CATHETER ARRANGEMENT INCLUDING A VALVE ELEMENT ELASTICALLY DEFORMABLE BY FLUID PRESSURE

Abstract

A catheter arrangement and use of a catheter arrangement in infusion therapy. The catheter arrangement includes a catheter with a housing body, a hollow needle, a tube fitted onto a distal end of the housing body, a valve element arranged in the housing body with a fluid passage, and a fluid-conducting path extending through the housing body, the fluid passage and the tube. The needle extends longitudinally through the fluid-conducting path in a state of readiness of the catheter arrangement, and is drawn out of the fluid-conducting path in a state of use of the catheter arrangement. The valve element has an elastic wall portion through which the fluid passage extends. The fluid passage can be shifted by 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.

Claims

1. A catheter arrangement, comprising: a catheter comprising 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 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, the valve element has comprising 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—is configured to be shifted by 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.

2. The catheter arrangement according to claim 1, wherein 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.

3. The catheter arrangement according to claim 2, wherein 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.

4. The catheter arrangement according to claim 2, wherein the inlet-side fluid positive pressure which is required for opening the fluid passage is between 0.2PSI and 0.4 PSI and wherein the inlet-side fluid negative pressure which is required for opening the fluid passage is between 5.0 PSI and 7.0 PSI.

5. The catheter arrangement according to claim 1, wherein the elastic wall portion has a cupola-shaped curvature, and wherein the fluid passage is arranged in the region of an apex point of the curvature.

6. The catheter arrangement according to claim 5, wherein 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.

7. The catheter arrangement according to claim 5, wherein 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.

8. The catheter arrangement according to claim 5, wherein 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.

9. The catheter arrangement according to claim 5, wherein an axial height of the cupola-shaped curvature is smaller than a radial diameter of the elastic wall portion.

10. The catheter arrangement according to claim 1, wherein the fluid passage is formed by a slot arrangement which has at least one first slot and a second slot that form at least one common intersecting point.

11. The catheter arrangement according to claim 10, wherein the slot arrangement further comprises a third slot, and wherein the at least one first slot, the second slot and the third slot are arranged in a star-shaped manner, forming form two common intersecting point.

12. The catheter arrangement according to claim 10, wherein the slot arrangement further comprises a third slot, and wherein the at least one first slot, the second slot and the third slot are arranged in a star-shaped manner, forming only one common intersecting point.

13. The catheter arrangement according to claim 10, wherein 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.

14. The catheter arrangement according to claim 1, wherein at least one further fluid passage is made to extend through the elastic wall portion, wherein the at least one 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.

15. The catheter arrangement according to claim 14, wherein 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.

16. The catheter arrangement according to claim 14, wherein the elastic wall portion comprises a first elastic wall portion and a second elastic wall portion, wherein the first elastic wall portion has at least one recessed or raised profiling in a region of the fluid passage, and/or the second elastic wall portion has at least one recessed or raised further profiling in the region of the at least one further fluid passage.

17. The catheter arrangement according to claim 1, wherein the valve element has an encircling radial collar which is fixed in an encircling radial groove of the housing body, wherein the housing body is configured as a single piece.

18. The catheter arrangement according to claim 1, wherein the valve element has a radial collar which is fixed between two joined-together housing parts of the housing body.

19. The catheter arrangement according to claim 10, wherein the at least one first slot and the second slot are arranged in a cross-shaped manner, forming the at least one common intersecting point.

20. The catheter arrangement according to claim 11, wherein the at least one first slot, the second slot and the third slot are arranged in a H-shaped manner, forming the two common intersecting points.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0024] 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.

[0025] FIG. 1 shows, in a schematic perspective illustration, an embodiment of a catheter arrangement according to the invention with a catheter and a hollow needle, wherein the catheter arrangement is in a state of readiness.

[0026] FIG. 2 shows the catheter arrangement according to FIG. 1, wherein the hollow needle has been drawn out of the catheter in the proximal direction and is arranged separately therefrom.

[0027] FIG. 3 shows, in a schematically highly simplified and partially cut-away longitudinal sectional illustration, a hollow housing body of the catheter with a valve element arranged therein.

