Understanding the Peritoneal Cavity
Peritoneal dialysis utilizes the body’s abdominal lining, known as the peritoneum, for filtering waste products from the blood. This process occurs within the peritoneal cavity, the space enclosed by the peritoneum inside the abdomen. The peritoneal cavity is a large, sterile space that contains organs such as the stomach, intestines, and liver.
The peritoneum is a thin, semipermeable membrane that lines the abdominal wall and covers the abdominal organs. It has an extensive network of tiny blood vessels, making it an ideal natural filter for dialysis. Its semipermeable nature allows small molecules like waste products and excess water to pass through, while larger molecules, such as blood cells and proteins, are retained. The peritoneal cavity’s large surface area, typically ranging from 1 to 2 square meters in adults, provides an ample exchange surface for the dialysis process.
The Peritoneal Dialysis Catheter
A peritoneal dialysis catheter is a flexible, thin tube designed for long-term use, allowing for the repeated introduction and drainage of dialysis solution. These catheters are typically made from biocompatible materials, most commonly silicone, which is well-tolerated by the body.
The internal segment of the catheter resides within the peritoneal cavity, featuring multiple side holes near its tip to facilitate efficient flow of dialysis solution. The external segment extends outside the body through a small opening in the skin, known as the exit site, and connects to the tubing system for dialysis exchanges. Between these two segments, the catheter typically has one or two cuffs. These cuffs help anchor the catheter in place under the skin and promote tissue ingrowth, which forms a barrier against bacterial migration along the catheter’s tract.
How the Catheter is Placed
The placement of a peritoneal dialysis catheter is a surgical procedure, usually performed by a general surgeon or a kidney specialist. It can be done under local anesthesia with sedation or general anesthesia, and is often an outpatient procedure or may require a short hospital stay.
There are two primary surgical approaches for catheter insertion: open surgery or laparoscopic surgery. In open surgery, a small incision is made near the belly button. The surgeon guides the catheter into the peritoneal cavity, positioning its tip in the lowest part of the abdomen for optimal drainage.
Laparoscopic surgery involves smaller incisions, through which a tiny camera and specialized instruments are inserted. This method allows the surgeon to visualize the catheter’s placement on a monitor, potentially reducing surgical trauma. After the internal portion is positioned, the catheter is tunneled subcutaneously (under the skin) away from the initial incision site to create a separate exit site. This subcutaneous tunnel helps reduce the risk of infection by providing a longer pathway for bacteria. The catheter is then secured, and the incisions are closed, leaving the external segment accessible for dialysis connections.
Life with a PD Catheter
Immediately following surgical placement, a healing period is necessary before the catheter can be used for regular dialysis exchanges. This period, often called the “break-in” phase, typically lasts two to four weeks, allowing tissues around the catheter to heal and cuffs to properly integrate. During this time, the catheter site must be kept clean and dry to prevent complications.
Daily life with a PD catheter involves careful management of the exit site to prevent infection, which is the most common complication. Patients are taught specific techniques for cleaning the area where the catheter exits the skin and for applying a sterile dressing. This routine care is performed daily or every other day. Maintaining meticulous hygiene, especially during dialysis exchanges, is important for preventing bacteria from entering the peritoneal cavity.
Patients with a PD catheter can generally shower once the exit site has healed, provided they protect the site from direct water exposure, often by using waterproof dressings. Clothing choices may need slight adjustments to avoid irritating the exit site or tugging on the catheter. The catheter remains a permanent fixture, allowing the convenience of performing dialysis treatments at home, often during the night while sleeping or during the day at scheduled intervals.