Dialysis is a medical procedure that takes over the work of failing kidneys, filtering waste products, excess salts, and fluids from the blood. This treatment becomes necessary when the kidneys can no longer perform their natural functions adequately, a condition known as kidney failure. Dialysis serves as a life-sustaining therapy, helping to maintain the body’s balance and prevent the accumulation of harmful substances. Its fundamental purpose is to mimic the kidney’s role in purification, ensuring the body’s internal environment remains stable.
Understanding Kidney Failure
Healthy kidneys maintain fluid and electrolyte balance, regulate blood pressure, produce hormones such as erythropoietin which stimulates red blood cell production, and activate vitamin D for bone health. They continuously process about 1 liter of blood per minute, removing waste products like urea, creatinine, and uric acid.
When kidneys fail, these vital functions cease or become severely impaired. Toxins and waste products begin to build up in the bloodstream, leading to a condition called uremia, which can cause symptoms like fatigue, nausea, and confusion. The body also retains excess fluid, causing swelling in the legs, ankles, or around the heart and lungs, potentially causing shortness of breath. Imbalances in electrolytes such as potassium and phosphorus can occur, posing risks to heart rhythm and bone health.
Types of Dialysis Explained
When kidney function declines to a severe level, medical intervention becomes necessary to remove accumulated waste and fluid from the body. Dialysis offers two primary methods: hemodialysis and peritoneal dialysis. Both purify the blood to compensate for failed kidney function.
Hemodialysis involves filtering the blood outside the body using an artificial kidney machine. Peritoneal dialysis uses the natural lining of the patient’s abdomen, the peritoneum, as a filter. A special solution is introduced into the abdominal cavity, where it absorbs waste products, and is later drained.
Hemodialysis: Procedure and Patient Experience
Hemodialysis typically involves diverting blood from the patient’s body through a specialized filter called a dialyzer. This device contains thousands of tiny hollow fibers, and as blood flows through these fibers, a dialysate solution flows around the outside in the opposite direction. Waste products and excess fluid move from the blood across a semipermeable membrane in the fibers into the dialysate, while beneficial substances like red blood cells and proteins remain in the blood. The cleansed blood is then returned to the patient’s body.
To facilitate this external blood circulation, a vascular access point is surgically created. The most common and preferred type is an arteriovenous (AV) fistula, which is created by surgically joining an artery and a vein, typically in the arm, allowing the vein to enlarge and strengthen over several weeks or months. Another option is an AV graft, which uses a synthetic tube to connect an artery and a vein, ready for use sooner but with a higher risk of infection and clotting compared to a fistula. For immediate or temporary access, a central venous catheter can be inserted into a large vein.
Hemodialysis sessions are generally conducted three times a week, with each session lasting approximately three to five hours, depending on the patient’s size, remaining kidney function, and the amount of waste to be removed. During a session, patients sit or recline while connected to the dialysis machine. Some patients may experience side effects such as muscle cramps, low blood pressure, or nausea during or immediately after treatment, which are typically managed by the healthcare team.
Peritoneal Dialysis: Procedure and Patient Experience
Peritoneal dialysis utilizes the peritoneum, a membrane lining the abdominal cavity, as a natural filter for the blood. A soft, thin tube, known as a peritoneal catheter, is surgically placed through the abdominal wall, typically near the navel, and remains there permanently. This catheter provides the access point through which dialysate, a special fluid containing dextrose or other osmotic agents, is introduced into the peritoneal cavity.
Once inside the abdomen, the dialysate dwells there for a prescribed period, usually between four and eight hours. During this “dwell time,” waste products, toxins, and excess fluid from the blood vessels that line the peritoneum naturally pass across the membrane into the dialysate, driven by osmotic pressure and diffusion. After the dwell time, the fluid, now laden with impurities, is drained out of the abdomen and discarded. This cycle of filling, dwelling, and draining is referred to as an exchange.
There are two main types of peritoneal dialysis: Continuous Ambulatory Peritoneal Dialysis (CAPD) and Automated Peritoneal Dialysis (APD). With CAPD, exchanges are performed manually by the patient, typically three to five times a day, at home or at work, allowing for considerable flexibility in scheduling. APD uses a cycler machine to perform the exchanges automatically, usually overnight while the patient sleeps, providing more freedom during the day. The presence of the permanent catheter requires meticulous care to prevent infections, such as peritonitis, which is an inflammation of the peritoneum.
Living with Dialysis: Common Facts and Considerations
Adjusting to life with dialysis involves significant lifestyle changes, particularly regarding diet and fluid intake. Patients typically follow strict dietary restrictions to manage the accumulation of waste products and excess fluids between treatments. This often includes limiting sodium to control thirst and fluid retention, potassium to prevent dangerous heart rhythm abnormalities, and phosphorus to protect bone health. Protein intake may also need to be adjusted, as protein breakdown produces waste products that dialysis must remove.
Managing medications is another constant aspect of daily life for dialysis patients. Many individuals require multiple prescriptions to control blood pressure, prevent anemia (often needing erythropoietin-stimulating agents), manage bone disease with phosphorus binders and vitamin D supplements, and address other co-existing medical conditions. Adherence to these medication regimens is important for overall health and to minimize complications.
Despite the benefits of dialysis, patients may still face various potential complications over time. These can include cardiovascular issues, which are a leading cause of morbidity and mortality, often exacerbated by fluid overload and electrolyte imbalances. Infections, particularly at vascular access sites for hemodialysis or the peritoneal catheter site for peritoneal dialysis, are also a concern. Other common issues include anemia, bone disease due to mineral imbalances, and chronic inflammation, which can affect overall well-being and energy levels.
Dialysis significantly impacts daily life, requiring careful planning around treatment schedules, whether it’s clinic visits for hemodialysis or home exchanges for peritoneal dialysis. While travel is possible, it demands advance planning to arrange for treatments in different locations. Maintaining employment can be challenging for some, depending on the physical demands of their job and the energy levels post-treatment. A supportive healthcare team, including nephrologists, nurses, dietitians, and social workers, plays an important role in helping patients navigate these challenges and adapt to their ongoing treatment.