Syringe for obtaining the target volume of blood

Abstract

A syringe for obtaining a target volume of blood is proposed. The syringe (1) comprises a syringe (2), wherein a plunger (4) is arranged in the syringe (2) and can be displaced along a displacement direction (X). In addition, the syringe (2) and the plunger (4) together provide a first stopper (20) and a second stopper (22), wherein the first stopper (20) is configured to position a filter (100) at a predetermined position along the displacement direction (X), thereby defining a target volume of blood and a buffer volume. In addition, the second stopper (22) is configured to prevent the plunger (4) from discharging more than the buffer volume from the syringe (1) when the plunger (4) is pushed toward the distal end (30) of the syringe (1) along the displacement direction (X) to obtain the target volume of blood. In addition, the syringe (1) facilitates the syringe (1) to fill itself with the target volume of blood by a self-filling procedure using blood under pressure (such as arterial blood) and using a filter (100) located in the plunger (4).

Description

Technical Field

[0001] The present invention relates to a syringe. In particular, the present invention relates to a syringe for obtaining a target volume of blood from a patient and for easily discharging a sample, i.e., the obtained target volume of blood, by only pushing a plunger for a short time, and to a method for filling a syringe with a target volume of blood and for easily discharging a sample, and to a package including a syringe. Such a syringe may include a mechanism for obtaining a target volume of blood, in particular a volume sufficient for blood gas detection. Background Art

[0002] Patient blood management focuses on improving patient care by managing the handling of blood, including the appropriate use of blood during patient care and assessment. However, for most users of syringes, obtaining a blood sample is a trivial task and only a small amount of blood is required, so the amount of blood sample is not a priority for the user, although it is an hourly task for some patients. Especially for blood gas testing, the amount of blood required is very small, so the user needs to handle the syringe very carefully. The inventors of the present invention recognized the need to provide accurate blood acquisition with a syringe. Summary of the invention

[0003] It can be seen that an object of the present invention is to provide an improved syringe, in particular to improve the ergonomics of drawing blood and to increase the safety of syringe operation.

[0004] This problem is solved by a syringe according to claim 1. Further embodiments and advantages of the invention are contained in the dependent claims and the description.

[0005] Technical terms are used according to their common sense. If specific meanings are conveyed to certain terms, the definitions of the terms are given below, in the context in which these terms are used.

[0006] According to a first aspect of the present invention, a syringe for obtaining a target volume of blood is provided. The syringe comprises a syringe, wherein a plunger is arranged in the syringe to be displaced along a displacement direction, and wherein the syringe and the plunger together provide a first stopper and a second stopper. The first stopper is configured to position a filter at a predetermined position along the displacement direction, thereby defining a target volume of blood and a buffer volume of blood. The second stopper is configured to prevent the plunger from discharging a buffer volume of blood more than the target volume when the plunger is pushed toward the distal end of the syringe along the displacement direction. In addition, the plunger comprises a filter, wherein the filter is configured to be gas permeable when the filter is not in contact with blood, and the filter is configured to become gas and fluid impermeable when in contact with blood. In addition, when the filter is gas impermeable, the plunger is fluid-tightly sealed, and the plunger is configured to guide air out of the syringe and through the filter toward the outside of the syringe during the self-filling process of the syringe until the blood contacts the filter, and then the filter becomes gas impermeable and liquid impermeable.

[0007] The advantageous use of this syringe will be briefly summarized below.When the self-filling process begins, the plunger of the syringe is preferably set to the first stopper by the user, and the target volume of blood including the blood of the buffer volume will be obtained at this first stopper.The blood entering is pushed into the compartment formed by the plunger and syringe combination until the compartment is filled, because the blood contacts the filter at this time, and then changes its gas and liquid permeability, so now prevents gas from passing through the filter.No gas can leave or enter the syringe through the plunger and its filter.Then, the user can release the syringe from the attachment to the patient's blood vessel, and can close / seal the tip of the syringe with, for example, a cap or a ventilation (ventilation) tip cap.This ventilation tip cap is known to the technician, and there is an exemplary description in the applicant's European patent application EP 1 549 385.Therefore, in a preferred embodiment, the syringe includes a ventilation tip cap.When sealing the tip with, for example, a ventilation tip cap, air cannot enter the syringe from the tip.However, the syringe of the present invention allows easy ventilation of the sample, and only needs to push the plunger in a short time. This push moves the plunger from the first stopper to the second stopper, and after the syringe is released from being attached to the blood vessel, the blood of the buffer volume and any air present in the syringe are pushed out of the syringe and enter the vent cap. In particular, the buffer volume can include blood, air or any other fluid. The size of the buffer volume is selected so that after the buffer volume is removed from the syringe by the vent tip cap of the syringe, the blood of the target volume may be in the syringe. In this way, the "loose" air still in the syringe after the self-filling process is completed can be pushed out by the tip of the syringe. If the vent tip cap is installed on the tip, the loose air can be squeezed through the vent tip cap by the user with the plunger. Because the movement of the plunger is subsequently blocked by the second stopper, the position of the stopper can be used to limit the blood volume contained in the compartment. Therefore, the first stopper sets the volume before the exhaust, and the second stopper sets the volume after the exhaust, i.e. the target volume of blood.

[0008] In other words, the plunger is used to obtain the target volume (see FIG. 1 ) together with the filter at the first stop, ie the stop closer to the distal end 30 of the syringe. Figure 1 ). The plunger is used to vent the syringe so that the entire syringe from the filter to the syringe tip is filled with blood. This is performed because you need to get any "loose" air out of the blood volume into the syringe prior to transport and subsequent analysis. The tip of the syringe is sealed by a cap, or preferably a vented tip cap that allows air to be vented out. This will be clarified and explained below in the context of embodiments of the present invention.

