Filter assembly and container for collecting blood comprising the filter assembly

Abstract

A filter assembly is disclosed, comprising a pre-filter support layer (84), wherein the pre-filter support layer (84) comprises a non-woven fabric of fibers, the non-woven fabric having a pore size. A first mesh filter layer (85) is arranged downstream of the pre-filter support layer (84), wherein the first mesh filter layer (85) has a first mesh size, wherein the pore size of the pre-filter support layer (84) is equal to or greater than the first mesh size of the first mesh filter layer (85). A container for collecting body fluids comprising such a filter assembly and a method for manufacturing such a filter assembly are also disclosed.

Description

Technical Field

[0001] The present invention relates to a filter assembly, to suitable uses of such a filter assembly, to a container for collecting body fluids comprising such a filter assembly and to a method for manufacturing such a filter assembly. Background Art

[0002] Filter assemblies known from the prior art are used to filter different types of fluids such as body fluids to remove aggregates, particles or specific cells from the fluids. A particularly suitable application of the filter assembly is the filtration of blood. Whole blood includes three main cellular components, i.e. red blood cells, white blood cells (also referred to as white blood cells) and thrombocytes (also referred to as platelets). The main non-cellular component of blood is plasma.

[0003] Whole blood or blood components can be separated and further processed for various uses, particularly as infusion products.

[0004] Filter assemblies are also used in the process of autologous transfusion during surgical procedures; that is, the patient's blood is recovered and reinjected into the patient during surgery. This is also known as intraoperative blood salvage, or autologous blood transfusion or autologous cell salvage. Filter assemblies have been used for many years and have gained more attention over time because the risks associated with exogenous (independent donor) blood transfusions have attracted more attention and become more fully recognized. Several medical devices have been developed to assist in salvaging the patient's own blood in the perioperative setting. This procedure is often used in cardiothoracic and vascular surgery, during which blood usage is traditionally high.

[0005] Whole blood that is recovered during surgery but exposed to surgery, air, etc., has different properties than blood collected in a blood bank from a donor for the purpose of exogenous body transfusion. For example, blood salvage requires the removal of blood clots, non-cellular material such as medications or fluids used during surgery, bone fragments, and surgical debris.

[0006] Commercially available filters for blood filtration and for removing leukocytes and / or thrombocytes from whole blood or blood components are manufactured using membrane technology, fiber technology or a combination of the two technologies. WO 2013 / 110694 A1 describes a blood filter comprising a first fiber having at least one groove extending in the longitudinal direction of the fiber.

[0007] Filtering drained blood usually results in the formation of foam in the filtered blood. One method to avoid the formation of foam in drained blood is to use a defoamer in a reservoir that collects drained blood for autologous infusion or extracorporeal circulation. In the past, polydimethylsiloxane (PDMS)-hydrophobic silica was widely used as a defoamer. However, PDMS leaches into the blood, where it emulsifies. It is assumed that most of the PDMS will be found in the waste after the cleaning procedure, but it cannot be ruled out that a part of the PDMS is found in the red blood cell concentrate, which is autologously infused into the patient. Even if PDMS-hydrophobic silica is non-toxic, due to capillary blockage and postoperative death, silica is particularly associated as a possible source of embolism and is no longer used as a defoamer. Therefore, only PDMS without silica is used today. The defoaming principle for PDMS remains unchanged, although the silica particles that physically act to "break" bubbles are no longer applied to medical devices, they are still used for non-medical defoaming.

[0008] However, there is still a need for alternative defoaming concepts. Summary of the invention

[0009] A first object of the present invention is to provide a material which allows reducing the formation of foam in filtered body fluids, such as drained blood, and at the same time reducing the risk of leaching of chemicals into the filtered body fluids.

[0010] Filter assemblies such as those described above are typically used with certain bodily fluid collection containers, particularly blood collection containers.

[0011] These containers are used to collect blood during surgical interventions in patients. Thereafter, the blood is processed (washed) in order to remove undesirable components of the blood and to increase the concentration of red blood cells in the blood. After processing the blood, the blood can be autologously transfused to the patient to avoid the necessity of providing the patient with blood donations.

[0012] Prior art blood collection containers include a filter socket that is manually tied to the top cover of the container. Currently, there is no possibility of automation of this process, thus increasing the overall manufacturing costs for such containers. The filter material is treated with an antifoaming agent that reduces the risk of foam formation in the blood. However, these antifoaming agents leach from the filter into the blood and are therefore applied to the patient when the blood is autologously transfused into the patient (as described above).

[0013] Furthermore, due to the specific design of certain filters comprising several layers of nonwoven fabrics, nonwoven fabrics which may in some cases also be obtained from short fibers, a single layer of loose fibers or chemical binders or lubricants used to entangle the fibers and create the nonwoven structure may leach and may therefore contaminate the collected blood.

[0014] Blood collection containers known from the prior art are usually connected to a device that protects against unwanted overflow of the blood collection container. This anti-overflow device (trap) is the only non-reusable component of the entire device. The use of the anti-overflow device is mandatory. The anti-overflow device must be manually assembled to the vacuum circuit by the operator after cleaning and disinfection in the hospital before use. A typical anti-overflow device is a 100ml glass with an input cannula and an output cannula, wherein a floating element is restricted in the output cannula. In the case where blood overflows from the blood collection container into the vacuum line connected to the blood collection container, the blood is sucked into the glass. The increased level of blood in the glass causes the floating element (float) to rise until the level is too high, causing the floating element to block the output cannula. Then, the vacuum used to suck blood into the blood collection container is interrupted. In this case, the operation must be interrupted and the blood collection device, the anti-overflow device and the connected vacuum line must be replaced. The anti-overflow device must be cleaned and disinfected for further use. This may take up to several minutes. Since the blood collection container usually has a volume of at least 3 liters, such overflow events occur only in the case of massive bleeding. Thus, the medical staff may already feel stressed due to the critical condition of the patient. If additional work is necessary in this situation, the staff may decide to interrupt the collection of intraoperative drained blood for subsequent autologous transfusion and rely on exogenous transfusion when necessary.

[0015] When collecting blood from a patient during surgery, a smoke filter is usually provided in the vacuum line for generating a vacuum in the container and thus in the cannula for aspirating blood from the patient. The smoke filter serves to filter the surgical smoke and to prevent the smoke from blocking an antibacterial filter which protects the vacuum pump from contamination by the surgical air. The smoke filters known from the prior art are separate multiple-use or single-use disposable medical devices or accessories which are manually integrated into the vacuum line of an apparatus for aspirating blood from a patient.

[0016] Finally, an antibacterial or antiviral filter is connected to the vacuum line and is used to protect the pump from surgical air contamination. The antibacterial or antiviral filter is disposable and can be used single or multiple times. Single-use filters are usually integrated into the vacuum line.

[0017] A second object of the present invention is to provide a body fluid collection container, in particular a blood collection container, which can be manufactured more simply and cheaper than body fluid collection containers known from the prior art. In addition, the use of the body fluid collector container will be simpler than the use of body fluid collection containers known from the prior art.