[0028] FIG. 4 shows, in an illustration corresponding to FIG. 3, an alternative refinement of the hollow housing body.

[0029] FIG. 5 shows an enlarged illustration of a detail of the valve element in a sectional view corresponding to FIGS. 3 and 4.

[0030] FIG. 6 shows the valve element according to FIG. 5 in a direction looking axially at a fluid passage.

[0031] FIG. 7 shows, in an illustration corresponding to FIG. 6, an embodiment of a valve element according to the invention with an alternatively configured fluid passage.

[0032] FIG. 8 shows, in an illustration corresponding to FIGS. 6 and 7, a further embodiment of a valve element according to the invention with an alternatively configured fluid passage.

[0033] FIG. 9 shows, in a schematic longitudinal sectional illustration, a further embodiment of a valve element according to the invention with a cupola shape of flat design.

[0034] FIG. 10 shows, in a schematic perspective illustration, a further embodiment of a valve element according to the invention with a further fluid passage formed from two circumferential slots.

[0035] FIG. 11 shows a greatly simplified schematic sectional illustration for clarifying further features of the valve element according to FIG. 10.

[0036] FIG. 12 shows, in a perspective sectional illustration, a further embodiment of a valve element according to the invention.

[0037] FIG. 13 shows, in a perspective sectional illustration, a further embodiment of a valve element according to the invention,

[0038] FIG. 14 shows, in a schematic perspective illustration, a further embodiment of a valve element according to the invention which can be transferred in a fluid-pressure-induced manner between a stable first state (FIG. 16) and a stable second state (FIG. 17).

[0039] FIG. 15 shows, in a schematic longitudinal sectional illustration, the valve element according to FIG. 14.

[0040] FIGS. 16 and 17 show the valve element according to FIGS. 14 and 15 in said first state (FIG. 16) and the second state (FIG. 17).

[0041] FIG. 18 shows, in a schematic perspective illustration, a further embodiment of a valve element according to the invention.

[0042] FIG. 19 shows the valve element according to FIG. 18 in a further perspective view with a direction looking at a proximal wall side of the elastic wall portion.

[0043] FIG. 20 shows a further embodiment in a schematic side view.

DETAILED DESCRIPTION

[0044] According to FIGS. 1 and 2, a catheter arrangement 1 for use in infusion therapy is provided and has a catheter 2 and a hollow needle 3. The catheter arrangement 1 may also be referred to as peripheral indwelling venous canula or peripheral indwelling venous catheter. The catheter arrangement 1 is applied in a manner known to a person skilled in the art in the region of the back of a hand or a crook of the arm of a patient and serves in particular for parenteral liquid therapy, an intravenous administration of medicaments, and/or for taking blood.

[0045] The catheter 2 has a hollow housing body 4, a tube element 5 and a valve element 6 (FIG. 3). In FIG. 3, the housing body 4 and the tube element 5 are provided with continuous hatching. This does not necessarily mean that the housing body 4 and the tube element 5 are linked as a single piece.

[0046] 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.

[0047] In an embodiment which is not illustrated graphically, the housing body does not have fastening wings.

[0048] 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.

[0049] The catheter 2 has a fluid-conducting path F (FIGS. 2 and 3) which is made to extend through the catheter 2 in an axial direction of the catheter 2 between a proximal inlet side E and a distal outlet side A. The fluid-conducting path F runs here from the distal end 9 into the housing body 4, more specifically: into a cavity 11 of the housing body 4, from there further in the distal direction through a fluid passage 12 of the valve element 6, and from there through the tube element 5 and the point 13 thereof as far as the outlet side A.

[0050] 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.

[0051] 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 FIG. 2, is covered by means of a safety element 16 in a manner known to a person skilled in the art. The hollow needle 3 is joined together at its proximal end to a needle attachment 17. The needle attachment 17, like the hollow needle 3, is configured in a manner known to a person skilled in the art. To this extent, in particular a further explanation of the configuration here of the needle attachment 17 can be omitted.

