Patent Application
20230321404
The invention relates to a catheter arrangement, comprising a catheter, which has a hollow housing body, a tube element fitted onto a distal end of the housing body, a valve element which is arranged in the housing body and is provided with a fluid passage, and a fluid-conducting path which is made to extend longitudinally through the housing body, the fluid passage and the tube element between a proximal inlet side and a distal outlet side, and comprising a hollow needle which, in a state of readiness of the catheter arrangement, is made to extend longitudinally through the fluid-conducting path, and which, in a state of use of the catheter arrangement, is drawn out of the fluid-conducting path in the proximal direction.
A catheter arrangement of this type is known from EP 1 911 485 B1 and is provided for use in infusion therapy. According to customary medical parlance, the known catheter arrangement may also be referred to as an indwelling venous catheter. The known catheter arrangement has a hollow housing body in the form of a hollow-cylindrical catheter bushing, to the distal end of which a tube element, which is referred to as a catheter, is attached. A valve element with a fluid passage is arranged in the hollow-cylindrical catheter bushing. A fluid-conducting path is made to extend longitudinally through the hollow-cylindrical catheter bushing, the fluid passage and the tube element between a proximal inlet side and a distal outlet side. In addition, the known catheter arrangement has a hollow needle which is attached to a needle bushing. In a state of readiness of the catheter arrangement, said hollow needle is made to extend longitudinally in the distal direction and through the catheter bushing, the fluid passage in the valve element and through the tube element starting from the proximal inlet side in the direction of the distal outlet side. In a state of use of the catheter arrangement, the hollow needle is drawn out of the fluid-conducting path in the proximal direction. In the case of the known catheter arrangement, the valve element is configured in the form of a flat disk. In order to actuate the valve element, a valve actuation element is arranged in the catheter bushing and can be shifted in the axial direction relative to the valve element. The valve actuation element interacts with a fluid-conducting component which can be connected proximally to the catheter bushing. In a connected state of the fluid-conducting component, the valve actuation element is shifted in the distal direction by mechanical contact connection of the valve element, as a result of which the fluid passage is opened. When the fluid-conducting component is removed, the valve actuation element is shifted in the proximal direction, contact with the valve element is ceased and the fluid passage is thereby closed.
It is the object of the invention to provide a catheter arrangement of the type mentioned at the beginning which has a simple design and permits improved use safety in comparison to the prior art.
This object is achieved in that the valve element has an elastic wall portion through which the fluid passage is made to extend, and in that the wall portion is elastically deformable under the action of a fluid pressure, wherein the fluid passage—in the state of use of the catheter arrangement—can be shifted by means of a fluid-pressure-induced elastic deformation of the wall portion between an open state, in which the fluid passage is open, and a closed state, in which the fluid passage is closed. The solution according to the invention makes it possible in particular to dispense with a valve actuation element which is arranged in the housing body, for shifting the fluid passage between the open position and the closed position. This is because, instead of a customary actuation of the valve element brought about by mechanical contact, according to the invention—in simple terms—a fluid-pressure-induced actuation is provided. By this means, the fluid passage can be shifted between the closed state and the open state depending on a fluid differential pressure prevailing in the fluid path between the inlet side and the outlet side. In contrast to customary catheter arrangements, release and sealing of the fluid-conducting path by means of the valve element is possible to this extent independently of a fluid-conducting component possibly connected proximally to the housing body. The fluid-conducting path can thereby be released and/or sealed solely depending on the prevailing fluid differential pressure independently of the presence or absence of such a fluid-conducting component. This firstly provides improved use safety and also permits a particularly simple design of the catheter arrangement. The fluid passage is made to extend through the elastic wall portion of the valve element. The fluid passage is preferably formed by at least one opening which is openable and closable in a manner induced by deformation and thus fluid pressure, in particular in the form of a slot and/or a slot arrangement with a plurality of slots. The elastic wall portion is elastically deformable differently depending on the sign and value of the prevailing fluid differential pressure. In the open state, the fluid-conducting path is released via the open fluid passage between the inlet side and the outlet side. In a state of the catheter applied on a patient, a medicinal fluid can thus be administered to the patient or blood taken from the patient, depending on the direction of flow through the fluid-conducting path. In the closed position, the fluid-conducting