[0018] The first and second objects are achieved by a filter assembly and a container for collecting body fluids having the features described below.

[0019] According to a first aspect of the invention, a filter assembly is provided which comprises a pre-filtration support layer. The pre-filtration support layer in turn comprises a non-woven fabric of fibers or consists essentially of a non-woven fabric of fibers. Thus, the fibers are arranged such that gaps are formed between the fibers. Thus, an average pore size of the non-woven fabric is obtained (for depth filtration).

[0020] A first (woven) mesh filter layer (for surface filtration) is arranged downstream of the pre-filtration support layer, wherein the first mesh filter layer has a first mesh size, wherein the pore size of the pre-filtration support layer is equal to or larger than the first mesh size of the first mesh filter.

[0021] The terms "upstream" and "downstream" refer to the flow direction of the fluid to be filtered by the filter assembly. With this arrangement, the pre-filtration support layer does not change or limit the filtering performance of the first mesh filter layer, but is mainly used to stabilize the first mesh filter layer and hold the first mesh filter layer in place. Some of the particles that would otherwise be filtered by the first mesh filter layer have been filtered by the pre-filtration support layer, so that the filtering load of the first mesh filter layer is reduced. Therefore, the pre-filtration support layer not only stabilizes the first mesh filter layer, but the pre-filtration support layer is also used to avoid premature blocking of the first mesh filter layer.

[0022] The filter assembly also includes a filter holder arranged downstream of the mesh filter layer. The filter holder contacts both the pre-filter support layer and the first mesh filter layer. In this way, the filter holder can also stabilize the pre-filter support layer and the first mesh filter layer. Therefore, the filter holder is used to hold the pre-filter support layer and the first mesh filter layer in place; the filter holder is used as a structural support. The filter assembly is an independent filter assembly (self-sustaining filter assembly) or the filter assembly can be a part with a filter layer (overmolding).

[0023] Surprisingly, it has been found that such a filter assembly can be used very well for filtering blood and other body fluids. If such a filter assembly is used, the formation of foam in blood and other body fluids is effectively prevented. Thus, defoaming agents are not necessary, thereby completely avoiding the risk of leaching of chemicals into the filtered body fluids.

[0024] The use of a filter assembly comprising a pre-filter support layer and a mesh filter layer instead of a conventional filter (made of fibers, foams or membranes only) is associated with the effect that extremely reproducible filtering conditions can be met. While conventional filters have an average pore size, wherein many holes are larger or smaller than the average pore size, mesh filters have a clearly defined mesh size that does not vary substantially. For processing, thin meshes, in particular with a smaller mesh size, require a support, which can be another open mesh or a continuous filament nonwoven material, such as a spunbond material.

[0025] In an embodiment, the filter holder is made of plastic and is overmolded on a portion of the pre-filtration support layer and a portion of the first mesh filter layer. Thus, the filter holder tightly connects the two layers together and is particularly simple for good stability of the two layers.

[0026] In an embodiment, the pre-filtration support layer and the first mesh filter layer are not separate components, but are formed integrally and thus create a structural composite material. "Structural composite material" means that the pre-filtration support layer and the first mesh filter layer can be made of the same material but have different structures (the pre-filtration support layer is a nonwoven fabric; the first mesh filter layer is a mesh or grid).

[0027] In an embodiment, the first mesh layer is made of a plurality of interconnected wires forming a screen or grid or mesh.Thus, vertically arranged wires and horizontally arranged wires are connected to each other at connection points in order to form a grid.

[0028] In an embodiment, the filter assembly comprises a second mesh filter layer. The second mesh filter layer has a second mesh size, wherein the second mesh size is equal to or greater than the pore size of the pre-filter support layer. Thus, the pre-filter support layer is arranged between the first mesh filter layer and the second mesh filter layer. Thus, the first mesh filter layer, the pre-filter support layer and the second mesh filter layer are arranged in a sandwich-like manner, wherein the pre-filter support layer is surrounded by the first mesh filter layer and the second mesh filter layer, i.e., the downstream arrangement is second mesh filter layer-filter support layer-first mesh filter layer in sequence. This arrangement is used for a particularly stable arrangement of the mesh layers and therefore for a particularly stable filter assembly.

[0029] In an embodiment, the filter holder is also overmolded onto a portion of the second mesh layer to tightly connect that layer to the other two layers as well.

[0030] Pre-filtration support layer

[0031] As mentioned above, the pre-filtration support layer comprises or consists essentially of a continuous filament spunbond nonwoven fabric. Said fabric is obtained in a continuous filament nonwoven process (meltblowing and spunbonding) starting with extrusion of fragments or granules of raw materials. The length of the filaments is theoretically infinite, so the risk of leaching out fibers (as observed in needle felt nonwoven fabrics) is substantially lower than in needle felt materials.

[0032] In embodiments, the individual fibers of the pre-filter support fabric may have any desired cross-section, such as a circular, oval, rectangular, square or triangular cross-section. Mixtures of fibers having different cross-sections are also possible.

[0033] The fibers of the pre-filtration support layer can generally also have any shape. However, it turns out that particularly good filtration can be achieved if the fibers or at least a portion of the fibers comprise at least one groove extending in the longitudinal direction of the respective fiber. By way of example, the fibers can comprise three grooves each extending in the longitudinal direction of the fiber. Aggregates, fats and / or platelets can then be filtered particularly well from the blood or another body fluid flowing through the filter assembly.

[0034] In an embodiment, at least a portion of the fiber has a lobate cross section. In an embodiment, such a lobate cross section can be achieved by forming grooves in the fiber along the longitudinal direction. A trilobate cross section is a particularly good suitable example of a lobate structure. Such trilobate fibers are generally known, for example, from WO 2013 / 110694 A1, the entire disclosure of which is incorporated herein by reference.

[0035] In an embodiment, the fibers constituting the nonwoven fabric of the pre-filtration support layer may be spunbond fibers or meltblown fibers. Although spunbond fibers generally have a fiber diameter of at least 20 μm or more, meltblown fibers may have a smaller diameter of less than 20 μm.

[0036] The fiber can be a single component, a bicomponent or a multicomponent fiber including "island in the sea" fibers. The fiber can be composed of a polymer or a mixture of polymers. Suitable materials for the fiber are, for example, polyester, polyethylene, polypropylene, polybutene, polymethylpentene, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, (butylene terephthalate-co-polyalkylene terephthalate) copolymers, nylon 6,6, nylon 6,9, nylon 6 / 12, nylon 11, nylon 12, cellulose acetate, cellulose acetate propionate or a combination 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 fiber that has been produced. Thus, physical treatment is more suitable than the deposition of chemicals because during the use of the filter assembly, this chemical may potentially leach from the fiber or the fabric produced by the fiber.

