Dialysis: Types, How It Works, Side Effects and What to Expect

What Is Dialysis?

Dialysis is a treatment for people whose kidneys can no longer remove enough waste products, excess fluid and minerals from the blood.

Healthy kidneys continuously filter the blood and help regulate fluid levels, blood pressure and minerals such as potassium and sodium.

When kidney function becomes severely reduced, dialysis can take over part of this work.

Dialysis can help patients feel better and live longer, but it does not cure kidney failure or completely replace all the functions of healthy kidneys.

When Is Dialysis Needed?

Dialysis is generally considered in advanced kidney failure.

The decision is not based on one blood test alone. Doctors also consider symptoms, laboratory results, fluid buildup and complications caused by reduced kidney function.

Possible signs that dialysis may be needed include:

• Severe fatigue
• Loss of appetite
• Nausea or vomiting
• Shortness of breath
• Swelling in the legs or body
• Difficult-to-control fluid buildup
• High potassium levels
• Confusion or reduced concentration
• Symptoms caused by accumulation of waste products

Patients with advanced chronic kidney disease should discuss treatment options early with a nephrologist so there is time to prepare properly.

What Are the Main Types of Dialysis?

The two main forms are hemodialysis and peritoneal dialysis.

Hemodialysis

Hemodialysis removes blood from the body, passes it through a special filter called a dialyzer, and then returns the cleaned blood to the patient.

The machine helps remove:

• Waste products
• Excess salt
• Extra fluid
• Certain unwanted minerals

Hemodialysis can be performed in a dialysis center or, for selected patients, at home.

In-center treatment is often performed approximately three times per week, although the exact schedule and duration are individualized.

What Is Dialysis Access?

Hemodialysis requires reliable access to the bloodstream.

The main access types are:

Arteriovenous Fistula

A surgeon connects an artery to a vein, usually in the arm.

A fistula is often preferred when possible because it can last a long time and generally has a lower risk of infection and clotting than some other access types.

Arteriovenous Graft

A synthetic tube is used to connect an artery and vein.

A graft may be used when the patient's blood vessels are not suitable for a fistula.

Dialysis Catheter

A catheter is a tube inserted into a large vein, often in the neck.

It can be used when dialysis needs to begin quickly or while a fistula or graft is being prepared.

Because catheters have a higher infection risk, they are often avoided for long-term use when another access option is possible.

Peritoneal Dialysis

Peritoneal dialysis filters the blood inside the patient's own body.

It uses the lining of the abdomen, called the peritoneum, as a natural filter.

A soft catheter is surgically placed into the abdomen. Dialysis fluid is then introduced through the catheter.

While the fluid remains inside the abdomen, waste products and excess fluid move from the blood into the dialysis solution.

The used fluid is later drained and replaced with fresh solution.

Types of Peritoneal Dialysis

There are two common approaches.

Continuous Ambulatory Peritoneal Dialysis

The patient manually replaces the dialysis fluid several times during the day.

No dialysis machine is required during the exchange itself.

Automated Peritoneal Dialysis

A machine called a cycler automatically exchanges the dialysis fluid, usually during the night while the patient sleeps.

Peritoneal dialysis can offer greater flexibility because treatment is performed at home, but patients must follow strict hygiene procedures to reduce infection risk.

What Happens During Hemodialysis?

During treatment, the patient is connected to the dialysis machine through the vascular access.

Blood travels through the dialyzer, where waste products and extra fluid are removed.

The cleaned blood then returns to the body.

During the session, the medical team monitors blood pressure, heart rate, fluid removal and the function of the dialysis access.

What Are the Common Side Effects?

Side effects vary between patients and may depend on the type of dialysis and the person's overall health.

Possible problems during or after hemodialysis include:

• Low blood pressure
• Muscle cramps
• Dizziness
• Nausea
• Headache
• Fatigue after treatment
• Itching
• Bleeding or bruising around the access
• Access infection or blockage

Peritoneal dialysis can also cause infection around the catheter or an infection inside the abdomen called peritonitis.

Any fever, unusual pain, redness, swelling or problems with the dialysis access should be reported promptly to the dialysis team.

Does Dialysis Affect Diet and Fluids?

Many patients need to make changes to their diet and fluid intake.

Depending on blood test results and the type of dialysis, doctors or dietitians may recommend controlling:

• Salt
• Potassium
• Phosphorus
• Fluid intake
• Protein intake

Dietary recommendations are individualized.

Patients should not severely restrict foods or fluids without guidance from their kidney-care team.

Can Patients Work or Travel While on Dialysis?

Many people on dialysis continue working, exercising and travelling.

However, treatment requires planning.

Patients receiving in-center hemodialysis need to arrange dialysis sessions at their destination before travelling.

Home dialysis may provide more scheduling flexibility for some patients.

The dialysis team can help patients plan around work, travel and everyday activities.

Dialysis or Kidney Transplant?

For suitable patients, kidney transplantation may provide an alternative to long-term dialysis.

Some patients receive dialysis while waiting for a donor kidney, while others may receive a transplant before dialysis becomes necessary.

Not every patient is medically suitable for transplantation, and some people remain on dialysis long term.

The best option depends on the patient's overall health, kidney disease, age, donor availability and personal circumstances.

Living With Dialysis

Starting dialysis is a major change, but many patients adapt to treatment and continue active lives.

Good results depend on:

• Attending all prescribed treatments
• Caring for the dialysis access
• Taking medications correctly
• Following individualized dietary advice
• Monitoring fluid intake
• Reporting symptoms early
• Attending regular nephrology follow-up

Dialysis is not simply a machine treatment. It is long-term kidney replacement therapy that requires cooperation between the patient, nephrologist, dialysis nurses, dietitians and other healthcare professionals.