path is sealed fluid-tightly by means of the closed fluid passage. By means of the solution according to the invention, said fluid-tight seal, unlike in the case of conventional catheter arrangements with a valve actuation element, can also be present if a possible fluid-conducting component is connected to the proximal inlet side of the fluid-conducting path, more precisely: to the hollow housing body. In the state sealed fluid-tightly, in particular a blood return in the proximal direction is opposed. By this means, in particular an inadvertent escape of blood through the proximal inlet side is opposed. In order to ensure operation of the valve element so as to meet requirements, preferably at least the elastic wall portion is manufactured from an elastomeric material. Alternatively, the entire valve element can be manufactured from an elastomeric material. Suitable materials include in particular silicone, rubber or the like. The tube element may also be referred to as a catheter attachment. The hollow housing body may also be referred to as a catheter hub. The hollow needle may also be referred to as a canula. In accordance with customary medical parlance, the catheter arrangement may also be referred to as a peripheral indwelling venous catheter or peripheral indwelling venous canula. The tube element is preferably configured to be flexurally flexible. The tube element is preferably fitted directly onto the hollow housing body. For this purpose, a force-fitting, form-fitting and/or materially bonded joining connection formed between the housing body and the tube element Is preferably provided. For the force-fitting connection between the housing body and the tube element, a metal sleeve which is pressed proximally to the tube element can be provided. A suitable materially bonded joining connection can be in particular an adhesive connection. The tube element and/or the housing body are preferably manufactured from plastic. The housing body can be formed as a single part or in multiple parts. The housing body, at its proximal end facing away from the tube element, preferably has a connector portion for connection to a complementary connector portion of a medical fluid-conducting component, for example a medical syringe. The connector portion is preferably configured as a Luer connector. The hollow needle serves in a manner known to a person skilled in the art for venipuncture and for introducing the tube element into the punctured vein of the patient. When the catheter is applied in such a manner, the catheter arrangement takes up the state of readiness. After this, the hollow needle is drawn proximally out of the catheter, conventionally disposed of and the catheter arrangement is thereby transferred into the state of use. In the state of readiness, the hollow needle and the valve element preferably interact as follows: the hollow needle is made to extend through the fluid passage such that the latter is widened in the radial direction as a result of elastic deformation of the wall portion and bears fluid-tightly, in an elastically prestressed manner, against an outer circumference of the hollow needle. When the hollow needle is drawn out proximally, the elastic wall portion springs back inwards in the radial direction, as a result of which the fluid passage is closed.
In a refinement of the invention, the elastic wall portion is configured in such a manner that the fluid passage—in the state of use of the catheter arrangement and starting from its closed state—remains in the closed state in the event of a neutral fluid pressure, and can be shifted into the open state by means of an inlet-side fluid positive pressure and/or an inlet-side fluid negative pressure, wherein an inlet-side fluid negative pressure which is required for opening the fluid passage is greater in terms of value than an inlet-side fluid positive pressure which is required for the opening. Expressed in other words, the wall portion is elastically deformable to different extents depending on the direction of the pressurization. This results in a valve element behaviour that depends on the direction of the pressurization. In this refinement of the invention, the inlet-side fluid negative pressure which is required for opening the fluid passage is greater in terms of value than the inlet-side fluid positive pressure which is required for the opening. The inlet-side fluid negative pressure is equivalent to an outlet-side fluid positive pressure. This refinement of the invention ensures that flow can pass through the fluid-conducting path in the distal direction at comparatively lower fluid pressures than in the proximal direction. The elastic wall portion is preferably configured in such a manner that the inlet-side fluid positive pressure required for opening the fluid passage is achieved during a conventional gravity-driven infusion. By means of an appropriate configuration of the elastic wall portion, the inlet-side fluid negative pressure or outlet-side fluid positive pressure required for releasing the fluid-conducting path in the proximal direction is higher than the inlet-side fluid positive pressure which is required for releasing the fluid-conducting path in the distal direction. By this means, an inadvertent blood return in the proximal direction and in particular an escape of blood in the proximal direction is opposed in a simple and particularly effective manner. In order to achieve the previously described, direction-dependent behaviour, the elastic wall portion can be configured in particular in the shape of a small hat, a cup, a funnel, a dome, a cupola or a spherical cap.