[0037] In an embodiment, the pore size of the pre-filtration support layer is in the range of 20 μm to 150 μm, in particular 30 μm to 140 μm, in particular 40 μm to 130 μm, in particular 50 μm to 120 μm, in particular 60 μm to 110 μm, in particular 70 μm to 100 μm, in particular 80 μm to 90 μm. The 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.

[0038] A first mesh filter and a second mesh filter

[0039] In an embodiment, the first mesh filter layer may include a polymer or may be made entirely of a polymer such as polyester, polyethylene, polypropylene, polybutylene, polymethylpentene, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, (butylene terephthalate-co-polyethylene terephthalate) copolymer, nylon 6,6, nylon 6,9, nylon 6 / 12, nylon 11, nylon 12, cellulose acetate, cellulose acetate propionate or a combination thereof. Thus, non-hydrophobic or hydrophilic materials are particularly suitable for producing the mesh filter layer. This can also increase the hydrophilicity of the material used to produce the mesh filter layer or increase the hydrophilicity of the filter that has been produced. Thus, physical treatment is more suitable than deposition of chemicals because such chemicals may potentially leach from the mesh filter during use of the container. The appropriate surface area of ​​the mesh filter layer is 300 cm 2 Up to 1000cm 2 , especially 400cm 2 Up to 900cm 2 , especially 500cm 2Up to 800cm 2 , especially 600cm 2 Up to 700cm 2 range.

[0040] In an embodiment, the mesh filter layer is made of the same material as the pre-filtration support layer.

[0041] In another embodiment, the second mesh filter layer is identical in structure to the first mesh filter layer except the mesh size of the second mesh filter layer. In this case, the first mesh filter layer and the second mesh filter layer are very similar in structure. This is conducive to the manufacture of the filter assembly.

[0042] In an embodiment, the line or silk of the first mesh filter layer and / or the second mesh filter layer has a circular cross section. However, other cross sections, such as elliptical, rectangular, square or triangular cross sections are also possible. Equally, mixtures of lines or silks with different cross sections are also possible.

[0043] In an embodiment, the first mesh size of the first mesh filter layer and / or the second mesh size of the second mesh filter layer is in the range between 20 μm and 150 μm, in particular between 30 μm and 140 μm, in particular between 40 μm and 130 μm, in particular between 50 μm and 120 μm, in particular between 60 μm and 110 μm, in particular between 70 μm and 100 μm, in particular between 80 μm and 90 μm. The 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, for example 115 μm, 120 μm or 40 μm are particularly suitable.

[0044] In an embodiment, the nonwoven fabric of the pre-filtration support layer has regions with different pore sizes. This enables the pre-filtration support layer to have at least two regions with different filtering capabilities. For example, the first region of the pre-filtration support layer can have a pore size in the range of 20 μm to 60 μm, particularly 25 μm to 55 μm, particularly 30 μm to 50 μm, particularly 35 μm to 45 μm, particularly 38 μm to 42 μm, i.e., about 40 μm. In an embodiment, the pore size of the first region is 40 μm. The second region has a pore size different from the first region. In an embodiment, the pore size of the second region is in the range of 60 μm to 120 μm, particularly 65 μm to 95 μm, particularly 70 μm to 90 μm, particularly 75 μm to 85 μm, particularly 78 μm to 82 μm, i.e., about 80 μm. In an embodiment, the pore size of the second region is 80 μm.

[0045] In another embodiment, the pre-filtration support layer has three zones or regions of different filtration capabilities due to different pore sizes of the nonwoven fabric.

[0046] Therefore, in an embodiment, as explained with respect to the previous embodiment, the first and second regions may be combined with a third region having a pore size different from the pore size of the first region and the pore size of the second region. Thus, in this embodiment, the pore size of the third region is in the range of 100 μm to 140 μm, particularly 105 μm to 135 μm, particularly 110 μm to 130 μm, particularly 115 μm to 125 μm, particularly 118 μm to 122 μm, i.e. about 120 μm. In an embodiment, the pore size of the third region is 120 μm.

[0047] The arrangement of at least three regions of different pore sizes in the pre-filtration support layer provides a pore size gradient. In one example, the gradient starts with a pore size of 40 μm in the first region, followed by a pore size of 80 μm in the second region and a pore size of 120 μm in the third region. In this case, the pore size gradient is a step gradient of pore sizes. Any combination of pore sizes in such a step gradient is conceivable.

[0048] The first mesh filter layer and / or the second mesh filter layer may also have regions with different mesh sizes, for example, as described above with respect to the pre-filter support layer.

[0049] Thus, in an embodiment, regions (or gradients) of different mesh sizes are formed by establishing a gradient of mesh sizes within the nonwoven fabric of the pre-filtration support layer or within the meshes of the first mesh filter layer and / or the meshes of the second mesh filter layer, respectively.

[0050] In an embodiment, the pre-filter support layer, the first mesh filter layer and optionally the second mesh filter layer extend in the vertical extension direction and the horizontal extension direction. Thus, the vertical extension direction is vertically aligned during the normal operation of the filter assembly. Similarly, the horizontal extension direction is horizontally aligned during the normal operation of the filter assembly. The nonwoven fabric of the pre-filter support layer and / or the first mesh filter layer and / or the second mesh filter layer (if present) have a first region in the first height of the vertical extension direction and a second region in the second height of the vertical extension direction. The second height is different from the first height. The first region and the second region have different mesh sizes and present different filtering capabilities. Therefore, the filter assembly has a vertical gradient of filtering capability. Thus, the lowest region usually has the lowest filtering capability (the filtering capability allows the lowest flow rate) but has the highest filtering performance (the filtering performance filters the smallest particles). Similarly, the highest region usually has the highest filtering capability but has the lowest filtering performance. The middle region usually has an intermediate filtering capability and filtering performance.

[0051] The exemplary pore sizes and mesh sizes indicated above obviously apply to the previously described embodiments.

[0052] In an embodiment, the filter assembly does not include any defoaming agent. By avoiding the use of such defoaming agents, 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.

[0053] One aspect of the invention relates to the use of a filter assembly having the features described above for filtering a body fluid in vitro. The body fluid may be blood, urine, bile, tissue fluid, semen, lymph, saliva or cerebrospinal fluid. Blood is a particularly suitable body fluid to be filtered.

[0054] In one aspect, the present invention relates to a method for filtering body fluid by causing the body fluid to flow through a filter assembly according to the foregoing description. The flow of body fluid can be achieved by gravity or by applying an external force such as low pressure to the body fluid or by a container into which the filter body fluid is to be aspirated. The method can be performed in vitro or ex vivo, while the patient donating the body fluid to be filtered is connected to the filter device for filtering the donor fluid. In an embodiment, the method is a medical method for aspirating intraoperative cell salvage (ICS) from a patient in need. ICS is typically used for patients undergoing surgery or invasive surgery, and is intended to provide these patients with autologous transfusion of blood or blood components. More details on this method are given in subsequent sections.

