JP2008510511A - Two-stage blood filtration to produce exchange fluid - Google Patents

Abstract

The present invention relates to a two-stage hemodialysis system for a patient. In one embodiment, the system includes a first filtration device (210) that contains blood (255) from a patient (200) and a first filtrate (285). A filtered blood component (265) is produced. The system further includes a second filtration device (220) that contains the first filtrate (285) and produces exchange liquid (275) and waste products. It is preferable that at least one of the first and second filtration devices is a Taylor vortex stirring blood filtration device (10).

Description

  A preferred embodiment of the present invention relates to multi-stage filtration where continuous filtration removes various grades of filtrate. The preferred embodiment of the present invention is particularly useful for regenerating fluids lost during hemodialysis.

  Traditionally, dialysis is a maintenance therapy used to treat kidney disease. There are two approaches to this. One is peritoneal dialysis where the treatment is performed inside the patient, ie within the patient's peritoneum. Peritoneal dialysis uses the patient's peritoneal membrane as a blood filter. The abdominal cavity is filled with dialysate, which creates a concentration gradient between the bloodstream and dialysate. Toxins diffuse from the patient's bloodstream into the dialysate, which must be regularly replaced with fresh dialysate.

  The second technique is by filtration dialysis. Filtration dialysis includes two main techniques, hemodialysis and hemofiltration. Both operate outside the body by drawing blood from the patient, processing the blood to remove toxins, and returning the processed blood to the patient. However, each process functions with a different physical separation technique.

  Hemodialysis results in the removal of toxins from the blood by diffusion. The patient's blood flows too much on one side of the membrane, while dialysate flows too much on the other side. The membrane selectively allows small molecules to flow. Due to the concentration gradient between blood and dialysate, small molecule toxins diffuse into the dialysate. At the same time, nutrients present in the dialysate, such as electrolytes and other chemicals, diffuse into the blood. The processed blood is then returned to the patient.

  Hemofiltration results in the removal of toxins from the blood by convection. The patient's blood is passed through a filter that is permeable to plasma water and molecules that are typically smaller than 20,000 daltons. The resulting filtrate of plasma water, called “blood waste”, contains “desired small molecules” including water, toxic blood components, small nutrient molecules and electrolytes. Because treated blood lacks important components lost during filtration and its volume is substantially reduced, an exchange solution is added to the treated blood before reintroduction to the patient. There must be. Depending on the demand for hemofiltration, the replacement fluid can be added before or after hemofiltration.

  In addition to these two blood purification techniques, a combination of hemodialysis and hemofiltration known as hemodiafiltration has been used. Hemodiafiltration provides toxic removal from the blood by both diffusion and convection. As with hemofiltration, the blood volume and nutrient / electrolyte lost in the process of hemodiafiltration must be replaced with an exchange solution.

  In general, exchange fluids are designed to replicate healthy plasma water with respect to pH and electrolyte and nutrient concentrations. However, the replacement fluid can also be adjusted to correct for abnormalities in individual patients. In many cases, biocompatible buffers such as citrate, lactate, acetate, bicarbonate, etc. are the base material for the exchange solution. This buffer can be supplemented with electrolytes such as chlorine, sodium, calcium, magnesium, potassium, phosphoric acid, and nutrients such as glucose and dextrose as required by the patient.

  Disadvantages of these blood treatment methods include the difficulties and costs associated with producing large quantities of exchange fluids that are free of contaminants that are harmful to the patient. In addition, hemodialysis, hemofiltration, and hemodiafiltration produce large amounts of medical waste that is expensive to process. Consequently, waste from these systems must be reused to produce biocompatible and low cost replacement or dialysate. Thereby, it is possible to eliminate the necessity of generating a large amount of an exchange solution or dialysate from the outside. Filtration of patient blood waste produced during hemodialysis meets these needs.

  Another problem faced by people using known methods of hemodialysis is clogging of the filter, referred to as “concentration polarization”. As a result of the selective permeability of the filter, the filtered material that cannot pass through the filter may have a high concentration on the surface of the filter. This phenomenon can be clearly explained in the case of a “dead end” filter such as a coffee filter. During the course of the filtration process, the filtered material (coffee residue) deposited on the filter creates a flow resistance against the liquid (coffee) that can pass through the filter, ie the filtrate. As a result, the filtrate flow rate decreases and the filtration efficiency decreases.

Various solutions to the concentration polarization problem have been proposed. These increase the velocity and / or pressure of the liquid (see, for example, Merin et al, (1980) J. Food Proc. Pres. 4 (3): 183-198) and generate turbulence in the supply channel (Blatt et al, Membrane Science and Technology, Plenum Press, New York, 1970, pp. 47-97), pulsing the feed stream on a filter (Kennedy et al, (1974) Chem. Eng. ScL 29: 1927-1931), designing channels to generate tangential flow and / or Dean vortices (Chung et al, (1993) J. Memb. ScL 81: 151-162), generating Taylor vortices (E.g. Lee and Lueptow (2001) J. Memb. ScL 192: 129-143 and U.S. Pat. Nos. 5,194,145, 4,675,106, which are incorporated herein by reference in their entirety). No. 4,753,729, No. 4,816,151, No. 5,034,135, No. 4,740,331, No. 4,670,176, No. 5,738,792). In US Pat. No. 5,034,135, Fischel discloses generating a Taylor vortex to promote blood fractionation. Fischel also describes a variation in the width of the gap between the rotary spinner and the cylindrical housing, but does not teach this variation in width along a circumferential cross section.
Merin et al, (1980) J. Food Proc. Pres. 4 (3): 183-198 Blatt et al, Membrane Science and Technology, Plenum Press, New York, 1970, pp. 47-97 Kennedy et al, (1974) Chem. Eng. ScL 29: 1927-1931 Lee and Lueptow (2001) J. Memb. ScL 192: 129-143 U.S. Pat.No. 5,194,145 U.S. Pat.No. 4,675,106 U.S. Pat.No. 4,753,729 U.S. Pat.No. 4,816,151 U.S. Pat.No. 5,034,135 U.S. Pat.No. 4,740,331 U.S. Pat.No. 4,670,176 U.S. Pat.No. 5,738,792

  As the inner member rotates relative to the outer member, a Taylor vortex is created in the gap between the coaxially arranged cylindrical members. Taylor Couette-type filtration devices produce strong vortices that are concentrated along the filter and that mix the filtered material into the liquid to be processed, due to instability of the centrifugal flow (Taylor instability). produce. In general, a cylindrical filter rotates inside a stationary outer housing. It has been observed that film deposition due to concentration polarization is very slow compared to dead-end or tangential filtration. In fact, the filtration efficiency can be improved by about 100 times.

  The use of Taylor vortices in rotary filtration devices has been applied to the separation of plasma from whole blood (see, eg, US Pat. No. 5,034,135). In this application, the separation device had to be inexpensive and disposable for a single use of the patient. In addition, these separators only needed to operate for a relatively short time (about 45 minutes). In addition, the filtration device was sized to accept a blood flow (approximately 200 ml / min) that could be reliably collected from the donor. This technology has brought significant improvements to the blood processing industry. The advantages and improved filtration efficiency found in a rotary filtration system (Taylor vortex) have not yet been studied in other commercial liquid separation fields, including kidney dialysis.

  Therefore, configuring an improved hemodialysis system can significantly reduce the need for artificial replacement fluid. In addition, the improved hemodialysis system can generate Taylor vortices to mitigate the concentration polarization problem commonly found in known filtration methods.

  In one embodiment, the invention relates to a two-stage hemodialysis system for a patient. The system includes a first filtration device that receives blood from a patient and produces a first filtrate and processed blood. The system further includes a second filtration device that receives the first filtrate and produces exchange liquid and waste products. Preferably, at least one of the first and second filtration devices has a Taylor vortex stirring blood filtration device.