In a further refinement of the invention, the inlet-side fluid negative pressure which is required for opening the fluid passage exceeds the inlet-side fluid positive pressure which is required for opening the fluid passage by 15 times to 25 times, preferably by 20 times. Expressed in other words, in this embodiment of the invention, the elastic wall portion is configured in such a manner that the fluid passage can be opened in the direction of the patient in the event of a comparatively small positive pressure. By contrast, the fluid passage can be opened in the event of a comparatively high inlet-side fluid negative pressure and thus equivalently in the case of comparatively high vein-side fluid positive pressures. This affords numerous advantages in the use of the catheter arrangement.
In a further refinement of the invention, the inlet-side fluid positive pressure which is required for opening the fluid passage is between 0.2 PSI and 0.4 PSI, preferably 0.3 PSI, and the inlet-side fluid negative pressure which is required for opening the fluid passage is between 5.0 PSI and 7.0 PSI, preferably 6.0 PSI. The previously mentioned value ranges have proven particularly advantageous in practice and are achieved by a corresponding configuration of the elastic wall portion. By means of the previously mentioned value ranges, in particular reliable opening of the fluid passage during a conventional gravity infusion is achieved. In addition, the fluid passage is prevented from inadvertently opening due to patient-side influences, for example a movement of the patient, sneezing, coughing, vomiting and the associated, physiologically increased outlet-side (vein-side) fluid positive pressure.
In a further refinement of the invention, the elastic wall portion has a cupola-shaped curvature, wherein the fluid passage is arranged in the region of an apex point of the curvature. A behaviour of the valve element that is dependent on the direction of the fluid pressurization can be achieved in a structurally simple manner by the cupola-shaped curvature and the arrangement of the fluid passage in the region of the apex point. The shape of the elastic wall portion arising in this refinement of the invention may be referred to in particular as a cupola or dome. Furthermore preferably, the apex point of the curvature is arranged on an imaginary central longitudinal axis of the fluid-conducting path.
In a further refinement of the invention, the cupola-shaped curvature of the elastic wall portion is concave in the direction of the proximal inlet side and convex in the direction of the distal outlet side. This orientation of the cupola-shaped curvature in particular ensures that the fluid-conducting path can be released comparatively “more easily” in the distal direction than in the proximal direction.
In a further refinement of the invention, the cupola-shaped curvature of the elastic wall portion is convex in the direction of the proximal inlet side and concave in the direction of the distal outlet side. The inventors have found that, by this means, a less turbulent or even laminar flow through the fluid passage in the direction of the proximal inlet side can be achieved. Expressed in other words, the curvature of the elastic wall portion which is convex in the proximal direction and concave in the distal direction permits a low-turbulence or even turbulence-free aspiration of liquid. If the catheter arrangement is used for taking blood, haemolysis can thereby be avoided in a simple, but particularly effective manner. Haemolysis is understood as meaning the dissolution of red blood cells as a consequence of a mechanical destruction of the cell membrane. Such a mechanical destruction can take place, for example, as a consequence of a turbulent flow and the forces occurring in the process. In addition, the present refinement permits a comparatively turbulent flow in the distal direction. By this means, for example in the case of an infusion directed in the distal direction, an accumulation of germs putting health at risk in the region of the valve element can be avoided.
In a further refinement of the invention, the valve element has a radially outer elastic articulated wall portion which is adjacent to the cupola-shaped curvature and, under the action of an infusion-induced fluid pressure and/or an aspiration-induced fluid pressure, permits an alternate sudden eversion of the cupola-shaped curvature between a stable first state, in which the cupola-shaped curvature is arched distally, and a stable second state, in which the cupola-shaped curvature is arched proximally. This refinement of the invention permits in particular a low-turbulence or even laminar flow through the fluid passage both in the distal and in the proximal direction. Advantages are thereby achieved both during an infusion and during an aspiration. In particular, the haemolysis already explained can be avoided. The articulated wall portion permits an alternate eversion, pushing out and/or buckling of the elastic wall portion together with the cupola-shaped curvature depending on the direction of the fluid flow. Depending on the direction of the fluid flow, the valve element “jumps” between the first state and the second state. Expressed in simplified terms, the valve element in this refinement has flip-flop properties. The articulated wall portion is preferably annular. Furthermore preferably, the cupola-shaped curvature is bounded in the circumferential direction by the, in particular annular, articulated wall portion. The articulated wall portion preferably has a smaller wall thickness in comparison to the cupola-shaped curvature.
