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DIALYSATE REGENERATION SYSTEM FOR normal condition. Pumps may also regulate blood flow.

PORTABLE HUMAN DIALYSIS Moreover, pumps may be provided to introduce additional

substances, such as anticoagulants, into the blood. Pumped

CROSS-REFERENCE TO OTHER anticoagulants, such as heparin or citrate, may prevent clot

APPLICATIONS 5 ting of the blood on surfaces that are in contact with the blood.

In addition, the machines may include sensors, such as tem

The present application claims priority from U.S. Provi- perature sens0rs as well as heaters to maintain the dialysate at

sional Patent Application Ser. No. 60/532,759 filed Dec. 24, substantially the same temperature as the blood. 2003, hereby incorporated by reference in its entirety for all

Although effective, a patient must adjust to various complications presented by dialysis treatment. For example,

TECHNICAL FIELD patients may have to travel to a dialysis treatment facility,

such as a hospital or clinic, for the dialysis treatment. Since

The present disclosure relates generally to apparatus, sys- dialysis typically is required on a schedule, such as three or

terns and methods related to dialysis systems. 15 more treatments a week, such visits to the dialysis treatment

facility may be time-consuming and limiting to a patient. For

BACKGROUND example, the dialysis treatments may limit a patient's ability

to easily travel. For example, patients who select to travel may

With renal failure, physiological disturbance may occur have t0 prearrange for a visit at a different facility. Such

within an animal system. Such disturbances may include 20 arrangements may be difficult, thus making travel for a dialy

failure of the system to fully excrete various body toxins and sjs patient complicated failure of the system to maintain homeostasis of water and

required minerals. Dialysis treatments may be used to com- In some situations, dialysis treatments may be performed at

pensate for such renal failure home. Although, such home situations may be more conve

Two types of dialysis therapies are commonly available, 25 nient' the equipment may be of substantial size which may

hemodialysis and peritoneal dialysis. Hemodialysis treat- cause an inconvenience to the patient. Further additional

ments typically utilize a hemodialysis machine, which oper- equipment, such as a water purification system may be

ates as an external artificial kidney, to separate body toxins required. The water purification system may further compli

from the blood. A patient may be coupled to the hemodialysis cate the process and require additional room further compli

machine by insertion of catheters into the patient's veins and 30 eating home dialysis treatments.

arteries thus coupling the patient to the machine such that the it should be appreciated that typical dialysis machines may

patient'sbloodflowtoandfromthehemodialysismachine.In be 0f such a size to prevent portability. For example, some

the hemodialysis machine, the blood engages a dialysate into dialysis machines are substantially the size of a refrigerator,

which the blood toxins are transferred. thus preventing easy portability. The lack of portability of

Peritoneal dialysis cleans the blood without removing the 35 SUch dialysis machines may limit life choices for a dialysis

blood to an external system. Briefly, with peritoneal dialysis, patient For example, many dialysis patients, whether using

a dialysate may be infused into a patient's peritoneal cavity home treatment or a dial is treatment facilities have to limit

through a catheter implanted in the cavity. The dialysis solu- , , , , ... , , . ,.. ,

0 . . , . . J , J . travel and other opportunities due to the required time and the

tion contacts the patient s peritoneal membrane and waste, .. . . . „ \, . ^ ^ Ti. * . ^ ^ ^ .

^ . , ^ ^ ^. ^, , , , ^ limited choices lor their treatments. It is noted that the time

toxins and excess water pass from the patient s bloodstream 40 , „ , ,. , . „ , .

, ., , , , • , , , rj,, required lor hemodialysis may vary. For example, in some

through the peritoneal membrane and into the dialysate. 1 he n , . . , r ,

transfer of the waste, toxins and water from the bloodstream systems' hemodialysis treatment may last about four hours,

into the dialysate occurs due to diffusion and osmosis, i.e., an Thls substantial period of time and the necessity to use a

osmotic gradient occurs across the membrane. The spent treatment facility or a home-based non-portable umt prevents

dialysate may drain from the patient's peritoneal cavity, 45 a patient from traveling, etc.

removing the waste, toxins and excess water, from the patient. In addition to the time required for such dialysis treat

The cycle is repeated as necessary. ments, the cost of dialysis provide additional complications,

