A filtering technique used to remove waste products from the blood and excess fluid from the body as a treatment for kidney failure. The kidneys normally filter about 1,500 litres of blood daily. They maintain the fluid and electrolyte balance of the body and excrete wastes in the urine. Important elements, such as sodium, potassium, calcium, amino acids, glucose, and water are reabsorbed. Urea, excess minerals, toxins, and drugs are excreted. Dialysis is used to perform this function in people whose kidneys have been damaged due to acute kidney failure or chronic kidney failure. Without dialysis, wastes accumulate in the blood. In chronic kidney failure, patients may need to have dialysis several times a week for the rest of their lives or until they can be given a kidney transplant. In acute kidney failure, dialysis is carried out more intensively until the kidneys are working normally. There are 2 methods of dialysis: haemodialysis and peritoneal dialysis. In both methods, excess water and wastes in the blood pass across a membrane into a solution (dialysate), which is then discarded. Haemodialysis filters out wastes by passing blood through an artificial kidney machine. The process takes 2–6 hours. Peritoneal dialysis makes use of the peritoneum (the membrane that lines the abdomen) as a filter. The procedure is often carried out overnight or continuously during the day and night. Both types of dialysis carry the risk of upsetting body chemistry and fluid balance. There is also a risk of infection within the peritoneum in peritoneal dialysis.


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