Continuous Ambulatory Peritoneal Dialysis (CAPD) is a medical treatment designed to support kidney function when the kidneys can no longer effectively filter waste products and excess fluid from the blood. This form of dialysis often allows individuals to perform their treatment in the comfort and privacy of their own homes. Unlike in-center treatments, CAPD integrates into a person’s daily routine, providing a different approach to long-term kidney support. It utilizes the body’s own internal membrane to clean the blood.
Understanding the CAPD Process
Continuous Ambulatory Peritoneal Dialysis functions by using the peritoneum, a natural membrane lining the abdominal cavity, as a filter. This thin membrane contains a rich network of tiny blood vessels, making it suitable for exchanging waste products and fluids. A soft, flexible tube, known as a catheter, is surgically placed into the abdomen to allow access to this peritoneal space.
The process begins with the “fill” step, where a sterile dialysis solution, called dialysate, is introduced into the peritoneal cavity through the catheter. This solution contains dextrose (a type of sugar), which plays a crucial role in the filtration process. The dextrose creates an osmotic gradient, drawing excess water and waste products from the blood vessels within the peritoneum into the dialysate.
Following the fill, the dialysate remains in the abdomen for a prescribed period, known as the “dwell time,” which commonly lasts between 4 to 6 hours. During this time, waste substances like urea and creatinine move from the capillaries in the peritoneum into the dialysate through a process called diffusion. Excess fluid is pulled in by osmosis, allowing for a gentle and steady removal of toxins.
Once the dwell time is complete, the “drain” step occurs. The waste-filled dialysate is drained from the abdominal cavity, typically into an empty bag, using gravity. This used fluid, now containing the removed waste and excess water, is then discarded. The entire sequence of filling, dwelling, and draining is referred to as an “exchange” or “session.” Individuals typically perform three to five exchanges throughout the day, with one longer dwell time overnight while sleeping. Each manual exchange takes approximately 30 to 40 minutes to complete.
Who Is CAPD For?
Continuous Ambulatory Peritoneal Dialysis is a treatment option for individuals diagnosed with end-stage renal disease (ESRD), a condition where the kidneys have failed and can no longer adequately filter waste products from the blood. CAPD is considered an alternative to hemodialysis, offering a home-based approach to treatment.
Candidacy for CAPD involves several considerations beyond medical necessity. Patients need to be in overall stable health and prefer home-based therapy, which offers more flexibility than in-clinic treatments. The ability to perform daily exchanges independently or with trained caregiver assistance is also important. A suitable home environment that supports necessary hygiene and supply storage is also part of the assessment.
Daily Life with CAPD
Life with Continuous Ambulatory Peritoneal Dialysis involves integrating the exchange routine into one’s daily schedule. An advantage of CAPD is the independence and flexibility it offers, as treatments can be performed at home, at work, or even while traveling, without the need for a machine. This allows individuals to maintain more control over their time and daily activities compared to other forms of dialysis.
Patients and their caregivers undergo training to learn the steps of performing exchanges and managing equipment. This training covers practices such as aseptic technique, important for preventing infections. It ensures individuals are comfortable and proficient in handling dialysate bags, connecting and disconnecting tubing, and monitoring the process.
While exchanges require time each day, the periods between them allow for normal activities. Many individuals schedule exchanges around mealtimes and bedtime, making the therapy a consistent part of their routine. This continuous, gentle nature of CAPD can lead to fewer dietary restrictions and a more stable fluid balance compared to other dialysis modalities.
Managing CAPD Safely
Maintaining hygiene and aseptic technique is important for individuals undergoing CAPD to prevent complications. The main concern is peritonitis, an infection of the peritoneum, which can occur if bacteria enter the abdominal cavity, often through the catheter or during an exchange. Adhering to proper handwashing before touching the catheter or equipment helps prevent this type of infection.
Patients are taught to recognize signs of problems, such as cloudy dialysate, an indicator of peritonitis, along with abdominal pain, fever, nausea, or vomiting. Prompt medical attention is necessary if these signs appear, as early treatment can reduce its severity and impact on the dialysis regimen. Regular medical check-ups are also part of the routine to monitor overall health and treatment effectiveness.
Proper care of the catheter exit site, where the tube exits the skin, is important for infection prevention. This involves daily cleaning of the site and careful handling to prevent trauma or irritation. Individuals on CAPD follow prescribed dietary and fluid restrictions, which a renal dietitian helps manage, to ensure proper nutrient intake and fluid balance.