Filter assembly and container for collecting body fluids comprising a filter assembly

Abstract

A filter assembly for filtering a body fluid is disclosed, the filter assembly comprising a filter system and a filter holder, wherein the filter system is composed of at least two layers. The first layer is an antifoam layer made of a loosely woven mesh fabric of monofilaments and having an embossed three-dimensional structure configured for entrapping foam accumulating in the body fluid. The second layer is a mesh filter layer and is arranged downstream of the antifoam layer. A container for collecting a body fluid comprising such a filter assembly is also disclosed.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit and priority of European application No. 19181285.8, filed on 19 June 2019, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to filter assemblies, suitable uses of such filter assemblies, and containers for collecting bodily fluids that include such filter assemblies. Background Technology

[0004] Filter assemblies known from the prior art are used to filter different types of fluids, such as bodily fluids, to remove aggregates, particles, or specific cells from said fluid. A particularly suitable application for filter assemblies is the filtration of blood. Whole blood or blood components can be separated and further processed for various uses, particularly as infusion products.

[0005] Filter assemblies are also used in autologous transfusion procedures during surgery; that is, the patient's blood is recovered during surgery and reinfused into the patient. This is also known as intraoperative blood salvage (IOBS), or autologous blood transfusion or cell salvage. Filter assemblies have been used for many years and have gained increasing attention over time due to growing awareness and concern about the risks associated with allogeneic (other donor) blood transfusions. Several medical devices have been developed to assist in salvaging the patient's own blood in the perioperative setting. This procedure is frequently used in cardiothoracic and vascular surgeries, where blood usage is traditionally high.

[0006] Whole blood recovered during surgery but exposed to the procedure, air, etc., has different characteristics from blood collected from donor blood banks for allogeneic transfusion purposes. For example, blood resuscitation requires the removal of blood clots, noncellular substances such as medications or fluids used during surgery, bone fragments, and surgical debris.

[0007] Autologous blood circulation or intraoperative blood resuscitation is often accompanied by foam formation. The formation of blood foam (sometimes referred to as "skimming") is related to the collection or transport of blood in the presence of air in large tubing (e.g., using a Jankauer cannula), and is therefore related to turbulence during the aspiration process.

[0008] One method to avoid foam formation in drained blood is to use defoamers in the reservoirs that collect the drained blood for autologous infusion or extracorporeal circulation. In the past, polydimethylsiloxane (PDMS) – hydrophobic silica – was widely used as a defoamer. However, PDMS can partially leach into the blood, emulsifying within it. In IOBS, it is assumed that most of the PDMS will be found in the waste after the washing procedure, but it cannot be ruled out that some PDMS may be found in the red blood cell concentrate that is autologously infused to the patient. Even though PDMS – hydrophobic silica – is non-toxic, it is associated with potential sources of embolism due to capillary blockage and postoperative death and is no longer used as a defoamer. Therefore, only silica-free PDMS is used today. The defoaming principle used for PDMS remains unchanged, although silica particles that physically "break" bubbles are no longer used in medical devices, they are still used for non-medical defoaming.

[0009] However, alternative defoaming concepts are still needed. Summary of the Invention

[0010] The object of this invention is to provide a filter system that allows for the reduction or even prevention of foam formation in filtered bodily fluids, such as drained blood, while simultaneously reducing the risk of chemicals leaching into the filtered bodily fluids.

[0011] This objective is achieved by a filter component having the features described below.

[0012] Therefore, a filter assembly for filtering bodily fluids is provided, the filter assembly including a filter system and a filter retainer, wherein the filter system and the filter retainer are in contact with or connected to each other.

[0013] The filter system consists of at least two layers.

[0014] - The first layer is a defoaming layer, which is made of a loosely woven monofilament mesh fabric with an embossed three-dimensional structure. This three-dimensional structure is specifically designed to trap foam accumulated in bodily fluids.

[0015] -The second layer is a mesh filter layer, and

[0016] -The mesh filter layer is arranged downstream of the defoaming layer.

[0017] The terms "upstream" and "downstream" refer to the flow direction of the fluid to be filtered by the filter assembly. Therefore, the fluid to be filtered first comes into contact with the defoaming layer and then with the mesh filter layer.

[0018] This filter assembly is well-suited for filtering blood and other bodily fluids. Using this assembly effectively prevents the formation of foam in blood and other bodily fluids. The assembly allows for the mechanical removal of foam. Therefore, defoamers are not necessary, completely eliminating the risk of chemical leaching into the filtered bodily fluids. This filter assembly is particularly useful for autologous infusion storage devices or containers.

[0019] Surprisingly, it was found that using a defoaming layer with an embossed 3D structure removed or reduced foam. A potential mechanism might be the retention of foam within the defoaming layer. The spatial 3D structure allows for the trapping of air bubbles formed in bodily fluids; that is, the bubbles are trapped within the spatial structure. Another mechanism might be that the foam bubbles are broken up as they pass through a downstream mesh filter.

[0020] The 3D structure of embossing can take the form of a rhombus pattern, which has regularly arranged protrusions and depressions of a certain height. Spatial patterns can also be described as Z-shaped or pyramidal structures.

[0021] As previously mentioned, the defoaming layer is a structured, loosely woven mesh fabric.

[0022] In an embodiment, the defoaming layer includes mesh openings between 100 μm and 500 μm, particularly between 150 μm and 400 μm, particularly between 200 μm and 350 μm, and more particularly between 250 μm and 300 μm, for example, 250 μm.

[0023] The mesh count (typically the number of threads per cm) of the loose mesh fabric that forms the defoaming layer can be between 10n / cm and 50n / cm, particularly between 10n / cm and 30n / cm, and even more particularly between 10n / cm and 20n / cm, such as 12n / cm to 16n / cm.

[0024] The defoaming layer is made of monofilament fibers with a diameter between 100 μm and 350 μm, particularly between 150 μm and 300 μm, and even more particularly between 200 μm and 300 μm, such as 200 μm, 250 μm, and 300 μm. The monofilament fibers can be made of any thermoplastic material, but are preferably made of polypropylene (PP), polyethylene (PE), polyetheretherketone (PEEK), etc. Polypropylene is the most preferred material.

[0025] The weight of the defoaming layer can be 50g / m² 2 Up to 250g / m 2 Specifically 100g / m 2 Up to 200g / cm 2 More notably, 150g / m 2Up to 200g / cm 2 For example, 98g / m 2 Up to 103g / cm 2 180g / m 2 Up to 190g / cm 2 156g / m 2 .

[0026] The thickness of the defoaming layer can be from 150μm to 650μm, particularly from 200μm to 500μm, particularly from 250μm to 400μm, particularly from 300μm to 350μm.

[0027] The defoaming layer can also be a sponge-like structure, for example, made of polyurethane or polyester foam.

[0028] In one embodiment, the first mesh layer is made of a plurality of interconnected lines forming a grid or mesh. Thus, vertically arranged lines and horizontally arranged lines are connected to each other at connection points to form a grid.

[0029] In one embodiment, the wires or filaments of the mesh filter layer have a circular cross-section. Other cross-sections, such as elliptical, rectangular, square, or triangular cross-sections, are also possible. Similarly, mixtures of wires or filaments with different cross-sections are also possible.

[0030] In this embodiment, the mesh size of the mesh filter layer is in the range of 20 μm to 160 μm, particularly 30 μm to 140 μm, particularly 40 μm to 130 μm, particularly 50 μm to 120 μm, particularly 60 μm to 110 μm, particularly 70 μm to 100 μm, and particularly 80 μm to 90 μm. Ranges of 100 μm to 130 μm, 105 μm to 125 μm, 70 μm to 90 μm, 75 μm to 85 μm, 30 μm to 45 μm, and 35 μm to 40 μm are particularly suitable.

[0031] In embodiments, the mesh filter layer may comprise or be made entirely of polymers, such as polyester, polyethylene, polypropylene, polybutene, polymethylpentene, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, (butylene terephthalate-co-alkylene terephthalate) copolymer, nylon 6,6, nylon 6,9, nylon 6 / 12, nylon 11, nylon 12, cellulose acetate, cellulose acetate propionate, or combinations thereof. Thus, non-hydrophobic or hydrophilic materials are particularly suitable for producing the mesh filter layer. The hydrophilicity of the materials used to produce the mesh filter layer or the hydrophilicity of an already produced filter can also be increased. Therefore, physical treatment is more suitable than chemical deposition, as such chemicals may potentially leach from the mesh filter during container use.

[0032] The appropriate surface area of ​​the mesh filter layer is 300 cm². 2 Up to 1000cm 2 , especially 400cm 2 Up to 900cm 2 Especially 500cm 2 Up to 800cm 2 Especially 600cm 2 Up to 700cm 2 Within the range.

[0033] In another preferred embodiment, the filter assembly includes a pre-filter layer (depth filter) arranged downstream of the defoaming layer and upstream of the mesh filter layer; that is, sandwiched between the defoaming layer and the mesh filter layer.

[0034] The pre-filter layer comprises or is substantially composed of nonwoven fibers or fabric. The fibers are arranged such that gaps are formed between the randomly deposited fibers. These gaps can be defined as openings with an average pore size. Thus, the pore size of the nonwoven fabric is obtained.

[0035] The pore size of the pre-filter material is smaller than that of the upstream defoaming layer but larger than that of the downstream mesh filter material.

[0036] In this embodiment, the pre-filter layer comprises or is substantially composed of a spunbond nonwoven fabric. The individual fibers of this fabric can have any desired cross-section, such as circular, elliptical, rectangular, square, or triangular. Mixtures of fibers with different cross-sections are also possible.

[0037] The fibers of the pre-filtration layer can typically have any shape. However, particularly good filtration can be achieved if the fibers, or at least a portion thereof, include at least one groove extending along the longitudinal direction of the respective fiber. For example, the fibers may include three grooves, each extending along the longitudinal direction of the fiber. Aggregates, fats, and / or platelets can then be filtered particularly well from blood or another bodily fluid flowing through the filter assembly.

[0038] In one embodiment, at least a portion of the fiber has a leaf-shaped cross-section. In another embodiment, this leaf-shaped cross-section can be achieved by forming grooves in the fiber along the longitudinal direction. A trilobal cross-section is a particularly suitable example of a leaf-shaped structure. Such trilobal fibers are generally known, for example, from WO 2013 / 110694 A1, the entire contents of which are incorporated herein by reference.

[0039] In this embodiment, the fibers of the nonwoven fabric constituting the pre-filter layer can be spunbond fibers or meltblown fibers. Although spunbond fibers typically have a fiber diameter of at least 20 μm or greater, meltblown fibers can have a smaller diameter of less than 20 μm.

[0040] The pre-filter layer comprises or is substantially composed of a continuous filament spunbond nonwoven fabric. The fabric is obtained in a continuous filament nonwoven process (meltblown and spunbond) in which fragments or particles of raw material are first extruded. The length of the filaments is theoretically infinite.

[0041] The fibers of the pre-filter material can be single-component, bi-component, or multi-component fibers, including "island" fibers. The fiber can be composed of a single polymer or a mixture of polymers. Suitable materials for the fiber are, for example, polyester, polyethylene, polypropylene, polybutene, polymethylpentene, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, (butylene terephthalate-co-alkylene terephthalate) copolymer, nylon 6,6, nylon 6,9, nylon 6 / 12, nylon 11, nylon 12, cellulose acetate, cellulose acetate propionate, or combinations thereof. Thus, non-hydrophobic or hydrophilic materials are particularly suitable for producing the fiber. This can also increase the hydrophilicity of the material used to produce the fiber or increase the hydrophilicity of the already produced fiber. Therefore, physical treatment is more suitable than chemical deposition, as such chemicals may potentially leach from the fiber or the fabric produced from the fiber during use of the filter assembly.

[0042] In this embodiment, the pore size of the pre-filter layer is in the range of 20 μm to 150 μm, particularly 30 μm to 140 μm, particularly 40 μm to 130 μm, particularly 50 μm to 120 μm, particularly 60 μm to 110 μm, particularly 70 μm to 100 μm, and particularly 80 μm to 90 μm. Ranges of 100 μm to 130 μm, 105 μm to 125 μm, 70 μm to 90 μm, 75 μm to 85 μm, 30 μm to 45 μm, and 35 μm to 40 μm are particularly suitable.

[0043] As mentioned above, a filter system may include two or three layers.

[0044] In the case of a two-layer system, the first layer is an antifoaming layer and the second layer is a mesh filter layer. Such a two-layer system can be used for filtration with larger pore sizes. The mesh filter can have a mesh size of 120 μm, with 50% open permeability and 34% closed permeability.

[0045] In a three-layer system, the first layer is a defoaming layer, the second (intercalated) layer is a pre-filter layer (depth filter material), and the third layer is a mesh filter layer. Such a three-layer system can be used for filtration with relatively small pore sizes. The mesh filter layer can have a mesh size of 40 μm, with 40% open permeability and 12% very closed permeability.

[0046] In a particularly preferred embodiment, the filter system includes: a defoaming layer having a mesh size between 200 μm and 300 μm, preferably 250 μm; a pre-filtering layer having a pore size between 50 μm and 100 μm, preferably 70 μm; and a mesh filter layer having a mesh size between 30 μm and 50 μm, preferably 40 μm.

[0047] The filter assembly also includes a filter retainer. This filter retainer contacts the defoaming layer, optional pre-filter layer, and mesh filter layer of the filter system. In this way, the filter retainer also stabilizes the filter system. Therefore, the filter retainer is used to hold the different layers of the filter system in place; the filter retainer acts as a structural support. The filter assembly can be a stand-alone filter assembly (self-supporting filter assembly), or it can be a component with filter layers (overmolded).

[0048] The filter retainer is made of plastic and overmolded onto at least a portion of the filter system. It is preferable that the overmolding is performed on all layers of filter material in the filter system, rather than just the outer layer. This can be achieved by impregnating the filter material into molten plastic. As the plastic cools and hardens, a retainer structure (a type of cage) is formed that encloses the filter material layers. The retainer structure tightly bonds the layers of the filter system together and is particularly effective for ensuring good stability of the filter system layers.

[0049] Surprisingly, this filter assembly was found to work very well for filtering blood and other bodily fluids. Using this filter assembly effectively prevents the formation of foam in blood and other bodily fluids. Therefore, defoamers are not necessary, completely eliminating the risk of chemicals leaching into the filtered bodily fluids.

[0050] In this implementation, the filter assembly does not contain any defoamer. By avoiding the use of such defoamers, the risk of defoaming chemicals leaching into the fluid flowing through the filter assembly is completely prevented. This improves the quality of the fluid filtered by the filter assembly.

[0051] One aspect of the present invention relates to the use of a filter assembly having the features described above for filtering bodily fluids in vitro. The bodily fluids can be blood, urine, bile, tissue fluid, semen, lymph, saliva, or cerebrospinal fluid. Blood is a particularly suitable bodily fluid to be filtered.

[0052] In another aspect, the present invention relates to a method for filtering bodily fluids by causing the fluids to flow through a filter assembly as described above. The flow of the bodily fluids can be achieved by gravity or by applying an external force to the fluids, such as low pressure, or by passing the fluids through a filter into a container. The method can be performed externally or when a patient donating bodily fluids to be filtered is connected to a filter device for filtering the donated fluids.

[0053] In this implementation, the method is a medical approach for intraoperative cell rescue (ICS) from patients in need. ICS is typically used for patients undergoing surgery or invasive procedures and is intended to provide these patients with autologous infusion of blood or blood components. Further details regarding this method are given in subsequent sections.

[0054] In another aspect, the present invention relates to a container for collecting bodily fluids, the container comprising a filter assembly as a filter module as described in the above detailed description.

[0055] This container includes a container shell with a bodily fluid inlet, which allows bodily fluid to enter the inlet section of the container shell. Additionally, the container includes a bodily fluid collection section and a vacuum connector for connecting a vacuum source to the container shell. In this way, negative pressure can be applied to the inlet section and the bodily fluid collection section. Thus, the vacuum source is typically connected to the vacuum connector of the container shell via a vacuum line.

