hemodialys

Hemodialysis is a renal replacement therapy used to remove waste products, excess fluids, and balance electrolytes when the kidneys can no longer perform these tasks adequately. It relies on a hemodialyzer, or dialyzer, containing a semipermeable membrane. Blood flows on one side while a specially prepared dialysate flows on the other; solutes diffuse across the membrane and fluid is removed by ultrafiltration under pressure.

Blood is circulated through an extracorporeal circuit and connected to the patient via vascular access. The preferred permanent access is an arteriovenous fistula, created surgically to connect an artery and a vein. Alternatives include an arteriovenous graft or, when needed temporarily, a central venous catheter. Dialysis treatments are commonly performed three times per week, with sessions lasting about 3 to 5 hours, either in a dialysis center or at home with appropriate training.

Dialysate composition is carefully tailored to maintain stable electrolyte and acid–base status, and its quality is strictly controlled to protect the patient. Water quality for dialysate must meet stringent standards to prevent contamination.

Common indications include end-stage kidney disease and certain cases of acute kidney injury requiring ongoing dialysis. Potential complications during or after dialysis include low blood pressure, cramps, nausea, and infection or stenosis related to the access. Long-term dialysis can be associated with specific conditions such as dialysis-related amyloidosis. Kidney transplantation remains an alternative cure, while peritoneal dialysis is a related but distinct modality.