[0009] Typically, the movement or displacement between the barrel and the plunger is interrupted by a first and / or second stop. The first stop limits the displacement between the plunger and the barrel, thereby creating a certain volume in the syringe so that the target volume of blood (including the buffer volume of blood) can be pressed into the syringe. Figure 1 and its description hereinafter. The syringe of the present invention provides the particular advantage that only the required amount of blood is drawn from the patient. Thus, by drawing only the required amount of blood, no unnecessary stress is placed on the patient. Furthermore, the first stop may be arranged to define a target volume of blood (including a buffer volume of blood) which is sufficient to perform a blood gas test with the target volume of blood. Preferably, the target volume of blood and the position of the first stop may be defined according to a specific blood gas test. Furthermore, the movement and / or displacement between the plunger and the syringe may be interrupted by a second stop which is particularly configured to prevent the plunger from discharging blood when pushed in the displacement direction, which is also referred to Figure 1 The first stopper and the second stopper are understood as elements that provide a stop function of the plunger in the displacement direction, which will be explained in more detail in the context of specific embodiments below.

[0010] As will become apparent and elucidated from the following explanation, the syringe of the present invention facilitates the filling of the syringe itself with a target volume of blood and a buffer volume of blood by a self-filling procedure using blood under pressure (such as arterial blood) and using a filter located at or in the plunger. In addition, the present invention facilitates easy aeration of the sample, i.e., the target volume of blood can be obtained by only pushing the plunger for a short time. This will be described in more detail below.

[0011] In detail, the plunger comprises, has and / or is combined with a filter, i.e. a filter element and / or component having a filtering and / or blocking function. Depending on whether the filter is in mechanical contact with the blood, the filter has the function of changing its gas permeability, in particular air permeability. In other words, when the filter is not in contact with the blood, i.e. before using the syringe of the present invention, the filter is gas permeable, and when the filter comes into contact with the patient's blood during use of the syringe by the user, the filter becomes gas-impermeable, preferably air-impermeable. Therefore, placing the filter in a position selected by the manufacturer / user of the syringe allows obtaining the desired target volume of blood even during the self-filling process of the syringe as described herein.

[0012] The term "filter" should be interpreted broadly in the context of the present invention, such that any component that is constructed to allow gas (preferably air) to pass when not in contact with blood (i.e., is gas permeable) and is constructed to block gas when in contact with blood (i.e., becomes gas impermeable) should qualify as a filter of the syringe of the present invention.

[0013] When the filter is gas impermeable, the plunger is fluid-tightly sealed. In other words, when the filter is in its gas impermeable state, then the plunger seals the enclosed volume of the barrel / syringe in a fluid-tight, preferably blood-tight, manner from the rest of the syringe, which extends from the barrel to the opening of the syringe into which the plunger is introduced. This can be seen, for example, in Figure 1 and 2 This can be clearly seen in the examples.

[0014] In addition, the plunger is configured to direct air out of the syringe and through the filter toward the exterior of the syringe during the self-filling process of the syringe. Thus, in this state, the plunger provides a fluid connection between the syringe and the filter and between the filter and the exterior of the syringe (i.e., the surrounding atmosphere). In this state, air can flow from the syringe through the plunger, through the filter, and then be directed by the passageway outside the syringe. The air passageway inside the plunger can be an exemplary mechanical structure for this function, such as Figure 1 and 2 The above is exemplarily described in the embodiments of the present invention.

[0015] In other words, the syringe is a self-filling syringe, which can be used to obtain blood from a patient. Thus, the syringe can be attached to an arterial vessel of the patient. The blood in the arterial vessel is under pressure; therefore, it is sufficient to simply attach the syringe to the patient, without having to actively draw blood from the patient with negative pressure. During this self-filling process of the syringe, the plunger allows / facilitates the transfer of air from the barrel of the syringe through the plunger and the filter of the plunger out of the syringe. Since blood enters the barrel of the syringe during such a process, the air previously present in said part of the barrel must be transferred out of the syringe. The plunger of the syringe of the present invention provides this functionality by means of, for example, a channel and a filter. This functionality will be explained in more detail below and can be seen, for example Figure 1 and 2 collected in the embodiments.

[0016] Thus, such a syringe is configured to automatically fill with a predetermined volume of blood (i.e., a target volume of blood including a buffer volume of blood) without requiring the user to pull back or withdraw the plunger. Thus, use of such a syringe during a self-filling process will result in a stoppage of further blood flow into the syringe when the desired volume is reached because at this point in time the filter in or at the plunger becomes impermeable to gas / air / fluid and no further blood can enter the syringe.

[0017] The first stop, the second stop and the filter are selected / positioned on the syringe so that when the plunger reaches the first stop during the self-filling process of the syringe, the filter target volume of blood has been received by the syringe barrel and the filter is in contact with the blood. In this way, it is ensured that the filter changes its fluid permeability at the time / state when the target volume of blood has been received. No more air / blood can pass through the filter, and after the syringe is removed from, for example, the patient's arterial blood vessel, when a cap is provided thereon in the syringe, the received blood can be safely stored after discharge.

[0018] In addition, when the filter is not in contact with blood, i.e. in its initial state or condition, when it is sold to the user, the filter is configured to change, alter and / or adjust the plunger to be gas-permeable, open and / or permeable. In addition, the filter is configured to change, alter and / or adjust the plunger to be fluid-tightly sealed when the filter has been in contact with blood and has therefore closed its permeability to fluids and gases, preferably at least to air. Therefore, to a certain extent, when the plunger is gas-permeable, the plunger is configured to provide and / or establish a self-filling effect of the syringe. When blood under pressure (such as arterial blood) contacts the distal opening of the syringe, the blood is transported into the syringe of the syringe. In addition, when the filter is fluid-tightly sealed, i.e. when the filter of the syringe / plunger is in contact with blood and is therefore impermeable to blood and / or air, the filter is configured to seal the syringe respectively to prevent blood from passing through the filter.