  In another embodiment, the invention relates to a two-stage hemodialysis system for another patient. The system includes a dialyzer that receives blood and dialysate from a patient and produces dialysate and treated blood. The system further includes a filtration device that receives the dialysis drainage and produces recycled dialysis drainage and waste.

  In another embodiment, a method for performing hemodialysis of a patient can be performed according to the present invention. A first filtration device configured to create a Taylor vortex is provided, and a second filtration device is provided as well. Blood is introduced from the patient into the first filtration device, and the first filtrate from the first filtration device is introduced into the second filtration device. The replacement fluid can then be obtained from the second filtration device.

  In other embodiments, a second method of performing hemodialysis of a patient can be performed in accordance with the present invention. A first filtration device is provided and a second filtration device configured to create a Taylor vortex is also provided. Blood is introduced from the patient into the first filtration device, and the first filtrate from the first filtration device is introduced into the second filtration device. The replacement fluid can then be obtained from the second filtration device.

  In other embodiments, other methods of performing patient hemodialysis can be performed in accordance with the present invention. A dialysis device and a filtration device are provided. Blood is introduced from the patient into the dialysis machine, and dialysis drainage from the dialysis machine is introduced into the filtration device. The reused dialysate can then be obtained from the filtration device.

  Conventionally, the hemodialysis process is performed in one stage. In other words, blood is removed from the patient and passed through a single filtration device to remove waste and then returned to the patient. Unfortunately, blood is a heterogeneous liquid composed of both larger and smaller molecules than these waste products, and the size of these molecules generally ranges from 300-6000 daltons. As a result, filtration devices that remove these waste products from blood often inadvertently remove many small molecules such as water and electrolytes during filtration. In this case, these small molecules must be replenished prior to reintroduction of blood into the patient.

  In a typical device, blood is pumped from the patient at a rate of 300-440 mL / min. Approximately half of this is filtered from the blood and discarded as blood waste. Therefore, during 30 hours of dialysis, 20-30 liters of replacement fluid must be replenished to keep the patient's blood volume constant. Of course, most of the filtrate in such a dialysis process contains water and other desired small molecules.

  One embodiment of the present invention is intended to use a multi-stage filtration process to recapture most of this desired filtrate and mix it with the treated blood. This is intended to improve the amount of blood returned to the patient without using excess artificial replacement fluid. In one embodiment of the invention, two-stage filtration is used. The first stage uses a filtration device that is permeable to water, small nutrient molecules, and waste products, as in the prior art. In the second stage, the blood waste from the first stage filtration apparatus is passed through a second filtration apparatus that filters out large waste molecules. Thereafter, the plasma water filtrate coming out of the second filtration device can be used as a clean and biocompatible exchange solution to increase the amount of blood returned to the patient. Of course, in other embodiments, more stages may be required to filter out a particular waste product from other similar sized molecules.

  Various filtering devices can be used for both the first and second stages of one embodiment of the present invention. FIG. 1 shows a cross-sectional view of one filtration device 10 that can be used in the present invention. In this filtration device, a single rotor creates a Taylor vortex. In the illustrated embodiment, hemodialysis is performed using the filtration device 10 to filter molecules of a specific size (including waste products) from the blood. In other embodiments, the filtration device 10 can be used to more generally transfer material from one liquid. In yet another embodiment, the filtration device 10 can be used to transfer heat from a single liquid. As is well known to those skilled in the art, the present invention should not be limited to medical applications only.

  In one embodiment, the filtration device 10 includes a cylindrical container 12 that houses a cylindrical rotor 14. There is a gap 16 between the container 12 and the rotor 14, and in a preferred embodiment, the rotor 14 is coaxially disposed within the container 12. In other embodiments, different configurations and configurations for the container and rotor may be selected to suit other liquids and other Taylor vortex generating means.

  In the illustrated embodiment, the cylindrical peripheral wall of the rotor 14 is at least partially composed of a filtration membrane 18 and partially defines the interior 20 of the rotor. The rotor interior 20 is further defined by the top and bottom walls of the rotor 14, which may or may not include a filtration membrane. As shown in FIG. 1, the filtration membrane 18 can be used as the first stage of a two-stage dialysis method. This filtration membrane functions as a dialysis membrane and is permeable to water, electrolytes, small nutrient molecules, and small to medium molecules that make up waste products in the blood. In a typical application, dialysis membrane 18 is permeable to molecules up to about 10,000 daltons in molecular weight. In other applications, the dialysis membrane 18 may be more or less permeable in the range of 6000 to 20000 daltons. In another embodiment, the filtration membrane can be used in the second stage of a two-stage dialysis process. At this time, the filtration membrane is permeable to molecules with a mass of up to about 300 Daltons. Thus, plasma water, electrolytes and small nutrient molecules flow into the rotor interior 20 as filtrate and heavier waste products are filtered off. In other embodiments, different degrees of filtration and / or heat transfer can be achieved by using different filtration membranes. For example, in heat conduction applications, the filtration membrane may have a non-permeable structure. However, this structure is an efficient conductor of heat.

  In the illustrated embodiment, the cylindrical container 12 has three liquid ports 22, 24 and 26. Two of 22 and 24 are connected to a gap 16 between the container 12 and the rotor 14, and 26 exits from the interior 20 of the rotor. In other embodiments, there may be different liquid inlet / outlet configurations. For example, in one embodiment, only one liquid inlet / outlet leads to the gap between the container and the rotor, and two inlets / outlets lead to the interior of the rotor.

  In one embodiment, two pivot pins 30, 32 are installed at each end of the axis A of the cylindrical container 12. These pivot pins 30, 32 define a rotational axis A with respect to the rotor 14 to facilitate free rotation of the rotor 14. As shown, the lower pivot pin 32 can be hollow, allowing a liquid movement path between the container 12 and the rotor 14. Of course, in other embodiments, the upper pivot pin 30 can be hollow to accommodate another liquid inlet / outlet. Other means of facilitating rotation can also be applied, such as a ball bearing mechanism or other means as is well known to those skilled in the art.

  In one embodiment of the invention, the rotor 14 is free to rotate within the cylindrical container 12. To control this rotation, a rotary magnet 34 can be mounted inside the rotor 14 and an external rotating magnetic field (not shown) can also be arranged to interact with the rotary magnet 34. . By controlling the external magnetic field, the magnet 34 and thus the rotor 14 can be rotated at a speed that varies in different directions. In a preferred embodiment of the present invention, the rotor 14 can be rotated at a speed sufficient to generate Taylor vortices in the liquid in the gap 16 between the rotor 14 and the container 12. By creating a Taylor vortex in this void 16, the filtration efficiency can be dramatically improved. As known to those skilled in the art, other means of rotating the rotor 14 to create a Taylor vortex may be used in accordance with the present invention. For example, in one embodiment, the motor can be attached to at least one of the pivot pins attached to the rotor 14, eg, the upper pivot pin 30.

  In one embodiment, the rotating magnetic field that controls the rotor 14 can be generated by a series of magnetic coils arranged around the top of the filtration device 10. These electrical coil assemblies can be semi-arced (C-shaped cross section) that can be closed around the device 10, although other configurations are possible.

  While the size of the device 10 shown is considered sufficient for hemodialysis, larger or smaller filtration devices may be used for other liquids to be processed in other applications.

