Artificial Kidney

Abstract

The present application discloses an artificial kidney. An implantable or wearable kidney enclosure is cylindrical, oval or other non-angular (e.g., non-rectangular or non-cubic) and has a circular or elliptical blood filter that provides a blood flow pattern radially outward from an internal central arterial source. Due to the efficient flow of the circular filter design, the enclosure can be made into a cylindrical low-profile shape, thereby forming a compact enclosure that is very suitable for implantable and wearable dialysis applications.

Description

Summary of the invention

[0001] The present disclosure relates to an implantable or wearable low-profile artificial kidney shell having a radial blood flow pattern. The shell is cylindrical, oval or other non-angular (e.g., non-rectangular or non-cubic). The interior space sandwiching the filter plate has complex blood flow control fins or pipes to provide additional blood flow control and blood distribution on the circular filter plate. The pressure distribution (pressure difference) between the blood side and the dialysate side is controlled to ensure that the pressure difference does not cause damage to the filter plate (e.g., irreversible fracture or deformation).

[0002] The design provides a compatible smooth exterior shape and small low profile compact design for transplantable kidney applications. The radial blood flow pattern closely resembles the blood flow pattern in a real kidney where a single arterial source in a small area flows into a large area and distributes the blood evenly over the filter.

[0003] This summary is provided to introduce in simplified form a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. These and various other features and advantages will be apparent from reading the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The described technology is best understood from the following detailed description of various implementations read in conjunction with the accompanying drawings.

[0005] Figure 1 is a diagram of the kidney.

[0006] Figure 2 is a schematic diagram of a conventional rectangular renal hemofilter.

[0007] Figure 3 is a schematic diagram of a circular kidney filter.

[0008] Figure 4a is a stereoscopic view of the low-profile enclosure of the artificial kidney. Figure 4b yes Figure 4a Cross-sectional view of the cladding.

[0009] Figure 5 is a schematic diagram of an example kidney filter.

[0010] Figure 6 is a schematic diagram of an example of a plurality of kidney filter units.

[0011] Figure 7 is a schematic diagram of another example of a multiple kidney filter unit.

[0012] Figure 8a is a cross-sectional view of an example kidney filter, Figure 8b is a cross-sectional view of an alternative example kidney filter.

[0013] Fig. 9 is a diagram of the filter chamber distribution. DETAILED DESCRIPTION

[0014] To date, wearable and implantable artificial kidney housings have been designed in a straight or square shape to accommodate rectangular blood filters. However, square housings with sharp corners are not suitable for implantable devices because they may be uncomfortable or irritating to the patient when implanted. For rectangular filters housed in a straight housing, blood flows from one end of the device to the other, and blood flowing over the blood filter flows evenly across the surface filter starting from a single arterial inlet source.

[0015] However, the blood flow pattern in a real kidney is that blood enters from a single artery and then fans out over a distribution of capillaries over a larger area. According to the present disclosure, a circular or elliptical flat plate filter provides a blood flow pattern similar to a real kidney, radiating from a central arterial source to the filter outer diameter through the blood filter plate.

[0016] The present disclosure relates to an implantable or wearable renal enclosure that is cylindrical, oval, or other non-angular (e.g., non-rectangular or non-cubic) in shape, having a circular or elliptical hemofilter that provides a blood flow pattern radially outward from an internal central arterial source. Due to the efficient flow of the circular filter design, the enclosure can be made cylindrical and low profile, resulting in a compact enclosure that is well suited for implantable and wearable dialysis applications.

[0017] The area surrounding the filter plate may have complex blood flow control fins or channels to provide additional blood flow control and blood distribution over the circular filter plate.

[0018] Furthermore, controlling the pressure distribution (pressure differential) between the blood side and the dialysate side of the hemofilter ensures that the pressure differential does not cause damage (eg, irreversible rupture or deformation) to the filter plates.

[0019] In the following description, reference is made to the accompanying drawings that form a part of this document, and at least one specific implementation is shown in the accompanying drawings by way of illustration. The following description provides additional specific implementations. It should be understood that other implementations are conceived and can be made without departing from the scope or spirit of the present disclosure. Therefore, the following specific embodiments should not have a restrictive meaning. However, the present disclosure is not limited thereto, and an understanding of various aspects of the present disclosure can be obtained through the discussion of the examples provided below.