In a typical hemodialysis machine, blood may be separated for the patient, the treatment facilities, health insurance com

from surrounding dialysate solution by a semi-permeable panies, Medicare, etc. For example, treatment facilities have

membrane. The membrane contains pores which may allow 50 large expenses for maintaining and staffing the treatment

substances in normal molecular solution and the solvent to facility.

pass through the membrane, but it may be configured to T , r,- , • T

r , 0 P1 ' , , ,. , , In addition, the costs of dialysis itself may be expensive. In

prevent the passage ol large molecules, such as high molecu- j..^. ... . ,. . . ,.

f • 1 ^ ^ • 1 Ti 1 ^ ^ J-j T1 1 ^1 addition to the cost ol the dialysis machines, recurring costs

lar weight proteins and cellular constituents ol the blood. 1 he _ , , , ; , •

,? .., r, . 0- lor dialysate and environmental waste may be cost prombi

membrane further may prevent the passage ol bacteria. Since 55 . .

the apparatus operates by diffusion and osmosis, the dialysate tlve- For example, in conventional hemodialysis, a large

solution, also referred to generally as dialysate, typically amount of dialysate, for example about 120 liters, is used to

contains physiological concentrations of some membrane- dlalyze the blood during a single hemodialysis therapy. The

passing dissolved normal constituents of the blood, such as sPent dialysate is then discarded. The large amount of used

various electrolytes. The dialysate also may include various so dialysate may increase the costs of dialysis. Additionally,

concentrations of substances which may be desired to be costs may be increased due to the large amounts of purified

introduced into the blood stream by diffusion, such as drugs, water that are needed. For example, costs may be increased

dextrose, etc. due to equipment to generate, store and use purified water.

In addition to the above membrane, the typical hemodialy- Further, such dialysate, needles, and other medically-consis machine may include various pumps and sensors. Pumps, 65 taminated products, must be appropriately discarded, which or bubblers, may be utilized to introduce oxygen into the may further increase costs of and time associated with dialydialysate so as to maintain the oxygen content of the blood in sis treatment.

SUMMARY

A dialysate regeneration chamber is provided. In one embodiment, the dialysate regeneration chamber may include a toxin trap configured to selectively trap toxins, and 5 repel select cations.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is illustrated by way of example and not by 10 way of limitation in the figures of the accompanying drawings, in which the like references indicate similar elements and in which:

FIG. 1 is a schematic illustration of an exemplary dialysis system in accordance with the present disclosure;

FIG. 2 is a schematic illustration of a dialysate regeneration 15 cartridge for use in the exemplary system shown in FIG. 1 according to an embodiment of the present disclosure;

FIG. 3 is a cross-sectional view of an ion-selective fabric included within the dialysate regeneration cartridge taken along line 3-3 of FIG. 2; 20

FIG. 4 is a graph illustrating the ammonium binding capacity of an acid-treated fiber for use in the dialysate regeneration cartridge of FIG. 2.

FIG. 5 is a graph illustrating the activity of urease immobilized on an activated fiber for use in the dialysate regenera- 25 tion cartridge of FIG. 2.

FIG. 6 is a schematic enlargement of an ion-selective urease-immobilized fiber, taken along arrow 6 of FIG. 3, illustrating molecule movement and entrapment of toxins within the ion-selective urease-immobilized fabric.

FIG. 7 is a schematic illustration of another embodiment of a dialysis system in accordance with the present disclosure.

FIGS. 8-13 are graphs illustrating various characteristics of ion-selective, urease-immobilized, activated fibers for use in the dialysate regeneration cartridge of FIG. 2.

DETAILED DESCRIPTION

30

35

An exemplary dialysis system for use in dialysis is illustrated at 10 in FIG. 1. The dialysis system may include a dialysis chamber 12 and a dialysate regeneration chamber or 40 dialysate regeneration cartridge 14. Briefly, dialysis chamber 12 may include a blood compartment and a dialysate compartment. Toxins may be transferred from the blood to dialysate due to diffusion and osmosis across the semi-permeable membrane separating the two compartments. The transferred 45 toxins may saturate the dialysate in the dialysate compartment. Saturate, as used herein, includes any level of increased toxin, such that saturated dialysate is dialysate with an increased toxin level.