  In hemodialysis applications, the air gap 16 between the rotor 14 and the inner wall of the container 12 is selected to generate sufficient Taylor vortices in the blood. The air gap 16 is determined by the diameter of the rotor 14 and the number of revolutions per minute (RPM), and these variables can be changed by those skilled in the art. When the centrifugal speed is in the range of 2000-2500 RPM and the rotor diameter is in the range of about 0.1 inch (2.54 mm) to 10 inch (254 mm), the width of the air gap 16 sufficient to create a Taylor vortex is about 0. 0.003 inch (0.0762 mm) to 0.3 inch (7.62 mm). More desirably, when the rotor 14 has a diameter of about 1 inch (25.4 mm) and rotates at about 2400 RPM, if the width of the gap 16 is about 0.03 inch (0.762 mm), sufficient vortices are generated. Can be made. In the preferred embodiment of the filtration device 10, the rotor is approximately 2 inches (50.8 mm) in diameter and slightly longer than 6 inches (152.4 mm).

  FIGS. 2-4 illustrate some additional structural features of various embodiments of the above hemodialysis device used in a two-stage filtration process. In particular, different forms and configurations of the device housing and rotor are shown, which can be implemented to achieve various advantages. In FIG. 2, the above embodiment is shown. As can be seen more clearly in this figure, the rotor 14 has a cylindrical shape and is arranged coaxially in the cylindrical container 12. Therefore, the width of the gap 16 is constant around the device 10. In this relatively simple embodiment, the configuration of an appropriate rotational speed of the rotor 14 can be made easier, and the strength of the Taylor vortex is almost constant over the entire circumference of the filtration membrane 18.

  FIG. 3 shows another configuration of the container 12 and the rotor 14. In this embodiment, the container 12 and the rotor 14 each have the same cross section as in FIG. 2, but are no longer arranged coaxially. Therefore, as shown in FIG. 3, the width of the gap 16 varies around the container 16. Since the Taylor number reflecting the strength of the generated vortex is directly proportional to the width of the air gap, the portion of the rotor 14 far from the wall of the container 12 receives a larger Taylor vortex than the portion near the wall. As the rotor 14 passes through large portions of these voids, any concentration polarization or any clogging remaining in the filtration membrane 18 is “blown” by the stronger vortex and the clogged portion of the membrane 18 resumes. As a result, for each revolution, the longitudinally extending cross section of the filtration membrane 18 can be “cleaned” by passing through a wide portion of the gap 16 to improve the efficiency of the device 10. In addition, where the gap 16 is narrow, the shear force in the gap increases and this changing shear force also tends to increase mass transfer through the filtration membrane 18. Therefore, at every point of the dialysis membrane 18 in the rotor 14, the shear force can be increased and the vortex can be reduced every rotation.

  In FIG. 4, another configuration of the container 12 and the rotor 14 is shown, which also creates a void having a non-constant width. In this configuration, the container 12 and the rotor 14 are arranged in the same manner as in FIG. 2, but the container 12 further incorporates a protrusion 42 into the wall. Thus, the width of the gap 16 varies around the container 12 and becomes wider at the protrusion 42, producing the advantages as described with reference to FIG. The abrupt change in width and width in this embodiment can further draw out the vortex properties that promote dialysis. In other embodiments, the container 12 and the rotor 14 can have other cross-sectional shapes such that the width of the gap 16 is variable.

  Returning to FIG. 1, one method of using the hemodialysis apparatus 10 will be described with reference to the drawings. Arrows 36, 38, and 40 indicate the flow input and output to and from the device 10. In the illustrated embodiment, blood from the patient flows through the gap 16 between the rotor 14 and the container 12, and water, small nutrient molecules, electrolytes and waste products are filtered into the interior 20 of the rotor. Due to the concentration gradient between blood and plasma water that initially exists across the membrane 18, certain waste products selectively flow through the dialysis membrane 18 into the plasma water, thus dialyzing the blood. . The rotor 14 rotates at a speed sufficient to create a Taylor vortex in the blood, preventing concentration polarization near the dialysis membrane 18. Thus, one embodiment of the present invention allows the use of a smaller, more biocompatible blood filtration device 10.

  More specifically, the blood inlet 22 is located at the top of the cylindrical container 12 and the blood outlet 24 is located at the bottom. This allows blood flow from the top to the bottom of the container, simply using gravity energy and blood inflow pressure. The device 10 is preferably designed such that a desired amount of waste by-products is extracted during the time that a certain amount of blood travels from the top to the bottom of the blood filtration device 10. A water and waste by-product outlet 26 is located at the bottom of the rotor 14. In the preferred embodiment, this solution is further filtered after flowing through the device 10, further details of which are described below.

  In another embodiment, dialysate can be used to facilitate hemodialysis. Another liquid inlet / outlet can be attached to the top of the device 10 to allow dialysate to flow into the device. As will be described in more detail with reference to FIG. 6, waste products diffuse into the dialysate and are carried away from the apparatus by the flow of dialysate drainage. Other modifications may also be made in accordance with the present invention.

  Shown in FIG. 5 is a cross-sectional view of another embodiment that can be used with the present invention, where two rotor devices create a Taylor vortex. The illustrated apparatus can desirably be used in a two-stage blood filtration system, one example of which is described in detail with reference to FIG. In the illustrated embodiment, the filtration device 110 is used to perform hemodialysis, and unwanted waste products are filtered from the blood and transferred to dialysate or “dialysis drainage”. In other embodiments, device 110 can be used to more generally transfer material from one liquid to another. In yet another embodiment, device 110 is used to transfer heat from one liquid to another. As is well known to those skilled in the art, the present invention should not be limited to medical applications only.

  In one embodiment, the filtration device 110 includes a cylindrical container 112 that houses a cylindrical outer rotor 114. A first gap 116 exists between the container 112 and the external rotor 114, through which blood flows. In the preferred embodiment, the outer rotor 114 is coaxially disposed within the cylindrical container 112. In other embodiments, other configurations and configurations for the container and rotor may be selected as described with reference to FIGS.

  In the illustrated embodiment, the cylindrical peripheral wall of the outer rotor 114 is at least partially composed of a filtration membrane 118 and partially constitutes the interior 120 of the outer rotor. The interior 120 of the outer rotor is further defined by the top and bottom walls of the outer rotor 114, which may or may not include a filtration membrane. As shown in FIG. 5, the filtration membrane 118 is a dialysis membrane. This filtration membrane 118 selectively facilitates the diffusion of molecules smaller than about 10,000 daltons, so that the device 110 can function as the first stage device of the two stage blood filtration system shown in FIG. In other embodiments, different degrees of filtration and / or heat transfer can be achieved by using different filtration membranes. For example, in heat conduction applications, the filtration membrane may have a non-permeable structure. However, this structure is an efficient conductor of heat.

  In one embodiment, two pivot pins 130, 132 are disposed at both ends on the axis A of the cylindrical container 112. These pivot pins 130, 132 define a rotational axis A with respect to the outer rotor 114, facilitating free rotation of the rotor 114. As shown, the pivot pins 130, 132 may be hollow as well, providing a liquid movement path that passes between the container 112 and the outer rotor 114. In other embodiments, other means of facilitating rotation can be applied, such as a ball bearing mechanism or other means as is well known to those skilled in the art.

  In one embodiment of the present invention, the outer rotor 114 is free to rotate within the cylindrical container 112. To control this rotation, a rotating magnet 134 can be mounted inside the external rotor 114 and an external rotating magnetic field (not shown) can be configured to interact with the rotating magnet 134. it can. By controlling the external magnetic field, the magnet 134, and thus the external rotor 114, can be rotated at different rates in different directions. In the preferred embodiment of the present invention, the outer rotor 114 can be rotated at a speed sufficient to generate Taylor vortices in the liquid in the gap 116 between the outer rotor 114 and the container 112. By creating a Taylor vortex in this first void 116, the filtration efficiency can be dramatically improved. As known to those skilled in the art, other means of rotating the outer rotor 114 to create Taylor vortices can be used in accordance with the present invention. For example, in one embodiment, the motor can be attached to at least one of the pivot pins attached to the outer rotor 114, such as the upper pivot pin 130, for example.

