Apparatus and method for controlling ultrafiltration during hemodialysis
First Claim
1. An apparatus for controlling ultrafiltration during hemodialysis having below mean dialyzer blood pressure and above atmospheric pressure sections, said below mean dialyzer blood pressure section comprising:
- a fresh dialysate supply line and a first portion of a spent dialysate removal line;
a pair of matched positive displacement units each including valves and interrelated switching means, the first of said units being interconnected to said supply line by a mix point and pressure reducing means; and
a hemodialyzer for the dialysis and ultrafiltration of blood including inlet and outlet blood ports, an inlet dialysate port for the entry of fresh dialysate and an outlet dialysate port for the exit of spent dialysate;
said above atmospheric pressure section comprising;
a second portion of the spent dialysate removal line interconnected to said first portion of said spent dialysate removal line by pressure increasing means;
the second of said positive displacement units being in fluid communication with the second portion of said spent dialysate removal line;
a dialysate drain line in fluid communication with the second portion of said dialysate removal line; and
ultrafiltrate removal means connected between the second portion of said spent dialysate line and said drain line adapted to withdraw dialysate from said removal line and transfer same to said drain line;
said valves and switching means adapted to cause concurrently one of said units to fill with fresh dialysate as fresh dialysate is supplied to said dialyzer while the other unit fills with spent dialysate as spent dialysate is drained and to alternate functions after said valves are reversed.
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Accused Products
Abstract
Hemodialysis ultrafiltration apparatus comprises a dialyzer. A closed circuit is provided for supplying fresh dialysate to and for removing spent dialysate from the dialyzer. Blood is supplied to and removed from the dialyzer. The closed circuit for supplying fresh dialysate and removing spent dialysate is apportioned into below mean dialyzer blood pressure and above atmospheric pressure sections, with the dialyzer being positioned in the below mean dialyzer blood pressure section. A mechanism is provided for controlling the pressure of fresh dialysate introduced into the below mean dialyzer blood pressure section to substantially match the pressure on the dialysate side of the dialyzer. A mechanism is provided for controlling the above atmospheric pressure portion of the spent dialysate circuit. A pump removes spent dialysate of equivalent ultrafiltrate volume from the closed circuit to control the rate of ultrafiltrate removal from blood in the dialyzer, thus affecting the pressure on the dialysate side of the dialyzer required to sustain that rate.
A method of hemodialytic ultrafiltration is carried out substantially in accordance with the above-described apparatus.
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Citations
11 Claims
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1. An apparatus for controlling ultrafiltration during hemodialysis having below mean dialyzer blood pressure and above atmospheric pressure sections, said below mean dialyzer blood pressure section comprising:
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a fresh dialysate supply line and a first portion of a spent dialysate removal line; a pair of matched positive displacement units each including valves and interrelated switching means, the first of said units being interconnected to said supply line by a mix point and pressure reducing means; and a hemodialyzer for the dialysis and ultrafiltration of blood including inlet and outlet blood ports, an inlet dialysate port for the entry of fresh dialysate and an outlet dialysate port for the exit of spent dialysate;
said above atmospheric pressure section comprising;a second portion of the spent dialysate removal line interconnected to said first portion of said spent dialysate removal line by pressure increasing means; the second of said positive displacement units being in fluid communication with the second portion of said spent dialysate removal line; a dialysate drain line in fluid communication with the second portion of said dialysate removal line; and ultrafiltrate removal means connected between the second portion of said spent dialysate line and said drain line adapted to withdraw dialysate from said removal line and transfer same to said drain line; said valves and switching means adapted to cause concurrently one of said units to fill with fresh dialysate as fresh dialysate is supplied to said dialyzer while the other unit fills with spent dialysate as spent dialysate is drained and to alternate functions after said valves are reversed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification