Multi-pass dialysis

Abstract

A system for dialysis is disclosed. The system includes 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 source of fresh dialysis fluid in series with the dialysis fluid inlet port, a pump connected with the source of the fresh dialysis fluid, and at least one of a balance chamber or a flow channel between the dialysis fluid outlet port and the dialysis fluid inlet port for balancing a flow of fresh dialysis fluid and spent dialysis fluid to the dialysis fluid inlet port. 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 a flow of fresh dialysis fluid to the dialyzer.

What is claimed is: 
     
         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 source of fresh dialysis fluid in series with the dialysis fluid inlet port;   a pump connected with the source of the fresh dialysis fluid; and   at least one of a balance chamber or a flow channel between the dialysis fluid outlet port and the dialysis fluid inlet port for balancing a flow of fresh dialysis fluid and spent dialysis fluid to the dialysis fluid inlet port, and wherein 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 a flow of fresh dialysis fluid to the dialyzer.   
     
     
         2 . The dialysis system of  claim 1 , further comprising a first multi-position valve for connection between the patient and the blood pump; and
 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;   
     
     
         3 . The dialysis system of  claim 2 , further comprising a filter operably connected between the dialysis fluid outlet and inlet ports. 
     
     
         4 . A method for conducting hemodialysis, the method comprising:
 providing a hemodialysis system, the hemodialysis system comprising a blood pump, a dialyzer, a drip chamber, a source of fresh dialysis fluid, and a drain;   providing access to and from blood vessels of the patient through valves connected to the blood pump and the drip chamber;   circulating dialysis fluid from the source to the dialyzer;   pumping blood from the patient and to the patient through the dialyzer;   recirculating used dialysis fluid to the dialyzer, wherein the used dialysis fluid optionally includes a proportion of fresh dialysis fluid; and   draining the used dialysis fluid, wherein wastes from blood of the patient are transferred to the dialysis fluid in passing through the dialyzer.   
     
     
         5 . The method of  claim 4 , further comprising periodically reversing a flow of the blood to and from the patient through the dialyzer by reversing the valves. 
     
     
         6 . The method of  claim 4 , wherein the hemodialysis system further comprises a balancing system between the source and the drain, and further comprising balancing a flow of dialysis fluid to and from the dialyzer. 
     
     
         7 . The method of  claim 6 , wherein the balancing system comprises at least one balancing chamber or at least one flow channel. 
     
     
         8 . The method of  claim 4 , wherein a flow rate of the blood pumped to and from the patient is slowed in proportion to a number of passes of the dialysis fluid makes through the dialyzer. 
     
     
         9 . The method of  claim 4 , wherein the valves are configured to allow simultaneous blood flow to and from the patient or for single-needle operation. 
     
     
         10 . A method of performing hemodialysis, the method comprising:
 providing a hemodialysis system comprising a blood pump, a dialyzer, and a drip chamber;   providing access to and from blood vessels of a patient;   pumping blood from the patient through the dialyzer and returning the blood to the patient;   circulating fresh dialysis fluid to the dialyzer;   recirculating the used dialysis fluid to the dialyzer, wherein the used dialysis fluid optionally includes a proportion of fresh dialysis fluid; and   draining the used dialysis fluid, wherein wastes from blood of the patient are transferred to the dialysis fluid in passing through the dialyzer.   
     
     
         11 . The method of  claim 10 , further comprising mixing fresh dialysis fluid with used dialysis fluid before the step of recirculating. 
     
     
         12 . The method of  claim 10 , further comprising measuring at least one property of the used dialysis fluid during hemodialysis to determine a ratio of used to fresh dialysis fluid. 
     
     
         13 . The method  claim 10 , further comprising filtering at least a portion of the used dialysis fluid before the step of recirculating. 
     
     
         14 . The method of  claim 10 , wherein the dialysis fluid is recirculated a number of passes so that the dialysis fluid is saturated with at least one waste product before the step of draining.