[0020] Go to Figure 1 , shows a medical diagram of a normal kidney. When a kidney is unusable or no longer functions properly, the various enclosures and hemofilters described herein may be used to replace such a kidney. Figure 1 Shown is a single artery entering the kidney and dividing into a fan-shaped array of capillaries.

[0021] Figure 2 A conventional rectangular hemofilter is shown schematically. Blood enters at a first end and flows relatively linearly along the length of the filter to a second (opposite) end.

[0022] Figure 3 A circular hemofilter and a blood flow pattern radially outward from the central hole are shown. This blood flow from the central region outward toward the outer edge of the disc is closer to Figure 1 Flow pattern of a natural kidney shown.

[0023] Such as Figure 3 The circular hemofilter shown is similar to Figure 4a Used with the cylindrical cladding shown, Figure 4a This is a stereoscopic view of the cylindrical exterior of the artificial low-profile enclosure. It can be seen that all the external edges are rounded.

[0024] In some implementations, the cylindrical enclosure has a low profile (may even be referred to as a disk or disc). Figure 4a As shown, "low profile" means that the thickness "th" dimension is less than the diameter "D" of the cladding. The cylindrical cladding has a compact configuration.

[0025] like Figure 4a One of the two tubes shown leading into the center of the cylinder is labeled as the connection for blood input (artery), the second tube is for the dialysate flow (cleansing fluid).

[0026] Figure 4b A cross-sectional view of the enclosure is shown, illustrating the internal structure of the filter enclosure, the placement of circular filter plates (four plates in this example), and the blood flow pattern and dialysate flow pattern over the filter plates from the center (inner diameter) to the outer diameter of the filter plates.

[0027] Various other flow configurations and multiple set of plate configurations may be utilized. Figure 5The example in is a schematic diagram of blood and dialysate flowing through a pair of hemofilters. In this configuration, blood and clean dialysate enter the enclosure in the inner diameter of the flat plate filter. First, blood passes through the top filter in the upper chamber, and toxins pass through the top filter plate into the clean dialysate. Blood continues to flow to the outer diameter domain and returns to the lower chamber where the filtering function continues through the lower filter plate as the blood flows from the outer diameter domain to the inner domain. Note that reverse flow will perform the same filtering function and is independent of the flow direction of the blood and dialysate or any combination of flow directions.

[0028] Figure 6 is a schematic diagram of blood and dialysate flow for multiple filter units. The figure shows multiple filter units connected in a parallel configuration. Parallel blood flow means that the input blood is directly connected to each filter unit. For reference, Figure 4b The enclosure in FIG. 1 is specifically a two-unit enclosure design. However, the enclosure can be extended to multiple filter units of length "n", but at the expense of increasing the enclosure height.

[0029] Figure 7 is a schematic diagram of blood and dialysate flow for multiple filter units. The figure shows multiple filter units connected together in a serial flow configuration for blood flowing out of an artery and a serial flow configuration for dialysate flow. In the series configuration, each filter unit is daisy-chained, and blood passes through the first unit, then the second unit, and so on, until it passes through the nth unit.

[0030] Note that any combination of serial and parallel blood flow patterns and dialysate flow patterns can be configured. The serial flow pattern is easier to achieve when multiple filter units are daisy-chained together. However, the disadvantage is that the blood pressure of the first unit to obtain the initial blood input is likely to be higher, and the blood pressure decreases in the higher-order filter units, which is undesirable because high mechanical strength is required to support the higher mechanical pressures associated with the high operating pressures of the serial design. The parallel flow configuration has the advantage of equal blood and dialysate operating pressures for each of the nth filter units. This comes at the expense of a more complex housing design to accommodate multiple filter units.

[0031] FIG8A shows a cross-sectional view of one filter unit and enclosure shape. In this design, the cross-sections of the upper and lower chambers are tapered so that the cross-sectional area perpendicular to the direction of blood flow (indicated by the red arrows with white outlines) is approximately constant from the inner diameter to the outer diameter, thereby making the blood pressure on the surface of the filter plate approximately uniform. The enclosure design that achieves uniform pressure on the filter plate simplifies the filter mechanical design to resist breakage. For example, the filter can have uniform thickness and support spacing. Note that for clarity, Figure 8aThe flow direction of the dialysate is not shown.

