- The peritoneal membrane acts as a semipermeable barrier, allowing toxins like urea, creatinine, and excess electrolytes to pass through while retaining larger proteins and blood cells in the bloodstream.
- The effectiveness of peritoneal dialysis depends on the peritoneal membrane's surface area, permeability characteristics, and the concentration gradient maintained between the blood and dialysate solution, as noted in 2.
- After several hours of dwell time (typically 4-6 hours for manual exchanges or shorter periods for automated dialysis), the waste-filled fluid is drained out and replaced with fresh dialysate.
- This process is repeated multiple times daily, either manually through continuous ambulatory peritoneal dialysis (CAPD) or using a cycler machine overnight in automated peritoneal dialysis (APD), with the choice of method depending on patient needs and preferences, as discussed in 1.
In terms of the specifics of how peritoneal dialysis works,
- the dialysate fluid is infused into the peritoneal cavity, where it comes into contact with the peritoneal membrane, allowing for the exchange of waste products and excess fluids, as described in 1.
- the peritoneal membrane is dominated by small pores, which allow for the transport of water and small-molecular-size solutes, including electrolytes, by way of both diffusion and convection, as noted in 2.
- the glucose in the dialysis solution generates an osmotic force that drives convection, allowing for the removal of waste products and excess fluids, as discussed in 2.
Overall, peritoneal dialysis is an effective treatment for patients with end-stage kidney disease, and its effectiveness depends on a variety of factors, including the peritoneal membrane's surface area, permeability characteristics, and the concentration gradient maintained between the blood and dialysate solution, as supported by the most recent and highest quality study 1.