Dialysis

Introduction

If your kidneys can no longer clean your blood well enough to keep you healthy, dialysis takes over part of that work. It is a treatment, not a cure. For some people, dialysis is a long-term therapy that continues for years. For others, it is a bridge to a kidney transplant. For a smaller group, it is used for a short time while the kidneys recover from a sudden injury.

This article is written for people who have already been told they need dialysis, or whose kidney function is approaching the point where the conversation is being raised, and for their families. It explains what dialysis is, the main types and how they differ, what happens during a session, how dialysis fits around daily life, the risks involved, and how dialysis sits alongside the option of a kidney transplant. The aim is to help you walk into appointments with your nephrologist (kidney specialist) understanding the choices and the language being used.

Starting dialysis is a major change. The medicine is detailed, but the day-to-day reality is something most people gradually learn to manage. Many people on dialysis continue to work, travel, raise families, and live full lives, while accepting that the treatment is now a regular part of the week.

What Is Dialysis?

Healthy kidneys do several jobs at once. They filter waste products and extra water out of the blood, balance salts and minerals, help control blood pressure, support red blood cell production, and keep bones healthy by managing calcium and phosphate. When the kidneys fail, these jobs stop being done properly, and waste products and fluid build up in the body.

Dialysis is a way of cleaning the blood from outside the body, using a machine or a special fluid, to do part of the filtering work that the kidneys can no longer do. It removes waste molecules such as urea and creatinine, takes off extra fluid, and helps correct levels of potassium, sodium, and acid in the blood. It does not replace every kidney function — for example, it does not produce hormones — so other medications are usually needed alongside.

Dialysis is most often started when kidney function has dropped to a very low level (a stage usually called end-stage kidney disease or kidney failure), and when symptoms or blood tests show that the body can no longer cope without help. It can also be started in an emergency, such as when potassium levels are dangerously high, when fluid is overloading the heart or lungs, or after a sudden kidney injury.

Why Dialysis Is Needed

The most common reason for long-term dialysis is chronic kidney disease (CKD) that has progressed to kidney failure. The leading causes worldwide include:

• Diabetes — high blood sugar over many years damages the small filtering units in the kidneys
• High blood pressure (hypertension) — sustained high pressure injures the kidney's blood vessels
• Glomerulonephritis — a group of conditions causing inflammation of the kidney's filters
• Polycystic kidney disease — an inherited condition in which cysts gradually replace healthy kidney tissue
• Obstruction or reflux problems in the urinary tract over long periods
• Autoimmune diseases such as lupus that affect the kidneys

Acute kidney injury (AKI) — a sudden drop in kidney function from severe illness, dehydration, certain medications, or sepsis — can also require short-term dialysis. In most AKI cases the kidneys recover and dialysis is stopped.

Decisions about when to start long-term dialysis are based on a combination of blood test results (especially estimated glomerular filtration rate, or eGFR), symptoms, fluid status, and how the person is feeling overall. KDIGO (Kidney Disease: Improving Global Outcomes) guidelines emphasise that the timing of dialysis start is individualised rather than driven by a single number.

Types of Dialysis

There are two main types of dialysis: haemodialysis and peritoneal dialysis. Both do the same essential job but in different ways and in different settings. Within each type, there are variations — including options performed at home. Choosing between them depends on your medical situation, your lifestyle, your support at home, and discussion with your kidney team.

Haemodialysis

In haemodialysis, blood is taken out of the body, passed through a filter called a dialyser (sometimes called an artificial kidney), and returned to the body. The dialyser contains thousands of tiny hollow fibres. Blood flows on one side of the fibres; a specially prepared fluid called dialysate flows on the other. Waste products and extra fluid pass from the blood into the dialysate, which is then discarded.

A typical session lasts around four hours and is done three times a week. The schedule may vary depending on the unit and individual factors, but most people settle into a Monday-Wednesday-Friday or Tuesday-Thursday-Saturday pattern. During the session, you sit or recline in a chair while connected to the machine. Many people read, watch films, sleep, or talk with other patients during their session.

Haemodialysis can be delivered in several settings:

• In-centre haemodialysis — performed at a hospital or dedicated dialysis unit, with nurses and technicians running the machine. This is the most common arrangement.
• Home haemodialysis — performed by the patient (often with a trained partner) in their own home, after training. Sessions may be more frequent and sometimes shorter, or longer and overnight.
• Nocturnal haemodialysis — done overnight while sleeping, either at home or in some specialised units. Longer, slower sessions are gentler on the body and allow more freedom during the day.