[0032] Figure 8b is a cross-sectional view of a filter unit and a housing shape having asymmetric upper and lower chamber dimensions. In this design, the cross-sections of the upper and lower chambers are tapered (e.g. Figure 8a ). However, in this design, the total cross-sectional area of ​​the lower chamber is increased relative to the upper chamber by a fixed value to maintain approximately similar pressures between the upper and lower surfaces. This strategy of having asymmetric cross-sectional areas to achieve isobaric pressures can be used in areas where there is serial blood or dialysate flow. Even in the parallel configuration design described above, a single filter unit is composed of a serial path between the upper and lower chambers.

[0033] The enclosure design strategy presented here is to achieve uniform pressure across the flat filter surface and between the filter plates by designing for a roughly uniform cross-sectional area (perpendicular to the flow of blood and dialysate).

[0034] A simple linear taper shape of the filter from the inner diameter to the outer diameter can be used to roughly maintain a constant pressure on the surface. Other shape profiles can be used to more accurately maintain a constant pressure distribution, such as Fig. 9 shown.

[0035] Fig. 9 The distribution of chamber heights in relation to the diameter of the blood filter plate (eg, the inner diameter to the outer diameter of the filter plate) is graphically shown. Fig. 9 In this particular example shown, the ID radius is 10 mm and the OD radius is 33.5 mm. The y-axis represents the chamber height "h" which has a non-linear profile shape that follows the equation to maintain a constant flow cross-sectional area: h = R1 / R, where R is the radial position on the filter and R1 is the ID radius of the filter.

[0036] In summary, described herein is a cylindrical, oval, or other non-angular (e.g., not rectangular or cubic) implantable or wearable renal enclosure configured to receive a circular or oval blood filter. The circular or oval filter has a blood flow pattern radially outward from an internal central arterial source. There may be multiple filters in the enclosure, configured in parallel or in series.

[0037] The above description and examples provide a complete description of the structure and use of exemplary implementations of the present invention. The above description provides additional specific implementations. It should be understood that other implementations are contemplated and can be made without departing from the scope or spirit of the present disclosure. Therefore, the above specific embodiments should not have a restrictive meaning. However, the present disclosure is not limited thereto, and an understanding of various aspects of the present disclosure can be obtained through the discussion of the examples provided.

[0038] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties should be understood as being modified by the term "about", whether or not the term "about" immediately appears. Accordingly, unless indicated to the contrary, the foregoing numerical parameters are approximations that can vary depending upon the desired properties sought by those skilled in the art utilizing the teachings disclosed herein.

[0039] As used herein, the singular forms "a," "an," and "the" include implementations with plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise.

[0040] Spatially relative terms include, but are not limited to, "bottom", "lower", "top", "up", "below", "beneath", "above", "on top", "above", etc., and are used for convenience of description to describe the spatial relationship of (multiple) elements to another element. Such spatially relative terms also encompass different orientations of the device in addition to the specific orientations depicted in the drawings and described herein. For example, if the structure depicted in the drawings is reversed or turned over, then portions previously described as being below or below other elements would be located above or above these other elements.

[0041] Since many implementations of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. Furthermore, structural features of different implementations may be combined in yet another implementation without departing from the claims.

[0042] Further Examples Example 1. An artificial kidney, comprising: an annular hemofilter, the annular hemofilter having a circular or elliptical shape, the hemofilter having a central axis; and a shell, the shell having a cross-sectional shape corresponding to the hemofilter orthogonal to the central axis, the shell further having: an internal volume, the internal volume for receiving the annular hemofilter therein, an inlet, the inlet being close to the central axis, the inlet being fluidly connected to the internal volume to receive blood flow therein; an outlet, the outlet being fluidly connected to the internal volume to receive blood flow therefrom; and a second outlet, the second outlet being fluidly connected to the internal volume to receive toxins therefrom; and wherein the inlet is fluidly connected to a first chamber in the shell, and the outlet is fluidly connected to a second chamber in the shell, the first chamber and the second chamber being separated by the annular hemofilter.

[0043] Example 2. An artificial kidney as described in the example, characterized in that the outlet is close to the central axis.

