Dialysis system
AssigneeCalifornia Institute of Technology
InventorWilliam A. Mueller
Life of this patent
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Abstract
The improved hemodialysis system utilizes a second polymeric membrane having dialyzate in contact with one surface and a urea decomposition solution in contact with the other surface. The membrane selectively passes urea from the dialyzate into the decomposition solution, while preventing passage of positively charged metal ions from the dialyzate into the solution and ammonium ions from the solution into the dialyzate.
Claims19
A system for selectively removing urea from an aqueous liquid containing urea and positive metal cations comprising in combination:
- a container divided into a first chamber and a second chamber by means of a continuous sheet of cationically charged polymeric membrane selectively permeable to urea and having low permeability to cations;
- said first chamber including means for receiving said liquid;
- and
- said second chamber receiving a solution containing a urea decomposition agent whereby said cations are repelled by said membrane and retained in said liquid and urea permeates through the membrane into the solution and is decomposed into bicarbonate and ammonium, the ammonium being retained in the solution in the second chamber.
A method of selectively removing urea from an aqueous liquid containing urea and positive metal cations comprising the steps of:
- placing the liquid in contact with a first surface of a cationically charged polymeric membrane selectively permeable to urea and having low permeability to cations;
- placing an urea decomposition solution containing an urea decomposition agent in contact with a second surface of the membrane;
- and
- selectively permeating urea from the liquid through the membrane into the solution thereby decomposing urea into ammonium cations and bicarbonate whereby the ammonium cations are retained in the decomposition solution and the metal cations are retained in the liquid.
An artificial kidney machine comprising in combination:
- enclosure means having an inlet and an outlet, and having a wall surface formed of a cationically charged membrane defining a channel for flowing urea containing blood past one surface of the membrane;
- urea removal means comprising walls defining a chamber, said chamber including a solution of urease having a concentration at least 25% by weight of the urea content of the blood;
- and
- means for supplying the urea permeate from the second surface of the membrane to the urease solution.
Dependencies are inferred from the claim text.