Pre- and post-dilution integrated hemodiafiltration filter

Abstract

The present invention relates to a pre-dilution and post-dilution integrated hemodialysis filter, comprising a filter body, a blood chamber inlet cover and a blood chamber outlet cover respectively provided at both ends of the filter body, a filtration section and a treatment section provided in the inner cavity of the filter body, and a replacement fluid interface, a dialysate inlet, and a dialysate outlet connected to the inner cavity of the filter body. The filter body is an integrated tubular structure, an integrated hollow fiber membrane is fixed to the inner cavity of the filter body, a glue injection hole penetrating the wall thickness of the filter body is provided in the middle of the filter body, a colloid is filled inside the glue injection hole to bond the gaps between the membrane filaments of the integrated hollow fiber membrane to form a sealing layer, and the sealing layer is bonded to the inner cavity of the filter body to separate the inner cavity of the filter body into a filtration section and a treatment section. The present invention realizes an integrated design of replacement fluid filtration and hemodiafiltration treatment through a bidirectional filtration method, optimizes product performance, and simplifies product structure.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a pre-dilution and post-dilution integrated hemodialysis filter. Background Art

[0002] Hemodiafiltration (HDF) combines the advantages of hemodialysis (HD) and hemofiltration (HF), namely, the removal of small molecules by diffusion and middle molecules by convection. Conventional hemodialysis (HD) is inadequate in removing middle-molecular toxins and can induce the production of new toxins, leading to a high rate of hemodialysis complications, reduced quality of life, and increased mortality. Hemodiafiltration (HDF) simulates the glomerular filtration principle of a normal human kidney, filtering out and removing middle-molecular substances and water from the blood by convection, thereby effectively removing middle-molecular toxins, reducing hemodialysis complications, improving patients' quality of life, prolonging survival, and reducing mortality.

[0003] Compared with conventional hemodialysis (HD), hemodiafiltration (HDF) offers more stable hemodynamics and better patient tolerance. Intolerances such as hypotension, headache, and nausea and vomiting during dialysis are significantly reduced. HDF effectively removes middle-molecular toxins such as β2-microglobulin and PTH, which helps control dialysis bone disease. It also improves patients' antioxidant capacity, clears inflammatory mediators, and reduces dehydration, all of which contribute to improving their condition. HDF is a renal replacement therapy that more closely resembles the principles of normal glomerular filtration than HD.

[0004] Existing dual-chamber hemodiafiltration devices employ a split-type design, such as the one disclosed in CN111905173A. The filtration chamber and purification chamber are separate structures connected by a double connector, requiring the installation of two sets of hollow fiber membranes. This results in a complex structure, inconvenient assembly, and high production costs. Furthermore, after passing through the filtration chamber, blood must enter the hollow portion of the double connector and then the hollow fiber membranes installed in the purification chamber. This increases the probability of red blood cell collisions and can easily cause damage to red blood cells. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a pre- and post-dilution integrated hemodialysis filter with a simple structure, convenient assembly and low manufacturing cost.

[0006] The present invention is achieved through the following technical solutions:

[0007] A pre- and post-dilution integrated hemodialysis filter comprises a filter body, a blood chamber inlet cover and a blood chamber outlet cover respectively covering the two ends of the filter body, a filtration section and a treatment section arranged in the inner cavity of the filter body, and a replacement fluid interface, a dialysate inlet and a dialysate outlet connected to the inner cavity of the filter body. The filter body is an integrated tubular structure, and the inner cavity of the filter body is provided with an integrated hollow fiber membrane which is sealed with colloid at both ends (the membrane pores in the sealed part are still unobstructed) and fixed on the inner side of the blood chamber inlet cover and the blood chamber outlet cover respectively. A glue injection hole is provided in the middle of the filter body which runs through the wall thickness. The inner side of the glue injection hole is filled with colloid to bond the gaps between the membrane filaments of the integrated hollow fiber membrane to form a closed layer (the membrane pores in the closed layer are still unobstructed). The closed layer is annularly bonded to the inner cavity of the filter body to separate the inner cavity of the filter body into a filtration section and a treatment section.

[0008] In a preferred embodiment of the present invention, as a pre-dilution integrated hemodialysis filter, the upper end of the filter body is a filtration section with a membrane area of 0.5-0.9 m2 and an average membrane pore size of 7-15 nanometers, and the lower end is a treatment section with a membrane area of 0.6-2.5 m2 and an average membrane pore size of 7-15 nanometers.

[0009] In another preferred embodiment of the present invention, as a post-dilution integrated hemodialysis filter, the upper end of the filter body is a treatment section, the membrane area is 0.6-2.5 m2, the average membrane pore size is 7-15 nanometers, and the lower end is a filtration section, the membrane area is 0.5-0.9 m2, and the average membrane pore size is 7-15 nanometers.

[0010] In order to facilitate the formation of a sealing layer, the inner cavity of the filter body has an annular step, and the sealing layer is arranged at the annular step.

[0011] In order to adapt to the flow of blood and water, the hollow fiber membrane preferably has an outer diameter of 180-280 μm, an inner diameter of 150-200 μm, a membrane wall thickness of 15-40 μm, and a three-layer structure, with the inner layer being the endothelial layer, the middle layer being the sponge support layer, and the outer layer being the exothelial layer.

[0012] In order to protect the glue injection port, a closed ring is provided on the outer cover of the glue injection hole in the middle of the filter body.

[0013] In order to ensure the sealing performance, a sealing layer is respectively provided inside the blood chamber inlet cover and the blood chamber outlet cover.

[0014] The beneficial effects of the present invention are:

[0015] (1) The pre-dilution and post-dilution integrated hemodiafiltration device is designed based on the hemodiafiltration (HDF) treatment principle, which is closer to the normal glomerular filtration mechanism. It imitates the function of glomerular cells filtering blood toxins and renal tubules recycling water, and is a more effective method of renal replacement therapy.

[0016] (2) In principle, the pre- and post-dilution integrated hemodialysis filter can filter the replacement fluid that is about to enter the blood and remove bacteria, endotoxins and disinfectants that may remain in the replacement fluid. Therefore, the safety of treatment is improved. In addition, the purified replacement fluid slowly penetrates into the blood through the micropores of the filter membrane wall and gently mixes with the blood, which reduces the external pressure on the red blood cells, thereby reducing the possibility of changes in their structure and function, preventing the destruction of red blood cells, and reducing the occurrence of anemia symptoms in patients.

[0017] (3) By cleverly utilizing the bidirectional filtration performance of the hemodiafiltration membrane, the filtration direction and filtration contact surface are selected according to the characteristics of different media, so that the filtration can be carried out efficiently, while at the same time, the impact on the medium components (such as red blood cells and platelets in the blood) is minimized; through the bidirectional filtration method, the replacement fluid filtration and hemodiafiltration treatment are integrated into a design, which optimizes the product performance and simplifies the product structure;

[0018] (4) Through integrated design, precise filtration of the replacement fluid, gentle mixing with blood, and high-efficiency dialysis filtration treatment are achieved in one product. During the entire process, blood flows in the interconnected pores of the hollow fiber membrane, ensuring continuous blood flow. This eliminates redundant components and cavities, reduces the chances of red blood cell collision and damage, and makes the dialysis filtration treatment process more standardized and controllable, further reducing the risk of treatment.

[0019] (5) Pre-dilution hemodiafiltration treatment involves diluting the blood before dialysis to reduce blood viscosity, and then performing dialysis filtration on the blood. This reduces the coagulation of the dialysis membrane during dialysis, reduces the amount of anticoagulants used during dialysis, and reduces the long-term complications of hemodialysis. Post-dilution hemodiafiltration treatment involves performing dialysis filtration on the blood without dilution, and then diluting the blood, so the clearance rate is higher.

[0020] (6) Glue is injected through special processes and equipment, so that the gaps between the colloid-bonded membrane filaments are filled inside the injection hole to form a closed layer (the membrane pores in the closed layer are still unobstructed). The closed layer is annularly bonded to the inner cavity of the filter body to separate the inner cavity of the filter body into a filtration section and a treatment section, realizing the functions of pre- and post-dilution hemodiafiltration (HDF), greatly simplifying the product structure, reducing product components and product production processes, and reducing product costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the pre-dilution and post-dilution integrated hemodialysis filter of the present invention. DETAILED DESCRIPTION

[0022] The following detailed description of preferred embodiments of the present invention is provided in conjunction with the accompanying drawings to facilitate understanding of the advantages and features of the present invention by those skilled in the art, thereby providing a clearer and more precise definition of the scope of protection of the present invention. Directional terms used in the present invention, such as "up," "down," "front," "back," "left," "right," "top," and "bottom," are intended solely to refer to the directions of the accompanying drawings. Therefore, the directional terms used are intended to illustrate and facilitate understanding of the present invention and are not intended to limit the present invention.

[0023] Example 1:

[0024] like Figure 1 The pre-dilution integrated hemodialysis filter shown has an overall length of 250-500 mm and a diameter of 25-60 mm. It includes a filter body 1, a blood chamber inlet cover 3 and a blood chamber outlet cover 4 respectively covering the two ends of the filter body, a filtration section and a treatment section arranged in the inner cavity of the filter body 1, and a replacement fluid interface 6, a dialysate inlet 7, and a dialysate outlet 8 connected to the inner cavity of the filter body 1.

[0025] The filter body 1 is an integrated hollow structure, with the upper end cover being covered with a blood chamber inlet cover 3, and the lower end cover being covered with a blood chamber outlet cover 4. Sealing layers 5 are respectively provided in the blood chamber inlet cover 3 and the blood chamber outlet cover 4. The inner cavity of the filter body 1 is provided with an integrated hollow fiber membrane 2 which is closed at both ends with a colloid sealing layer 5 (the membrane pores in the closed part are still unobstructed) and fixed to the inner side of the blood chamber inlet cover 3 and the blood chamber outlet cover 4 respectively. A glue injection hole 10 which runs through the wall thickness is provided in the middle of the filter body 1, and an annular step 11 is provided on the inner side of the glue injection hole 10. The gaps between the membrane filaments of the integrated hollow fiber membrane are filled with colloid to form a sealing layer 9 (the membrane pores in the sealing layer are still unobstructed). A sealing ring 12 is provided on the outer periphery of the glue injection hole 10. The sealing layer 9 divides the inner cavity of the filter body into a filtration section and a treatment section, wherein the upper end is the filtration section and the lower end is the treatment section.

[0026] Specifically, in this embodiment, the upper end of the pre-dilution integrated hemodialysis filter is the hollow fiber membrane replacement fluid filtration section, that is, from top to bottom, between the replacement fluid interface 6 and the dialysate inlet 7; the lower end is the hollow fiber membrane hemodiafiltration treatment section, that is, from top to bottom, between the dialysate inlet 7 and the dialysate outlet 8. The hollow fiber membranes 2 are in the same group, and their filtration section and treatment section are connected. Through specific processes and equipment, the gaps between the membrane fibers are bonded and sealed with polyurethane glue at the upper end of the dialysate inlet 7, forming a polyurethane glue sealing layer 9. The polyurethane glue sealing layer 9 has a thickness of 1-3 cm, and the sealing layer 9 is annularly bonded and sealed at the annular step 11 on the inner wall of the filter body 1. A closed replacement fluid filtration cavity is formed at the upper end of the pre-dilution integrated hemodialysis filter, which becomes the replacement fluid filtration section; a closed dialysate convection and diffusion treatment cavity is formed at the lower end of the pre-dilution integrated hemodialysis filter, which becomes the hemodialysis filtration treatment section, and the hollow fiber membrane runs through the filtration section and the treatment section, and the inner hole of the hollow fiber membrane (blood channel) runs through the entire product.

[0027] In the present embodiment, the membrane area of the upper filter section is 0.5-0.9 m2, and the average pore size of the membrane is 7-15 nanometers. The membrane area of the lower treatment section is 0.6-2.5 m2, and the membrane pore size is 7-15 nanometers. The replacement fluid is filtered and purified by the upper filter membrane, and the purified replacement fluid enters the inner side of the hollow fiber membrane uniformly through the micropores on the outer side of the hollow fiber membrane, and gently mixes with the blood flowing on the inner side of the membrane, so that the external pressure on the red blood cells is smaller, thereby reducing the possibility of changes in their structure and function, and preventing the red blood cells from being destroyed. The replacement fluid filtration section can effectively filter bacteria, endotoxins and disinfectant residues that may exist in the waterway and blood pipeline (the replacement fluid itself has control bacteria and endotoxin standards, and the waterway and blood pipeline are theoretically sterile), minimize the risk of bacteria, endotoxins and disinfectant contamination that may exist in the replacement fluid, ensure the purity of the replacement fluid, and thus ensure the quality of treatment and the safety of the patient.

[0028] In this embodiment, the lower treatment segment uses a highly permeable hollow fiber membrane to exchange the replacement fluid mixed into the blood, removing medium- and large-molecule toxins such as β2 microglobulin and PTH. This significantly improves the effectiveness of hemodialysis treatment and reduces the incidence of long-term complications associated with hemodialysis. Pre-dilution hemodiafiltration (HDF) can reduce blood cell loss and destruction, effectively control anemia, and reduce the patient's erythropoietin dosage. During treatment, the hollow fiber membrane reduces coagulation, reducing heparin usage and helping to reduce long-term complications of hemodialysis.

[0029] Among them, the blood chamber inlet cover, blood chamber outlet cover, and filter main body shell are made of medical grade polypropylene (PP) or polycarbonate (PC), acrylonitrile-butadiene-styrene copolymer (ABS) materials; the inner sealing layer (O-ring) of all covers are made of medical grade pure silicone; the high-permeability hollow fiber membrane material is polysulfone (PSU) or polyethersulfone (PES), polyethylene terephthalate (PET), polycarbonate (PC) raw materials; the membrane is encapsulated with medical grade polyurethane glue (PU); the sealing dust covers on each interface are made of medical grade polypropylene (PP), PET, and nylon (PA).

[0030] The pre-dilution integrated hemodialysis filter developed by improving and enhancing the traditional HDF pre-dilution technology can be used for patients intolerant to HDF, providing patients with safer and more comfortable HDF treatment products, improving the state of micro-inflammation in patients' bodies, and improving the quality of life of patients.

[0031] Example 2:

[0032] The difference from Example 1 is that the upper end of the filter body is the treatment section, and the lower end is the filtration section. A closed dialysate convection and diffusion treatment cavity is formed at the upper end of the post-dilution integrated hemodialysis filter, becoming the hemodiafiltration treatment section; a closed replacement fluid filtration cavity is formed at the lower end of the post-dilution integrated hemodialysis filter, becoming the replacement fluid filtration section, and the hollow fiber membrane runs through the treatment section and the filtration section, and the inner pores of the hollow fiber membrane (blood channel) run through the entire product.

[0033] In this embodiment, the upper treatment segment has a membrane area of 0.6-2.5 square meters and an average pore size of 7-15 nanometers. The lower filtration segment has a membrane area of 0.5-0.9 square meters and a pore size of 7-15 nanometers. The treatment segment uses a highly permeable hollow fiber membrane to exchange excess water from the blood while allowing the release of medium- and large-molecules such as β2 microglobulin and PTH. This significantly improves the effectiveness of hemodialysis treatment and reduces the incidence of long-term complications associated with hemodialysis.

[0034] In the present embodiment, the lower filter section can effectively filter bacteria, endotoxins and disinfectant residues that may be present in the waterway and blood pipeline (the replacement fluid itself has standards for controlling bacteria and endotoxins, and the waterway and blood pipeline are theoretically sterile), and minimize the risk of bacteria and endotoxin contamination that may be present in the replacement fluid, thereby ensuring the purity of the replacement fluid, thereby ensuring the quality of treatment and the safety of the patient. The replacement fluid is filtered and purified by a hollow fiber membrane, and the purified replacement fluid enters the inner side of the hollow fiber membrane uniformly through the micropores on the outer side of the hollow fiber membrane, and gently mixes with the blood flowing on the inner side of the membrane, so that the external pressure on the red blood cells is smaller, thereby reducing the possibility of changes in their structure and function, and preventing the red blood cells from being destroyed. Post-dilution hemodiafiltration (HDF) can reduce blood cell loss and destruction, effectively control anemia, and reduce the patient's erythropoietin dosage.

[0035] The post-dilution integrated hemodialysis filter developed by improving and enhancing the traditional HDF post-dilution technology can be used for patients intolerant to HDF, providing patients with safer and more comfortable HDF treatment products, improving the state of micro-inflammation in patients' bodies, and improving the quality of life of patients.

[0036] Compared with post-dilution hemodiafiltration treatment, pre-dilution clearance rate is slightly lower, the amount of replacement fluid is large, and it is not easy to coagulate; post-dilution clearance rate is high, the amount of replacement fluid is small, and it is easier to coagulate.

[0037] The high-permeability hollow fiber membrane used in the present invention has an outer diameter of 180-280 μm, an inner pore diameter (blood channel) of 150-200 μm, and a membrane wall thickness of 15-40 μm. The membrane has a three-layer structure, with a dense inner cortex, a sponge support layer in the middle, and a loose outer cortex. The pores in the inner cortex are smaller than those in the outer cortex, and the number of pores in the inner cortex is less (low porosity). The inner cortex is smoother and has a higher polyvinylpyrrolidone (PVP) content than the outer cortex, resulting in better hydrophilicity and less clotting. Therefore, the inner cortex is more suitable for blood flow, while the outer cortex is more suitable for water flow.

[0038] Filtration from the inside out: blood flows in the pores of the membrane, contacts the endothelial layer, and removes toxins and excess water through the principles of convection and diffusion; the pores of the endothelial layer of the membrane are smaller and have a lower porosity, which can better control the size and amount of the substances that pass through, and is beneficial to maintaining electrolyte balance; the surface of the endothelial layer is smooth and hydrophilic, so blood flow is not easy to coagulate and blood cells are not easily damaged, which is beneficial to the smoothness and safety of the hemodialysis treatment process.

[0039] Filtration from outside to inside: The replacement fluid flows on the outside of the membrane. The replacement fluid is pressured to pass through the outer cortex, sponge support layer, and endothelial layer. After filtration, it slowly enters the blood channel and mixes gently with the blood. The bacteria that may exist in the replacement fluid are intercepted by the outer cortex, and endotoxins and disinfectant residues pass through the outer cortex into the sponge support layer. When they reach the endothelial layer, they are intercepted by the endothelial layer and remain in the sponge support layer. In this way, the bacteria, endotoxins and disinfectant residues in the replacement fluid are filtered out, and the sponge support layer adsorbs the endotoxins and disinfectant residues, making the replacement fluid filtration effect better. Since the number of bacteria, endotoxins and disinfectant residues that may exist in the replacement fluid is extremely small, the sponge support layer cannot be saturated with adsorption during the treatment process. Therefore, filtration from outside to inside is reasonable and safe.

[0040] It should be noted that the parts not involved in the present invention are the same as the existing technology or can be implemented by using the existing technology.

[0041] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A pre-dilution and post-dilution integrated hemodialysis filter, comprising a filter body, a blood chamber inlet cover and a blood chamber outlet cover respectively provided at both ends of the filter body, a filtration section and a treatment section provided within the inner cavity of the filter body, and a replacement fluid interface, a dialysate inlet, and a dialysate outlet communicating with the inner cavity of the filter body, characterized in that: The filter body is an integrated tubular structure, and an integrated hollow fiber membrane is fixed in the inner cavity of the filter body. A glue injection hole is opened in the middle of the filter body and penetrates its wall thickness. The inside of the glue injection hole is filled with colloid to bond the gaps between the membrane filaments of the integrated hollow fiber membrane to form a closed layer. The inner pores of the hollow fiber membrane at the closed part are still unobstructed. The closed layer is bonded to the inner cavity of the filter body to separate the inner cavity of the filter body into a filtration section and a treatment section.

2. The pre-dilution and post-dilution integrated hemodiafiltration device according to claim 1, characterized in that: The upper end of the filter body is the filtration section, the membrane area is 0.5-0.9㎡, the average membrane pore size is 7-15 nanometers, and the lower end is the treatment section, the membrane area is 0.6-2.5㎡, and the average membrane pore size is 7-15 nanometers.

3. The pre-dilution and post-dilution integrated hemodiafiltration device according to claim 1, characterized in that: The upper end of the filter body is the treatment section, the membrane area is 0.6-2.5㎡, the average pore size of the membrane is 7-15 nanometers, and the lower end is the filtration section, the membrane area is 0.5-0.9㎡, and the average pore size of the membrane is 7-15 nanometers.

4. The pre-dilution and post-dilution integrated hemodiafiltration device according to claim 2 or 3, characterized in that: The inner cavity of the filter body has an annular step, and the sealing layer is arranged on the annular step.

5. The pre-dilution and post-dilution integrated hemodiafiltration device according to claim 2 or 3, characterized in that: The hollow fiber membrane has an outer diameter of 180-280 μm, an inner diameter of 150-200 μm, a membrane wall thickness of 15-40 μm, and a three-layer structure, wherein the inner layer is an endothelial layer, the middle layer is a sponge support layer, and the outer layer is an exothelial layer.

6. The pre-dilution and post-dilution integrated hemodiafiltration device according to claim 2 or 3, characterized in that: A closed ring is provided on the outer cover of the glue injection hole in the middle of the filter body.

7. The pre-dilution and post-dilution integrated hemodiafiltration device according to claim 2 or 3, characterized in that: A sealing layer is respectively provided inside the blood chamber inlet cover and the blood chamber outlet cover.

Images