| |
hemodialysis
(he″mo-di-al´ә-sis)
the use of principles of dialysis for removal of certain elements from the blood while it is being circulated outside the body in a hemodialyzer or through the peritoneal cavity (see peritoneal dialysis, done to remove toxic wastes from the blood of a patient with acute or chronic renal failure. Either the membrane lining the peritoneal cavity (in peritoneal dialysis) or a synthetic membrane (in extracorporeal hemodialysis) may be used as the dialyzing membrane. In the latter, once vascular access has been established, the patient's blood is pumped from the arterial circulation through the hemodialyzer and back into the venous circulation. In the dialyzer, it flows past a cellulosic or synthetic semipermeable membrane while
dialysate fluid flows past the other side of the membrane. Small molecules and ions diffuse through the membrane, passing from the
side on which the concentration is higher to the side on which it is lower. The dialysate fluid contains no urea or creatinine, so that these constituents are removed at maximum rates. Electrolytes such as sodium and potassium may be removed if necessary.
Large molecules and blood cells cannot pass through the membrane and, therefore, stay in the blood. Called also dialysis, kidney dialysis, and renal dialysis. adj., hemodialyt´ic., adj.
Copyright 2007. An Elsevier publication. All rights reserved.
Click here for important legal information about Dorland's Medical Dictionary.
|