  Inside the outer rotor 114, the inner rotor 144 can also be arranged coaxially, supported by upper and lower pivot pins 130, 132, in which case the second gap 146 is between the two rotors 114, 144. To occur. Although the inner rotor 144 may partially have another filtration membrane, in the preferred embodiment, the inner rotor is relatively impermeable and simply a second between the two rotors 114, 144. It only defines a void. As described above in more detail with respect to the container and the outer rotor, the inner rotor 144 can have different cross-sectional configurations, and the position of the inner rotor can be shifted to generate other liquids and Taylor vortices. Means can also be accommodated. In these alternative embodiments, the inner rotor 144 can be supported in a different structure than that which supports the outer rotor 114 and can be rotated about a different axis.

  In the preferred embodiment, the inner rotor 144 rotates freely within both the outer rotor 114 and the cylindrical container 112. To control this rotation, a second rotary magnet 148 can be mounted inside the inner rotor 144, and a second external rotating magnetic field (not shown) can be coupled with the second rotary magnet 148. It can be configured to interact. In the illustrated embodiment, the second rotary magnet 148 for the inner rotor 144 is located at the top of the device 110 and the rotary magnet 134 for the outer rotor 114 is located at the bottom of the device 110. Yes. In this way, two separate and independent magnetic fields can control the rotation of the two rotors 114 and 144. As described in more detail above, the second rotary magnet 148 attached to the inner rotor 144 can be controlled in the same manner as that attached to the outer rotor 114. In a preferred embodiment, the inner rotor 144 can be rotated at a speed sufficient to generate a Taylor vortex in the second gap 146 between the inner and outer rotors. In a more preferred embodiment, the inner rotor 144 can be rotated in the opposite direction to the outer rotor 114 to generate an even stronger Taylor vortex. By generating Taylor vortices in the second gap 146, concentration polarization on the side of the filtration membrane 118 facing the inner rotor 144 can be prevented, and filtration efficiency can be further improved. As is known to those skilled in the art, other means can be used to rotate the inner rotor 144 to generate the Taylor vortex. For example, in one embodiment, the motor may be attached to at least one of the pivot pins attached to the inner rotor 144, such as the lower pivot pin 132.

  In one embodiment, the rotating magnetic field that controls the two rotors can be generated by a series of magnetic coils that surround the top and bottom of the filtration device 110. In the illustrated embodiment, pre-connected tubing (not shown) enters and exits the filtration device 110 on axis A so that these electrical coil assemblies can be closed around the device 110. It can be in the form of a semi-arc (C-shaped cross section).

  Although the illustrated size of the device 110 is believed to be sufficient for hemodialysis, in other applications, larger or smaller filtration devices may be used for specific fluids to be processed.

  In hemodialysis applications, the first gap 116 between the outer rotor 114 and the inner wall of the container 112 is selected to generate sufficient Taylor vortices in the blood. This first air gap 116 is determined by the diameter of the outer rotor and the number of revolutions per minute (RPM), and these variables can be varied by those skilled in the art. With a centrifugal speed in the range of about 1000-5000 RPM and a diameter of the outer rotor in the range of about 0.1-10 inches (2.54-254 mm), the width of the gap 116 sufficient to create a Taylor vortex is about 0. 0.003 inch (0.0762 mm) to 0.3 inch (7.62 mm). More desirably, if the diameter of the outer rotor is about 1 inch (25.4 mm) and rotates at about 2400 RPM, the width of the air gap 116 of about 0.03 inch (0.762 mm) will result in sufficient vortexing. Can be generated.

  In the illustrated embodiment, the second gap 146 between the inner and outer rotors is selected to generate sufficient Taylor vortices in the dialysate. This second air gap 146 is determined by the difference in RPM and RPM between the inner and outer rotors. If the centrifugal speed is in the range of about 1000-5000 RPM and the diameter of the inner rotor is in the range of about 0.1-10 inch (2.54-254 mm), a Taylor vortex is created between the inner rotor 144 and the outer rotor 114. Sufficient gap 146 can have a width of about 0.003 inch (0.0762 mm) to 0.3 inch (7.62 mm). Preferably, the width of the second air gap 146 is about 0.03 inches (0.762 mm) for a field rotating about 0.8 inches (20.32 mm) and rotating at about 3600 RPM. Vortices can be generated. In this preferred combination of variables, the rotational speed of the inner rotor 144 is about 1200 RPM relative to the outer rotor 114. Alternatively, a powerful Taylor vortex can be created in the dialysate by rotating the inner rotor 144 in the opposite direction to the outer rotor 114.

  In various possible applications, the size and speed of the inner rotor, outer rotor, and outer container can vary significantly. For example, in certain industrial applications, the filtration device 110 can be designed on a much larger scale to accommodate liquids with higher flow rates and viscosities. Based on the teachings written herein, one of ordinary skill in the art can optimize the air gap and rotor size range, as well as the concentric speed and rotor rotation direction.

  In the embodiment shown, the cylindrical container has four liquid ports 122, 124, 126, 128. The first inlet 122 is located at the top of the cylindrical container 112, and the first outlet 124 is located at the bottom. In hemodialysis applications, this allows blood flow from the top to the bottom of the container, simply using the energy of gravity and the pressure of blood inflow. The device 110 is preferably designed such that a desired amount of waste by-products is extracted during the time that a certain amount of blood travels from the top to the bottom of the dialyzer 110. The second inlet 126 is located at the bottom of the outer rotor 114 and the second outlet 128 is located at the top of the outer rotor 114. In hemodialysis applications, dialysate flows through these ports and through the second gap 146 between the outer and inner rotors from the bottom to the top of the filtration device 110. In this preferred embodiment, the liquid flow path is designed to utilize counterflow mass transfer, meaning that the blood and dialysate passages are in opposite directions. Fresh dialysate is exposed to the dialyzed blood through the dialysis membrane 118, where the concentration gradient is lowest. However, as is well known to those skilled in the art, other numbers and configurations of liquid inlets and outlets may be used in accordance with the present invention.

  Since the first inlet and outlet 122 and 124 are present at the outer diameter of the container 112, it is not necessary to apply high pressure to this flow path. In such a situation, in the illustrated embodiment, blood is not pushed into the center of rotation of the outer rotor 114, and thus no fluid seal is required to prevent blood from entering the inner rotor 144. . A fluid seal may be added if higher fluid pressure is used in hemodialysis or other applications, or if the internal rotor 144 contains liquid to be filtered for some reason.

  In the preferred embodiment, dialysate passes through the lower pivot pin 132 toward the second gap 146 between the inner rotor and the outer rotor, but the first gap between the outer rotor 114 and the container 112. The second inlet 126 for dialysate is configured so that it does not descend to 116. In order to prevent the dialysate from moving into the first gap 116 between the outer rotor 114 and the container 112, a fluid seal 150 is incorporated at the upper pivot pin 130 in the illustrated embodiment. . The seal 150 may be any conventional polymer lip seal. Other seals may be combined as is well known to those skilled in the art. In an alternative embodiment, another fluid seal is incorporated into the lower pivot pin 132.

