n. fluid used in the dialysis process. In *haemodialysis the dialysate is purified tap water to which has been added a precise amount of electrolyte solution. In *peritoneal dialysis the dialysate is a commercially produced fluid containing electrolytes with glucose, glucose polymers, or amino acids.
(dialyzer) n. a medical device designed to allow controllable transfer of solutes and water across a semipermeable membrane separating blood and *dialysate solutions flowing countercurrent to each other. Most modern dialysers are based on hollow-fibre technology and are tube-shaped. Blood enters the top of the tube and travels, by capillary action, down a large number of hollow microfibres, which are embedded in polyurethane at each end of the dialyser tube for support. Dialysate enters the tube from the side, near the bottom of the tube. It runs in the opposite direction to the blood, around the hollow fibres and separated from the blood by the semipermeable membrane that constitutes the microfibre wall. A number of different dialyser membranes are in use, displaying a wide variety of permeabilities (related to pore size), biocompatibilities (not activating *cytokine or alternate pathway *complement responses in the blood), and costs.... dialyser
n. a glucose polymer solution produced by the hydrolysis of cornstarch and containing a spectrum of polymer molecules with an average molecular weight of 16,200 Da. It is used in the dialysate treatment of renal failure by *peritoneal dialysis. It exerts a strong osmotic effect, allowing removal of fluid without exposing the peritoneum to high levels of glucose. It is of most use when the dialysate is required to remain within the body for a long period, for instance overnight during chronic ambulatory peritoneal dialysis or during the day with automated peritoneal dialysis.... icodextrin
(PD) a form of renal replacement therapy (see dialysis) that utilizes the peritoneum as the semipermeable membrane separating blood and *dialysate. Peritoneal dialysis can be given as a temporary and emergency treatment using a rigid percutaneous cannula to deliver fluid into the peritoneal cavity; this cannula usually needs removal and/or replacement within a few days. Alternatively, PD can be used as a chronic treatment, either in the form of chronic ambulatory peritoneal dialysis (see CAPD) or automated peritoneal dialysis (APD), in which case fluid delivery is through a soft silastic catheter that is tunnelled subcutaneously out of the peritoneal cavity and is designed to stay in place for years. In all cases, the dialysis fluid is left within the peritoneal cavity for a period of time during which substances in the bloodstream diffuse into the fluid according to their concentration gradient and the permeability of the peritoneal membrane.... peritoneal dialysis
Health Encyclopedia