[0056] Furthermore, the container housing includes a filter module that separates the inlet section from the fluid collection section. More specifically, the filter module is arranged between the inlet section and the fluid collection section such that fluid must pass through the filter to flow from the inlet section to the fluid collection section. In other words, the filter module has a raw side and a clean side. The raw side faces the inlet section and the clean side faces the fluid collection section.

[0057] Specifically, the filter assembly, which is a filtration module, is arranged between the inlet section and the body fluid collection section, such that the defoaming layer faces the inlet section and the mesh filter layer faces the body fluid collection section.

[0058] In one embodiment, the container housing includes a hydrophobic filter (i.e., separate from the filter assembly) disposed between the fluid collection section and the vacuum connector. Thus, the term "between" refers to the direction of air flow drawn from the container (or the fluid collection section of the container housing) by a vacuum source during the intended operation of the container. Specifically, any fluid (particularly air and fumes) drawn from the interior of the container housing must pass through the hydrophobic filter before entering the vacuum line connected to the vacuum connector. Therefore, when a vacuum is generated by a vacuum pump, the hydrophobic filter acts as a protective element for the vacuum line connected to the vacuum connector of the container housing.

[0059] The novel filter module works synergistically with the hydrophobic filter, resulting in the effects described below. By constructing a filter module with a filter retainer and a filter assembly including an antifoaming layer, an optional pre-filtration layer, and a mesh filter layer, the design of the filter retainer is given greater flexibility compared to using prefabricated filter sockets similar to those in the prior art. Furthermore, the filter retainer and filter assembly can be manufactured together in a single manufacturing step, and the connection of the co-molded filter assembly component to the container is easily automated. This significantly reduces manufacturing costs and increases container performance due to more reliable and reproducible manufacturing steps.

[0060] An additional hydrophobic filter, arranged along the flow direction before the vacuum connector, serves both as an overflow prevention device and a fume filter. Therefore, the hydrophobic filter combines the performance of these elements, which are used as separate components according to existing technology, into a single element. This single element is thus included within the container housing. Therefore, it is not necessary to connect the single element to a separate vacuum line. No cleaning and / or sterilization of the hydrophobic filter is required. Instead, the hydrophobic filter can be designed as a disposable element to be discarded along with the entire container. Furthermore, this facilitates the use of the container.

[0061] Replacing conventional filters (made solely of fiber, foam, or membrane) with filter assemblies that include an antifoam layer, an optional pre-filter layer, and a mesh filter layer is associated with the ability to achieve highly reproducible filtration conditions. Conventional filters have an average pore size, with many pores larger or smaller than the average pore size, while mesh filters have a well-defined mesh size that remains essentially constant. Furthermore, the use of an antifoam layer reduces or even prevents foam formation.

[0062] In this implementation, the top cover or inlet section of the container housing and the filter retainer are manufactured as a single piece, i.e., they are integrally formed. This significantly simplifies the manufacturing process, as manual attachment of the filter to the container housing is no longer necessary. For example, the filter retainer and at least a portion of the container housing can be co-molded in a single injection molding step. The outlet of the inlet section of the container housing then integrally becomes the inlet to the interior of the filter retainer. Any bodily fluid entering the inlet section will then flow from the inlet section of the container housing toward the interior space of the filter retainer or be aspirated. Any bodily fluid must then pass through the filter assembly to reach the bodily fluid collection section.

[0063] As previously mentioned, the filter retainer and filter assembly do not contain defoamers. In the case of conventional filters, certain defoamers are necessary to avoid unwanted blood foaming; however, the blood pathway through the filter element is designed to cause foam formation in the blood to a very low degree. Without the use of defoamers, this agent will not leach into the body fluids, eliminating concerns about corresponding bodily fluid contamination.

[0064] In one embodiment, the filter retainer includes rods or supports that stabilize the filter material located inside the filter retainer. Such rods can be easily manufactured, for example, by injection molding directly onto the filter material. They prevent the filter material from collapsing and becoming wetted. Furthermore, they can be used during injection molding to carry molten plastic to create a recess at the bottom of the filter element.

[0065] In this implementation, the inlet region of the filter module is funnel-shaped. This funnel shape reduces the risk of foam formation in bodily fluids. Therefore, the funnel shape of the inlet region can also be considered as part of the concept of "defoaming by design" applied to the filter module in this implementation. Consequently, the filter retainer typically has this particular funnel-shaped inlet region, while the filter assembly does not need to have any specific design (as long as it is suitable for fitting into the filter retainer).

[0066] In this embodiment, the bottom of the filter module is not completely flat, but includes a notch facing the interior space of the filter module. Thus, in this embodiment, the notch extends substantially over the entire area of ​​the bottom of the filter module (specifically, the filter retainer). The bottom of the filter module then has a concave shape when viewed from the outside and a convex shape when viewed from the inside. This design of the bottom of the filter module also plays a role in the "defoaming by design" method employed in this embodiment. The notch at the bottom of the filter module can also be described as having a shape similar to the concavity of a champagne bottle. This shape prevents the spraying of bodily fluids through the filter module and reduces the drop height of the bodily fluids through the filter module. The lower the drop height, the lower the risk of foam formation in the bodily fluids.

[0067] In this implementation, the hydrophobic filter is integrated into the top cover of the container housing. This placement of the hydrophobic filter in the upper part of the container significantly reduces the risk of contact with bodily fluids. Furthermore, this integration into the top cover still allows for a compact design of the entire container.