[0052] The state shown with reference to FIG. 1 illustrates a state of readiness of the catheter arrangement 1, in which the hollow needle 3 is plugged from the inlet side E in the distal direction into the catheter 2. The hollow needle 3 is made to extend here through the housing body 4, the fluid passage 12 of the valve element 6 and the tube element 5, with the needle point 15 protruding over the point 13 in the distal direction.

[0053] 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.

[0054] 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.

[0055] 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 p.sub.E and, on the outlet side, a fluid pressure p.sub.A prevail in the fluid-conducting path F. The inlet-side fluid pressure p.sub.E 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 p.sub.A 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. p.sub.E=p.sub.A. If the inlet-side fluid pressure p.sub.E exceeds the outlet-side fluid pressure p.sub.A, an inlet-side fluid positive pressure Δp.sub.E is present. An inlet-side fluid positive pressure Δp.sub.1 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 Δp.sub.1.

[0056] If the inlet-side fluid pressure p.sub.E falls short of the outlet-side fluid pressure p.sub.A, an inlet-side fluid negative pressure −Δp.sub.E is present. This is equivalent to an outlet-side fluid positive pressure Δp.sub.A. An inlet-side fluid negative pressure −Δp.sub.2 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 Δp.sub.3 is required for opening the fluid passage 12. This may also be referred to as the outlet-side opening positive pressure Δp.sub.3.

[0057] The fluid differential pressures Δp.sub.1, −Δp.sub.2 and Δp.sub.3 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 Δp.sub.3 is greater than the required inlet-side fluid positive pressure Δp.sub.1. Expressed in other words, the required inlet-side fluid negative pressure −Δp.sub.2 is greater in terms of value than the required inlet-side fluid positive pressure Δp.sub.1.

[0058] Furthermore, it is understood that, in the clinical use of the catheter arrangement, states with a neutral fluid pressure, i.e. p.sub.E=p.sub.A, 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.

[0059] In the embodiment shown, the elastic wall portion 18 is configured in such a manner that the inlet-side opening positive pressure Δp.sub.1 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 Δp.sub.2is 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.

[0060] 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.

[0061] For this purpose, it is provided here that the elastic wall portion 18 has a cupola-shaped curvature W (FIG. 5). The fluid passage 12 is arranged in the region of an apex point S of the curvature W. The cupola-shaped curvature W is curved outwards in the direction of the outlet side A and inwards in the direction of the inlet side E. Expressed in other words, the cupola-shaped curvature W is configured to be concave in the direction of the proximal inlet side E and convex in the direction of the distal outlet side A. In the embodiment shown, the elastic wall portion 18 has a constant wall thickness, and therefore the wall sides of the elastic wall portion 18 that are opposite one another in the thickness direction are made to extend in parallel.

[0062] In further embodiments, the elastic wall portion does not have a constant wall thickness.

[0063] 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 FIG. 3.

[0064] 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 (FIG. 3). The housing body 4 is configured as a single piece here.

[0065] 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.

[0066] 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.

[0067] In the alternative embodiment shown with reference to FIG. 4, the housing body 4a has a two-part configuration with a first housing part 41a and a second housing part 42a. The valve element 6 is fixed between the two housing parts 41a, 42a. For the installation, the valve element 6 is pushed in the axial direction from the inlet side E into the first housing part 41a. An elastic deformation of the valve element 6 is not necessarily required here. After the valve element 6 is introduced, the second housing part 42a is pushed axially and in the distal direction into the first housing part 41a and the valve element 6 is thereby fixed between mutually axially opposite end surfaces of the first housing part 41a and of the second housing part 42a. The two housing parts 41a, 42a are then joined together in a manner known to a person skilled in the art, for example are adhesively bonded or welded.

[0068] 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.

[0069] In particular, the fluid passage may differ in configuration. In the simplest case, the fluid passage is formed by an individual slot.