[0055] In one aspect, the present invention relates to a container for collecting body fluids. Such a container comprises a container housing with a body fluid inlet, which allows body fluids to enter an inlet portion of the container housing. In addition, the container comprises a body fluid collection portion and a vacuum connector for connecting a vacuum source to the container housing. In this way, negative pressure can be applied to the inlet portion and the body fluid collection portion. Thus, the vacuum source is typically connected to the vacuum connector of the container housing via a vacuum line.

[0056] In addition, the container housing includes a filter module separating the inlet portion from the body fluid collection portion. More specifically, the filter module is arranged between the inlet portion and the body fluid collection portion such that the body fluid needs to pass through the filter in order to flow from the inlet portion to the body fluid collection portion. In other words, the filter module has a pristine side and a clean side. The pristine side faces the inlet portion and the clean side faces the body fluid collection portion.

[0057] The filter module further comprises a filter assembly according to the aforementioned description. Thus, the filter assembly is arranged in a filter holder. Therefore, the filter holder is used to support the filter assembly on the downstream side of the filter assembly. This arrangement is particularly suitable for stabilizing the mesh filter of the filter assembly both from the upstream side (on the upstream side, the mesh filter layer is stabilized by the pre-filter support layer) and from the downstream side (on the downstream side, the mesh filter layer is stabilized by the filter holder). In addition, this arrangement is particularly suitable for achieving foam-free filtration of body fluids such as blood.

[0058] In an embodiment, the container housing includes a hydrophobic filter arranged between the body fluid collection portion and the vacuum connector. Thus, the term "between" relates to the flow direction of air sucked from the container (or the body fluid collection portion of the container housing) by the vacuum source during the intended operation of the container. That is, any fluid (particularly air and smoke) sucked from the interior of the container housing needs to pass through the hydrophobic filter before entering the vacuum line connected to the vacuum connector. Therefore, the hydrophobic filter is used as a protective element for the vacuum line of the vacuum connector connected to the container housing when the vacuum is generated by the vacuum pump.

[0059] The novel filter module and the hydrophobic filter work together so that this combination causes the effect described below. By constructing a filter module with a filter holder and a filter assembly comprising a pre-filter support layer and a mesh filter layer, the design of the filter holder is given more flexibility than the situation of using a prefabricated filter socket similar to the prior art. In addition, the filter holder can be manufactured together with the filter assembly in a single manufacturing step, and the connection of the co-molded filter assembly parts and the container is easy to be automated. Due to more reliable and reproducible manufacturing steps, this significantly reduces manufacturing costs and increases the performance of the container. Safety is further improved by streamlining the loop that the user must manually connect, therefore preventing use errors (referring to IEC62366-1:2015 and the file FDAGuidance Applying Human Factors and Usability Engineering to Medical Devices Guidance for Industry and Food and Drug Administration Staff issued on February 3, 2016).

[0060] The hydrophobic filter arranged in the flow direction before the vacuum connector serves both as a smoke filter and as an overflow prevention device. The hydrophobic filter thus combines the properties of these elements, which are used in the form of separate components according to the prior art, in a single element. This single element is thus included in the container housing. It is therefore not necessary to connect the single element to an independent vacuum line. It is not necessary to clean and / or sterilize the hydrophobic filter. Instead, the hydrophobic filter can be designed as a disposable element that is discarded together with the entire container. In addition, this facilitates the use of the container.

[0061] In an embodiment, the top cover or inlet portion of the container housing and the filter holder are manufactured as one-piece, that is, the top cover or inlet portion and the filter holder are formed integrally. Since it is no longer necessary to manually attach the filter to the container housing, this significantly simplifies the manufacturing steps. For example, the filter holder and the container housing (at least a portion thereof) can be co-molded in a single injection molding step. Thus, the outlet of the inlet portion of the container housing becomes the inlet of the interior of the filter holder integrally. Any body fluid entering the inlet portion will then flow or be sucked from the inlet portion of the container housing toward the inner space of the filter holder. Any body fluid must then pass through the filter assembly to reach the body fluid collection portion.

[0062] In an embodiment, the filter holder and filter assembly are free of antifoaming agents. Although some antifoaming agents are necessary in the case of conventional filters to avoid undesirable foaming of the blood, the design of the blood path through the filter element tends to cause foam formation only to a very low extent. If an antifoaming agent is not used, such an agent will not leach into the body fluids, so that there is no need to worry about corresponding contamination of the body fluids.

[0063] In an embodiment, the filter holder comprises a rod or a pillar that stabilizes the filter material inside the filter holder. Such a rod can be easily produced by, for example, injection molding directly on the filter material. The rod can prevent the filter material from collapsing and getting wet. In addition, the rod can be used to carry molten plastic to produce a punt at the bottom of the filter element during injection molding.

[0064] In an embodiment, the inlet area of ​​the filter module is funnel-shaped. This funnel shape reduces the risk of foam formation in body fluids. Therefore, the funnel shape of the inlet area can also be considered as part of the concept "defoaming by design" applied to the filter module in an embodiment. Thus, the filter holder typically has an inlet area with this specific funnel shape, and the filter assembly does not need to have any specific design (as long as the filter assembly is suitable for the filter holder).

[0065] In an embodiment, the bottom of the filter module is not completely flat, but includes a recess towards the inner space of the filter module. Thus, in an embodiment, the recess extends substantially over the entire area of ​​the bottom of the filter module (particularly the filter holder). Then, the bottom of the filter module has a concave shape when observed from the outside of the filter module, and has a convex shape when observed from the inside of the filter module. This design of the bottom of the filter module also plays a role in the "defoaming by design" method adopted in the embodiment. The recess at the bottom of the filter module can also be described as a shape similar to the depression of a champagne bottle. This shape avoids the spraying of body fluids passing through the filter module and reduces the drop height of body fluids passing through the filter module. The lower the drop height, the lower the risk of foam formation in the body fluids.

[0066] In an embodiment, the hydrophobic filter is integrated into the top cover of the container housing. Thus, the hydrophobic filter is arranged in an upper position of the container, so that the risk of contact with body fluids is significantly reduced. In addition, this integration in the top cover of the container still allows a compact design of the entire container.

[0067] In an embodiment, the hydrophobic filter includes a filter housing and a filter material disposed in the filter housing. Although the hydrophobic filter can generally be designed as a replaceable element, in an embodiment, the hydrophobic filter is intended to be a disposable element that is discarded with the entire body fluid collection container. The life of the hydrophobic filter is generally longer than the life of the body fluid collection container, so that it is generally not necessary to replace the hydrophobic filter during the expected operation of the body fluid collection container.

[0068] The hydrophobic filter can also be a mesh filter, in which a mesh size of 1μm to 20μm, in particular 3μm to 19μm, in particular 4μm to 18μm, in particular 5μm to 17μm, in particular 6μm to 16μm, in particular 7μm to 15μm, in particular 8μm to 14μm, in particular 9μm to 13μm, in particular 10μm to 12μm is suitable.