[0068] In this embodiment, the hydrophobic filter includes a filter housing and filter material disposed within the filter housing. Although hydrophobic filters can typically be designed as replaceable elements, in this embodiment, the hydrophobic filter is intended to be a disposable element disposed of along with the entire body fluid collection container. The hydrophobic filter typically has a longer lifespan than the body fluid collection container, so that it is generally not necessary to replace the hydrophobic filter during the intended operation of the body fluid collection container.

[0069] Hydrophobic filters can also be mesh filters, wherein mesh sizes of 1 μm to 20 μm, particularly 3 μm to 19 μm, particularly 4 μm to 18 μm, particularly 5 μm to 17 μm, particularly 6 μm to 16 μm, particularly 7 μm to 15 μm, particularly 8 μm to 14 μm, particularly 9 μm to 13 μm, and particularly 10 μm to 12 μm are suitable.

[0070] Hydrophobic filters are designed to filter air drawn from a container used to collect bodily fluids by a vacuum source, or more precisely, from the bodily fluid collection section of that container. The hydrophobic filter protects the vacuum source from fumes (especially surgical fumes), particles (such as bone or tissue fragments), and blood, and also reduces the contamination load on the hydrophobic antimicrobial filter associated with the pump and therefore located downstream of the hydrophobic filter.

[0071] In an embodiment, the hydrophobic filter includes a filter material comprising or composed of a hydrophobic polymer, such as polytetrafluoroethylene (PTFE), particularly expanded PTFE (ePTFE).

[0072] In this embodiment, the hydrophobic filter includes a filter material comprising or composed of a non-hydrophobic polymer, such as a polyester (e.g., PET) treated with a hydrophobic polymer, particularly a hydrophobic PET mesh. Because the element's contact with blood is accidental and very limited in time (instantaneous), and due to its (top cap) location, the risk of the hydrophobic treatment leaching into the blood is minimal. However, the hydrophobic treatment must be biocompatible.

[0073] In one embodiment, the hydrophobic filter comprises a pleated filter material. By pleating the filter material, an effective filtration surface can be increased without increasing the overall space required for the hydrophobic filter.

[0074] In an embodiment, the pleated filter material has a filtration surface area that is at least 3 times, particularly at least 4 times, particularly at least 5 times, particularly at least 6 times, particularly at least 7 times, or particularly at least 8 times higher than the surface area of ​​the filter element accommodating the hydrophobic filter. The filtration surface area can be 3 to 8 times, particularly 4 to 7 times, or particularly 5 to 6 times higher than the surface area of ​​the filter element accommodating the hydrophobic filter. For example, if the filter element has a 5cm... 2 Up to 20cm 2 The total filter surface area can be 15cm. 2 Up to 160cm 2 Within this range. Therefore, this arrangement allows for the integration of a large filtration surface area into filter elements with very low space requirements. Compared to top covers known from the prior art, this is advantageous for integrating a hydrophobic filter into the top cover of the container housing without increasing the size of the top cover.

[0075] In this embodiment, the container is specifically designed to receive blood as a bodily fluid. That is, in this embodiment, the bodily fluid referred to in this specification is blood.

[0076] The less foam formation in the collected body fluids, the better the quality or the higher the yield of the collected fluid. In the case of blood as a body fluid, lower foam formation leads to lower hemolysis and lower platelet activation, which in turn results in higher blood recovery rates and better quality from separate drainage blood processing steps. The mechanical stress of red blood cells is a basis for hemolysis. Foam formation can be an indicator of biological stress.

[0077] On one hand, the present invention relates to a body fluid collection device comprising a vacuum source and a container as described above. Thus, the vacuum source is directly connected to the vacuum connector of the container via a vacuum line. There are no components other than the vacuum line between the vacuum source and the container.

[0078] Known body fluid collection devices in the prior art have the following general configuration: body fluid collection container – vacuum line – spill prevention device – smoke connector – smoke filter – vacuum line – vacuum pump. Therefore, a total of six connection points are required. If the vacuum source is directly connected to the connector as in the aspect currently discussed in this invention, only two connection points are needed: body fluid collection container – vacuum line – vacuum source. Therefore, integrating the hydrophobic filter into the container housing of the body fluid collection container makes the separate spill prevention device, separate smoke connector, and separate smoke filter redundant. When relying on this aspect of the invention, the three separate parts, each with two connection points, can be completely skipped. This significantly reduces the workload for medical personnel preparing the body fluid collection device for use.

[0079] In the event of a significant overflow from the fluid collection section of the container housing, the collected fluid may pass through a hydrophobic filter. The fluid may then enter the vacuum line connected to the vacuum connector of the container housing. In this embodiment, the vacuum line includes a hydrophobic antibacterial filter to protect the pump. Therefore, a small amount of fluid overflow will have no consequences. Conversely, some hydrophobic vacuum lines can remain operational even in the presence of contaminants or fluid accumulation. The guiding principle is to reduce the assembly complexity of the vacuum line to improve usability.

[0080] In this embodiment, the vacuum line includes an integrally formed antimicrobial filter. Therefore, the antimicrobial filter is not an additional component but an integral part of the vacuum line.

[0081] In this embodiment, the antimicrobial filter is a hydrophobic filter. Therefore, the antimicrobial filter can also be used to effectively prevent any liquid, such as that entering the vacuum line due to an overflow event from the fluid collection section of the container housing, from entering the pump located downstream of the antimicrobial filter. An additional chamber can be provided for this antimicrobial filter to contain any contaminants from the filter. This chamber can then also be used to receive excess fluid drawn through the vacuum line due to an overflow event.