[0019] As mentioned above, the syringe can be regarded as a self-filling syringe, which can be used to obtain blood from a patient. Therefore, the syringe can be attached to the patient's arterial blood vessel. The blood in the arterial blood vessel is under pressure; therefore, it is sufficient to simply attach the syringe to the patient, without the need for, for example, the user to extract blood from the patient's body with negative pressure. The pressurized blood flows into the syringe, so that the air in the syringe needs an outlet. In the case of removing the syringe from the arterial blood vessel, the plunger needs to be sealed, otherwise the blood will flow out of the syringe. Therefore, the filter as mentioned above is located at and / or inside the plunger. As long as the filter is not in contact with the blood, the air can pass through the filter, thereby providing an outlet for the air and allowing the blood to be pressed into the syringe. However, when the syringe is removed from the arterial blood vessel, the plunger needs to be sealed so that the blood contained in the syringe cannot leave the syringe. In order to seal the syringe with the plunger, the filter becomes airtight when the target volume of blood is in the syringe. With the help of the first and second stoppers, the plunger can be positioned, and thus the filter can be positioned so that only the required amount of blood is obtained. This not only increases the safety and reliability of the blood removal process at the point of care, but also allows the syringe to be easily handled during the blood removal process and safely and easily transported to a post-system, particularly a pneumatic one. This can be done after the sample has been properly expelled and when the syringe is provided with a cap on the tip.

[0020] The syringe described here can preferably be an extruded or injection molded body made of plastic or plastic composite material, which has a generally circular cross-section. In the syringe, the plunger is positioned so that it can also preferably be made of plastic or plastic compound. A portion of the plunger is configured to be manipulated by the user of the syringe. At the other end of the plunger, rubber can be foreseen, which is configured to create a fluid and / or gas tight seal between the plunger and the syringe. In addition, the plunger is located in the syringe so that the plunger can move along the extrusion portion of the syringe. The plunger moves in the syringe in a displacement direction, which is determined by the geometry of the syringe.

[0021] According to an exemplary embodiment of the present invention, the plunger includes a channel, and the filter is at least partially located in the channel. The channel is configured to guide air out of the syringe and through the filter toward the exterior of the syringe during the self-filling process of the syringe.

[0022] In other words, the channel provides a gas connection between the syringe and the filter and between the filter and the outside of the syringe, i.e., the surrounding atmosphere. Air can flow from the syringe through the channel, the filter, and then be guided by the channel outside the syringe. Detailed embodiments of such a plunger are described in Figure 1 and 2 Shown in.

[0023] According to an exemplary embodiment of the present invention, the syringe comprises a proximal end, a first opening for introducing the plunger into the syringe is located at the proximal end, and the syringe comprises a distal end, a second opening for receiving a target volume of blood is located at the distal end. In addition, the second stop is positioned closer to the first opening than the first stop.

[0024] According to an exemplary embodiment of the present invention, the channel has a first hole at the proximal end of the plunger, and the channel has a second hole at the distal end of the plunger. The filter is at least partially located within the channel and between the first hole and the second hole of the channel.

[0025] According to another exemplary embodiment, the filter is configured to allow gas to pass through the channel of the plunger when the filter is gas permeable (i.e., when it is not in contact with blood), and the filter is configured to seal the channel of the plunger in a fluid-tight manner, i.e., when the filter is gas impermeable, gas and fluid-tightly seal the channel of the plunger.

[0026] In other words, the plunger seals the syringe fluid-tightly at the inner surface of the syringe, for example using a piston including a sealing element, such as in Figure 1 However, in the part of the plunger where the channel and filter are located (see for example Figure 1 and 2 ), the sealing functionality of the plunger depends on whether the filter is in contact with blood. In the case where the syringe is currently filled with blood but the filter has not yet come into contact with the blood, only air is ventilated / guided through the filter, and the filter has and maintains its functionality of allowing air to pass through. However, when the blood reaches the filter, the filter changes its permeability and prevents further passage of gas / air / fluid through the filter. Therefore, due to the position of the filter relative to the rest of the syringe, a target volume of blood (including a buffer volume of blood) can be obtained without the user intervening in the process of stopping the flow of blood into the syringe. Because the plunger now also prevents the fluid / blood from flowing out of the syringe at the part of the plunger where the filter and the channel are located (because the filter does not allow blood to pass through), in this case, the plunger completely seals the syringe in a fluid-tight manner. Therefore, when the filter is gas-impermeable, the filter is configured to seal the channel of the plunger in a fluid-tight manner.

[0027] According to an exemplary embodiment of the present invention, the first stopper is configured for positioning the filter at a predetermined position along the displacement direction to define a target volume of blood including a buffer volume.

[0028] As described above, due to the position of the filter relative to the rest of the syringe, the target volume of blood required by the user / manufacturer can be obtained without the user intervening in the process of stopping the flow of blood into the syringe. When the filter changes its permeability, the flow of blood into the syringe is automatically stopped.

[0029] According to an exemplary embodiment of the present invention, the syringe includes a vent tip cap on the syringe tip. The vent tip cap is configured to prevent air from entering the syringe through the tip, and the vent tip cap is configured to allow air to be pushed out of the syringe from the interior of the syringe, particularly the syringe barrel, through the vent tip cap when the plunger moves from the first stopper to the second stopper.