[0069] The hydrophobic filter is intended to filter the air drawn by the vacuum source from the container for collecting body fluids, or more precisely from the body fluid collecting part of the container. The hydrophobic filter protects the vacuum source from smoke (in particular surgical smoke), particles (such as bone fragments or tissue fragments) and blood, and also reduces the contamination load of the hydrophobic antibacterial filter associated with the pump and therefore located downstream of the hydrophobic filter.

[0070] In an embodiment, the hydrophobic filter comprises a filter material comprising or consisting of a hydrophobic polymer, such as polytetrafluoroethylene (PTFE), in particular expanded PTFE (ePTFE).

[0071] In an embodiment, the hydrophobic filter comprises a filter material comprising or consisting of a non-hydrophobic polymer, such as a polyester (such as PET) treated with a hydrophobic polymer, in particular a hydrophobic PET mesh. Since the contact of the element with the blood is accidental and very limited in time (instantaneous) and due to the position (of the top cover), the risk of the hydrophobic treatment leaching into the blood is small. However, the hydrophobic treatment must be biocompatible.

[0072] In an embodiment, the hydrophobic filter comprises a pleated filter material. By pleating the filter material, the effective filter surface can be increased without increasing the overall space required for the hydrophobic filter.

[0073] In an embodiment, the pleated filter material has a filtration surface area that is at least 3 times, in particular at least 4 times, in particular at least 5 times, in particular at least 6 times, in particular at least 7 times, in particular at least 8 times higher than the surface area of ​​the filter element that accommodates the hydrophobic filter. The filtration surface area may be 3 to 8 times, in particular 4 to 7 times, in particular 5 to 6 times higher than the surface area of ​​the filter element that accommodates the hydrophobic filter. For example, if the filter element has a 5 cm 2 Up to 20cm 2 The total filtration surface can be 15cm 2 Up to 160cm 2 Thus, with this arrangement, a large filter surface area can be incorporated into a filter element with only a very low space requirement. This facilitates the integration of a hydrophobic filter into a top cover of a container housing without increasing the size of the top cover in comparison to top covers known from the prior art.

[0074] In an embodiment, the container is particularly suitable for receiving blood as a body fluid. That is, in this embodiment, the body fluid referred to in this specification is blood.

[0075] The less foam formation in the collected body fluid, the better the quality or higher the yield of the collected body fluid is achieved. In the case of blood as body fluid, lower foam formation leads to lower hemolysis and lower platelet activation, which in turn leads to higher blood recovery and better quality from the separate drain blood processing step. Mechanical stress on red blood cells is one basis for hemolysis. The formation of foam can be an indicator of biological stress.

[0076] In one aspect, the invention relates to a body fluid collection arrangement comprising a vacuum source and a container according to the preceding description, wherein the vacuum source is directly connected to a vacuum connector of the container via a vacuum line, and there are no component parts between the vacuum source and the container other than the vacuum line.

[0077] The body fluid collection arrangement known from the prior art has the following overall setup: body fluid collection container-vacuum line-anti-overflow device-smoke connector-smoke filter-vacuum line-vacuum pump. Therefore, a total of six connection points need to be established. If the vacuum source is directly connected to the connector as in the currently discussed aspect of the invention, only two connection points need to be established: body fluid collection container-vacuum line-vacuum source. Therefore, integrating the hydrophobic filter into the container housing of the body fluid collection container makes a separate anti-overflow device, a separate smoke connector and a separate smoke filter redundant. When relying on this aspect of the invention, three separate parts, each with two connection points, can be completely skipped. This significantly reduces the workload of medical personnel in preparing the body fluid collection arrangement for use.

[0078] In the case of a large overflow of the body fluid collection portion of the container housing, what may happen is that the collected body fluid passes through the hydrophobic filter. The body fluid may then enter the vacuum line of the vacuum connector connected to the container housing. In an embodiment, the vacuum line includes a very hydrophobic antibacterial filter to protect the pump. Thus, a small overflow of such body fluid will not have any consequences. In contrast, some hydrophobic vacuum lines are able to remain operational in the presence of contaminants or liquid accumulation. The guiding principle is to reduce the assembly complexity of the vacuum line to improve usability.

[0079] In an embodiment, the vacuum line comprises an integrally formed antibacterial filter. Thus, the antibacterial filter does not represent an additional component part, but an integral part of the vacuum line.

[0080] In an embodiment, the antibacterial filter is a hydrophobic filter. Thus, the antibacterial filter can also be used to effectively prevent any liquid that enters the vacuum line, for example due to an overflow event of the body fluid collection portion of the container housing, from entering the pump arranged downstream of the antibacterial filter. Such an antibacterial filter can be equipped with an additional chamber to accommodate any contaminants of the filter. Such a chamber can then also be used to accommodate excess body fluid that is sucked through the vacuum line due to an overflow event.

[0081] In an embodiment, the antibacterial filter has a pore size or mesh size that is small enough to filter viruses out of the fluid (particularly air) that is sucked through the vacuum line. In this case, the antibacterial filter also has antiviral properties. Thus, the antibacterial filter can be denoted as an antiviral filter.

[0082] On the one hand, the present invention relates to a method for manufacturing a container according to the aforementioned description. Thereby, the top cover of the container housing of the container and the filter holder of the container are co-molded. That is, the top cover and the filter holder are manufactured as one piece, or in other words, the top cover and the filter holder are formed or integrally molded. This manufacturing process is significantly easier than the manufacturing processes known from the prior art. This manufacturing process combines the previous method steps of producing the container housing and subsequently attaching the filter to the container housing into a single manufacturing step, namely a co-molding step. This manufacturing process can be realized, for example, by injection molding.

[0083] Although the filter assembly can also be molded together with the filter holder, other methods are also adopted in the embodiment of the manufacturing method. More specifically, in this embodiment, after the filter holder has been produced, the filter assembly is applied (for example, by molding) to the filter holder. Thus, the filter holder itself can be molded together with the top cover of the container housing. In this way, it is not necessary to produce different molds for the different mesh sizes of the filter module to be applied to the container housing. On the contrary, in this embodiment, only a single mold is required to produce a large number of container housing top covers with an integrally formed filter holder, wherein, different filter assembly filters can be applied to the filter holder thereafter, thereby obtaining a container housing top cover providing different filtering performances (especially the different mesh sizes of the filter assembly).

[0084] On the one hand, the present invention relates to a medical method for aspirating intraoperative cell salvage (ICS) from a patient in need. ICS is typically used for patients undergoing surgery or invasive surgery, and is intended to provide autologous transfusion of blood or blood components to those patients. The method includes the steps described below. First, a blood suction line is connected to a blood inlet of a container for collecting blood. In addition, a vacuum line is connected to a 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 a container according to the aforementioned description. Therefore, the container includes a container housing with a blood inlet, which allows blood to enter an inlet portion of the container housing. In addition, the container housing also includes a blood collection portion. Thus, the vacuum source is typically connected to the vacuum connector of the container housing via a vacuum line.