[0082] In this embodiment, the antimicrobial filter has a sufficiently small pore size or mesh size to filter out viruses from the fluid (specifically air) drawn in through the vacuum line. In this case, the antimicrobial filter also has antiviral properties. Therefore, the antimicrobial filter can be referred to as an antiviral filter.

[0083] On one hand, the present invention relates to a method for manufacturing a container according to the foregoing description. In this method, the top cover of the container shell and the filter holder of the container are co-molded. That is, they are manufactured as a single piece, or in other words, they are integrally formed or molded. This manufacturing process is significantly easier than manufacturing processes known from the prior art. This manufacturing process combines the previous method steps of producing the container shell and subsequently attaching the filter to the container shell into a single manufacturing step, namely, the co-molding step. This manufacturing process can be achieved, for example, by injection molding.

[0084] While the filter assembly and filter holder can be co-molded together, other methods are employed in embodiments of the manufacturing process. More specifically, in this embodiment, the filter assembly is applied (e.g., by molding) into the filter holder after it has been manufactured. Thus, the filter holder itself can be co-molded with the top cover of the container housing. In this way, it is not necessary to produce different molds for different mesh sizes of the filter modules to be applied to the container housing. Instead, in this embodiment, only a single mold is needed to produce a large number of container housing top covers with integrally formed filter holders, wherein different filter assemblies can subsequently be applied to the filter holder to obtain container housing top covers that provide different filtration performances (in particular, different mesh sizes of the filter assemblies).

[0085] On one hand, the present invention relates to a medical method for intraoperative cell rescue (ICS) from patients in need. ICS is commonly used for patients undergoing surgery or invasive procedures and is intended to provide autologous infusion of blood or blood components to those patients. The method includes the steps described below. First, a blood aspiration line is connected to the blood inlet of a container for collecting blood. Furthermore, a vacuum line is connected to the vacuum connector of the container and to a vacuum source, such as a vacuum pump. In this way, when the vacuum source is activated, a low pressure can be applied to the interior of the container. The container is the one described above. Therefore, the container includes a container housing with a blood inlet that allows blood to enter the inlet section of the container housing. Furthermore, the container housing also includes a blood collection section. Thus, the vacuum source is typically connected to the vacuum connector of the container housing via a vacuum line.

[0086] Furthermore, the container housing includes a filter module that separates the inlet section from the fluid collection section. More specifically, the filter module is arranged between the inlet section and the fluid collection section such that blood drawn from the patient must pass through the filter to flow from the inlet section to the fluid collection section. In other words, the filter module has a raw side and a clean side. The raw side faces the inlet section and the clean side faces the fluid collection section.

[0087] Once all components are assembled, the vacuum source is activated. Blood is then aspirated from the patient (e.g., during a surgical intervention) through the blood aspiration line into the receiving section of the blood collection container. The blood then passes through a filter and reaches the blood collection section. Thereafter, blood can be aspirated from the blood collection container for further processing and / or autologous infusion to the patient.

[0088] On one hand, the present invention relates to a method for manufacturing a filter assembly according to the foregoing description. As already mentioned, such a filter assembly includes a filter retainer, an antifoaming layer, an optional pre-filter layer, and a mesh filter layer.

[0089] The filter retainer is located downstream of the mesh filter layer. The mesh filter layer is, in turn, located downstream of the defoaming layer and, optionally, the pre-filter layer.

[0090] The method is characterized in that a filter retainer (made of plastic) is overmolded onto a portion of a filter system comprising an antifoaming layer, an optional pre-filtration layer, and a mesh filter layer, such that the filter retainer contacts and stabilizes the individual filter layers of the filter system. Therefore, only a single manufacturing step is required to position the filter retainer around the layers of filter material, as the filter retainer is manufactured in-situ. This is significantly advantageous for the manufacture of filter assemblies compared to filtration devices known from the prior art. The filter retainer can also form the base area of ​​the filter assembly. Thus, the filter retainer can form the base of the filter assembly, while simultaneously embedding the filter material layers near the base to secure them.

[0091] In one embodiment, the different layers of the filter system are initially formed into flat strips. These flat strips are then shaped to the desired form of the filter assembly. This desired shape can be, for example, the shape of a cylindrical sheath, wherein the sheath has a circular, elliptical, rectangular, or square ground area. The free ends of the shaped strips are then joined together. In one embodiment, the joining of the free ends of the shaped strips can be achieved by a welding process. Alternatively, the joining can be formed as a non-welded joint. The given shape is secured by partially overmolding the layers of the filter system using a filter retainer. This method of manufacturing a filter assembly according to one aspect of the invention is significantly simpler than manufacturing techniques employed according to the prior art. More specifically, in the prior art, tubular filter devices typically made from two welded strips require cutting. Since welding and cutting two tubular strips can generate particles that can leach into the fluid passing through the filter, the corresponding manufacturing steps are significantly more difficult and increase the risk of particulate contamination.