  In one method of practicing the present invention, blood is exposed to the dialysis membrane 118 along with the Taylor vortex, resulting in a minimal concentration polarization layer in the first gap 116 between the outer rotor 114 and the container 112, and the patient's blood. The ability to remove low molecular weight waste products from is maximized. In the process of passing through the filtration device 110, the dialysate is also exposed to the Taylor vortex, resulting in a minimal concentration polarization layer near the inside of the dialysis membrane 118, resulting in low molecular weight waste in the flow of dialysis drainage. The ability to mix into the maximum. In a preferred embodiment, the spent dialysate exiting device 110 can then be directed to another filtration device to produce a reused clean dialysate.

  With reference to FIG. 6, an exemplary method of performing hemodialysis will be described using the apparatus depicted in FIG. Inside the apparatus 110, the inner and outer rotors rotate in opposite directions at a speed sufficient to create a Taylor vortex in the liquid between the outer rotor 114 and the container 112 and between the inner rotor 144 and the outer rotor 114. Yes. Blood is collected from the patient at a specific flow rate 136 and enters the hemodialysis device 110 through the blood inlet 122 at the top of the device 110. Dialysate also enters the hemodialyzer 140, in this case from the bottom and through the second dialysate inlet 126. The two liquids receive forces from the two rotors, and Taylor vortices form inside. This reduces most of the concentration polarization in the dialysis membrane 118 of the outer rotor 114, and a more constant waste stream moves through the dialysis membrane 118 into the dialysate. The dialysate passes through the second air gap 146 between the outer rotor and the inner rotor, passes through the blood filtration device 110, and exits from the top through the dialysate outlet 128, but the processed blood is at the bottom of the device 110 And exits through blood outlet 124 at the back of the patient.

  In other embodiments, other Taylor vortex stirrer filters are used, as further described in co-pending US patent application Ser. No. 10 / 797,510, which is incorporated herein by reference in its entirety. can do.

  One problem with many of the above hemodialysis methods is that dialysis membranes can be permeable to water as well as waste products. Therefore, a large amount of plasma water accompanies the waste that moves through the dialysis membrane, and the flow rate of the processed blood that flows through the blood outlet is drastically reduced from the blood that enters the hemodialysis device. This problem is particularly acute in the filtration device 10 illustrated in FIG. In one embodiment, a sterile exchange solution can be added to the dialyzed blood after processing at the confluence before returning to the patient. However, in this embodiment, there is a risk that the patient will be exposed to the contaminated replacement fluid, and the cost of the replacement fluid increases the cost of hemodialysis.

  FIGS. 7A and 7B are schematic illustrations of an alternative embodiment of a two-stage hemodialysis system according to the present invention, in which exchange fluid is generated from blood waste from the first-stage filtration device and artificial replacement fluid. Has eased the need. The illustrated embodiment differs in the order of steps to achieve the objective, but shares many mechanisms of action. Therefore, the components of these two systems will be described together, and the differences will be emphasized as necessary in subsequent descriptions. The direction of the various liquid flows flowing through these systems is illustrated by arrows.

  The patient is represented by the leftmost rectangle 200. In a typical example, it is assumed that patient 200 has kidney disease that causes uremic metabolic abnormalities. This is believed to be due to the intermediate molecular weight molecules (300-6000 Daltons) removed by healthy kidneys causing pathological toxicity in these patients. To alleviate this accumulated toxicity, such patients 200 are typically subjected to regular dialysis treatment to remove these intermediate molecular weight molecules. In other embodiments, as will be appreciated by those skilled in the art, the patient 200 may have other illnesses where dangerous or toxic substances are present in the patient's blood. In still other embodiments, the source of liquid to be filtered need not be a patient. This process can also be used in an industrial setting, for example when the liquid is a heterogeneous liquid that needs to extract intermediate sized molecules.

  The device used in the first stage of this two-stage hemodialysis system can be described as a hemofiltration apparatus 210. As explained above, such a device 210 generally produces a filtrate containing molecules smaller than a certain size. As is well known to those skilled in the art, the filtration membrane used in apparatus 210 can have a wide variety of features and can be selected to filter any of a number of different sized particles. . In one embodiment, blood filtration device 210 is configured to filter out molecules having a molecular weight of 10,000 daltons or less. In this embodiment, the filtrate preferably contains intermediate molecular weight molecules that are toxic to the patient 200.

  The device used in the second stage of this two-stage hemodialysis system can be described as an ultrafiltration device 220 and is so called because it is permeable to smaller molecules. In the preferred embodiment, the purpose of the ultrafiltration device 220 is to filter out intermediate molecular weight toxic molecules from the heterogeneous solution, leaving only water and other desired small molecules. In a preferred embodiment, it is used in the ultrafiltration device 220 to allow molecules with a molecular weight of about 300 Daltons or less to pass through, and thus to separate potentially toxic waste products from the remaining solution. The filtration membrane to be selected is selected. In other embodiments, the filtration membrane may allow only molecules with a molecular weight of about 200 Daltons or less to pass through and prevent other suspected toxic molecules from coming out as filtrate.

  The same or different types of filtration devices can be used for blood filtration device 210 and ultrafiltration device 220. These can include, for example, conventional hollow fiber dialysis membrane cartridges or other filtration devices well known to those skilled in the art. In a preferred embodiment, this device is a Taylor vortex stirring filtration device that functions similarly to the filtration device 10 described above with reference to FIG. As explained above, these filtration devices can have any combination of various sizes, shapes and speeds of the rotor and outer frame to accommodate different viscosity and flow rates of processing liquid.

  A waste bag 230 is used to collect unwanted waste products generated from this two-stage hemodialysis system. In one embodiment, the waste bag 230 should collect much of the same waste that would normally be collected by a healthy kidney. Of course, the waste bag 230 can represent any of a number of means for collecting and / or discarding waste, and is not necessarily a physical container having a particular shape and size. In accordance with applicable laws and regulations, waste bags 230 often must be collected as hazardous waste that requires attention to disposal. Due to the unique properties of the present invention, the volume of waste produced by a two-stage hemodialysis system can be much less than that produced from a typical single-stage dialysis process.

  A supplemental replacement fluid source 240 is also shown in FIGS. 7A and 7B, although the two systems are shown in different locations. Although most of the replacement fluid to keep the patient's blood volume constant can be generated from the patient's own blood waste, a relatively small amount of artificial replacement fluid may still be required during processing. Even if the two-stage filtration system is fully functional, in order to keep the patient's blood volume constant, the volume corresponding to the medium molecular weight waste molecules must generally be replaced. In one embodiment, it is estimated that roughly 3 liters of artificial replacement fluid must be added to the patient's bloodstream every 3 hours, and roughly 3 liters of waste is removed during the same time frame. Yes. As explained above, this represents a significant improvement from the 20-30 liter volume required for general processing.

  Supplemental artificial replacement fluids can be produced in a variety of ways but must be sterile, pyrogen-free and generally at body temperature. As shown in Lee Henderson and Erminia Beans paper “Successful Production of Sterile Pyrogen-Free Electrolyte Solution by Ultrafiltration”, Kidney International, 14, 522-25, 1978, which is incorporated herein by reference in its entirety. Thus, in one embodiment, the artificial replacement fluid can be produced from ordinary tap water. In other embodiments, such liquids can be produced by other methods well known to those skilled in the art.

  In FIG. 7A, an anticoagulant source 250, which is an optional component of a two-stage blood filtration device, is shown. The anticoagulant supply source 250 has, for example, a heparin supply source that prevents blood from coagulating outside the body by mixing with blood. In other embodiments, other filtration-enhancing methods or methods that prevent flocculation and other undesirable liquid properties may be used. For example, water may be added to other heterogeneous solutions to facilitate vortex generation in the filtration devices 210 and 220.