[0085] In addition, the container housing includes a filter module separating the inlet portion from the body fluid collection portion. More specifically, the filter module is arranged between the inlet portion and the body fluid collection portion so that blood drawn from the patient needs to pass through the filter in order to flow from the inlet portion to the body fluid collection portion. In other words, the filter module has a pristine side and a clean side. The pristine side faces the inlet portion and the clean side faces the body fluid collection portion.

[0086] If all components have been assembled, the vacuum source will be activated. Blood is then drawn from the patient (e.g., during a surgical intervention) through the blood suction line into the receiving portion of the blood collection canister. The blood then passes through the filter and reaches the blood collection portion. Thereafter, blood can be drawn from the blood collection container for further processing of the blood and / or autologous transfusion of the blood into the patient.

[0087] On the one hand, the present invention relates to a method for manufacturing a filter assembly according to the above description. As already mentioned, such a filter assembly comprises a filter holder, a mesh filter layer and a pre-filter support layer. The pre-filter support layer comprises a non-woven fabric of fibers. Thus, the non-woven fabric has a first mesh size. The filter holder is arranged downstream of the first mesh filter layer. The first mesh filter layer is in turn arranged downstream of the pre-filter support layer. The first mesh filter layer has a second mesh size, wherein the first mesh size is equal to or greater than the second mesh size.

[0088] The method is characterized in that a filter holder (which is made of plastic) is overmolded on a portion of the pre-filtration support layer and a portion of the first mesh filter layer so that the filter holder contacts and stabilizes both the pre-filtration support layer and the first mesh filter layer. Therefore, in order to place the filter holder around the two layers of filter material, only a single manufacturing step is necessary because the filter holder is manufactured in situ. Compared with the filtering devices known from the prior art, this is significantly beneficial to the manufacture of the filter assembly. The filter holder can also form the ground area of ​​the filter assembly. Therefore, the filter holder can form the base of the filter assembly and at the same time embed the filter material layer near the base to fix the filter material layer.

[0089] In an embodiment, the first mesh filter layer and the pre-filter support layer initially form a flat belt. The flat belt then forms the desired shape of the filter assembly. The desired shape can be, for example, the shape of a barrel jacket, wherein the barrel has a circular ground area, an elliptical ground area, a rectangular ground area or a square ground area. The free ends of the shaped belts are then connected to each other. In an embodiment, the connection of the free ends of the shaped belts can be achieved by a welding process. Alternatively, the connection can be formed as a non-welded joint. The given shape is fixed by locally overmolding the pre-filter support layer and the first mesh filter layer using a filter holder. This manufacturing method of the filter assembly according to one aspect of the present invention is significantly simpler than the manufacturing technology adopted according to the prior art. More specifically, in the prior art, the tubular filtration arrangement structure made of two welding belts conventionally requires cutting. Since welding and cutting two tubular belts may produce particles that can be leached into the fluid passing through the filter, the corresponding manufacturing steps are significantly more difficult and increase the risk of particle contamination.

[0090] All embodiments of the described filter assembly can be combined in any desired manner and can be transferred to the described use, the described container for collecting body fluids and the described method, and in each case vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Further details of various aspects of the present invention will be described below with respect to exemplary embodiments and accompanying drawings. In the accompanying drawings:

[0092] Figure 1 is a perspective view of an embodiment of a blood collection can;

[0093] Figure 2 yes Figure 1 A side view on the wide side of the tank;

[0094] Figure 3 is viewed from the narrow side of the tank Figure 1 Detail of the upper part of the tank;

[0095] Figure 4A is a schematic depiction of a manufacturing process for an embodiment of a filter assembly;

[0096] Figure 4B yes Figure 4A An enlarged detail of the area circled and marked with letters AA in FIG.

[0097] Figure 5A is a partial cutaway depiction of another embodiment of a filter assembly;

[0098] Figure 5B yes Figure 5A An enlarged detail of the area circled and marked with the letter T;

[0099] Figure 6 is a schematic depiction of the microstructure of a pre-filtration support layer and a mesh filtration layer of an embodiment of a filter assembly; and

[0100] Figure 7 is a schematic depiction of another embodiment of a filter assembly. DETAILED DESCRIPTION

[0101] Figure 1 is a perspective view of a blood collection can 1 used as a container for collecting body fluids. The blood collection can 1 comprises a can housing 2 with a top cover 3. Three different blood inlets 4 are arranged in the top cover 3. Usually, only one of these blood inlets 4 is used to connect a blood suction line to the blood collection can 1 in order to draw blood from a patient into the interior of the can housing 2. The rightmost blood inlet 4 is designed as a 3 / 8 inch connection. The middle blood inlet 4 is designed as a Luer inlet, wherein the leftmost blood inlet 4 is designed as a suction line connector sized to accommodate a typical blood suction line.

[0102] Each of the blood inlets 4 is fluidly connected to a blood receiving portion 5 arranged on the inner side of the top cover 3. The blood receiving portion 5 is in fluid communication with the interior of a filter module 6 (serving as a filter assembly), which includes a skeleton structure 7 serving as a filter holder. Inside the skeleton structure 7, two layers of filter material 8 are arranged. The filter material 8 includes a pre-filter support layer and a mesh filter layer made of a medical grade mesh. If blood enters the receiving portion 5 of the blood collection tank 1 through the blood inlet 4, the blood flows to 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 portion 9 of the tank housing 2.

[0103] The blood collection canister 1 comprises a vacuum connector 10 in the top portion 3 of the canister housing 2, which is intended to be connected to a vacuum line and connected via the vacuum line to a vacuum pump serving as a vacuum source. Air or any other gas present in the blood collection part 9 that is sucked into the connected vacuum line through the vacuum connector 10 needs to pass through a hydrophobic filter 11 that is arranged between the blood collection part 9 and the vacuum connector 10.

[0104] The blood collection can 1 further comprises a safety valve 12 which limits the amount of negative pressure that can be achieved within the interior of the can housing 2. Thus, the safety valve 12 serves to reduce the risk of the blood collection can 1 imploding due to an undesirably low negative pressure within the interior of the can housing 2.

[0105] The bottom 13 of the filter module 6 has a concave shape when viewed from the outside, ie it comprises a recess towards the inside of the filter module 6 .

[0106] Blood that has entered the canister housing 2 through the blood inlet 4 and has passed through the filter material 8 is collected in the blood collection portion 9. The blood can then be drawn from the blood collection canister 1 through the blood outlet 14 to be further processed and / or autologously transfused to a patient.

[0107] Figure 2 The side view shows the blood collection container 1 on the wide side. Figure 1 Thus, the same reference numerals are used for the same elements. Figure 1 Instructions given. Figure 2 In the figure, the connection between the filter module 6 and the blood receiving part 5 of the tank housing 2 can be seen. Figure 2 Obviously, blood can only enter the interior of the filter module 6 from the blood receiving part 5 and then needs to pass through the filter material 8 in order to reach the blood collecting part 9 of the tank housing 2. Therefore, the filter module 6 separates the blood receiving part 5 from the blood collecting part 9.