[0092] All embodiments of the described filter assembly can be combined in any desired manner and can be transferred to the described uses, the described containers for collecting bodily fluids, and the described methods, and in each case, the reverse. Attached Figure Description

[0093] The following description will provide further details on various aspects of the invention with reference to exemplary embodiments and accompanying drawings. In the drawings:

[0094] Figure 1 This is a perspective view of an embodiment of a blood collection tank;

[0095] Figure 2 yes Figure 1 A side view of the wide side of the can;

[0096] Figure 3 It was observed from the narrow side of the can. Figure 1 Detailed image of the upper part of the jar;

[0097] Figure 4A This is a schematic diagram of a first embodiment of the filter system according to the present invention; and

[0098] Figure 4B This is a schematic diagram of a second embodiment of the filter system according to the present invention. Detailed Implementation

[0099] Figure 1This is a perspective view of a blood collection vessel 1, used as a container for collecting bodily fluids. The blood collection vessel 1 includes a vessel shell 2 with a top cover 3. Three different blood inlets 4 are arranged in the top cover 3. Typically, only one of these blood inlets 4 is used to connect a blood suction line to the blood collection vessel 1 to draw blood from the patient into the interior of the vessel shell 2. (Rightmost view) Figure 1 Blood inlet 4 is designed as a 3 / 8-inch connection. The middle blood inlet 4 is designed as a Luer inlet, and the leftmost blood inlet 4 is designed as a blood aspiration line connector sized to accommodate a typical blood aspiration line.

[0100] Each blood inlet in the blood inlet 4 is fluidly connected to a blood receiving section 5 disposed on the inner side of the top cover 3. The blood receiving section 5 is in fluid communication with the interior of the filter module 6 (which serves as a filter assembly), the filter module 6 including a skeleton structure 7 that serves as a filter retainer.

[0101] Inside the skeleton structure 7, a material layer of the filter system 8 is arranged. The filter material or filter system 8 includes an antifoaming layer and a mesh filter layer made of medical-grade mesh. If blood enters the receiving section 5 of the blood collection tank 1 through the blood inlet 4, the blood flows into or is drawn into the interior of the filter module 6. Thereafter, the blood passes through the filter material 8 and reaches the blood collection section 9 of the tank shell 2.

[0102] The blood collection container 1 includes a vacuum connector 10 in the top section 3 of the container housing 2. The vacuum connector 10 is intended to connect to a vacuum line and, via the vacuum line, to a vacuum pump used as a vacuum source. Air or any other gas present in the blood collection section 9 and drawn into the connected vacuum line through the vacuum connector 10 needs to pass through a hydrophobic filter 11, which is arranged between the blood collection section 9 and the vacuum connector 10.

[0103] The blood collection container 1 also includes a safety valve 12, which limits the amount of negative pressure that can be achieved inside the container housing 2. Therefore, the safety valve 12 is used to reduce the risk of the blood collection container 1 imploding due to undesirable low negative pressure inside the container housing 2.

[0104] When viewed from the outside, the bottom 13 of the filter module 6 has a concave shape, that is, the bottom 13 includes a notch facing the interior of the filter module 6.

[0105] Blood that has entered the tank housing 2 through the blood inlet 4 and passed through the filter material 8 is collected in the blood collection section 9. The blood can then be drawn from the blood collection tank 1 through the blood outlet 14 for further processing and / or autologous infusion to the patient.

[0106] Figure 2 A side view shows the blood collection container 1 on its wide side. Figure 1 Blood collection tank 1. Therefore, the same reference numerals are used for the same components. See also: Figure 1 The given explanation. Figure 2 In the image, the connection between the filter module 6 and the blood receiving section 5 of the tank shell 2 can be observed. Figure 2 It is evident that blood can only enter the interior of the filter module 6 from the blood receiving section 5, and then needs to pass through the filter material 8 to reach the blood collection section 9 of the tank housing 2. Therefore, the filter module 6 separates the blood receiving section 5 from the blood collection section 9.

[0107] Figure 3 It shows from Figure 1 A partial cross-sectional view observed from the narrow side of the blood collection vessel 1. Thus, the same reference numerals are used again for the same elements. Refer again to the description given above.

[0108] exist Figure 3 In the depiction, a funnel-shaped inlet 15 can be observed arranged in the inlet region of the filter element. Blood entering the filter module 6 from the blood receiving section 5 must pass through this funnel-shaped inlet 15. The funnel-shaped inlet 15, together with the filter material 8 of the filter module 6 and the concave bottom 13, serves to reduce foam formation in the blood passing through the filter module 6. This reduced foam formation results in better blood quality than foamy blood and a higher collection yield due to the lower hemolysis rate.

[0109] In addition, Figure 3 As can be observed in the description, the hydrophobic filter 11 comprises a pleated filter material. Due to this pleating of the filter material, the effective filtration surface area is significantly increased. For example, the filter material of the hydrophobic filter 11 has a surface area of ​​approximately 60 cm². 2 The total filtration surface area. Therefore, the hydrophobic filter itself occupies only approximately 10 cm² in the top cover 3 of the tank housing 2. 2 Therefore, by folding the filter material, the effective filter surface area is six times larger than the surface area required by the hydrophobic filter element 11.

[0110] Figure 4A A first embodiment of the filter system 8 according to the present invention is shown. Figure 4A The filter system 8 is shown to be made of an antifoam layer 8a and a mesh layer 8b.

[0111] The defoaming layer 8a is made of a loose mesh fabric with a three-dimensional (3D) embossed structure for foam trapping. Figure 4A (and also) Figure 4BIn the embodiment shown, the spatial structure of the defoaming layer is a rhomboid pattern, which has regularly arranged protrusions and depressions of a certain height. This structure or weave pattern is also known as a Goffery rhombus. The depressions form units for capturing the foam of the formed biofluid.

[0112] The thickness of the defoaming layer 8a can be greater than the thickness of the downstream pre-filter layer 8c or the mesh layer 8b. In this embodiment, the thickness of the defoaming layer 8a can be greater than the thickness of 2 to 3 filaments. The three-dimensional structure and thickness of the defoaming layer mean that the pores in the fabric are not all in the same plane.

