What is hemodialysis?

Hemodialysis is a treatment that cleans your blood when your kidneys can no longer do it adequately on their own. A machine — sometimes called an artificial kidney or dialyzer — filters your blood outside your body, removes waste products and excess fluid, and then returns the clean blood to you.

Most people on hemodialysis go to a dialysis center three times a week, with each session lasting about 3 to 4 hours. Some people choose to do hemodialysis at home, which can allow for more frequent and shorter sessions.

How does a hemodialysis session work?

Before hemodialysis can begin, you need a way for the machine to access your bloodstream. This is called vascular access, and there are three types:

AV fistula — A surgeon connects an artery and vein in your arm, usually near the wrist or elbow. Over time, the vein grows larger and stronger. This is the preferred access because it lasts longer and has fewer complications. It takes 2–3 months to mature before it can be used — so it needs to be created well before you need dialysis.
AV graft — A synthetic tube connecting artery and vein. Used when a fistula isn't possible. Can be used sooner than a fistula.
Central venous catheter — A temporary tube inserted into a large vein in the neck or chest. Used for urgent dialysis when no permanent access is ready. More prone to infection, so it's a bridge — not a long-term solution.

During a session

Two needles are placed into your access site. Blood flows out through one needle, passes through the dialyzer filter (which removes waste and extra fluid), and returns through the second needle. Most people read, watch TV, or sleep during their sessions.

What are the side effects?

Hemodialysis is generally well tolerated, but some people experience:

  • Low blood pressure during or after treatment — can cause dizziness, nausea, or cramps
  • Fatigue after sessions, often called the "dialysis hangover"
  • Itching from waste products
  • Muscle cramps, especially toward the end of a session
  • Sleep problems
  • Anemia (low red blood cell count), treated with medications

Many side effects improve over time as your body adjusts, and your dialysis team can make adjustments to reduce them.

Diet on hemodialysis

Because dialysis only cleans your blood three times a week — not continuously like healthy kidneys — you need to be careful about what builds up between sessions.

  • Potassium: Limit high-potassium foods like bananas, oranges, potatoes, and tomatoes. Too much potassium can affect your heart rhythm.
  • Phosphorus: Limit dairy, nuts, beans, and dark colas. High phosphorus weakens bones and can cause itching.
  • Fluid: Limit fluid intake between sessions — your kidneys are no longer removing excess fluid continuously.
  • Sodium: Limit salt to help control thirst and blood pressure.
  • Protein: Unlike pre-dialysis CKD, people on hemodialysis actually need more protein.
A renal dietitian is an essential part of your dialysis care team. Ask your nephrologist for a referral — a personalized meal plan makes a big difference.

Hemodialysis vs. peritoneal dialysis

Hemodialysis is not the only dialysis option. Peritoneal dialysis (PD) uses the lining of your abdomen as a filter and can be done at home — often overnight while you sleep. Both options have advantages depending on your lifestyle, health, and personal preference. Your nephrologist will help you understand which is right for you.

Our physicians serve as Medical Directors for DaVita Dialysis centers in Northwest Indiana. Learn more about dialysis at DaVita ↗