[0070] In the configuration according to FIG. 6, the fluid passage 12 is formed by a slot arrangement 21, 22 which has a first slot 21 and a second slot 22. The first slot 21 and the second slot 22 are each made to extend as radial slots in the radial direction R and form a common intersecting point P. In the embodiment shown, the latter coincides with the apex point S of the cupola-shaped curvature W. The first slot 21 and the second slot 22 are arranged in a cross-shaped manner with respect to each other and are oriented with respect to each other here. The slot arrangement 21, 22 thereby assumes a “+”-shaped configuration. The slot arrangement 21, 22 is made to extend in the axial direction through the wall thickness of the elastic wall portion 18. The fluid passage 12 is shown here with reference to FIG. 6 in its closed state. In said closed state, subsections 181, 182, 183, 184 of the elastic wall portion 18, which subsections 181, 182, 183, 184 are separated from one another by the slot arrangement 21, 22, lie fluid-tightly against one another. The subsections 181 to 184 are in each case approximately triangular, which is intended to be clarified schematically by the dashed lines shown in FIG. 6. During a corresponding fluid pressurization of the elastic wall portion 18, the subsections 181 to 184 are arched and unfolded in the axial direction relative to the remaining portions of the elastic wall portion, as a result of which the fluid passage 12 is opened. This arching or unfolding of the subsections 181 to 184 takes place either in the direction of the outlet side A or in the direction of the inlet side E depending on the prevailing fluid pressure conditions.

[0071] Further embodiments of valve elements 6a to 6i according to the invention are shown with reference to FIGS. 7 to 20. The valve elements 6a to 6i are substantially identical in respect of their design and their operation to the valve element 6. In order to avoid repetitions, primarily substantial differences of the valve elements 6a to 6i will therefore be explained below. Otherwise, what has been already disclosed with regard to the valve element 6 is noted and express reference is made thereto. The valve elements 6a to 6i can be used instead of the valve element 6 for the catheter arrangement 1.

[0072] The valve element 6a according to FIG. 7 provides a slot arrangement 21a, 22a, 23a with a first slot 21a, a second slot 22a and a third slot 23a. Said slots are arranged so as to form two common intersecting points P, P′ and, in the embodiment shown, form a H shape. The slot arrangement 21a, 22a, 23a separates subsections 181a, 182a of the elastic wall portion 18a. Said subsections have an approximately rectangular configuration, which is clarified in turn by the dashed lines. The fluid passage 12a formed by the slot arrangement 21a, 22a, 23a is shown in its closed state in FIG. 7. Upon shifting into the open state, the subsections 181a, 182a unfold elastically in the axial direction.

[0073] The valve element 6b shown with reference to FIG. 8 provides a slot arrangement 21b, 22b, 23b with a first slot 21b, a second slot 22b and a third slot 23b. These slots are arranged so as to form precisely one common intersecting point P″ and, in the embodiment shown, form a star shape. The slot arrangement 21b, 22b, 23b separates subsections 181b, 182b, 183b of the elastic wall portion 18b. Said subsections have an approximately triangular configuration, which is clarified in turn by the dashed lines. The fluid passage 12b formed by the slot arrangement 21b, 22b, 23b is shown in its closed state in FIG. 8. Upon shifting into the open state, said subsections 181b, 182b, 183b unfold elastically in the axial direction.

[0074] In contrast to the valve element 6, the valve element 6c according to FIG. 9 has a comparatively flat cupola-shaped curvature Wc. This is achieved by a maximum height H of the cupola-shaped curvature Wc being smaller than a radial diameter D of the elastic wall portion 18c. In the embodiment shown, a ratio between the axial height H and the radial diameter D is approximately 1:5. The valve element 6c has improved flow properties in comparison to the valve element 6. To this end, reference is made to a direct comparison between FIGS. 3 and 9. In the fitting situation shown with reference to FIG. 3, what is referred to as a dead space is identified by reference sign T. The dead space T extends annularly on a radially outer region of the distal wall side 25 of the valve element 6. Even in the open state of the valve element 6 an only slow or, in the worst case, even no fluid flow arises in the dead space T. The dead space T is relatively narrow because of the comparatively pronounced cupola-shaped curvature W and therefore the flow only passes weakly or, in the worst case, does not pass therethrough. For this purpose, by contrast, the fitting situation of the valve element 6c shown with reference to FIG. 9 has a dead space Tc which is relatively large and thus the flow can pass therethrough comparatively readily. This is because of the comparatively flat cupola-shaped curvature Wc. The flat cupola-shaped curvature Wc permits an improved fluid flow in the radially outer region of the distal wall side 25c. In the simplest case, the fluid passage 12c can be formed by a single longitudinal slot. Alternatively, a configuration of the fluid passage 12c as a slot arrangement according to the preceding and/or following description is possible.