Home and more frequent forms of haemodialysis are associated in studies with better fluid control, fewer dietary restrictions, and often better quality of life. They require commitment, space at home, and a reliable water and electricity supply, and are not suitable for everyone.

Peritoneal Dialysis

Peritoneal dialysis (PD) uses the lining of your own abdomen — called the peritoneum — as the filter. A soft plastic tube called a PD catheter is placed surgically into the abdomen, with the inside end resting in the peritoneal cavity and the outside end on the skin. Dialysis fluid is run in through the catheter, left to dwell inside the abdomen for several hours, and then drained out, taking waste products and extra fluid with it. The fresh fluid is then run in again. Each fill-dwell-drain cycle is called an exchange.

PD is done at home, almost always by the patient themselves after training. There are two main forms:

• Continuous ambulatory peritoneal dialysis (CAPD) — manual exchanges done during the day, typically four times, each taking around 30 minutes. Between exchanges, the person can carry on with normal activities.
• Automated peritoneal dialysis (APD) — a small machine called a cycler performs exchanges automatically overnight while the person sleeps. The days are then free of exchanges, or may need only one daytime fill.

PD allows more flexibility for many people, particularly those who work, study, or travel. It avoids the need to attend a dialysis unit three times a week, and it is gentler on the body in some respects because it is done daily. It does require a clean space at home for storing fluid bags and doing exchanges, and careful attention to hygiene to reduce the risk of infection.

Continuous Renal Replacement Therapy (CRRT)

For people who are critically ill in intensive care with acute kidney injury, a slower, continuous form of haemodialysis called CRRT may be used. It runs 24 hours a day at a gentle rate and is suited to patients whose blood pressure or heart function would not tolerate standard haemodialysis. CRRT is a short-term hospital treatment, not an ongoing form of dialysis for home or outpatient use.

Vascular Access and the PD Catheter

Dialysis cannot work without a reliable way to get blood out of the body (for haemodialysis) or fluid in and out of the abdomen (for peritoneal dialysis). Setting this up is one of the most important steps before starting treatment.

Access for Haemodialysis

Three main options exist:

• Arteriovenous (AV) fistula — a surgical connection between an artery and a vein, usually in the forearm. Over weeks to months, the vein enlarges and strengthens, becoming able to handle the high blood flows needed for dialysis. Fistulas last the longest, have the lowest infection risk, and are favoured by KDOQI and most international guidelines as the preferred long-term access where possible.
• AV graft — a synthetic tube placed under the skin to connect an artery and a vein, used when a fistula cannot be made. Grafts can be used sooner than fistulas but have a higher rate of clotting and infection.
• Central venous catheter — a soft tube placed into a large vein in the neck, chest, or groin. Catheters can be used immediately, which is useful when dialysis must start urgently, but they have the highest risk of infection and are generally used as a temporary bridge to a fistula or graft.

If a fistula or graft is planned, it is best to create it well before dialysis is expected to start, to allow time to mature. People with advancing kidney disease are often referred for access surgery several months ahead.

PD Catheter

The peritoneal dialysis catheter is placed in a short procedure, usually under general or local anaesthesia. It is typically left to settle for around two weeks before being used, to reduce the risk of leaks and infection. The exit site on the skin needs regular cleaning and inspection to keep it healthy.

Choosing Between Haemodialysis and Peritoneal Dialysis

For many people, both forms of dialysis are medically reasonable, and the choice comes down to personal circumstances. Nephrologists often have a structured education session, sometimes called shared decision-making or modality choice education, to walk through the options.

Factors that may influence the decision include:

• Home situation — space for storage, clean area for exchanges, support from family
• Work and lifestyle — need for flexibility, ability to travel, hours of work
• Distance from a dialysis unit — in-centre haemodialysis requires regular travel
• Medical factors — previous abdominal surgery, hernias, heart and lung disease, vascular health
• Manual dexterity and vision — some forms of home therapy require careful technique
• Preference — some people prefer the structure and social contact of a unit; others prefer the autonomy of home therapy

Many people do not stay on the same modality forever. It is common to switch — for example, from peritoneal dialysis to haemodialysis after several years, or vice versa — as medical circumstances change.