In a further refinement of the invention, an axial height of the cupola-shaped curvature is smaller than a radial diameter of the elastic wall portion. Expressed in other words, the cupola-shaped curvature is comparatively flat. The inventors have found that advantageous flow properties can be achieved by this refinement of the invention. In particular, an accumulation of standing liquid at the outer edge of the convexly arched, cupola-shaped curvature is avoided. In association therewith, the accumulation of health-endangering germs and/or biofilms in said region is avoided.
As a result, this refinement of the invention permits improved patient safety. The axial height is preferably at maximum 50%, preferably at maximum 40%, particularly preferably at maximum 30%, of the radial diameter.
In a further refinement of the invention, the fluid passage is formed by a slot arrangement which has at least one first slot and a second slot, which slots are arranged preferably in a cross-shaped manner, particularly preferably in a “+”-shaped manner, forming at least one common intersecting point. The first slot and the second slot are oriented transversely, preferably perpendicularly, with respect to each other. The elastic wall portion is subdivided into different subsections by the slot arrangement. Said subsections are bounded and/or separated from one another by the first slot and/or the second slot. Depending on the prevailing fluid pressure, said subsections can be shifted relative to one another by elastic deformation. If the subsections are moved away from one another, the fluid passage is shifted into the open state. If the subsections lie fluid-tightly on one another, the fluid passage is in the closed state. This refinement of the invention is structurally simple and robust.
In a further refinement of the invention, the slot arrangement has a third slot, wherein the first slot, the second slot and the third slot are arranged in particular in a H-shaped manner, forming two common intersecting points. Such an, in particular H-shaped, arrangement permits in particular a comparatively large opening cross section of the fluid passage in the open state.
In a further refinement of the invention, the slot arrangement has a third slot, wherein the first slot, the second slot and the third slot are arranged in particular in a star-shaped manner, forming precisely one common intersecting point. The first slot, the second slot and the third slot are preferably in each case arranged offset by 120° with respect to one another such that a star-shaped configuration of the slot arrangement with a centrally arranged intersecting point is produced. The inventors have found that particular advantages can thereby be obtained. In a further refinement of the invention, the valve element has an encircling radial collar which is fixed in an encircling radial groove of the housing body, the housing body is configured as a single piece. The encircling radial collar can be manufactured separately from the elastic wall portion and then joined together therewith. Alternatively and preferably, the valve element is configured as a single piece such that the radial collar and the elastic wall portion are linked as a single piece. The radial groove is formed in the interior of the housing body and, for the installation of the valve element, is preferably accessible from the proximal inlet side. By means of the single-piece configuration of the housing body, a particularly simple design and, in association therewith, cost-effective manufacturing can be achieved.
In a further refinement of the invention, the elastic wall portion has at least one first pair of rib elements and one second pair of rib elements that are in each case arranged opposite one another in pairs with respect to the at least one common intersecting point, wherein the first pair of rib elements is arranged offset radially further outwards with respect to the intersecting point than the second pair of rib elements. The first pair of rib elements is preferably assigned to a first hollow needle with a first diameter. The second pair of rib elements is preferably assigned to a second hollow needle with a second diameter. The first diameter here is comparatively larger than the second diameter. The rib elements of the first pair may also be referred to as first rib elements. The rib elements of the second pair may also be referred to as second rib elements. Both the first and the second rib elements serve in each case for reinforcing regions of the elastic wall portion. The rib elements are preferably in each case linked as one piece with the elastic wall portion. In one refinement, the rib elements are manufactured as separate components and then fitted onto the elastic wall portion. The rib elements and the different spacing thereof from the intersecting point of the slot arrangement bring about an advantageous deformation behaviour of the elastic wall portion. The first rib elements and/or the first pair of rib elements bring about an advantageous deformation behaviour during use of the first hollow needle. The second rib elements and/or the second pair of rib elements bring about an advantageous deformation behaviour during use of the second hollow needle. The rib elements are preferably in each case arranged on a proximal side of the elastic wall portion. The rib elements preferably have a triangular shape, with in each case one point of the triangle being directed towards the intersecting point. In further refinements, the rib elements can have a shaping differing therefrom.
