Multi-pass dialysis
View Patent ↗A system for dialysis is disclosed. The system uses renal failure therapy fluid, such as dialysis fluid, several times before it is discarded. In a home hemodialysis application, the patient's blood is passed through the dialyzer several times, that is, multiple passes through the dialyzer, until the dialysis fluid is saturated or near saturation, with waste products from the patient's blood. In peritoneal dialysis, the dialysate is used at least twice within the patient's peritoneal cavity, i.e., multiple passes, before it is discarded. This has the effect minimizing the amount of dialysate a patient must handle and dispose of in the dialysis process.
1. A dialysis system, comprising:
a dialyzer having dialysis fluid inlet and outlet ports;
a blood pump connected to the dialyzer for pumping blood from a patient;
at least one drip chamber in series with the dialyzer;
a first multi-position valve for connection between the patient and the blood pump;
a second multi-position valve for connection between the patient and the drip chamber, wherein the first valve and the second valve are capable of connection in a first position for the first valve to allow a flow of blood from the patient to the blood pump and the second valve to allow a flow of the blood from the drip chamber to the patient, and are capable of connection in a second position for the second valve to allow a flow of blood from the patient to the blood pump and the first valve to allow a flow of the blood from the drip chamber to the patient;
at least one source of fresh pre-mixed dialysis fluid in fluid communication with the dialysis fluid inlet port;
a pump connected with the at least one source of the fresh pre-mixed dialysis fluid;
interconnecting lines between the patient and the valves for drawing blood from the patient and returning the blood to the patient;
a connection from the dialysis fluid outlet port to the dialysis fluid inlet port that allows recirculation of spent dialysis fluid from the outlet port to the inlet port; and
a controller programmed to cause (i) a flow of spent dialysis fluid that has passed through the dialyzer to be directed through the connection and mixed with a flow of fresh pre-mixed dialysis fluid from the at least one source, and (ii) the mixed flow of spent dialysis fluid and fresh pre-mixed dialysis fluid to be directed to the dialysis fluid inlet port, such that a number of passes of spent dialysis fluid through the dialyzer is set by a ratio of a flow of spent dialysis fluid within the dialyzer to the flow of fresh pre-mixed dialysis fluid, the ratio low enough that the fresh pre-mixed dialysis fluid from the at least one source is used during therapy.
2. The dialysis system of claim 1 , wherein the dialysis fluid outlet port connects to the dialysis fluid inlet port through a flow channel or a flow balancing system.
3. The dialysis system of claim 1 , further comprising a balancing system operably connected to the at least one source of fresh pre-mixed dialysate dialysis fluid and to the dialyzer for balancing a flow of dialysate dialysis fluid to and from the dialyzer.
4. The dialysis system of claim 1 , further comprising a filter operably connected between the dialysis fluid outlet and inlet ports.
5. The dialysis system of claim 1 , further comprising a used dialysis fluid pump.
6. The dialysis system of claim 5 , wherein at least one of the pumps is a peristaltic pump.
7. The dialysis system of claim 1 , wherein the interconnecting lines between the patient and the valve are configured for simultaneous withdrawal and return of blood to the patient, or for sequential withdrawal and return of the blood.
8. The dialysis system of claim 1 , wherein the ratio is less than 10:1.
9. The dialysis system of claim 1 , wherein the ratio is 4:1.
10. A dialysis system, comprising:
a dialyzer having dialysis fluid inlet and outlet ports;
a blood pump connected to the dialyzer for pumping blood from a patient;
at least one drip chamber in series with the dialyzer;
a plurality of valves, the valves in a first condition allowing blood to be pumped from the patient to the blood pump and from the blood pump through the dialyzer and drip chamber back to the patient;
at least one source of fresh pre-mixed dialysis fluid in fluid communication with the dialysis fluid inlet port;
a fresh dialysis fluid pump connected fluidly with the at least one source of the fresh pre-mixed dialysis fluid and the dialysis fluid inlet port;
a spent dialysis fluid pump connected fluidly to the dialysis fluid outlet port;
a connection from the dialysis fluid outlet port to the dialysis fluid inlet port that allows recirculation of spent dialysis fluid from the outlet port to the inlet port to be pumped by at least the spent dialysis pump; and
a controller programmed to cause (i) a flow of spent dialysis fluid that has passed through the dialyzer to be directed through the connection and mixed with a flow of fresh pre-mixed dialysis fluid from the at least one source, and (ii) the mixed flow of spent dialysis fluid and fresh pre-mixed dialysis fluid to be directed to the dialysis fluid inlet port, such that a number of passes of spent dialysis fluid through the dialyzer is set by a ratio of a flow of spent dialysis fluid within the dialyzer to the flow of fresh pre-mixed dialysis fluid, the ratio low enough that the fresh pre-mixed dialysis fluid from at least one source is used during therapy.
11. The dialysis system of claim 10 , wherein the dialysis fluid outlet port connects to the dialysis fluid inlet port through a flow channel or a flow balancing system.
12. The dialysis system of claim 10 , which is configured for simultaneous withdrawal and return of blood to the patient, or for sequential withdrawal and return of the blood.
13. The dialysis system of claim 10 , wherein the ratio is less than 10:1.
14. The dialysis system of claim 10 , wherein the ratio is 4:1.
15. The dialysis system of claim 1 , wherein the controller is configured such that the number of passes of spent dialysis fluid through the dialyzer is set by the ratio of the flow of spent dialysis fluid within the dialyzer to the flow of fresh pre-mixed dialysis fluid, independent of any ultrafiltrate removal.