What Is Dialysis? A Simple Guide to How It Works and What to Expect
09/30/2025
Your kidneys play a vital role in maintaining overall health by filtering waste products and excess fluid from your blood. However, when chronic kidney disease or kidney failure occurs, the kidney function declines, and they can no longer perform these essential tasks. According to the National Kidney Foundation, approximately 786,000 people in the United States live with end-stage kidney disease (ESKD), with nearly 558,000 relying on dialysis sessions to survive.
When symptoms of kidney failure appear, patients often need dialysis to help remove waste from the blood and regulate fluid levels. Dialysis may need to be performed for the rest of your life, unless a kidney transplant is an option. This guide explores the main types of dialysis, focusing on hemodialysis, which is the preferred treatment for many patients.
Understanding Dialysis: How It Works
Dialysis treatment is a process that artificially removes waste products and excess fluid from the blood when the kidneys can no longer perform these functions. The two main types of dialysis are:
- Hemodialysis (most common and preferred)
- Peritoneal dialysis
Both methods help maintain electrolyte balance, remove waste products, and sustain life, but they function differently.
Types of Dialysis: Hemodialysis vs. Peritoneal Dialysis
Hemodialysis: The Preferred Dialysis Treatment
Hemodialysis is the most commonly used dialysis treatment. This process involves a dialysis machine that filters waste products from the blood through an artificial kidney (dialyzer) before returning the filtered blood back into your body.
- Where It’s Performed: A dialysis center, hospital, or at home with proper training (hemodialysis at home). Learn more about home dialysis options here.
- Procedure: Blood is drawn from a blood vessel, filtered, and returned to the body.
- Frequency: Standard treatments occur three times a week, but home hemodialysis may be done more frequently.
- Side Effects: Common side effects include muscle cramps during the procedure, low blood pressure, and fatigue.
A minor surgical procedure is required to create a vascular access point for hemodialysis. The most common options include an AV fistula or graft or a tube called a catheter placed in a vein in your neck.
Peritoneal Dialysis: An Alternative Procedure
Peritoneal dialysis (PD) works differently by using the peritoneal membrane in the abdomen to filter the blood. A dialysis solution is introduced into the abdominal cavity through a catheter, allowing waste products to be absorbed before being drained.
There are two dialysis options under peritoneal dialysis:
- Continuous Ambulatory Peritoneal Dialysis (CAPD): Performed manually several times during the day without a machine.
- Automated Peritoneal Dialysis (APD): Uses a machine overnight (haemodialysis or automated peritoneal dialysis).
Peritoneal dialysis can be done at home, providing more independence, but it carries a higher risk of infection. Research shows that hemodialysis provides better long-term survival rates for many patients. However, many people on dialysis have lived well on dialysis for 20 or even more years.
What to Expect When You Start Dialysis
The Hemodialysis Process
- A vascular access point is used to draw blood.
- The dialysis machine removes waste products and excess fluid from the blood.
- The filtered blood is returned to your body through the same access.
- A dialysis care team closely monitors the procedure, ensuring patient safety, adjusting fluid removal as needed, and checking for any potential complications like clotting or infections.
Dialysis Treatment Side Effects and Risks
- Common Side Effects: Low blood pressure, dizziness, and nausea. Some patients also experience headaches, itching, or muscle cramps.
- Possible Risks: Infections, clotting, and electrolyte imbalances. Long-term dialysis patients may also develop heart complications due to fluid and electrolyte fluctuations.
- Studies Show: Patients on more frequent hemodialysis experience better blood pressure control and lower mortality rates. According to studies from the National Kidney Foundation, those who undergo longer or more frequent dialysis sessions have improved survival rates and a better quality of life.
Managing Life on Dialysis: Diet, Lifestyle, and Support
Dialysis Diet: Nutritional Considerations
- Follow a dialysis diet by reducing sodium and potassium intake to prevent fluid retention and heart complications.
- Need to be careful with fluid from your blood intake to prevent swelling and breathing difficulties. Excessive fluid intake can lead to complications such as high blood pressure and heart strain.