In a further refinement of the invention, at least one further fluid passage is made to extend through the elastic wall portion, wherein the further fluid passage is formed by at least two circumferential slots made to extend longitudinally in the circumferential direction of the elastic wall portion, and wherein the at least two circumferential slots are arranged offset radially outwards relative to the fluid passage. The inventors have found that this refinement of the invention permits an even better administration of liquid (infusion) and removal of liquid (aspiration) through the valve element. The further fluid passage formed by the at least two circumferential slots—basically corresponding to the fluid passage — can be transferred between an open and a closed state depending on the prevailing fluid pressure. The properties of the fluid passage and of the further fluid passage are preferably coordinated with one another in such a manner that a fluid-pressure-induced opening and closing takes place in an alternating manner. For example, the fluid passage can be closed during an aspiration and the further fluid passage opened. Conversely, during an infusion, the further fluid passage is preferably closed and the fluid passage opened. Of course, a refinement which is the other way around to this is also possible. The corresponding fluid-pressure-induced opening and closing properties of the fluid passage and of the further fluid passage are preferably achieved by an appropriate shaping, thickness and/or selection of material in the region of the fluid passage and the further fluid passage. The at least two circumferential slots are preferably arranged offset with respect to one another by 180° in the circumferential direction.
In a further refinement of the invention, the circumferential slots are in each case longer on a distal side of the elastic wall portion than on a proximal side of the elastic wall portion, and/or the fluid passage has at least one slot which is longer on the proximal side of the elastic wall portion than on the distal side of the elastic wall portion. Accordingly, the at least two circumferential slots are not designed approximately rectilinearly, but rather in an inclined manner with respect to one another on their end regions lying opposite one another in the longitudinal direction. This inclination brings about said difference in length of the circumferential slots between the distal and the proximal side. Said difference in length and/or inclination of the end regions causes the circumferential slots to be comparatively more easily releasable, that is to say at lower pressures, during an aspiration of liquid (in the proximal direction) than during an infusion (in the proximal direction). A corresponding statement applies analogously in respect of the at least one slot of the fluid passage. In a further refinement of the invention, the length ratios of the circumferential slots and of the at least one slot are designed the other way around to the preceding refinement.
In a further refinement of the invention, the elastic wall portion has at least one recessed or raised profiling in the region of the fluid passage, and/or the elastic wall portion has at least one recessed or raised further profiling in the region of the further fluid passage. The profiling and/or further profiling enables an improved directional dependency in the opening and closing behaviour f the fluid passage and/or further fluid passage to be achieved. If the profiling and/or further profiling is raised, a local increase in regions of the wall thickness of the elastic wall portion is thereby achieved. Consequently, the elastic wall portion is locally stiffened and/or reinforced. If the profiling and/or further profiling is recessed, this achieves a local reduction in regions of the wall thickness of the elastic wall portion. The wall thickness which is reduced in this manner brings about a local weakening.
In a further refinement of the invention, the valve element has a radial collar which is fixed between two joined-together housing parts of the housing body. By means of the at least two-part configuration of the housing body, a comparatively simple installation of the valve element can be achieved. For this purpose, the radial collar of the valve element is fixed in the axial direction between the two housing parts. The housing parts are then fixedly joined together in a manner known to a person skilled in the art, for example by means of an adhesively bonded or welded connection.
The invention also relates to a valve element for a catheter arrangement, having an elastic wall portion through which a fluid passage is made to extend, wherein the wall portion is elastically deformable under the action of a fluid pressure, and wherein the fluid passage can be shifted by means of a fluid-pressure-induced elastic deformation of the wall portion between an open state, in which the fluid passage is open, and a closed state, in which the fluid passage is closed. With regard to advantages associated with the configuration according to the invention of the valve element, what has been stated with regard to the catheter arrangement according to the invention is noted and express reference is made thereto. What has been disclosed to this extent with regard to the catheter arrangement according to the invention also applies mutatis mutandis to the valve element according to the invention. Refinements of the valve element according to the invention emerge from the features of the valve element of the refinements of the catheter arrangement according to the invention.
Further advantages and features of the invention emerge from the claims and from the description below of preferred exemplary embodiments of the invention which are illustrated with reference to the drawings.
According to
The catheter 2 has a hollow housing body 4, a tube element 5 and a valve element 6 (
The housing body 4 may also be referred to as a catheter hub and has a basically known basic shape with two laterally protruding fastening wings 7 and a connector portion 8.
In an embodiment which is not illustrated graphically, the housing body does not have fastening wings.