[0075] 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.

[0076] In contrast to the previously described embodiments, the valve element 6d according to FIG. 10 has a further fluid passage 26d. The further fluid passage 26d is made to extend through the elastic wall portion 18d and can be transferred in a manner induced by fluid pressure between an open state and a closed state. This basically corresponds to the fluid passage 12d which, in the embodiment shown, is formed by a single first slot 21d. The further fluid passage 26d has at least two circumferential slots 27d, 28d, which may also be referred to as the first circumferential slot 27d and second circumferential slot 28d. The circumferential slots 27d, 28d are made to extend in the circumferential direction of the elastic wall portion 18d which here is curved in a cupola-shaped manner. The circumferential slots 27d, 28d are arranged offset by 180° with respect to one another in the circumferential direction. The circumferential slots 27d, 28d are arranged mirror-symmetrically opposite one another and/or with respect to the fluid passage 12d, more precisely: the slot 21d thereof. The circumferential slots 27d, 28d are arranged offset outwards in the radial direction relative to the fluid passage 12d. The first slot 21d is in turn arranged in an apex point, not denoted specifically, of the cupola-shaped curvature.

[0077] 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.

[0078] It is shown with reference to FIG. 11 that the slot 21d of the fluid passage 12d has a proximal slot length L1 on the proximal wall side 24d. On the distal wall side 25d, the slot 21d has a different distal slot length L2. In the embodiment shown, the proximal slot length L1 is greater than the distal slot length L2. This assists an infusion-pressure-induced opening of the fluid passage 12d. For this purpose, by contrast, a converse ratio between the proximal slot length L1 and the distal slot length L2 would assist an aspiration-pressure-induced opening of the fluid passage 12d. Owing to the different slot lengths L1, L2, end regions which are opposite one another in the longitudinal direction of the slot 21d are inclined with respect to one another.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] The valve element 6e according to FIG. 12 differs by means of a profiling 30e which is present in the region of the fluid passage 12e. The profiling 30e is formed on the elastic wall portion 18e. The profiling 30e can basically be designed as a raised or recessed profiling. In the present case, the profiling 30e is recessed in the elastic wall portion 18e. The profiling 30e is recessed in the elastic wall portion 18e from the proximal wall side 24e. If the profiling instead is designed as a raised profiling, the profiling preferably protrudes from the elastic wall portion 18e starting from the distal wall side 25e. The profiling 30e leads to a reduced wall thickness of the elastic wall portion 18e in the region of the fluid passage 12e. The profiling 30e may also be referred to as an indentation, hollow, groove, channel or the like. The profiling 30e assists an infusion-pressure-induced opening of the fluid passage 21e.

[0083] 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.

[0084] In addition, the valve element 6e in accordance with the valve element 6d according to FIGS. 10 and 11 has a further fluid passage 26e, but this is not compulsory.

[0085] The valve element 6f according to FIG. 13 differs from the valve element 6e according to FIG. 12 in that further profilings 31f are present in the region of the further fluid passage 26f. The further profilings 31f are in each case arranged on the first circumferential slot 27f and the second circumferential slot 28f and influence the opening and closing behaviour of said circumferential slots. The further profilings 31f —corresponding to the profiling 30e—can be basically raised or recessed. In addition, the further profilings 31f can be arranged on the proximal wall side 24f and/or the distal wall side 25f of the elastic wall portion 18f. In the embodiment shown, the further profilings 31f are arranged on the proximal wall side 24f and are recessed in same. In a further refinement, the two further profilings are arranged and formed in a raised manner on the distal wall side 25f. In a further refinement, one of the further profilings is arranged on the proximal wall side and a further of the further profilings on the distal wall side.

[0086] It is understood that the profilings 30e, 31f shown with reference to FIGS. 12 and 13 for influencing the opening and closing behaviour of the fluid passage and of the further fluid passage can be combined and formed differently with one another. In addition, a combination with the different slot lengths shown with reference to FIG. 11 on the proximal and distal wall side is possible.

