Apparatus and method for automatically controlling hemodialysis at a pre-selected ultrafiltration rate

Claim 1

An improved closed dialysate circuit for use in hemodialysis comprising an above atmospheric pressure portion comprising dialysate supply and removal means and ultrafiltrate removal means and below atmospheric pressure portion comprising a hemodialyzer, said above atmospheric pressure portion including a dialysate supply line and a dialysate drain line, a portion of a kidney fresh dialysate supply line and a portion of a kidney spent dialysate removal line, first and second cylinder units having means for separating each said cylinders(s) into two chambers as said means moves between the ends of said cylinder, said first and second units each having valves and interconnected switching means effective to cause concurrently one of said units to fill with fresh dialysate as spent dialysate is discarded while the other said unit fills with spent dialysate as fresh dialysate is supplied to said kidney and to alternate functions after said valves are switched at the same time, and ultrafiltrate removal means connected between one of said dialysate lines and said dialysate drain line effective to withdraw dialysate from said line and transfer same to said dialysate drain line, and means for actuating said ultrafiltrate removal means independently of the means actuating said first and said second cylinder units and remotely located control means for controlling said ultrafiltrate removal means, and a degassifier located in the spent dialysate delivery line adjacent to the chamber of said cylinder unit to be filled therewith, said below atmospheric pressure portion including a portion of a kidney spent dialysate removal line, an artificial kidney having a membrane capable of permitting simultaneous dialysis and ultrafiltration of blood and a pair of inlet and outlet blood ports and a pair of inlet and outlet dialysate ports, pressure reducing means in the fresh dialysate supply line to said artificial kidney adjacent to said dialysate inlet port thereof, and pressure increasing means in the spent dialysate removal line from said kidney adjacent to said dialysate outlet port thereof.

Claim 9

A method for automatically controlling ultrafiltration during hemodialysis in a single pass system which comprises the steps of (1) providing a closed circuit having an artificial kidney below atmospheric pressure portion thereof and means for supplying fresh and removing spent dialysate from said kidney and for removing fresh dialysate from said circuit in an above atmospheric pressure portion of said circuit, (2) supplying blood to and from said kidney, (3) supplying fresh dialysate from means in said above atmospheric pressure portion of said circuit to said kidney, (4) withdrawing degassed dialysate from said closed circuit at a location in said above atmospheric pressure portion of said circuit at a rate pre-selected for removal of water from said blood, (5) returning spent dialysate from said kidney to said spent dialysate removal means, and (6) raising the pressure on said spent dialysate to a pressure higher than the pressure on said spent dialysate at the kidney exit port and to a pressure at least as high as the pressure on said fresh dialysate in said fresh dialysate supply means at a location intermediate said kidney and said spent dialysate removal means, and (7) removing gas bubbles from the pressurized spent dialysate solution produced in step 6 prior to returning the resultant gas-free spent dialysate to said spent dialysate removal means, and (8) controlling the rate of water removal from said blood in said kidney by controlling the rate of withdrawal of dialysate in the said above atmospheric pressure portion of said circuit.

Claim 10

A method for automatically controlling ultrafiltration during hemodialysis in a single pass system which comprises the steps of (1) providing a closed circuit having an artificial kidney below atmospheric pressure portion thereof and means for supplying fresh and removing spent dialysate from said kidney and for removing fresh dialysate from said circuit in an above atmospheric pressure portion of said circuit, (2) supplying blood to and from said kidney, (3) supplying fresh dialysate from means in said above atmospheric pressure portion of said circuit to said kidney, (4) withdrawing degassed dialysate from said closed circuit at a location in said above atmospheric pressure portion of said circuit at a rate pre-selected for removal of water from said blood, (5) returning spent dialysate from said kidney to said spent dialysate removal means, and (6) raising the pressure on said spent dialysate to a pressure higher than the pressure on said spent dialysate at the kidney exit port and to a pressure at least as high as the pressure on said fresh dialysate in said fresh dialysate supply means at a location intermediate said kidney and said spent dialysate removal means, and (7) removing gas bubbles from the pressurized spent dialysate solution produced in step 6 prior to returning the resultant gas-free spent dialysate to said spent dialysate removal means, and (8) controlling the rate of water removal from said blood in said kidney by controlling the rate of withdrawal of dialysate in the said above atmospheric pressure portion of said circuit.