[0030] According to an exemplary embodiment of the present invention, the syringe comprises a proximal end, at which a first opening for introducing a plunger into the syringe is located. The syringe comprises a distal end, at which a second opening for drawing a target volume of blood into the syringe is located. In addition, the second stop is positioned closer to the first opening than the first stop.

[0031] The first opening is preferably located on one side of the syringe, wherein the diameter of the first opening is preferably the same as the diameter of the entire syringe. Therefore, the plunger can be more easily inserted into the syringe, which facilitates the assembly of the syringe and the plunger. In addition, the syringe preferably includes a distal end, and the second opening is located at the distal end, wherein the diameter of the second opening is preferably smaller than the diameter of the syringe. At the second opening, blood can flow into the syringe. For example, an inlet can be inserted into a patient's body, and the second opening can be attached to the inlet, so that blood can be obtained from the patient's body. In addition, the second stopper is positioned closer to the first opening than the first stopper. With this construction, it can be ensured that only the required amount of blood is obtained from the patient's body, because the filter is positioned depending on the position of the first stopper. This can be easily seen from Figure 1 Furthermore, after the plunger has been pushed from the first stopper to the second stopper, a target volume of blood is obtained through the second stopper, thereby expelling a buffer volume of blood and air that may be present in the syringe before sample ventilation.

[0032] According to another exemplary embodiment of the present invention, the plunger includes a channel. The channel has a first hole pointing to the first opening of the syringe. The channel has a second hole pointing to the second opening of the syringe. A filter is at least partially located in the channel and between the first hole and the second hole. The filter is configured to discharge fluid through the channel of the plunger when the filter is in a first state. The filter is configured to seal the channel of the plunger in a fluid-tight manner when the filter is in a second state.

[0033] In other words, the plunger includes, has and / or forms a channel, a conduit and / or a pipeline. The channel has, includes and / or forms a first hole, which is pointed to and / or positioned to open toward the first opening of the syringe. In addition, the channel has, includes and / or forms a second hole and / or opening that is pointed to and / or toward the second opening of the syringe. In addition, the filter is at least partially located and / or oriented inside the channel and / or in the channel, and is located between the first hole and the second hole. The filter may include a first side facing the first hole and a second side facing the second hole, wherein the filter is configured to block any fluid between the first side and the second side of the filter when the filter is in contact with blood and / or soaked by blood. In addition, the filter is configured to, when the filter is gas permeable, be used to allow air to pass through the channel of the plunger for ventilation. In addition, the filter is configured to, when the filter is in a second state, that is, when the filter is gas impermeable, be used to seal and / or lock the channel of the plunger, respectively, fluid-tight and impermeable.

[0034] In an exemplary embodiment, the plunger includes a channel extending through the plunger, in particular along the displacement direction. When the syringe is attached to the arterial blood vessel and blood is pressed into the syringe, the channel expels air from the volume formed by the plunger in the syringe. Once the syringe is filled with the target volume of blood, the filter is positioned in the syringe so that the filter is completely covered and / or saturated with blood, thereby sealing the channel of the syringe. Therefore, no more blood can leave the syringe, and the blood can be safely delivered, in particular in a pneumatic column system.

[0035] According to another exemplary embodiment of the present invention, the first and / or second stopper defines a stop function along the displacement direction. This stop function is produced by form fit, friction fit and / or adhesion between the plunger and the syringe.

[0036] Preferably, the first and second stops comprise projections on the plunger and the syringe, thereby producing a form fit to achieve the stop function. Alternatively, the stop function can be produced by friction fit, wherein the diameter of the syringe is reduced at the position of the first and / or second stop, thereby producing the stop function. Alternatively, the stop function can be produced by adhesion force by changing the surface of the syringe and the plunger at the first and second stops, thereby increasing the adhesion force at the first and second stops. The advantage of form fit is that it ensures easy assembly and provides tactile feedback to the user of the syringe when the user overextends the displacement between the plunger and the syringe. The advantage of friction fit is that the material of the syringe and the plunger can be adapted to produce a restriction along the displacement direction. The specific advantage of adhesion is that less space is required.

[0037] According to a further exemplary embodiment of the invention, the stop function is configured to be exceeded by applying a force in the displacement direction, in particular a force between 2 N and 100 N.

[0038] Preferably, the stop function is thereby configured to generate a force that is large enough so that it blocks a force applied by a user of the syringe, thereby generating the stop function. Preferably, the stop function can be overcome by the user of the syringe by applying a force, in particular greater than 2N to 100N. An advantage of a smaller force, in particular a force between 2N and 30N, is that the assembly of the plunger into the syringe is easier to handle. An advantage of a larger force, in particular a force between 40N and 100N, is that the user of the syringe cannot accidentally overcome the first stop and thus cannot draw too much blood from the patient. An advantage of this embodiment is that the assembly between the plunger and the syringe is simplified and that it is not possible to accidentally overcome the stop function.

[0039] According to another exemplary embodiment of the present invention, the syringe comprises a second protrusion located on the inner surface of the syringe. The plunger comprises a first protrusion and a third protrusion, which are in particular on the surface of the plunger. Therefore, the second protrusion of the syringe and the first protrusion of the plunger together form a first stop.

[0040] Two protrusions are located on the surface of the plunger, wherein the first protrusion forms part of the first stop and the third protrusion forms part of the second stop. In addition, the syringe includes a second protrusion on its inner surface, which combines with the first protrusion of the plunger to form the first stop. The protrusions on the surface of the plunger and on the surface of the syringe are preferably ridges or protrusions, or optionally depressions or recesses. The technical advantage of this embodiment is that by foreseeing the first and second protrusions on the surface, only small modifications to the plunger are required to achieve the first and / or second stop, which leads to increased safety in obtaining blood.