What Happens During a Dialysis Session

A Typical Haemodialysis Session

When you arrive at the unit, your weight, blood pressure, and temperature are checked. The change in weight since the previous session tells the team how much fluid needs to be removed. You are then connected to the machine through your fistula, graft, or catheter. Two needles are used for a fistula or graft — one to draw blood out, one to return it.

During the session, the machine pumps blood through the dialyser, and you are monitored throughout. Most people feel reasonably comfortable, though some experience cramps, low blood pressure, headache, or tiredness, especially when a large amount of fluid is being removed. The team adjusts the settings to keep the session as comfortable as possible.

At the end of the session, the needles are removed and pressure is applied until any bleeding stops. Your weight and blood pressure are checked again. Most people then go home and rest. Tiredness after dialysis is common and tends to improve over the first months as the body adjusts.

A Typical Day on Peritoneal Dialysis

On CAPD, the day is structured around four exchanges, often morning, midday, late afternoon, and bedtime. Each exchange takes about half an hour and is done in a clean room at home, at work, or wherever you happen to be, using sterile technique. Between exchanges, the fluid dwells in the abdomen and ordinary activities continue.

On APD, the cycler does the work overnight. You connect to it before bed, sleep while it cycles fluid in and out, and disconnect in the morning. Some people carry a small amount of fluid in the abdomen during the day for additional clearance.

Diet, Fluids, and Daily Habits

What you eat and drink matters more on dialysis than at almost any other time, because the kidneys are no longer fine-tuning your body's balance. A renal dietitian (a dietitian specialising in kidney disease) is usually part of the team and will give individual advice. Broad themes include:

• Fluid — people on haemodialysis usually need to limit how much they drink between sessions, because fluid that accumulates must be removed in the next session. People on peritoneal dialysis generally have more relaxed fluid limits because the treatment is daily.
• Potassium — high potassium levels can cause dangerous heart rhythm problems. Foods high in potassium (some fruits, vegetables, nuts, and chocolate) may need to be limited, especially on haemodialysis.
• Phosphate — high phosphate over time damages bones and blood vessels. Dairy, processed foods, cola drinks, and some meats are higher in phosphate. Medications called phosphate binders are often prescribed to take with meals.
• Sodium (salt) — reducing salt helps control thirst, blood pressure, and fluid gain between sessions.
• Protein — dialysis removes some protein, especially peritoneal dialysis. Most people on dialysis need a reasonable protein intake, in contrast to earlier stages of kidney disease where protein is sometimes restricted.

These recommendations are not the same for everyone. Blood tests track potassium, phosphate, calcium, albumin, and other markers, and the diet is adjusted over time. Trying to follow generic kidney-diet advice from the internet without your own team's input can lead to either over-restriction or unsafe choices.

Medications Alongside Dialysis

Dialysis does not replace all kidney functions, so additional medications are usually part of treatment. These commonly include:

• Phosphate binders — taken with meals to reduce phosphate absorption
• Active vitamin D or related medicines to support bone health
• Erythropoiesis-stimulating agents (ESAs) and iron, to treat the anaemia (low red blood cell count) that is common in kidney failure
• Blood pressure medications, often still needed even on dialysis
• Medications for diabetes, often in adjusted doses
• Anticoagulants during haemodialysis to keep blood from clotting in the dialyser circuit

Many other medications need dose adjustment in kidney failure, and some are removed by dialysis. It is important that every doctor and pharmacist you see knows you are on dialysis. Always carry an up-to-date medication list.

Risks and Complications

Dialysis is life-sustaining, but it carries risks. Awareness of common complications helps you and your team manage them early.

During Haemodialysis

• Low blood pressure during or after a session, particularly when removing larger volumes of fluid
• Muscle cramps, often from rapid fluid shifts
• Itching, related to mineral and waste imbalances
• Headache, nausea, or fatigue
• Access problems — clotting, narrowing, infection, or bleeding from a fistula, graft, or catheter

With Peritoneal Dialysis

• Peritonitis — infection of the abdominal lining, usually presenting as cloudy drainage fluid, abdominal pain, or fever. It is treated with antibiotics, sometimes added directly to the dialysis fluid. Strict hygiene during exchanges reduces the risk.
• Exit-site or tunnel infections around the catheter
• Hernias, because the abdomen holds fluid under pressure
• Catheter problems — blockage, displacement, or fluid leak
• Weight gain, because dialysis fluid contains glucose that is absorbed
• Membrane changes over time, which can reduce how well peritoneal dialysis works after many years

