Hemodialysis

Healthy kidneys filter the blood continuously, removing waste such as urea and creatinine, balancing salts such as potassium and sodium, controlling acidity and removing excess water. In kidney failure these substances build up and can cause tiredness, nausea, breathlessness, swelling and dangerous heart rhythms. Hemodialysis takes over part of this work. A machine pumps blood from your vascular access through a dialyser, a cylinder packed with thousands of hollow fibres. Your blood flows on one side of the fibre walls and a cleansing fluid called dialysate on the other; waste and salts move across the membrane, and the machine removes extra fluid by gentle pressure. A related form, hemodiafiltration, also clears larger molecules. Because dialysis is intermittent, waste and fluid build up again between sessions, which is why the regular schedule, the diet and the fluid limits matter so much.

Hemodialysis is started when chronic kidney disease reaches its final stage, often called end-stage kidney disease or kidney failure, and symptoms or blood results show that the kidneys can no longer keep the body in balance. Typical signs are severe tiredness, nausea, itching, poor appetite, fluid overload with swelling or breathlessness, and dangerous potassium or acid levels. Some people need short-term dialysis for acute kidney injury, which may recover. For travellers already on hemodialysis, the question is not whether to have dialysis but how to keep the schedule safely while away, whether on holiday, visiting family or working. For patients who travel for another treatment, such as joint replacement, heart surgery or cancer care, the kidney team plans dialysis around the operation or therapy, usually with a session the day before surgery and close monitoring afterwards. Peritoneal dialysis and kidney transplantation are alternatives to discuss with your nephrologist.

Each session follows a routine. You are weighed on arrival to estimate how much fluid to remove, and your blood pressure and temperature are checked. A nurse connects you to the machine through your access. With an arteriovenous fistula, an artery and a vein in the arm joined by a small operation, or a graft, a soft tube joining them, two needles are placed in the vessel; with a central venous catheter, a tube in a large vein in the neck or chest, the lines are connected directly. The machine then circulates your blood through the dialyser for about four hours while you rest, read or sleep, and a blood-thinning medicine prevents clotting in the circuit. Nurses monitor your blood pressure and the machine readings throughout, and the nephrologist reviews the prescription regularly. At the end, the blood is returned, the needles are removed and pressure is applied until bleeding stops. Monthly blood tests check adequacy, blood counts and minerals.

Anyone established on stable hemodialysis can usually dialyse away from home if a unit accepts them. Start planning about two to three months ahead, because places in holiday dialysis units are limited. The receiving unit normally asks for a referral letter from your nephrologist with your dialysis prescription, dry weight, access type and needle details, medicines and allergies; recent blood results; an electrocardiogram; and screening for hepatitis B, hepatitis C and HIV, usually from the last one to three months. Some units also ask about recent COVID-19 tests, MRSA status or other infections. A positive hepatitis result does not exclude you, but it affects which machine and room are used. Check that you are well enough to travel, that your access works reliably and what your health insurance covers. Bring enough of your own medicines, including phosphate binders and any injections, plus a copy of your recent records.

After a session some people feel washed out or dizzy for a few hours, and occasionally have cramps, while others feel better straight away; most return to normal activities the same evening. When travelling, build your plans around dialysis days: long flights are usually easier on the day after a session, when fluid and potassium levels are lowest. Keep to your fluid and diet limits, which can be harder with unfamiliar food and hot weather. Protect your fistula arm from tight straps and heavy bags. If you are abroad for another treatment, the hospital's nephrology team usually provides dialysis on the ward or in its unit, adjusts the timing around surgery or chemotherapy, and reviews the doses of medicines that are cleared by the kidneys. Before going home, ask for a written summary of each session, any changes to your prescription and the latest blood tests, so that your home unit can continue without gaps.

Hemodialysis is a well-established, routine treatment, but it carries risks that the unit's staff manage. During a session, low blood pressure, cramps, nausea and headache are the most common problems, often related to removing a lot of fluid, which is why fluid limits between sessions matter. Access problems include clotting or narrowing of a fistula or graft, bleeding from needle sites and, with catheters, infection that can spread to the bloodstream. Infections such as hepatitis B and C can in principle spread between patients in a dialysis unit, which is why units screen every patient and follow strict hygiene. Over the long term, people on dialysis face higher risks of heart disease, bone and mineral problems and anaemia, which are monitored and treated. Results are measured by blood tests of clearance, potassium, phosphate and haemoglobin, and by how well you feel. Dialysis can keep many people well for years, but it does not cure kidney failure.