[0041] In other words, the syringe includes a second protrusion on its inner surface to form a part of the first stop. In addition, the plunger includes a third protrusion, whereby the third protrusion is configured to form a part of the second stop. Preferably, the first, second and / or third protrusions are formed by ridges or protrusions extending from the surface of the syringe and / or plunger, or alternatively by depressions or recesses to form the first and / or second stops. The technical advantage of this embodiment is that the first and / or second stops can be produced by only minor modifications to the molds of the syringe and plunger, thereby providing an inexpensive and cost-effective way to produce a plunger and syringe that form the first and / or second stops.

[0042] According to another exemplary embodiment of the invention, the first and / or third protrusions of the plunger are each formed by a first, second and third diameter of the plunger, each diameter being located along the displacement direction. The second diameter is smaller and / or larger than the first and third diameters.

[0043] The plunger locally includes a first, second and third diameter so that a protrusion can be formed. In the case where the second diameter is greater than the first and third diameters, a bulge or protuberance is formed to provide the first and / or second protrusion. Alternatively, the second diameter is less than the first and third diameters so that the first and / or second protrusion is formed by a depression and / or recess. The technical advantage of this embodiment is that by implementing the parameters of the first, second and third diameters, the plunger can be adjusted to a variety of different syringes.

[0044] According to another exemplary embodiment of the present invention, the second protrusion of the needle cylinder is formed by the first, second and third diameters of the needle cylinder, each diameter being positioned along the displacement direction. In addition, the second diameter is smaller and / or larger than the first and third diameters.

[0045] The second protrusion of the syringe is formed by the local first, second and third diameters. In the case where the second diameter is smaller than the first and third diameters, the second protrusion is configured as a ridge protruding from the inner surface of the syringe. Alternatively, the second diameter is larger than the first and third diameters, thereby forming the first and / or second protrusion of the plunger as a recess or depression. The advantage of this embodiment is that by implementing the parameters of the first, second and third diameters, the syringe can be adjusted to multiple types of syringes. Figure 1 and Figure 2 An exemplary embodiment is shown and explained in the corresponding description.

[0046] According to another exemplary embodiment of the present invention, the first, second and / or third protrusions extend along a vertical direction, which is substantially orthogonal to the displacement direction. In addition, the first and / or third protrusions form a plane substantially orthogonal to the displacement direction, wherein the plane is configured to seal the syringe at least partially fluid-tight along the displacement direction.

[0047] In this context, by orthogonal is meant that the angle between the vertical direction and the displacement direction may vary between ±15°. In other words, the first, second and / or third protrusions extend parallel to the vertical direction. This embodiment comprises a rounding between the displacement direction and the vertical direction which is arranged on the surface of the syringe and / or on the surface of the plunger in combination with the first, second and / or third protrusions. Furthermore, the first and third protrusions form a plane which is in particular parallel to the vertical direction, wherein the plane additionally seals the syringe along the displacement direction and in particular seals the syringe in a fluid-tight manner along the displacement direction. An advantage of this embodiment is that by the orientation of the first and third protrusions a fluid-tight seal may be provided, whereby the impermeability or leakage tightness of the syringe may be improved. This may be achieved in particular in the embodiment of the present invention. Figure 1 and Figure 2 and described in the description of each figure.

[0048] According to another exemplary embodiment of the present invention, the inner surface of the barrel has an at least substantially constant diameter along the displacement direction.Thus, the barrel is configured to store liquid, wherein the first, second and / or third protrusion extends continuously around the barrel and / or the plunger.

[0049] In other words, except for the second protrusion, the diameter of the needle barrel is set to a value. The first, second and / or third protrusions extend continuously around the surface of the needle barrel and / or the surface of the plunger, thereby forming circumferential contact points. The advantage of this embodiment is that the stop function is achieved by means of the circumferential contact points, thereby generating a uniform force on the plunger, thereby improving the feeling of the stop function. This can be achieved in Figure 1 Seen in Figure 1 is described in the description of .

[0050] According to another exemplary embodiment of the present invention, the inner surface of the syringe forms a cone, in particular at the first opening of the syringe, which cone extends radially around the displacement direction. In addition, when the plunger is inserted into the syringe, the cone is configured to orient the plunger into the inner contour. The cone also forms part of the second stop together with the third protrusion of the plunger.

[0051] Preferably, the syringe forms a cone at the first opening, by means of which the plunger can be more easily inserted into the syringe. In addition, the user of the syringe can more easily grasp the cone, which increases the ergonomics of the syringe.

[0052] According to another exemplary embodiment of the present invention, the first stopper is located in the syringe so that the volume drawn into the syringe corresponds to the target volume and the buffer volume. The buffer volume is equivalent to 0.2 to 0.3 milliliters (mL) and is used when aerating the blood sample to obtain an air-free sample and the target volume.

[0053] The first stop is positioned so that when the plunger is displaced from the second opening of the syringe, blood is drawn into the syringe, the first stop forming a volume including a target volume of blood, in particular between 0.3 and 5 ml, and a buffer volume corresponding to 0.2 to 0.3 ml. This embodiment has the advantage that only the amount of blood required for blood gas detection is drawn, including a small safety in the form of a buffer volume so that the gas in the syringe can be discharged from the syringe without obtaining a too small amount of blood.

[0054] According to another exemplary embodiment of the present invention, the target volume is between 0.3 ml and 5 ml.

[0055] In other words, the syringe is capable of withdrawing 0.3 ml to 5 ml of blood.In a preferred embodiment, the target volume is between 0.5 and 2 ml, which has the beneficial effect that the operator of the syringe can monitor the volume more easily.