The connector portion 8 is arranged at a proximal end 9 of the housing body 4 and is configured in the present case in the form of a female Luer lock connection. The tube element 5 is arranged at a distal end 10 of the housing body 4 and is joined together fixedly to the housing body 4 in a manner known to a person skilled in the art. For example, the tube element 5 can be joined together for this purpose to the housing body 4 by means of a press connection, welded connection or adhesively bonded connection. A metal sleeve can be provided for the press connection and, by expansion of the tube element 5, can be pressed into the proximal end thereof. In addition, a configuration of the housing body linked in a single piece with the tube element is possible.
The catheter 2 has a fluid-conducting path F (
The fluid passage 12 can be shifted between a closed state and an open state in a manner described in yet more detail. In the closed state, the fluid passage 12 is closed and the fluid-conducting path F between the inlet side E and the outlet side A is thereby sealed fluid-tightly. In the open state, the fluid passage 12 is opened and the fluid-conducting path F between the inlet side E and the outlet side A is thereby released.
The hollow needle 3 is made to extend longitudinally between a proximal end 14 and a distally arranged needle point 15 which, in the state apparent with reference to
The state shown with reference to
In order to apply the catheter 2, the catheter arrangement 1 in its state of readiness is brought up to an appropriate vein of the patient and the vein is punctured by means of the needle point 15. The hollow needle 3 is pushed together with the tube element 5 into the punctured vein. The hollow needle 3 is then drawn out of the catheter 2 in the proximal direction, conventionally disposed of and the catheter arrangement 1 is thereby transferred into a state of use. In said state of use, the catheter 2 is applied to the patient and generally usable for several days. In the state of use, the fluid-conducting path F is either sealed fluid-tightly or released by means of the sealing element 6, depending on the use situation of the catheter 2.
The valve element 6 has an elastic wall portion 18. The fluid passage 12 is made to extend in a form described in yet more detail through the elastic wall portion 18 in the thickness direction thereof. The elastic wall portion 18 is elastically deformable under the action of a fluid pressure acting thereon. As a result of said fluid-pressure-induced elastic deformation, the fluid passage 12—at any rate in the state of use of the catheter arrangement 1—can be shifted between its open state and its closed state. In the open state, the fluid passage 12 is open such that the fluid-conducting path F between the inlet side E and the outlet side A is released. In the closed state, the fluid passage 12 is closed, as a result of which the fluid-conducting path F is sealed fluid-tightly by means of the closed fluid passage 12. In contrast to solutions known from the prior art, the valve element 6 can thus be opened and closed solely owing to the fluid pressure conditions prevailing in the fluid-conducting path F.
In the embodiment shown, the elastic wall portion 18 is configured in such a manner that different fluid pressures for opening the fluid passage 12 are required depending on the direction of passage through the fluid-conducting path F. For further explanation, it is assumed that, on the inlet side, a fluid pressure pE and, on the outlet side, a fluid pressure pA prevail in the fluid-conducting path F. The inlet-side fluid pressure pE acts on a proximal wall side 24 of the elastic wall portion 18, said proximal wall side 24 facing the inlet side E. The outlet-side fluid pressure pA acts on a distal wall side 25 of the elastic wall portion 18, said distal wall side 25 facing the outlet side A. Starting from its closed state, the fluid passage 12 remains closed in the event of a neutral fluid pressure, i.e. pE=pA. If the inlet-side fluid pressure pE exceeds the outlet-side fluid pressure pA, an inlet-side fluid positive pressure ΔpE is present. An inlet-side fluid positive pressure Δp1 is required for opening the fluid passage 12. This pressure may also be referred to as the required inlet-side fluid positive pressure or inlet-side opening positive pressure Δp1.
If the inlet-side fluid pressure pE falls short of the outlet-side fluid pressure pA, an inlet-side fluid negative pressure −ΔpE is present. This is equivalent to an outlet-side fluid positive pressure ΔpA. An inlet-side fluid negative pressure −Δp2 is required for opening the fluid passage 12. With regard to the outlet side A, it can also be mentioned that an outlet-side fluid positive pressure Δp3 is required for opening the fluid passage 12. This may also be referred to as the outlet-side opening positive pressure Δp3.
The fluid differential pressures Δp1, −Δp2 and Δp3 that are required for opening the fluid passage 12 differ depending on the direction of fluid pressurization of the elastic wall portion 18. In the embodiment shown, the required outlet-side fluid positive pressure Δp3 is greater than the required inlet-side fluid positive pressure Δp1. Expressed in other words, the required inlet-side fluid negative pressure −Δp2 is greater in terms of value than the required inlet-side fluid positive pressure Δp1.