Longer-term Health Issues

People on long-term dialysis are at higher risk of heart and blood vessel disease, bone and mineral disorders, anaemia, malnutrition, depression, and infections. Regular monitoring by the nephrology team aims to detect and treat these early. Cardiovascular disease is the leading cause of death in people on dialysis, and managing blood pressure, fluid balance, cholesterol, diabetes, and lifestyle factors is a central part of long-term care.

Dialysis and Kidney Transplant

For many people with kidney failure, a kidney transplant offers better long-term outcomes than long-term dialysis, including longer life expectancy and better quality of life for those who are suitable candidates. Not everyone is a candidate for transplant — medical fitness, the presence of other serious conditions, and individual factors all matter.

Transplants come from living donors (such as a relative or friend who is a match) or from deceased donors. Where transplant is an option, the kidney team often discusses it early, ideally before dialysis is started or soon after, because the assessment process takes time and a pre-emptive transplant (before dialysis is needed) is associated with the best outcomes.

Many people remain on dialysis while waiting, sometimes for years. Others continue on dialysis indefinitely if transplant is not suitable or not desired. Dialysis and transplant are complementary paths, not opposing choices.

Travel, Work, and Quality of Life

Dialysis is demanding, but it does not have to dominate your life. Many people continue working, studying, raising children, and pursuing the activities that matter to them.

• Work — depending on the type of work and the modality, many people on dialysis continue in employment. Home and overnight modalities offer more flexibility. Workplace adjustments may help.
• Travel — people on haemodialysis can usually arrange dialysis sessions at units in other cities or countries (often called holiday dialysis or visitor dialysis), with planning in advance. Peritoneal dialysis supplies can be delivered to a holiday destination.
• Exercise — regular physical activity is encouraged where safe. It helps cardiovascular health, mood, energy, and muscle strength. Even gentle activity on non-dialysis days can help.
• Mental health — depression and anxiety are common on dialysis and are often under-recognised. Counselling, peer support, and sometimes medication are all valid options. Talking to other people on dialysis — in the unit, in patient groups, or online — can be one of the most useful supports.
• Sexual health and fertility — kidney failure and dialysis can affect sexual function and fertility for both men and women. These topics are often not raised in clinic but can be discussed openly with the team. Some women on dialysis do conceive, although pregnancy is high-risk and requires specialist care.

Dialysis in Children

Children can need dialysis for many of the same reasons as adults — chronic kidney disease, inherited conditions such as congenital abnormalities of the kidney and urinary tract, certain glomerular diseases, or acute kidney injury. Paediatric nephrology teams care for children with kidney failure in dedicated units.

Peritoneal dialysis is often the preferred long-term option for children, particularly younger children and infants, because it can be done at home, allows school attendance, and avoids the vascular access challenges of haemodialysis in small bodies. Automated peritoneal dialysis overnight is especially well-suited because it leaves the day free for school and play.

Haemodialysis is used in older children, in those for whom peritoneal dialysis is not suitable, and in acute hospital situations. Vascular access in children is more technically demanding and the team takes particular care to preserve veins for the future.

Kidney transplant is usually the goal in children whenever possible, because long-term outcomes — including growth, schooling, and quality of life — are generally better with a working transplant than with long-term dialysis. Children on dialysis are also closely monitored for growth, nutrition, bone health, and development, with input from paediatric dietitians, social workers, psychologists, and teachers as part of the broader team.

Parents of children on dialysis often describe a steep learning curve. Most paediatric units offer training, written materials, and ongoing support to help families manage at home.

When Dialysis May Not Be Started or May Be Stopped

Dialysis is not always the right path for every person. For some patients — particularly older adults with multiple serious conditions, severe frailty, or limited life expectancy from another illness — the burden of dialysis may outweigh the likely benefit. In such cases, an approach called conservative or supportive kidney care focuses on symptom control, quality of life, and planning, without dialysis. KDIGO guidance supports shared decision-making in these situations.

People who have been on dialysis may also choose to stop dialysis, usually in consultation with family and the kidney team, when life is being shaped more by suffering than by living. This is a deeply personal decision, supported by palliative care services where available. The conversation is difficult but legitimate, and patients have the right to raise it.