[0056] According to a further exemplary embodiment of the invention, the needle cylinder has an at least partially constant diameter, wherein the ratio between the diameter and the maximum displacement length along the displacement direction is between 1:1.5 and 1:8.

[0057] Advantageously, the ratio between the length of the inner volume of the syringe and the diameter of the barrel is between 1:1.5 and 1:8. This ratio has the particular advantage that the use of the syringe is simplified for the operator of the syringe, since it ensures precise handling of the syringe, since the barrel of the syringe can be easily grasped, thus ensuring safe handling. A preferred ratio is between 1:2 and 1:6. This ratio has the surprising effect that a minimum of space is required for the syringe and the operator of the syringe has a great tactile feedback.

[0058] According to another aspect of the present invention, a method for filling a syringe with a target volume of blood is provided. The method comprises the step of providing a syringe, wherein a plunger is disposed in a syringe barrel and can be displaced along a displacement direction. In addition, the plunger comprises a filter. In addition, the syringe barrel and the plunger together provide a first stopper and a second stopper. The first stopper is configured to position the filter at a predetermined position along the displacement direction, thereby defining the target volume of blood and a buffer volume. In addition, the second stopper is configured to prevent the plunger from discharging a buffer volume greater than the blood used to obtain the target volume when pushed toward the distal end of the syringe along the displacement direction.

[0059] The method further comprises the step of directing blood into the syringe, thereby causing air to move out of the syringe barrel through the filter of the plunger to the outside of the syringe as long as the filter is not in contact with the blood. As a further step of bringing the blood into contact with the filter, the permeability of the filter is thereby changed from being permeable to gases when the filter is not in contact with the blood to being impermeable to gases when in contact with the blood. Furthermore, the step of sealing the plunger fluid-tightly by changing the permeability of the filter to be impermeable to gases is included as a method step in this aspect of the invention.

[0060] As has been described above and as will be explained below, the syringe and method of the present invention facilitate the syringe to fill itself with a target volume of blood by a self-filling procedure using blood under pressure (such as arterial blood) and using a filter located at or in the plunger. The blood in the arterial vessels is under pressure; therefore, it is sufficient to simply attach the syringe to the patient, without having to actively draw blood from the patient with negative pressure. During this self-filling process of the syringe, the plunger allows / facilitates the transfer of air from the syringe's barrel through the plunger and the plunger's filter out of the syringe. Since blood enters the syringe's barrel during such a process, the air previously present in said portion of the barrel must be transferred out of the syringe. The plunger of the syringe of the present invention provides this function by, for example, a channel and a filter. This function will be explained in more detail below and can be seen, for example, from Figure 1 and 2 collected in the embodiments.

[0061] It is clear to the reader skilled in the art that the aspects and embodiments described above with respect to the syringe are equally applicable to the method, as long as nothing to the contrary is explicitly stated herein.

[0062] According to another embodiment of the invention, the method further comprises pushing air out of the syringe from the interior of the syringe, in particular the barrel, through the tip of the syringe, preferably through the vent tip cap, and out of the syringe by moving the plunger from the first stopper to the second stopper.

[0063] According to another aspect of the present invention, there is provided a package comprising a syringe as described herein, wherein the plunger is located at the first stop.

[0064] According to another aspect of the present invention, as described above and below, a syringe is used to obtain blood. In other words, the syringe can be used to collect blood, especially whole blood, from a human or animal, especially for testing, such as blood gas analysis.

[0065] These and other features of the invention will become apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 A cross-sectional view of a syringe according to a first embodiment is shown.

[0067] Figure 2 A cross-sectional view of a syringe according to a second embodiment is shown.

[0068] Figure 3 A flow chart illustrating the steps of a method according to an embodiment is shown.

[0069] Figure 4 A flow chart illustrating the steps of a method according to an embodiment is shown.

[0070] The reference numerals used in the drawings and their meanings are listed in summary form in the reference numeral list. In principle, in the drawings, identical components are provided with identical reference numerals. DETAILED DESCRIPTION

[0071] Figure 1 The syringe 1 of the present invention is shown. The syringe 1 includes a plunger 4. Due to the geometric extension of the plunger 4 relative to the syringe 2, the plunger 4 ensures that the minimum amount and / or recommended amount of blood is obtained by the syringe 1, and since the second stopper 22 limits the displacement of the plunger 4 toward the distal end 30, the push length of the plunger 4 is minimized and / or limited, so the plunger 4 is easy to use. The plunger 4 includes an extension length 152 that is shorter than the extension length 150 of the syringe. In other words, the syringe 2 includes a first extension length 150, and the plunger 4 includes a second extension length 152. The second extension length 152 is shorter than the first extension length 150. When the plunger 4 is pushed from the first stopper 20 to the second stopper 22, the venting of the syringe is performed, preferably, the venting tip cap 200 is attached to the distal end 30. Since the plunger 4 is shorter, the required pushing force is smaller / shorter, which makes it easy to use the syringe 1. The syringe 1 includes a syringe 2 and a plunger 4, and the plunger 4 is arranged in the syringe 2 to be displaced along the displacement direction x. The syringe 2 and the plunger 4 together provide a first stop 20 and a second stop 22. The first stop 20 is configured to position the filter 100 at a predetermined position along the displacement direction X to define a target volume and a buffer volume of blood. The second stop 22 is configured to prevent the plunger 4 from discharging a buffer volume of blood that is greater than the target volume when pushed toward the distal end 30 of the syringe in the direction of the displacement direction X. This results in the syringe 1 being able to obtain only the required amount of blood, for example for blood gas testing, thereby reducing stress on the patient. In addition, the first stop 20 within the syringe 1 improves the operation of the syringe 1 because the first stop 20 generates tactile feedback when the required amount of blood is obtained.