[0108] Figure 3 Shows from Figure 1 1 is a partial cross-sectional view of a blood collection container 1 viewed from the narrow side. Thus, the same reference numerals are used again for the same elements. Reference is again made to the description given above.

[0109] exist Figure 3 In the depiction of FIG. 5 , it can be observed that a funnel-shaped inlet 15 is arranged in the inlet region of the filter element. The blood entering the filter module 6 from the blood receiving part 5 needs to 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-shaped bottom 13 serves to reduce foam formation in the blood passing through the filter module 6. This reduced foam formation results in blood having a better quality than foamy blood and a higher collection yield due to a lower hemolysis rate.

[0110] In addition, Figure 3 It can be observed from the depiction of that the hydrophobic filter 11 comprises a pleated filter material. Due to this folding of the filter material, the effective filter surface area is significantly increased. For example, the filter material of the hydrophobic filter 11 has a pleated surface area of ​​approximately 60 cm 2 The total filtration surface area of ​​the hydrophobic filter itself thus occupies only approximately 10 cm in the top cover 3 of the tank housing 2. 2 Thus, by pleating the filter material, the effective filtering surface area is six times greater than the surface area required for the hydrophobic filter element 11 .

[0111] Figure 4A Shows that it can be used as Figure 1 An exemplary manufacturing process of a filter module 6 of a filter module for a blood collection tank shown in . First, a flat strip 80 of a co-formed spunbond pre-filter (serving as a pre-filtration support layer) and a mesh filter (serving as a mesh filter layer) is provided. The flat strip 80 is shaped into a desired shape in subsequent manufacturing steps 100, 101, 102 and 103. Thereby, the flat strip 80 becomes a shaped filter material 8, which in this embodiment has the shape of a cylindrical sheath with an elliptical ground area. Thereby, the free ends 81 and 82 of the strip that have not been connected in the manufacturing step 102 are connected to each other to form a connection line 83 in the manufacturing step 103. The connection line 83 can be realized in the form of a seam similar to a welded seam or in the form of a seamless joint, i.e., a non-welded joint.

[0112] In general, the filter material 8 can then be inserted into the skeleton structure 7 of the bare filter module 6 so as to form a complete filter module 6 including the filter material 8. However, in an embodiment, the skeleton structure 7 is overmolded on the filter material formed, for example, by injection molding. Thereby, the skeleton structure 7 is partially embedded in the individual layers of the formed filter material (particularly at the bottom portion of the individual layers oriented toward the elliptical ground area) and is used to tightly connect the individual layers together. Thereby, the skeleton structure can also overmold seamless joints between the free ends of the formed filter material 8, and the seamless joints are also used for the tight connection of the formed filter material 8 between the free ends of the filter material 8 (i.e., along the vertical extension direction that is vertically aligned during normal operation of the assembled filter module 6).

[0113] Figure 4B Shown in Figure 4A The enlarged detail view of the area of ​​the belt 80 circled and marked with the letters AA in step 101 of FIG. This enlarged view shows that the belt 80 is composed of a pre-filter support layer 84 and a mesh filter layer 85. The structure of these two layers 84, 85 is also shown in FIG. Figure 4B While the pre-filtration support layer 84 is comprised of nonwoven fibers having a trilobal cross-section, the mesh filtration layer 85 is comprised of a conventionally formed medical grade mesh.

[0114] Figure 5A Shows that it can be Figure 1 Another embodiment of the filter module 6 used in conjunction with the blood collection canister shown in FIG. For illustration purposes only, the filter material 8 of this embodiment of the filter module 6 is partially cut away. Figure 5B , the area circled and marked with the letter T is depicted in an enlarged detail view. In this detail view, it can be observed that the filter material 8 includes a pre-filter support layer 84 composed of non-woven fibers with a trilobal cross-section and a first mesh filter layer 85 arranged on the side of the pre-filter support layer 84 facing the skeleton structure 7 of the filter module 6. In addition, the filter material 8 of this embodiment includes a second mesh filter layer 86 arranged on the side of the pre-filter support layer 84 opposite to the first mesh filter layer 85. Therefore, the pre-filter support layer 84 is surrounded between the first mesh filter layer 85 and the second mesh filter layer 86, and thus forms a sandwich-like structure together with the first mesh filter layer 85 and the second mesh filter layer 86.

[0115] Figure 6A depiction of the microstructure of the filter material 8 based on an electron microscope picture of the individual fibers constituting the pre-filtration support layer 84 is shown. In contrast to the nonwoven and generally disordered structure of the individual fibers constituting the pre-filtration support layer 84, the individual grid elements constituting the mesh filter layer 85 are highly ordered and are arranged horizontally and vertically so as to form an ordered grid. In this way, a highly repeatable and reproducible structure of the mesh filter layer 85 is obtained.

[0116] Figure 7 shows that it can be used for Figure 1 Another embodiment of the filter module 6 of the filter module of the blood collection tank shown in FIG. As discussed above Figure 1 Other embodiments of the filter module shown in, Figure 7 The filter module 6 comprises a skeleton structure 7 and a filter material 8. The filter material 8 comprises three zones with different filtering capacities, which are arranged one above the other in a vertical extension direction of the filter module in which the filter module 6 is vertically aligned during normal operation. The lowest zone 87 has a mesh size of 40 μm, so that only particles with a size less than 40 μm are allowed to pass. The middle zone 88 has a mesh size of 80 μm and has a slightly lower filtering capacity than the lowest zone 87, but compared to the first zone 87, the middle zone 88 enables a higher capacity to pass simultaneously. All three zones extend along the entire circumference of the filter module 6, i.e. along the entire circumference in a horizontal extension direction that is horizontally aligned during normal operation of the filter module 6.

[0117] The highest zone 89 has a mesh size of 120 μm and allows an even higher blood flow through the filter material 8 than the middle zone 88 if the blood level in the filter material 8 is so high that blood can flow through the highest zone 89. Thus, in this embodiment, the filter material 8 has a vertical gradient of mesh size that effectively prevents overflow of the filter module 6, because the vertical gradient of mesh size allows a higher volume of blood to pass through the filter material 8 depending on the level of blood or the amount of blood present in the interior of the filter module 6. The highest zone 89 can also be seen as a safety zone that allows proper functioning of the filter module 6 even in the case of high blood inflow. As a side effect, since the filtering capacity of the highest zone 89 is significantly lower than the filtering capacity of the lowest zone 87, the filtering effect is reduced in the case of such a high blood inflow into the filter module 6.

[0118] exist Figure 7In the embodiment of the present invention, the different filtering capacities of the various zones 87, 88 and 89 of the filter material 8 are achieved by combining meshes with different mesh sizes on one pre-filter support layer and the same pre-filter support layer. This is obviously advantageous for the manufacture of the filter material 8 and does not require modifications to the structure of the nonwoven fibers constituting the pre-filter support layer (which is in the pre-filter support layer). Figure 7 (not visible in the attached figure) for adjustment.