[0113] The defoaming layer is made of polypropylene (PP) with fiber diameters between 200μm and 300μm, such as 200μm, 250μm, and 300μm. The mesh count is between 12n / cm and 16n / cm. The mesh size or opening is between 250μm and 300μm.

[0114] The mesh filter layer 8b is made of interconnecting lines forming a grid or mesh. The mesh size of the mesh filter material 8b is between 40 μm and 120 μm, and is therefore smaller than the mesh size of the defoaming layer. Figure 4A In the embodiment shown, the filter system consists only of an antifoaming layer and a mesh filter layer, and the mesh size of the mesh filter material can be 120 μm. This filter system is suitable for filtration with larger pore sizes.

[0115] The filter system shown in Figure 8B consists of three layers: a defoaming layer 8a, a mesh filter layer 8b, and a pre-filter layer 8c arranged (or sandwiched) between the defoaming layer 8a and the mesh sheet layer 8b.

[0116] The pre-filter layer 8c is made of nonwoven fibers with a trilobal cross-section, while the mesh filter layer 8b is made of conventionally formed medical-grade mesh.

[0117] exist Figure 4B In the embodiment shown, the filter system consists of three layers (defoaming layer 8a, pre-filter layer 8c, and mesh filter layer 8b), and the mesh size of the mesh filter material can be 40 μm. This filter system is suitable for filtration with low pore size.

[0118] like Figure 4A and Figure 4B As shown in both diagrams, blood flows into the filter system 8 through the defoaming layer 8a. Foam bubbles contained in the blood are trapped within the 3D structure of the defoaming layer 8a and thus prevented from entering the downstream pre-filter layer 8c and mesh filter layer 8b. The blood flow exiting the filter system at the side of the mesh filter is foam-free.

[0119] The pressure depends on the pore size of the material used and its basis weight. The pressure is determined by capillary flow porosity determination. This method allows for the determination of the pore size (MFP, average flow orifice) of the filter material.

Claims

1. Filter assembly for filtering a body fluid, the filter assembly comprising a filter system and a filter holder, - wherein, - wherein the filter system and the filter holder are in contact with each other, - wherein the filter system is composed of at least two layers, - wherein a first layer is an antifoam layer made of a loosely woven mesh fabric of monofilament and having an embossed three-dimensional structure, - wherein a second layer is a mesh filter layer, and - wherein the mesh filter layer is arranged downstream of the antifoam layer.

2. The filter assembly of claim 1, wherein, The antifoam layer comprises mesh openings between 100 pm and 500 pm.

3. The filter assembly of claim 1 or 2, wherein, The antifoam layer is made of monofilament fibers having a diameter between 100 pm and 350 pm.

4. The filter assembly of one of claims 1 or 2, characterized in that The antifoam layer has a mesh number between 10 n / cm and 50 n / cm.

5. The filter assembly of claim 1 or 2, wherein, The mesh filter layer has a mesh size in the range between 20 pm and 150 pm.

6. The filter assembly of claim 1 or 2, wherein, The filter assembly further comprises a pre-filter layer arranged downstream of the antifoam layer and upstream of the mesh filter layer, wherein the mesh filter layer has a mesh size of approximately 40 pm.

7. The filter assembly of claim 1 or 2, wherein, The filter assembly does not comprise a pre-filter, wherein the mesh filter layer has a mesh size of approximately 120 pm.

8. The filter assembly of claim 6, wherein, The pre-filter layer comprises a spun-bonded nonwoven fabric.

9. The filter assembly of claim 6, wherein, The pre-filter layer has a pore size in the range between 20 pm and 150 pm.

10. The filter assembly of claim 1 or 2, wherein, The filter holder is made of plastic and overmolded on at least a portion of the filter system.

11. The filter assembly of claim 1 or 2, wherein, The filter assembly is free of antifoam agent.

12. The filter assembly of claim 10, wherein, The plastic is selected from ABS or polycarbonate.

13. The filter assembly of claim 1 or 2, wherein, The antifoam layer has a thickness of 150 pm to 650 pm.

14. The filter assembly of claim 1 or 2, wherein, The antifoam layer comprises pores distributed in a non-planar arrangement.

15. The filter assembly according to claim 1, the three-dimensional structure being configured for entrapping foam accumulated in the body fluid.

16. Use of the filter assembly according to any one of claims 1 to 15 for filtering a body fluid extracorporeally.

17. Use according to claim 16, characterized in that, The body fluid is blood.

18. A container for collecting a body fluid, the container comprising a filter assembly according to any one of claims 1 to 15 as a filter module.

19. The container of claim 18, further comprising: a container housing (2) having a body fluid inlet (4) through which a body fluid can enter an inlet section (5) of the container housing (2), a body fluid collection section (9), a vacuum connector (10) for connecting a vacuum source to the container housing (2) for applying a low pressure to the inlet section (5) and the body fluid collection section (9), and the filter assembly as a filter module (6) arranged between the inlet section (5) and the body fluid collection section (9) such that the antifoam layer faces the inlet section (5) and the mesh filter layer faces the body fluid collection section (9).

20. The container for collecting bodily fluid of claim 19, wherein, The container housing (2) additionally comprises a hydrophobic filter (11) arranged between the bodily fluid collection section (9) and the vacuum connector (10) in the direction of flow of air being sucked from the bodily fluid collection section (9) by a vacuum source during intended use of the container.

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