Furthermore, it is understood that, in the clinical use of the catheter arrangement, states with a neutral fluid pressure, i.e. pE=pA, cannot occur. This is because of the vein pressure which always exists and which acts on the outlet side on the elastic wall portion 18.
In the embodiment shown, the elastic wall portion 18 is configured in such a manner that the inlet-side opening positive pressure Δp1 is 0.3 PSI. By this means, in particular opening of the fluid passage in a manner meeting requirements is achieved during conventional gravity infusion. In addition, the elastic wall portion 18 here is configured in such a manner that the inlet-side opening negative pressure Δp2is 6 PSI. Such a negative pressure can be readily applied by means of a medical syringe connected to the connector portion 8 such that a blood aspiration meeting requirements is ensured. At the same time, inadvertent opening of the fluid passage 12 as a result of physiological phenomena on the part of the patient is opposed.
The previously described direction-dependent opening and closing behaviour of the fluid passage 12 is achieved by a configuration, which is described in yet more detail, of the elastic wall portion 18 and of the fluid passage 12 arranged therein.
For this purpose, it is provided here that the elastic wall portion 18 has a cupola-shaped curvature W (
In further embodiments, the elastic wall portion does not have a constant wall thickness.
As a result of the cupola-shaped curvature W, the valve element 6 has a configuration which, in visual language, may also be referred to as cupola-shaped, dome-shaped or approximately hemispherical. The valve element E here is rotationally symmetrical and is so with respect to a line of symmetry which coincides with the fluid-conducting path F that is shown schematically in
On its outer circumference, the valve element 6 has a radial collar 19 which encircles in the circumferential direction and protrudes from the elastic wall portion 18 in the radial direction R. The radial collar 19 is fixed in a radial groove 20 of the hollow housing body 4 (
In the embodiment shown, the entire valve element 6 is manufactured from an elastomeric material, for example silicone. This is not absolutely necessary. In an embodiment which is not illustrated graphically, only the elastic wall portion 18 is manufactured from an elastomeric material.
For the installation, the valve element 6 is introduced from the inlet side E in the distal direction into the cavity 11. In the process, the valve element 6 is slightly elastically compressed in the radial direction R. As soon as the radial collar 19 enters the region of the radial groove 20, the valve element 6 springs outwards in the radial direction R. By this means, the radial collar 19 enters into form-fitting engagement with the radial groove 20, as a result of which the valve element 6 is fixed captively in the housing body 4.
In the alternative embodiment shown with reference to
Instead 42a being a catheter housing, it can be a representative of a tube valve (for example, a silicone valve found in a Ported IVC) or integrated IVC.
In particular, the fluid passage may differ in configuration. In the simplest case, the fluid passage is formed by an individual slot.
In the configuration according to
Further embodiments of valve elements 6a to 6i according to the invention are shown with reference to
The valve element 6a according to
The valve element 6b shown with reference to
In contrast to the valve element 6, the valve element 6c according to
In a further embodiment, dead space T may also be reduced by shaping the catheter hub to conform to the shape of the valve. For example, the catheter hub may have a curved profile conforming with the dome or cupola shape of the valve. This helps to minimise dead space T and enhance the alignment of the valve and catheter hub during the assembly process. To minimise the dead space, the valve may be shaped to conform to the shape of the inner profile of the catheter hub. The catheter hub may also be shaped to conform to the shape of the valve.
In contrast to the previously described embodiments, the valve element 6d according to
In a further embodiment, instead of being oriented in the circumferential direction, the slots may be straight cuts and may be arranged in a radially manner.
It is shown with reference to
The circumferential slots 27d, 28d of the further fluid passage 26d have slot length ratios which are the other way around compared to the slot 21d. Expressed in other words, the circumferential slots 27d, 28d are in each case longer on the distal wall side 25d than on the proximal wall side 24d. This simplifies aspiration of liquid through the further fluid passage 26d.