Claims

1. A filter assembly, comprising a pre-filter support layer (84) and a first mesh filter layer (85) arranged downstream of the pre-filter support layer (84), wherein: The pre-filtration support layer (84) comprises a non-woven fabric of fibers, the non-woven fabric having a pore size, wherein the first mesh filter layer (85) has a first mesh size, wherein the pore size of the pre-filtration support layer (84) is equal to or greater than the first mesh size of the first mesh filter layer (85), Characterized in that the filter assembly (6) comprises a filter holder (7) arranged downstream of the first mesh filter layer (85), wherein the filter holder (7) contacts and stabilizes both the pre-filter support layer (84) and the first mesh filter layer (85) and the pre-filter support layer (84) and the first mesh filter layer (85) are in contact with each other.

2. The filter assembly according to claim 1, characterized in that The filter holder is made of plastic and is overmolded onto a portion of the pre-filter support layer (84) and a portion of the first mesh filter layer (85).

3. The filter assembly according to claim 1 or 2, characterized in that The filter assembly (6) includes a second mesh filter layer (86) arranged upstream of the pre-filter support layer (84), wherein the second mesh filter layer (86) has a second mesh size, wherein the second mesh size of the second mesh filter layer (86) is equal to or larger than the pore size of the pre-filter support layer (84).

4. The filter assembly according to claim 1 or 2, characterized in that The pre-filtration support layer (84) comprises a spunbonded nonwoven fabric.

5. The filter assembly according to claim 1 or 2, characterized in that: At least a portion of the fibers of the pre-filtration support layer (84) each include at least one groove extending in a longitudinal direction of the respective fiber.

6. The filter assembly according to claim 1 or 2, characterized in that: At least a portion of the fibers have a lobate-like cross-section.

7. The filter assembly according to claim 1 or 2, characterized in that: Each of the pre-filtration support layer (84), the first mesh filter layer (85) and the second mesh filter layer (86) has at least two regions of different pore sizes or mesh sizes with different filtration capabilities.

8. The filter assembly according to claim 1 or 2, characterized in that: The pre-filter support layer (84), the first mesh filter layer (85) and the second mesh filter layer (86) extend in a vertical extension direction and in a horizontal extension direction, wherein the vertical extension direction is vertically aligned during normal operation of the filter assembly, and the horizontal extension direction is horizontally aligned during normal operation of the filter assembly, wherein at least one of the nonwoven fabric of the pre-filter support layer (84), the first mesh filter layer (85) and the second mesh filter layer (86) has a first area (87) in a first height in the vertical extension direction and a second area (88) in a second height in the vertical extension direction, wherein the first area (87) and the second area (88) have different mesh sizes and exhibit different filtering capabilities.

9. The filter assembly according to claim 8, characterized in that The first region (87) and / or the second region (88) extend along the entire horizontal extension direction.

10. The filter assembly according to any one of claims 1 to 2 and 9, characterized in that: The filter assembly does not contain a defoaming agent.

11. The filter assembly according to claim 6, characterized in that At least a portion of the fibers have a trilobal cross-section.

12. The filter assembly according to claim 7, characterized in that Each of the pre-filtration support layer (84), the first mesh filter layer (85) and the second mesh filter layer (86) has at least three regions of different pore sizes or mesh sizes with different filtration capabilities.

13. Use of a filter assembly according to any one of claims 1 to 12 for filtering body fluids in vitro.

14. The use according to claim 13, characterized in that The body fluid is blood.

15. A method for manufacturing a filter assembly according to any one of claims 1 to 12, the filter assembly (6) comprising a filter holder (7), a first mesh filter layer (85) and a pre-filter support layer (84), wherein: The pre-filter support layer (84) comprises a non-woven fabric of fibers, the non-woven fabric having a first mesh size, wherein the filter holder (7) is arranged downstream of the first mesh filter layer (85), wherein the first mesh filter layer (85) is arranged downstream of the pre-filter support layer (84), wherein the first mesh filter layer (85) has a second mesh size, wherein the first mesh size is equal to or larger than the second mesh size, Characterized in that the filter holder (7) is overmolded on a portion of the pre-filter support layer (84) and a portion of the first mesh filter layer (85) so that the filter holder (7) contacts and stabilizes both the pre-filter support layer (84) and the first mesh filter layer (85).

16. The method according to claim 15, characterized in that The first mesh filter layer (85) and the pre-filter support layer (84) are manufactured in the shape of a flat strip (80), which then forms the desired shape of the filter assembly (6), wherein the desired shape is fixed by partially overmolding the pre-filter support layer (84) and the first mesh filter layer (85) with the filter holder (7).

17. A container for collecting body fluids, the container comprising: A container housing (2), the container housing (2) having a body fluid inlet (4), through which body fluid can enter an inlet portion (5) of the container housing (2); a body fluid collecting portion (9); a vacuum connector (10), the vacuum connector (10) being used to connect a vacuum source to the container housing (2) for applying a low pressure to the inlet portion (5) and the body fluid collecting portion (9); and a filter assembly (6) arranged between the inlet portion (5) and the body fluid collection portion (9), wherein the filter assembly (6) has a pristine side and a clean side, wherein the pristine side faces the inlet portion (5) and the clean side faces the body fluid collection portion (9), Characterized in that the filter assembly (6) is a filter assembly according to any one of claims 1 to 12.

18. The container for collecting body fluids according to claim 17, characterized in that: The container housing (2) further comprises a hydrophobic filter (11), which is arranged between the body fluid collection part (9) and the vacuum connector (10) along the flow direction of air sucked from the body fluid collection part (9) by the vacuum source during the intended use of the container.

19. The container according to claim 17 or 18, characterized in that The filter holder (7) is integrally formed with the top cover (3) of the container housing (2).

20. The container according to claim 19, characterized in that The filter holder (7) comprises a rod for stabilizing a mesh filter (8) which is arranged inside a space of the filter holder (7) surrounded by the rod.

21. The container according to any one of claims 17 to 18 and 20, characterized in that The inlet area (15) of the filter assembly (6) is funnel-shaped.

22. The container according to any one of claims 17 to 18 and 20, characterized in that The bottom (13) of the filter assembly (6) comprises a recess toward the interior space of the filter assembly (6).

23. The container according to claim 18, characterized in that The hydrophobic filter (11) is integrated into the top cover (3) of the container housing (2).

24. The container according to claim 18 or 23, characterized in that The hydrophobic filter (11) comprises a pleated filter material.

25. The container according to claim 24, characterized in that The pleated filter material has a filtering surface area which is at least three times higher than the surface area of ​​the filter element accommodating the hydrophobic filter (11).

26. A method for manufacturing a container according to any one of claims 17 to 25, characterized in that A top cover (3) of a container housing (2) of the container (1) and a filter holder (7) of the container (1) are co-molded so as to be produced in one piece.

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