- Limit phosphorus-rich foods like dairy and processed foods, as phosphorus buildup can weaken bones over time.
- Maintain a high-protein diet to help compensate for protein loss during dialysis treatments.
Adjusting to Dialysis Sessions
- Many patients can still work and enjoy daily activities with proper scheduling and lifestyle adjustments.
- Dialysis at home options, including home haemodialysis or peritoneal dialysis, provide greater flexibility, allowing patients to undergo treatment on their own schedule.
- Support from a dialysis team or dietitian can make adjustments easier. Mental health counseling or peer support groups can also help individuals adapt to life on dialysis.
- Adhering to prescribed medications and monitoring blood pressure regularly are essential for maintaining overall health while on dialysis.
Dialysis and Pregnancy
- Although rare, successful pregnancy while on dialysis is possible with close medical supervision and frequent dialysis sessions. Research indicates that increasing the frequency of dialysis can improve pregnancy outcomes.
- More frequent dialysis may be needed to maintain maternal and fetal health, as it helps regulate fluid balance and removes toxins more effectively.
- Pregnant women on dialysis require specialized care from a multidisciplinary team, including nephrologists and obstetricians, to manage risks and optimize health outcomes.
- Some women with end-stage kidney disease may choose to delay pregnancy until after a kidney transplant, as transplant recipients generally have better pregnancy outcomes.
Kidney Transplant: A Long-Term Solution
While many patients have lived well on dialysis, a kidney transplant is the best long-term solution for many people on dialysis.
- According to United Network for Organ Sharing, Over 90,000 people in the U.S. are waiting for a kidney transplant.
- Patients receiving a transplant often experience better kidney function, higher life expectancy, and improved quality of life.
- Living donors provide faster solutions than deceased donors.
Advancements in Dialysis Treatment
- Research into bioartificial kidneys could revolutionize dialysis equipment, potentially reducing or eliminating the need for traditional dialysis.
- Wearable dialysis devices are being developed to provide continuous blood filtration, improving patient mobility and quality of life.
- Personalized dialysis options allow for more tailored treatment plans, reducing side effects and enhancing patient outcomes.
- Alternative procedures, such as regenerative medicine and xenotransplantation, aim to restore kidney function without the need for dialysis.
- Advances in home dialysis technology enable safer and more efficient at-home treatments, giving patients greater independence.
A New Era for Dialysis Patients
With continuous advancements in dialysis technology, the future holds promising opportunities for better patient outcomes. As research progresses, treatment options will become more efficient, less invasive, and tailored to individual needs. Patients and caregivers can stay hopeful, knowing that medical innovation is making dialysis more manageable and improving quality of life every day.
Frequently Asked Questions
Hemodialysis usually lasts about 3 to 5 hours per session, typically three times a week.
Dialysis itself is not painful, but some patients may experience discomfort from needle insertion or muscle cramps during treatment.
Some patients experience fatigue after treatment, but proper nutrition and rest can help manage energy levels.
No, dialysis is a treatment that helps replace kidney function, but a kidney transplant is the only cure.
Avoid high-sodium, high-potassium, and high-phosphorus foods such as processed foods, bananas, and dairy products.
Dr. Allen Kaufman is the Chief Medical Officer and Senior VP for Clinical & Scientific Affairs at Dialyze Direct, with over four decades of experience in Nephrology. He began his career in 1980 and has held leadership roles including Chief of Nephrology & Hypertension at Beth Israel Medical Center (1998–2004), Chief of Dialysis at the Bronx VA Medical Center (1982–1990), and Chief of the Yorkville Dialysis Unit at Beth Israel and the Renal Research Institute (1990–2000). Dr. Kaufman has authored over 100 scientific publications and served as Principal or Co-Investigator on numerous NIH-funded research studies. A Fellow of the American College of Physicians, he is board-certified in Nephrology and Internal Medicine. He earned his medical degree from the University of Rochester and completed training at the Hospital of the University of Pennsylvania and Mount Sinai in New York. Dr. Kaufman is widely recognized with multiple “Best Doctor” and “Patients’ Choice” awards.