  A method for performing hemodialysis according to the present invention using the two-stage hemodialysis system illustrated in FIG. 7A will now be described in more detail. As indicated by the arrow 255 extending from the patient 200 to the hemodiafiltration device 210, the first stage of the process is blood collection from the patient. As is conventional, blood is collected through an IV tube connected to the artery of the patient's 200 arm. Of course, other means of collecting blood from a patient are well known to those skilled in the art. As explained above, blood flow from a typical patient is 300-450 ml / min. Therefore, in order to keep the patient's blood volume relatively constant, the liquid returning to the patient (arrow 265) must flow at a similar flow rate. As is conventional, fluid returning to the patient 200 returns through an IV tube connected to the patient's vein.

  In the optional second stage, blood flowing from patient 200 is mixed with anticoagulant from anticoagulant source 250. In this way, the performance of the hemodialysis system can be improved.

  The blood flowing from the patient 200 then passes through the hemodiafiltration device 210. Filtration device 210 can filter blood in a number of ways as is well known to those skilled in the art. In the preferred embodiment, the filtration device 210 operates similarly to the device 10 described in detail above. In this example, blood flows through the inlet 22 into the gap 16 between the container 12 and the rotor 14. The filter membrane 18 is designed so that molecules having a molecular weight of about 10,000 daltons or less can pass through the rotor interior 20. The blood flowing from the patient 200 includes a number of components, including water, electrolytes, small nutrient molecules, waste products, high molecular weight molecules (such as proteins), blood cells, and various other types of cells. The first four components listed above contain blood waste and enter the rotor interior 20 through the filtration membrane 18. In this way, the interior of the rotor is filled with water, electrolytes, small nutrient molecules, and waste products.

  On the other hand, the rotor 14 rotates at a speed sufficient to create a Taylor vortex in the blood flowing through the gap 16 between the rotor 14 and the container 12. These Taylor vortices mix the blood in this void 16 thereby mitigating the concentration polarization problem at the outer portion of the filtration membrane 18.

  Filtration device 210 has two outlets 24 and 26. The first outlet 24 is in communication with the gap 16 between the rotor 14 and the container 12. If the blood waste is not reused, blood components that are too large to pass through the filtration membrane 18 will exit the blood filtration device 210 through the outlet 24. In a typical example, the flow rate from the outlet 24 is approximately half of the flow rate entering the inlet 22. In this way, approximately half of the patient's blood contains water, the desired small molecules, waste products, and the other half contains larger molecules and cells exiting through the outlet 24. These larger components are represented by arrows 265 returning to the patient 200.

However, as shown by arrow 275, water and the desired small molecule are recirculated to the two-stage system as an exchange fluid, so the blood filtration device 210 cannot completely filter the incoming liquid and the patient The arrow 265 representing the treated blood and exchange fluid returned to the flow has a volume approximately equal to at least the blood flow 255 coming from the patient 200. Therefore, the reduced stream 265 has both larger constituents and an exchange solution free of unwanted waste products. Further details of this process are described below.

  A second outlet 26 in communication with the rotor interior 20 directs a liquid stream 285 having water, desired small molecules, and waste products at a flow rate that is approximately half of the blood flow 255 from the patient. This blood waste stream 285 enters the ultrafiltration device 220.

  As explained above, the ultrafiltration device 220 can function similarly to the filtration device 10. The filtration membrane 18 of the ultrafiltration device 220 is configured such that water and the desired small molecules enter the interior 20 of the rotor of the ultrafiltration device 220. As represented by arrow 285, the intermediate molecular weight waste is filtered off and transferred from the ultrafiltration device 220 to the waste bag 230. The filtrate, on the other hand, contains a clean, warm, biocompatible replacement fluid that can be used to increase blood flow back to the patient.

  In the example illustrated in FIG. 7A, the exchange fluid stream 275 generated from this patient is re-refluxed to the starting point of a two-stage filtration system where a T-junction mixes the exchange fluid stream 275 with the blood flow 255 from the patient. Is done. As is well known to those skilled in the art, the T-junction can be any of a number of devices having two liquid inputs and one liquid output. In one embodiment, the T-connector simply has a T-shaped tube cross section. This increases the volume of liquid entering the hemodialyzer 210 and the liquid flow 265 returning to the patient 200 increases as well. Supplemental artificial replacement fluid 240 may be introduced because the liquid flow may decrease due to loss of waste. According to a preferred embodiment of the present invention, the flow 265 returning to the patient 200 is approximately equal to the flow 255 exiting the patient 200 and the patient's blood volume is kept relatively constant.

  In a preferred embodiment, the exchange fluid can be supplemented with various additives. Typical additives include biocompatible buffers such as bicarbonate, lactate, citrate, acetate and the like. Other ingredients such as chlorine, sodium, calcium, magnesium, potassium, phosphate, dextrose, glucose, and any other molecules needed for a particular patient can also be added to the exchange solution.

  The example illustrated in FIG. 7B is very similar to that described above with respect to FIG. 7A. The only difference is in the T-branch position where the exchange fluid stream 275 generated from the patient re-enters the system. In FIG. 7B, this liquid flow 275 is mixed with the processed blood flow returning to the patient 200. In this way, just before reintroduction to the patient, the reduced stream 265 increases to be approximately the same as the extracted stream 255. In a preferred embodiment, flow meters can be installed at various locations in the two-stage system of FIGS. 7A and 7B, for example, to monitor fluid flow and provide feedback regarding the required amount of supplemental artificial replacement fluid. As is well known to those skilled in the art, various flow meters can be used provided that they are sterile and configured for use in a hospital environment.

  In both of these figures, the hemodialysis device 210 can utilize hemofiltration or hemodiafiltration including continuous venous-venous hemofiltration and continuous arterial-venous hemofiltration.

  Although FIGS. 7A and 7B illustrate continuous processing, it should be understood that it includes batch processing. Batch processing involves processing a portion of blood removed from a patient. The blood can then be processed to selectively remove components from the produced exchange fluid. The blood after this treatment can be mixed with an exchange solution and returned to the patient.

  In another embodiment, dialysate can be reused in a two-stage hemodialysis system. In general, once contaminated with waste products, the dialysate is discarded after passing once through a dialysis machine, such as filtration device 110, for example. As a result, prior art dialysis machines have many of the same inefficiencies as described above for filtration devices, requiring a large amount of exchange dialysate and producing a large amount of waste. Instead, according to the present invention, to separate the waste product from the dialysate, the dialysate solution containing the intermediate molecular weight waste product is subjected to a second filtration, such as either the filtration device 10 or 110. Can be sent to the device. The recycled dialysate emerging from this second filtration device as filtrate can then be used for further dialysis processes.

  FIG. 8 is a schematic diagram of such a two-stage blood filtration system in which clean and reused dialysate is generated from spent dialysate, alleviating the need for large amounts of exchange dialysate. As indicated above, the directions of the various liquid flows through the system are illustrated by arrows.

  The patient is represented by the leftmost square 300. In a typical example, patient 300 has features similar to those described above for patient 200. Alternatively, the two-stage system can be used in an industrial setting where the liquid to be filtered is a heterogeneous liquid that requires extraction of intermediate sized molecules.

  The device having the first stage of this two-stage blood filtration system is a hemodialysis apparatus 310. As is well known to those skilled in the art, the filtration membrane used in apparatus 310 can have a wide variety of characteristics and can be selected to filter any of a number of different sized particles. . In one embodiment, blood filtration device 310 is configured to filter out molecules having a molecular weight of 10,000 daltons or less. In one embodiment, hemodialyzer 310 is configured so that only molecules having a molecular weight of 10,000 daltons or less diffuse through the membrane.