The saturated dialysate also referred to as spent dialysate 50 may be directed into regeneration chamber 14 which may be configured to separate toxins from the spent dialysate. Once the toxins are removed from the spent dialysate, the dialysate may be considered refreshed and reused. A dialysate reservoir 16 may be provided to store purified dialysate and refreshed dialysate for use during the dialysis process.

It should be appreciated that although dialysis chamber 12, regeneration chamber 14 and reservoir 16 are shown as separate devices linked through couplers, such as tubing system 24, one or more the chambers and/or reservoir may be integrated together. Typically, the regeneration chamber is dis- 60 posed intermediate the dialysis chamber and the reservoir, however other configurations may be possible.

As described briefly above, dialysis chamber 12 of the exemplary embodiment may be subdivided into a blood compartment 18 and a dialysate compartment 20. Blood compart- 65 ment 18 may be separated from dialysate compartment 20 via a semi-permeable membrane 22. Blood, or any other suitable

55

fluid may be introduced into dialysis chamber 12 via inflow 30. Inflow 30 may be a blood inflow coupled to a patient's body, such that blood flows from the patient's body into blood compartment 18 in the direction of arrow A. Blood may flow into and through blood compartment 18 in the direction of arrow C. Blood may return to the patient's body through outflow 32.

The blood inflow 30 and the blood outflow 32 may include tubing system 24 (as shown in this embodiment), or any other conduit connecting the fluid source (such as the patient) to the dialysis chamber. Various pumps may be provided to enable flow into and out of the dialysis chamber. In some embodiments, the blood inflow and blood outflow may be incorporated in a dual-lumen device that permits bidirectional flow into and out of the blood compartment.

Dialysate, also referred to herein as dialysis fluid, may enter dialysate chamber 12 and flow through the dialysate chamber in the direction of arrow B. As described above, the dialysate typically includes physiological concentrations of membrane-permeable, dissolved normal constituents of the blood. The dialysate also may include various concentrations of substances that are desired to be introduced into the blood stream by diffusion such as select drugs, sugars, etc. Additionally, in some embodiments, oxygen may be bubbled into the dialysate.

While in the dialysis chamber 12, blood may be separated from dialysate by semi-permeable membrane 22. Semi-permeable membrane 22 may be any commercially available dialyzer membrane obtained from a standard dialyzer manufacturer. The typical dialyzer membrane, or semi-permeable membrane utilized in the dialysis system may allow substances in normal molecular solution and small molecules to pass through permeable pores, while preventing the passage of large molecules, such as bacteria, high-molecular proteins, and cellular constituents of the blood.

In some embodiments, semi-permeable membrane 22 may have a large surface area which may accommodate increased osmotic interchange between the blood and the dialysate. For example, blood may be distributed such that it flows along the membrane ensuring maximum contact with the semi-permeable membrane bathed by dialysate. It should be appreciated that other suitable flow mechanisms and configurations for contact and engagement with the semi-permeable membrane may be used.

Semi-permeable membrane 22 of dialysis chamber 12 may be permeable to system waste materials, including, but not limited to, urea, uric acid, creatinine, phosphate and other small organic waste molecules. As used herein, system waste materials may be referred to generally as toxins. Thus, the various toxins carried in the blood may diffuse across semipermeable membrane 22 (in the direction of arrow G), and mix with the dialysate contained within the dialysate compartment 20 of dialysis chamber 12.

Upon the receipt of the toxins, the concentration of the toxin molecules increase in the dialysate, and the concentration differential between the blood in blood compartment 18 and the dialysate in dialysate compartment 20, is reduced. Accordingly, when the dialysate contains a concentration of the toxins (such that the dialysate has an increased toxin level), the dialysate may be considered spent dialysate. The spent dialysate may not be as efficient in removing additional toxins from the blood across semi-permeable membrane 22 via diffusion. Thus, the spent dialysate may flow or be pumped such that the spent dialysate exits the dialysate chamber 12 through dialysate outflow 42.

Many currently available hemodialysis machines dispose of the spent dialysate. As an example, in some currently used hemodialysis systems, a patient's blood is pumped through a hemodialysis machine, via catheters inserted into the patient's veins and arteries, connecting the blood flow to and

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