hemodialysis

Hemodialysis is a form of renal replacement therapy that removes waste products and excess fluid from the blood when the kidneys are no longer able to perform these tasks effectively. In hemodialysis, the patient’s blood is pumped through an artificial kidney, or dialyzer, where it is cleaned by a dialysis solution called dialysate before being returned to the body. The process relies on a semipermeable membrane that allows waste products and excess fluids to move from blood into the dialysate by diffusion and ultrafiltration, while essential minerals and fluids are managed to maintain balance.

Most people receive hemodialysis in a hospital, dialysis center, or at home. Typical in-center schedules involve three 3- to 5-hour sessions per week, though the regimen can vary. Home hemodialysis may use shorter daily sessions or longer nocturnal treatments, depending on the patient’s condition and training.

Vascular access is required to provide reliable blood flow. The preferred access is an arteriovenous fistula, created surgically to connect an artery and a vein. If a fistula is not usable or not yet mature, a graft or a central venous catheter may be used.

Dialysis prescriptions specify how much blood is processed, how quickly blood is circulated, and the dialysate composition. Adequacy is assessed by measures such as Kt/V and urea reduction ratio. Dialysate typically contains electrolytes and bicarbonate to help restore acid–base balance.

Common risks include low blood pressure during treatment, cramping, infection or access problems, and electrolyte shifts. Serious but less common risks include dialysis disequilibrium syndrome and bleeding complications.

Hemodialysis controls symptoms of kidney failure but does not cure the underlying disease. Alternatives or adjuncts include peritoneal dialysis and kidney transplantation, as well as conservative management in some cases.