  In general, as explained above, a hemofiltration device has two liquids passing through it on each side of the filtration membrane. Since the aqueous solution exists on both sides of the membrane, the volume of the liquid is kept roughly the same, but if it can pass through and diffuse, the molecules there are likely to be in equilibrium through the membrane. This allows a dialysate with a relatively high concentration of electrolyte, salt, or other desired molecule to flow along one of the filtration membranes, and the patient's blood with a high concentration of waste by-products flows along the other side of the dialyzer Can be shed. The two solutions are in equilibrium with respect to molecules that can diffuse through the membrane, and typically result in a solution consisting of dialysate and waste products and treated blood containing additional desired small molecules. is there.

  The device used in the second stage of this two-stage blood filtration system can be described as an ultrafiltration device 320, so called because it is permeable to smaller molecules. In the preferred embodiment, the purpose of the ultrafiltration device 320 is to filter out toxic molecules of medium molecular weight from the heterogeneous solution, leaving only dialysate and other desired small molecules. In this preferred embodiment, the filtration membrane used in the ultrafiltration device 320 is selected to pass molecules having a molecular weight of about 300 Daltons or less, thereby separating potentially toxic molecules from the remaining solution. . In other embodiments, the filtration membrane can only pass molecules having a molecular weight of about 200 Daltons or less, preventing other potentially toxic molecules from coming out as filtrate.

  The same or different types of filtration devices can be used for the hemodialysis device 310 and the ultrafiltration device 320. As is well known to those skilled in the art, a number of possible hemodialyzers and filtration devices can be used. In the preferred embodiment, hemodialyzer 310 is a Taylor vortex mixer that functions similarly to filter 110 described above with reference to FIGS. The ultrafiltration device 320 is desirably a Taylor vortex stirring filtration device similar to the filtration device 10 described above. As explained above, these filtration devices can have any combination of various sizes, shapes and speeds of each of the rotor and housing to accommodate different viscosity and flow rates of processing liquid.

  A waste bag 330 is used to collect unwanted waste products generated from this two-stage hemodialysis system. In one embodiment, the waste bag 330 should collect as much of the same waste that would normally be collected by a healthy kidney. Of course, the waste bag 330 can represent any of the means for collecting and / or discarding waste, and need not be a physical container with a particular shape and size. Often, in accordance with applicable laws and regulations, the waste bag 30 must be collected as hazardous waste that requires attention to disposal. Due to the unique properties of the present invention, the waste volume produced by a two-stage hemodialysis system will be much less than that produced from a typical single-stage dialysis process.

  A dialysate source 350 is shown with a dialysate stream 355 entering the hemofiltration device 310. In one embodiment, the dialysate flow 355 entering the blood filtration device 310 is approximately equal to the blood flow 365 from the patient. Therefore, the blood flow 375 after the process of returning to the patient 300 is not substantially reduced compared to the blood flow from the patient. As explained above, the dialysate flowing through the device 310 moves along the side of the filtration membrane that is different from the blood flowing through the device 310. In order to promote the diffusion of waste products and prevent blood contamination, the dialysate must be sterile, pyrogen-free and generally at body temperature.

  In a preferred embodiment, the dialysate can be supplemented with various additives. Typical additives include biologically desired ingredients such as, for example, chlorine, sodium, calcium, magnesium, potassium, phosphate, dextrose, glucose, or other molecules necessary for a particular patient. These smaller molecules can diffuse into the treated blood back to the patient through the filtration membrane.

  A method for performing hemodialysis according to the present invention using the two-stage hemodialysis system shown in FIG. 8 will be described in more detail. As indicated by arrow 365 extending from patient 300 to hemodiafiltration device 310, the first stage of processing is blood collection from the patient. As is conventional, blood is collected through an IV tube connected to the artery of the patient's 300 arm. Of course, other means of collecting blood from a patient are well known to those skilled in the art. As explained above, blood flow from a typical patient is 300-450 ml / min. Therefore, in order to keep the patient's blood volume relatively constant, the liquid returning to the patient (arrow 375) must flow at a similar flow rate. As is conventional, fluid returning to the patient 300 returns through an IV tube connected to the patient's vein.

  The blood flowing from the patient 300 then passes through the hemodialyzer 310. Hemodialyzer 310 can dialyze blood in a variety of ways well known to those skilled in the art. In a preferred embodiment, the hemodialysis device 310 can operate similarly to the device 110 described in detail above. In this example, blood flows into the first gap 116 through the inlet 122. Dialysate flows into the second gap 146 through the inlet 126.

  The filtration membrane 118 separating the second gap 146 and the first gap 116 is designed so that molecules having a molecular weight of about 10,000 daltons or less can pass in either direction. The blood flowing from the patient 300 contains a number of components, including water, electrolytes, small nutrient molecules, waste products, high molecular weight molecules (such as proteins), blood cells, and various other types of cells. Dialysate flowing from dialysate source 350 includes water and other desired small molecules that can be replenished to the patient's treated blood. Thus, while dialysate and blood flow in the opposite directions through blood filtration device 310, blood accumulates the desired small molecules that diffuse from the dialysate and dialysate accumulates waste products that diffuse from the blood.

  On the other hand, the rotors 144 and 114 rotate at a speed sufficient to create a Taylor vortex in the blood flowing through the first gap 116 and in the dialysate flowing through the second gap 146. These Taylor vortices mix the liquid in both voids, thereby mitigating concentration polarization problems at the outer and inner portions of the filter membrane 118.

  Filtration device 310 has two outlets 124 and 128. The first outlet 124 is in communication with the first gap 116. In a typical example, the flow rate from the outlet 124 is generally the flow rate to the inlet 122 because water diffuses through the filter membrane 118 only because dialysate and blood have relatively equal flow rates. Is roughly equal. If there are minor differences, these can be corrected by using supplemental replacement fluids or by removing a small amount of post-treatment blood before returning it to the patient.

  A second outlet 128 in communication with the second gap 146 guides the flow of spent dialysate 385. This spent dialysate 385 enters the ultrafiltration device 320.

  As explained above, the ultrafiltration device 320 can function similarly to the filtration device 10. The filtration membrane 18 of the ultrafiltration device 320 is configured such that the dialysate substrate and the desired small molecule enter the rotor interior 20 of the ultrafiltration device 320. The intermediate molecular weight waste is filtered and transferred from the ultrafiltration device 320 to the waste bag 330. On the other hand, the filtrate now contains a clean, warm and biocompatible dialysate that can be used once again to diffuse waste from the patient's blood.

  The diffusion into the blood after treatment of the patient drastically reduces the concentration of the desired small molecules in the dialysate so that these molecules can be replenished from the desired small molecule source 390. In a preferred embodiment, the system can detect dialysate flow and add an appropriate amount of concentrate to the recycled dialysate through a T-connector.

  In the embodiment shown in FIG. 8, recycled dialysate 395 is introduced at the beginning of a two-stage filtration system, where the T-connector is reused and fresh dialysate stream is introduced. 365 is mixed. Ideally, only a very small amount of unused dialysate is needed after the system has run through the entire cycle.

  With variations on the embodiment shown in FIGS. 1-8, the present invention can be applied to numerous other applications. In a general sense, embodiments of the present invention can be used in any application where a filter loses performance due to clogging or concentration polarization and an exchange solution is desired. These applications include removal of salt from water, treatment of seawater for human consumption, treatment of seawater for agricultural use, reprocessing of wastewater for agricultural use, wastewater for human consumption Reprocessing, eg concentration of sugar or other desired components from plant sap such as sugarcane sap or maple sap, concentration of latex from rubber tree sap, such as those required in the pharmaceutical and electronics industries Includes removal of impurities from water for use, cooking oil recycling, motor lubricating oil and lubricating oil cycles, and production of sterile water for intravenous injection.