[0072] The plunger 4 comprises a channel 102 extending through the plunger 4 along the displacement direction X. The plunger 4 further comprises a seal 104 which seals the surface of the plunger 4 against the inner surface of the syringe 2. With the help of the seal 104, the only way for air is through the channel 102 and the filter 100 of the plunger. The filter 100 is located inside the channel 102. When the filter 100 is not in contact with blood, the filter 100 is gas permeable, and when the filter 100 is in contact with blood, the filter 100 is fluid-tightly sealed. The channel 102 comprises a first hole 130, which may comprise a handpiece for manipulating the plunger 4. Furthermore, the channel 102 comprises a second hole 132, which is located inside the syringe 2. In particular, air flows from the second hole 132 to the first hole 130 so that blood can be obtained in the syringe 2.

[0073] Figure 1 The syringe 1 is a preferred embodiment, wherein the plunger 4 includes a first protrusion 10 of the plunger 4 and a third protrusion 6 of the plunger 4. In addition, the syringe 2 includes a second protrusion 5. The first protrusion 10 of the plunger 4 and the second protrusion 5 of the syringe 2 are configured to form a first stopper 20. In addition, the third protrusion 6 of the plunger 4 and a cone 24 on the inner surface of the syringe 2 located at the first opening 28 are configured to form a second stopper 22. In addition, the plunger 4 is located in the syringe 2 and can be displaced along the displacement direction X. The vertical direction Y is substantially perpendicular to the displacement direction X. The second protrusion 5 of the syringe 2, the first protrusion 10 of the plunger 4, and the third protrusion 6 of the plunger 4 all extend along the vertical direction Y in this embodiment. In addition, the first opening 28 of the syringe 2 is configured to orient the plunger 4 into the syringe 2. A cone 24 attached to the first opening 28 is provided, which supports the orientation of the plunger 4 in the syringe 2. The first opening 28 is provided at the proximal end 26 of the syringe 2. At the distal end 30 of the barrel 2, a second opening 32 is foreseen. The second opening 32 is configured to be attached to a needle, a tip cap 200 or an access port in a patient's body.

[0074] Figure 2 An embodiment of a syringe 1 is shown. The plunger 4 includes a plunger top 106 configured to hold a seal 104 so as to seal the syringe 2 fluid-tightly against the inner surface of the syringe. In addition, the plunger 4 includes a third protrusion 6, which is formed by squeezing the plunger 4. Therefore, the plunger 4 can include a handpiece that facilitates the use of the syringe 1 and a third protrusion 6 for forming a part of the second stop 22. In addition, the syringe 1 includes a vent tip cap 200. The vent tip cap 200 can be attached to the syringe 1. After the syringe 1 has been filled with blood and removed from the patient, the vent tip cap 200 is attached to the syringe. With the attachment of the vent tip cap 200, the plunger 4 is pushed toward the vent tip cap 200 until the third protrusion 6 reaches the cone 24, thereby forming the second stop 22. By this push, the vent tip cap 200 ensures that air is removed from the syringe 1 and the target amount of blood is still in the syringe 1.

[0075] Figure 3A flow chart illustrating the steps of a method according to an embodiment is shown. The method comprises the step of providing S1 a syringe, in particular a syringe as described above and below. Furthermore, the method comprises the step of directing S2 blood into the syringe 1, causing air to move from the syringe 2 through the filter 100 of the plunger 4 to the outside of the syringe 1 as long as the filter 100 is not in contact with the blood. Furthermore, the method comprises the step of causing S3 blood to come into contact with the filter 100, thereby changing the permeability of the filter 100 from being permeable to gas when the filter 100 is not in contact with the blood to being impermeable to gas when in contact with the blood. Furthermore, the method comprises the step of sealing S4 the plunger 4 in a fluid-tight manner by changing the permeability of the filter 100 to be impermeable to gas. In other words, when the plunger 4 is located at the first stop 20, the syringe 1 can be attached to the patient. The plunger 4 at the first stop 20 can form a volume inside the syringe 2, which can include a target volume of blood and a buffer volume. Blood can enter the syringe 2, and air located in the syringe 2 can be pushed out of the syringe 1 through the filter 100. When the target volume of blood and the buffer volume are inside the syringe 2, the filter 100 becomes gas impermeable.

[0076] Figure 4 A flow chart illustrating the steps of a method according to an embodiment is shown. The method includes the steps of providing S1, guiding S2, causing S3 and sealing S4 in a fluid-tight manner. In addition, the method may include the step of pushing out S5 the syringe 1 from the inside of the syringe 1, in particular the syringe 2, through the tip of the syringe 1, preferably through the vent tip cap 200 by moving the plunger 4 from the first stop 20 to the second stop 22. In other words, the vent tip cap 200 can be attached to the syringe. The vent tip cap 200 is configured to release air from the syringe 1 and to ensure that the target volume of blood is retained in the syringe 1 when the air is pushed out of the S5 syringe. By pushing the plunger 4 against the second stop 22, air can be removed from the inside of the syringe. Therefore, the volume in the syringe 2 is reduced, so that the buffer volume is removed, and only the target volume of blood is retained in the syringe 1.

[0077] When referring to a singular noun, an indefinite or definite article is used, for example "a", "an" or "the", this includes the plural form of the noun unless otherwise specifically stated. In the context of the present invention, the term "about" or "approximately" means an interval of accuracy that will be understood by a person skilled in the art to still ensure the technical effect of the feature in question. The term generally means a deviation from the indicated numerical value of ±22%, preferably ±15%, more preferably ±10%, even more preferably ±5%.