[0044] Example 3. The artificial kidney as described in Example 1 is characterized in that both the first chamber and the second chamber have a height that gradually decreases from the central axis to the periphery of the shell.

[0045] Example 4. The artificial kidney as described in Example 3, characterized in that the first chamber and the second chamber are symmetrical to each other.

[0046] Example 5. The artificial kidney as described in Example 1 is characterized in that the shell is radially symmetric about the central axis.

[0047] Example 6. The artificial kidney of Example 1, further comprising a second inlet proximate the central axis, the second inlet fluidly connected to the interior volume to receive a flow of dialysate therein.

[0048] Example 7. The artificial kidney of Example 6, wherein the second outlet is proximate to the central axis and fluidly connected to the second inlet.

[0049] Example 8. The artificial kidney of Example 1, comprising a plurality of annular hemofilter pairs connected in series.

[0050] Example 9. The artificial kidney of Example 1, comprising a plurality of annular hemofilter pairs connected in parallel.

[0051] Example 10. An artificial kidney, comprising: an annular hemofilter having a circular or elliptical shape, the annular hemofilter having an inner diameter and an outer diameter; and a shell having a shape corresponding to the hemofilter, the shell having an internal volume for receiving the hemofilter therein, the artificial kidney having a radial blood flow path on the annular hemofilter from the inner diameter to the outer diameter.

[0052] Example 11. The artificial kidney of Example 10, further comprising a blood inlet centrally located in the enclosure and fluidly connected to the interior volume.

[0053] Example 12. The artificial kidney of Example 11, further comprising: a dialysate inlet centrally located in the enclosure and fluidly connected to the interior volume.

[0054] Example 13. An artificial kidney as described in Example 11, characterized in that the blood inlet is fluidly connected to a first chamber in the shell, and the blood outlet is fluidly connected to a second chamber in the shell, and the first chamber and the second chamber are separated by the annular blood filter.

[0055] Example 14. The artificial kidney as described in Example 13, characterized in that the blood outlet is close to the central axis.

[0056] Example 15. The artificial kidney of Example 13, wherein both the first chamber and the second chamber have a height that gradually decreases from the inner diameter to the outer diameter.

[0057] Example 16. The artificial kidney of Example 13, comprising a plurality of annular hemofilter pairs connected in series.

[0058] Example 17. The artificial kidney of Example 13, comprising a plurality of annular hemofilter pairs connected in parallel.

[0059] Example 18. A method of filtering blood, comprising: providing an artificial kidney having an annular hemofilter, the annular hemofilter having a circular or elliptical shape, the annular hemofilter having an inner diameter and an outer diameter; and causing blood to flow radially on the annular hemofilter from the inner diameter to the outer diameter.

[0060] Example 19. The method of Example 18, further comprising flowing blood radially over the second annular hemofilter from an outer diameter of the second annular hemofilter to an inner diameter of the second annular hemofilter.

[0061] Example 20. The method of Example 19, further comprising: inputting blood into the artificial kidney via an inlet proximate to the inner diameter of the annular hemofilter; and outputting blood from the artificial kidney via an outlet proximate to the inner diameter of the second annular hemofilter.

Claims

1. An artificial kidney, comprising: a hemofilter having a circular or oval shape; as well as The shell has a shape corresponding to the hemofilter, and the shell has an interior volume for receiving the hemofilter therein; a blood inlet located in the center of the blood filter, and A blood flow path flows radially outward from the inlet.

2. The artificial kidney according to claim 1, further comprising: A dialysate inlet is located at the center of the hemofilter.

3. The artificial kidney according to any one of the preceding claims, comprising more than one hemofilter having a circular or oval shape in the enclosure.

4. The artificial kidney according to claim 3, characterized in that: The more than one hemofilters are connected in series.

5. The artificial kidney according to claim 3, characterized in that: The more than one hemofilters are connected in parallel.

6. The artificial kidney according to any one of claims 1-2, 4-5, characterized in that: The cladding is flat from a central point to an outer diameter.

7. The artificial kidney according to any one of claims 1-2, 4-5, characterized in that: The cladding is tapered from a central point to an outer diameter.

8. The artificial kidney according to any one of claims 1-2, 4-5, characterized in that: The enclosure has no exposed corners or no external corners.

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