  Furthermore, when using molecular exclusion membranes or molecular sieve membranes, large-scale cellular biotechnological separations such as purification of cell supernatants and / or lysates from cellular materials in bioprocessors and fermentation equipment, for example. Can use this device for application

  Various materials, methods, and techniques as described above provide a number of ways to implement the invention. Of course, it is to be understood that not all described objectives or advantages are necessarily achieved in accordance with any particular embodiment described herein. Thus, for example, in a manner that achieves or optimizes one or several advantages as taught herein without necessarily achieving other objects or advantages that may have been taught or suggested herein. Those skilled in the art will recognize that the components can be made and the method implemented.

  Although the present invention has been described with respect to particular preferred embodiments, other embodiments of the invention, including changes in size, configuration, and materials, will be apparent to those skilled in the art in view of the disclosure herein. In addition, all features described in connection with any embodiment herein can be readily adapted to other embodiments herein. The use of different terms or reference numerals for like features in different embodiments is for clarity and does not imply other differences. Accordingly, the present invention is intended to be described solely by reference to the appended claims, and is not limited to the preferred embodiments disclosed herein.

FIG. 1 shows a cross-sectional view of one embodiment of a vortex stirring hemodialysis apparatus used in the present invention. FIG. 2 shows a cross-sectional view from the top of one embodiment of the apparatus of FIG. FIG. 3 shows a cross-sectional view of the second embodiment of the vortex stirring dialysis apparatus as viewed from above. FIG. 4 shows a cross-sectional view of the third embodiment of the vortex stirring dialysis apparatus as viewed from above. FIG. 5 shows a cross-sectional view of one embodiment of the dual rotor vortex stirrer of the present invention. FIG. 6 is a cross-sectional view of FIG. 5, highlighting the flow path for blood (outside gap) and dialysate (inside gap). FIG. 7a is a schematic diagram of a filtration dialysis system in which exchange fluid is generated from the patient's blood waste and mixed with blood drawn from the patient. FIG. 7b is a second schematic diagram of a filtration dialysis system in which a replacement fluid is generated from the patient's blood waste and mixed with the processed blood before returning to the patient. FIG. 8 is a schematic diagram of a filtration dialysis system, in which reused exchange fluid is obtained from dialysis waste fluid flowing from a dialysis machine.

Claims (24)

A first filtration device for receiving blood from a patient and producing a first filtrate and treated blood;
A second filtration device for receiving the first filtrate and producing exchange liquid and waste products;
A system for two-stage hemodialysis of a patient, wherein at least one of the first and second filtration devices comprises a Taylor vortex stirring blood filtration device.   Furthermore, the system of Claim 1 provided with the T-type connection part which mixes the blood after processing, and an exchange liquid, and produces a reduced blood flow.   The system according to claim 2, characterized in that the reduced blood flow is further increased by introduction of a replenishing exchange solution.   4. A system according to claim 3, characterized in that the replenishment exchange liquid is supplemented with at least one additive.   The system of claim 2, wherein the reduced blood flow is substantially equal to the blood flow from the patient.   The system of claim 1, further comprising a T-type connection that mixes blood from the patient with a replacement fluid to increase blood flow entering the first filtration device.   The system according to claim 6, characterized in that the blood flow to the first filtration device is further increased by introduction of a replenishing exchange solution.   The system according to claim 7, wherein the replenishment exchange liquid is supplemented with at least one additive.   The system of claim 1, further comprising an anticoagulant source for mixing the anticoagulant with blood from the patient. The Taylor vortex stirring blood filtration device is:
A housing having a housing wall;
A first rotor having a first wall having a filtration membrane and defining a first interior, wherein the first rotor is in the housing such that a first gap exists between the filtration membrane and the housing wall. A first rotor arranged inside and adapted to rotate therewith and rotating the first rotor in the housing at a speed sufficient to create a Taylor vortex in the first air gap The system according to claim 1, comprising first rotational drive means. The first filtration device includes:
A cylindrical housing with a housing wall;
A first cylindrical rotor having a first wall with a dialysis membrane, wherein the first cylindrical rotor is a first cylindrical rotor such that a first coaxial gap exists between the dialysis membrane and the housing wall. A first rotor disposed coaxially within the housing and adapted to rotate therein;
A second cylindrical rotor having a second wall, wherein the second cylindrical rotor is a first cylindrical rotor such that a second coaxial gap exists between the first and second walls. A second rotor that is coaxially disposed inside the cylindrical rotor and adapted to rotate therewith;
A first inlet in the housing wall that directs blood from the patient to the first coaxial gap and a first outlet in the housing wall that directs treated blood from the first coaxial gap;
A second outlet in the housing for directing a first filtrate from a second coaxial gap;
First rotational drive means for rotating a first cylindrical rotor inside said housing;
Characterized in that it comprises second rotational drive means for rotating the second cylindrical rotor inside the housing,
The system of claim 1. A dialyzer configured to receive blood from a patient and generate dialysis drainage and processed blood;
A two-stage hemodialysis system for a patient comprising a filtration device configured to receive dialysis drainage and produce recycled dialysate and waste products.   13. The system of claim 12, further comprising a T-type connection that mixes the high concentration dialysate with the reused dialysate for introduction into the dialyzer.   13. System according to claim 12, characterized in that at least one additive is replenished in a high concentration dialysate. At least one of the dialyzer and the filtration device
A housing having a housing wall;
A first rotor having a first wall having a filtration membrane and defining a first interior, wherein the first rotor is in the housing such that a first gap exists between the filtration membrane and the housing wall. A first rotor disposed inside and adapted to rotate therewith;
13. The first rotational drive means for rotating the first rotor in the housing at a speed sufficient to create a Taylor vortex in the first gap. system. Dialysis machine
A cylindrical housing with a housing wall;
A first cylindrical rotor having a first wall with a dialysis membrane, wherein the first cylindrical rotor is a first cylindrical rotor such that a first coaxial gap exists between the dialysis membrane and the housing wall. A first cylindrical rotor coaxially disposed inside the housing and adapted to rotate therein;
A second cylindrical rotor having a second wall, wherein the second cylindrical rotor is a first cylindrical rotor such that a second coaxial gap exists between the first and second walls. A second rotor that is coaxially arranged inside the cylindrical rotor and adapted to rotate therewith,
The system according to claim 12, comprising: Providing a first filtration device configured to generate a Taylor vortex;
Providing a second filtration device;
Introducing blood from the patient into the first filtration device;
Introducing the first filtrate from the first filtration device into the second filtration device;
Means for hemodialyzing a patient, comprising obtaining an exchange solution from a second filtration device.   18. The means of claim 17, further comprising the step of mixing the replacement fluid with the processed blood from the first filtration device.   18. The means of claim 17, further comprising the step of mixing the replacement fluid with the blood from the patient before introducing the blood from the patient into the first filtration device. Providing a first filtration device;
Providing a second filtration device configured to generate a Taylor vortex;
Introducing blood from the patient into the first filtration device;
Introducing the first filtrate from the first filtration device into the second filtration device;
Means for hemodialyzing a patient, comprising obtaining an exchange solution from a second filtration device.   21. The means of claim 20, further comprising the step of mixing the replacement fluid with the processed blood from the first filtration device.   21. The means of claim 20, further comprising the step of mixing the replacement fluid with the blood from the patient prior to introducing the blood from the patient into the first filtration device. Providing a dialysis machine;
Providing a filtration device;
Introducing blood and dialysate from the patient into the dialyzer;
Introducing dialysis drainage from the dialyzer into the filtration device;
Means for hemodialyzing a patient, comprising obtaining a reused dialysate from a filtration device.   24. The means of claim 23, further comprising the step of mixing the concentrated dialysate with the reused dialysate for introduction into the dialyzer.

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