[0087] The valve element 6g (FIGS. 14, 15) permits an alternate, sudden eversion of the elastic wall portion 18g between a first state (FIG. 16) and a second state (FIG. 17). The sudden eversion takes place depending on the respective pressurization and/or direction of the fluid flow. Expressed in simplified form, the valve element 6g has flip-flop characteristics—it flips and flops based on fluid direction.

[0088] 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.

[0089] It can furthermore be seen with respect to FIG. 15 that the elastic wall portion 18g has a wall thickness which increases in the radial direction R from the outside inwards and which is at its maximum approximately in the region of the apex point of the cupola-shaped curvature Wg. The wall thickness increasing from the outside inwards permits an improved stability of the elastic wall portion 18g both in the first state (FIG. 16) and in the second state (FIG. 17). The radially outer region with a minimal wall thickness may also be referred to as the annular wall portion 33g. The annular wall portion 33g assists an eversion meeting requirements because of its comparatively low wall thickness. Furthermore, the valve element 6g has a substantially cylindrical cylinder wall portion 34g (FIG. 15). The cylinder wall portion 34g, at any rate in the first state, is arranged on a radially inner side of the valve element 6g and at one end borders the proximal wall side 24g.

[0090] 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.

[0091] 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 (FIG. 17).

[0092] In the use of the valve element 6g, the operation thereof is in particular as follows: starting from the first state (FIG. 16), an infusion pressure is applied in order to infuse liquid. The infusion pressure brings about an opening of the fluid passage 12g. The valve element 6g remains here in its first state. The first state is to this extent stable. By means of a reduction in the infusion pressure, the fluid passage 12g is shifted into its closed state. In order to aspirate liquid, an aspiration pressure is applied. This aspiration pressure brings about a sudden eversion of the elastic wall portion 18g into the second state (FIG. 17), wherein the fluid passage 12g initially remains closed here. If the aspiration pressure is maintained and/or increased, the fluid passage 12g is in turn shifted into its open state such that liquid can flow from the outlet side A to the inlet side E. The second state taken up here is again stable. By means of a reduction in the aspiration pressure, the fluid passage 12g is shifted into its closed state. By renewed application of an infusion pressure, the valve element 6g can again be everted into its first state and the fluid passage 12g opened again for the infusion of liquid.

[0093] 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.

[0094] The valve element 6h according to FIGS. 18 and 19 differs from the valve elements shown up to now by a first pair P1 of rib elements and a second pair P2 of rib elements. The first pair of rib elements P1 has two rib elements 35h, 36h, which may also be referred to as the first rib element 35h and second rib element 36h. The second pair P2 of rib elements has two rib elements 37h, 38h, which may also be referred to as the third rib element 37h and fourth rib element 38h. The first rib element 35h and the second rib element 36h are arranged opposite each other in pairs with respect to the intersecting point P of the fluid passage 12h. The same applies analogously to the third rib element 37h and the fourth rib element 38h. The first pair P1 of rib elements is arranged offset radially further outwards with respect to the intersecting point P than the second pair P2 of rib elements.

[0095] 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.

[0096] 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.

[0097] 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 FIG. 19 should be understood as being purely by way of example. In further refinements, a shaping different thereto can be provided.

[0098] With reference to FIG. 20, a further embodiment is shown which—expressed in simplified terms—provides an inverted fitting of the valve element 6i into the housing body 4. The valve element 6i has in turn an elastic wall portion 18i with a cupola-shaped curvature Wi. The cupola-shaped curvature Wi is arched in the direction of the proximal inlet side E. Expressed in other words, the elastic wall portion 18i is convex in the direction of the proximal inlet side E and concave in the direction of the distal outlet side A. The inventors have found that the present embodiment permits improved flow properties during an aspiration of liquid. This is because, owing to the previously described orientation of the cupola-shaped curvature W.sub.i, reduced turbulences occur in the proximal flow direction. At best, even a laminar flow can be achieved. This opposes an undesirable haemolysis if the catheter arrangement is used for taking blood. Conversely, a turbulent flow in the distal direction is promoted. This prevents accumulations of germs.

[0099] 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.