What to Look for in a Dialysis Unit and Team

Where you receive dialysis matters. Useful things to look at and ask about include:

• The mix of modalities offered — in-centre, home haemodialysis, peritoneal dialysis
• The experience of the nephrology team in the modality you are choosing
• Infection rates and how the unit monitors quality and safety
• Availability of a renal dietitian, social worker, counsellor, and access surgeon
• Arrangements for emergencies and for travel or visitor dialysis
• Education and training programmes for home therapies
• How the team supports transplant assessment and the link to a transplant centre

Meeting more than one team before deciding, where possible, and bringing a family member to the first appointments are sensible steps.

Frequently Asked Questions

How long can a person live on dialysis?

There is no single answer. Some people live for many years — sometimes more than two decades — on dialysis. Outcomes depend on age, the underlying cause of kidney failure, other medical conditions (especially heart disease and diabetes), nutrition, adherence to the treatment plan, and access to good care. Your nephrologist can give a more personalised picture based on your situation.

Will I feel better once I start dialysis?

Many people who start dialysis when very symptomatic from kidney failure feel noticeably better within weeks — less nauseated, clearer-headed, more able to eat. The first weeks can also feel tiring as the body adjusts. Energy levels and overall well-being typically improve over the first few months.

Can I still eat normal food?

Diet on dialysis is more restricted than for someone with healthy kidneys, but it is not as restrictive as the diet often used in the earlier stages of kidney disease. A renal dietitian helps you find a balance — what to limit, what to enjoy, and how to plan meals you can stick with. Blood test results guide adjustments over time.

Is home dialysis safe?

Home dialysis is widely used and, with proper training, is safe for most suitable patients. Home therapies require commitment to technique, hygiene, and monitoring, and a back-up plan for problems. People on home therapies stay in close contact with the dialysis unit and attend regular review appointments.

Can I travel while on dialysis?

Yes, with planning. Haemodialysis patients can arrange sessions at units in other cities and countries, usually booking weeks to months in advance. Peritoneal dialysis fluid can be shipped to many destinations. Your dialysis unit's nursing team can guide you through the practicalities.

Does dialysis hurt?

Inserting the needles for haemodialysis can be uncomfortable, especially in the first weeks of using a new fistula. Numbing creams can help, and most people find it becomes easier with time. Peritoneal dialysis exchanges are usually painless once the catheter site has healed, though some people feel a brief sensation as fluid runs in or out.

Can I switch from one type of dialysis to another?

Yes. Switching between haemodialysis and peritoneal dialysis is common over the course of long-term treatment, for medical or personal reasons. It is not a failure to switch — it is a normal part of adapting treatment to changing circumstances.

Will being on dialysis stop me from getting a transplant?

No. Many people receive a kidney transplant after years on dialysis. Time on dialysis does not disqualify you from transplant. The assessment for transplant looks at overall fitness, other medical conditions, and donor availability rather than dialysis status alone.

What if I miss a session?

Missing haemodialysis sessions is risky. Fluid and waste products build up quickly, and missed sessions are linked to higher rates of emergency admission and serious complications. If you cannot attend, contact your unit as soon as possible so an alternative can be arranged. The same principle applies to skipped exchanges on peritoneal dialysis.

Can I keep working?

Many people on dialysis continue to work. Home therapies, evening shifts at dialysis units, and overnight modalities help fit treatment around employment. Your team can support conversations with employers about reasonable adjustments where helpful.

Conclusion

Dialysis is a major treatment that takes over part of the work of failing kidneys. It comes in different forms — haemodialysis in a unit or at home, peritoneal dialysis done at home during the day or overnight — and the right choice depends on medical factors, your life situation, and discussion with your kidney team. Alongside dialysis itself, diet, medications, vascular or peritoneal access, mental health, and the possibility of a kidney transplant all form part of the long-term picture.

Starting dialysis is the beginning of a new routine rather than the end of normal life. Most people find that, with time, the treatment becomes a manageable part of the week, and that the energy and clarity gained from cleaner blood are worth the structure dialysis requires. The most useful steps you can take are learning how your treatment works, building a trusting relationship with your nephrology team, paying attention to your access and your symptoms, and asking questions whenever something is unclear.