In one use of the valve element 6d, the operation thereof is in particular as follows. During an infusion of liquid (fluid flow in the distal direction) and an infusion pressure prevailing in this connection, the fluid passage 12d is shifted into its open state. In this case, the further fluid passage 26d preferably remains in its closed state. When the infusion pressure is increased, the further fluid passage 26d can be additionally shifted into its open state. During an aspiration of liquid (fluid flow in the proximal direction) and an aspiration pressure prevailing in this connection, the further fluid passage 26d is shifted into its open state. The fluid passage 21d remains here in its closed state. The previously described direction-dependent opening and closing behaviour of the fluid passage 12d and of the further fluid passage 26d is assisted by said slot length ratios.
Furthermore, it is understood that the fluid passage 12d can alternatively be formed by a slot arrangement according to the preceding or following description. In addition, the further fluid passage 26d can be formed by fewer or more than the two circumferential slots 27d, 28d shown here. For example, three, four, five, six or more than six circumferential slots are conceivable.
The valve element 6e according to
Furthermore, the fluid passage 12e has only one single first slot 21e. It is understood that the fluid passage 12e in further refinements can be formed by a slot arrangement according to the preceding or following description. In this case, the profiling is adapted to the specific refinement of the fluid passage.
In addition, the valve element 6e in accordance with the valve element 6d according to
The valve element 6f according to
It is understood that the profilings 30e, 31f shown with reference to
The valve element 6g (
For this purpose, the valve element 6g has an elastic articulated wall portion 32g. The elastic articulated wall portion 32g is arranged lying radially on the outside and at one end borders the elastic wall portion 18g and at the other end the radial collar 19g. The elastic articulated wall portion 32g is of annular design. In the region of the elastic articulated wall portion 32g the valve element 6g has a reduced wall thickness—in comparison to the adjacent wall portions. This reduced wall thickness permits said eversion and/or switching-over movement of the valve element 6g.
It can furthermore be seen with respect to
In the first state, the cupola-shaped curvature Wg is arched distally. Expressed in other words, the elastic wall portion 18g is concave in the first state in the direction of the proximal inlet side E and convex in the direction of the distal outlet side A.
In the second state, the elastic wall portion 18g is convex in the direction of the proximal inlet side and concave in the direction of the distal outlet side A. Accordingly, a cupola-shaped curvature Wg' which is inverted with respect to the cupola-shaped curvature Wg is present (
In the use of the valve element 6g, the operation thereof is in particular as follows: starting from the first state (
The valve element 6g permits particularly advantageous flow properties. Both the infusion and the aspiration of liquid can take place with reduced turbulence or at best even completely laminarly. This is because of the previously described alternate sudden eversion between the first and second state. If the valve element 6g is used within the scope of taking blood, in particular a disadvantageous haemolysis can be avoided.
The valve element 6h according to
The inventors have found that the hollow needle 3, which, in the state of readiness, is made to extend through the fluid passage 12h, may lead to an undesirable memory effect and thus to an at any rate partially remaining deformation of the elastic wall portion 18h. This memory effect is basically undesirable. The second pair P2 of rib elements opposes said memory effect. For this purpose, the rib elements 37h, 38h are arranged comparatively tightly against the intersecting point P of the fluid passage 12h. This results in a mechanical reinforcement of the elastic wall portion 18h which opposes said memory effect.
The first pair P1 arranged offset radially further outwards assists an elastic deformation, meeting requirements, of the elastic wall portion 18a during the aspiration and infusion of liquid.
In the embodiment shown, the first pair P1 and the second pair P2 and thus also all of the rib elements 35h, 36h, 37h, 38h are arranged on the proximal wall side 24h. In further refinements, at least one of the rib elements can be arranged on the distal wall side 25h. In addition, refinements are conceivable in which only one of the two pairs P1, P2 is present. Furthermore, the shaping of the rib elements that is shown with reference to
With reference to
It is obvious with reference to the preceding description that individual features of the valve elements 6 to 6i are considered in isolated form and can be combined with one another to form different combinations of features. For example, the flat cupola shape of the valve element 6c can be combined with the further fluid passage of the valve element 6d, the profilings of the valve elements 6e, 6f, the flip-flop properties of the valve element 6g and/or the rib elements of the valve element 6h.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 209 931.6 | Aug 2020 | DE | national |
This application is the United States national stage entry of International Application No. PCT/EP2021/071797, filed Aug. 4, 2021, and claims priority to German Application No. 10 2020 209 931.6, filed Aug. 6, 2020. The contents of International Application No. PCT/EP2021/071797 and German Application No. 10 2020 209 931.6 are incorporated by reference herein in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/071797 | 8/4/2021 | WO |
