Hemodialysis

A medical procedure that uses a special machine (a dialysis machine) to filter waste products from the bloodstream and to restore normal constituents to the blood. This remarkable feat shuffling multiple substances about is accomplished by virtue of the differences in the rates of their diffusion through a semipermeable membrane (a dialysis membrane). Although hemodialysis may be done for acute kidney failure, it is much more often employed for chronic renal disease. Hemodialysis is frequently done to treat end-stage kidney disease. Under such circumstances, kidney dialysis is typically administered using a fixed schedule of three times per week. There are other types of dialysis as, for example, peritoneal dialysis. Hemodialysis is commonly referred to as dialysis.

* * *

Dialysis of soluble substances and water from the blood by diffusion through a semipermeable membrane; separation of cellular elements and colloids from soluble substances is achieved by pore size in the membrane and rates of diffusion.

* * *

he·mo·di·al·y·sis or chiefly Brit hae·mo·di·al·y·sis .hē-mō-dī-'al-ə-səs n, pl -y·ses -.sēz dialysis (2a)

* * *

he·mo·di·al·y·sis (he″mo-di-alґə-sis) the removal of certain elements from the blood by virtue of the difference in the rates of their diffusion through a semipermeable membrane (see hemodialyzer). Two distinct physical processes are involved, diffusion and ultrafiltration (qq.v.). See also clearance. Called also dialysis, kidney dialysis, and renal dialysis.