[0078] Furthermore, the terms "first", "second", "third" or "(a)", "(b)", "(c)", "(d)" or "(i)", "(ii)", "(iii)", "(iv)", etc. in the specification and claims are used to distinguish similar elements and not necessarily to describe a sequential or chronological order. It is to be understood that the terms so used are interchangeable where appropriate and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0079] Reference numerals

[0080] 1 – Syringe

[0081] 2 – Syringe

[0082] 4 – Plunger

[0083] 5 – Second protrusion

[0084] 6 – The third protrusion

[0085] 10 – First protrusion

[0086] 20 – First stop

[0087] 22 – Second stop

[0088] 24 – Cone

[0089] 26 – Proximal

[0090] 28 – First Opening

[0091] 30 – Distal

[0092] 32 – Second opening

[0093] 100 – Filter

[0094] 102 – Channel

[0095] 104 – Seals

[0096] 106 – Plunger top

[0097] 130 – First hole

[0098] 132 – Second hole

[0099] 150 – First extension length

[0100] 152 – Second extension length

[0101] 200 – Vent end cap

[0102] X – displacement direction

[0103] Y – vertical direction

[0104] S1 – Provided

[0105] S2 – Boot

[0106] S3 – Caused

[0107] S4 – Fluid-tight seal

[0108] S5 – Push

Claims

1. A syringe for obtaining a target volume of blood, the syringe (1) comprising: Syringe (2), wherein the plunger (4) is arranged in the syringe (2) so as to be displaceable along a displacement direction (X), wherein the plunger (4) includes a filter (100), The syringe (2) and the plunger (4) together provide a first stopper (20) and a second stopper (22), wherein the first stopper (20) is configured to position the filter (100) at a predetermined position along the displacement direction (X) so as to define a target volume of blood and a buffer volume of blood, and wherein the second stopper (22) is configured to prevent the plunger (4) from discharging a buffer volume exceeding the blood volume required to obtain the target volume when the plunger (4) is pushed toward the distal end (30) of the syringe (1) along the displacement direction (X), The syringe (2) comprises a proximal end (26) at which a first opening (28) for introducing the plunger (4) into the syringe (2) is located, in, A second opening (32) for receiving a target volume of blood is located at the distal end (30) of the barrel (2), and wherein the second stopper (22) is positioned closer to the first opening (28) than the first stopper (20), wherein the filter (100) is configured to be gas permeable when the filter (100) is not in contact with blood, and wherein the filter (100) is configured to become gas impermeable when in contact with blood, wherein the plunger (4) is fluid tight when the filter (100) is gas impermeable, and The plunger (4) is configured to direct air out of the barrel (2) and through the filter (100) toward the exterior of the syringe (1) during a self-filling process of the syringe (1).

2. The syringe according to claim 1, wherein the plunger (4) comprises a channel (102), wherein the filter (100) is located inside the channel (102), and in, The passage (102) is configured to direct air out of the barrel (2) and through the filter (100) toward the exterior of the syringe (1) during a self-filling process of the syringe (1).

3. The syringe according to claim 2, wherein the channel (102) has a first aperture (130) at the proximal end of the plunger, wherein the channel (102) has a second aperture (132) at the distal end of the plunger, wherein the filter (100) is at least partially located within the channel (102) and between the first hole (130) and the second hole (132) of the channel, wherein the filter (100) is configured to allow gas to vent through the passage (102) of the plunger (4) when the filter (100) is gas permeable, The filter (100) is configured to fluid-tightly seal the passage (102) of the plunger (4) when the filter (100) is gas-impermeable.

4. The syringe according to any one of the preceding claims 1 to 3, wherein the syringe (1) comprises a vented tip cap (200) on the tip of the syringe (1), wherein the vent tip cap (200) is configured to prevent air from moving through the tip into the syringe (1), and in, The vent tip cap (200) is configured to allow air from inside the syringe (1), in particular the barrel (2), to be pushed out of the syringe (1) through the vent tip cap (200) when the plunger (4) moves from the first stopper (20) to the second stopper (22).

5. The syringe according to any one of the preceding claims 1 to 3, wherein the first stop (20) and / or the second stop (22) defines a stop function along the displacement direction (X), The locking function is produced by a form fit, a friction fit and / or adhesion between the plunger (4) and the syringe (2).

6. The syringe according to any one of the preceding claims 1 to 3, wherein the plunger (4) comprises a first protrusion (10), in particular on the surface of the plunger (4), wherein the syringe (2) comprises a second protrusion (5) on the inner surface of the syringe (2), The second protrusion (5) and the first protrusion (10) together form a first stopper (20), The plunger (4) comprises a third protrusion (6), wherein the syringe (2) comprises a cone (24) on the inner surface of the syringe (2) at the first opening (28), The third protrusion (6) and the cone (24) together form a second stopper (22).

7. The syringe according to claim 6, wherein the inner surface of the barrel (2) has an at least substantially constant diameter along the displacement direction (X) and is configured to store a liquid, The first, second and / or third protrusions extend continuously around the barrel (2) and / or the plunger (4).

8. A syringe according to any one of the preceding claims 1-3, wherein the inner surface of the syringe (2) forms a cone (24), in particular at the first opening (28) of the syringe (2), which cone extends radially around the displacement direction (X) and is configured to orient the plunger (4) into the inner contour when the plunger (4) is inserted into the syringe (2).

9. The syringe according to any one of the preceding claims 1 to 3, wherein the barrel (2) has an at least partially constant diameter, wherein: The ratio of the diameter to the maximum displacement length along the displacement direction (X) is between 1:1.5 and 1:

8.

10. A package comprising a syringe according to any one of claims 1 to 9, The plunger (4) is located at the first stopper (20).

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