As described in the introduction, peritoneal dialysis is one of the two established methods to remove toxins and excess water from the human body. The lining of the abdomen (peritoneum) is a thin, shiny membrane that has a surface of as much as two square meters and covers the entire abdominal cavity. Since the peritoneum has good blood circulation, it is an excellent natural filter membrane.


The principles of peritoneal dialysis


Peritoneal dialysis exploits this unique trait. First, a special fluid – the dialysis solution – is introduced at regular intervals to the abdominal cavity through a catheter. This fluid surrounds the peritoneum and allows metabolites to move from the tiny blood vessels into the dialysis fluid. Among the metabolites are the most well-known, such as urea and creatinine, as well as a number of other substances which gather in the blood of dialysis patients but are normally removed by healthy kidneys. The dialysis solution carrying these substances is then removed several hours later through the catheter and replaced by fresh solution.

In addition to the metabolites, excess water must also be removed from the patient’s body. Therefore, sugar is added to the dialysis solution in a concentration far higher than it is in the blood. This offers just one option of balancing the concentration: water flows from the blood through the membrane and into the solution with the high sugar content. This process is known as osmosis.