Cannula assembly

Abstract

The invention relates to a cannula assembly (1) for introducing into the umbilical cord of a newborn, which has an insertion region (2) arranged in the distal end region thereof and tapering in the distal direction, and a cannula (3) arranged adjacent to same in the proximal direction and having a crimped, expandable stent (4) arranged in the distal end region thereof, preferably with an outer diameter in the crimped state that is smaller than or equal to the outer diameter of the cannula (3), preferably with an inner diameter in the expanded state that is greater than or equal to the inner diameter of the cannula (3). The invention also relates to a set with a cannula assembly of this type comprising at least two inner cannulas with different tip designs.

Description

[0001] Cannula arrangement

[0002] The invention relates to a cannula arrangement for insertion into the umbilical cord of a newborn.

[0003] In newborns, especially premature babies, there may be a need for permanent medication or for the development of an extracorporeal blood circuit to support body functions, e.g. for extracorporeal membrane oxygenation or to support kidney function or other applications.

[0004] In principle, access to the bloodstream via the umbilical cord is possible for newborns, but this proves to be problematic because the umbilical cord closes itself shortly after birth due to a natural vascular spasm and can no longer be used after this time.

[0005] Against this background, it is an object of the invention to provide a cannula arrangement with which the umbilical cord can be cannulated not only in the blood-supplied state (i.e. before it is severed), but preferably also after it has been severed and the vascular spasm has started to occur, and can be reopened and used as an access, e.g. to realize an extracorporeal circulation, or for other applications, e.g. medication.

[0006] This object is achieved according to the invention with a cannula arrangement, at the distal end region of which an insertion region tapering distally is arranged, next to which a cannula is arranged in the proximal direction, at the distal end region of which a crimped, expandable stent is arranged.

[0007] In common usage, distal and proximal are understood as directions relative to a user of the cannula assembly during its intended use. Distal therefore means, from the user's perspective, toward the umbilical cord, and proximal indicates the opposite direction, i.e., toward the user.

[0008] The cannula, which is arranged proximally next to the insertion area, is therefore located behind the insertion area when viewed from distal to proximal.

[0009] The invention enables the use of the cannula assembly to dilate the umbilical cord with its tapered insertion area, facilitating the insertion of the cannula with its distally positioned, crimped stent into the umbilical cord. After expansion of the previously crimped stent, the umbilical cord is held open by the stent, thus overcoming the vascular spasm, allowing the umbilical cord to be used permanently as an access point.

[0010] The invention can preferably provide for the tapered insertion area to be uniformly tapered over its entire circumference. This preferably creates a rotationally symmetrical area. However, the tapering can also be uneven, so that there is no rotational symmetry in the insertion area.

[0011] In one possible embodiment, the stent at the distal end of the cannula can be connected to the end of the cannula, in particular, can be attached to it. In this embodiment, the end of the cannula does not protrude into the stent. However, it can also be provided that the end of the cannula lies within the stent. The stent can thus be attached externally to the cannula surface. The end of the cannula can lie internally in an axial portion of the stent, or it can penetrate the stent completely up to its distal end. Preferably, however, the cannula does not protrude distally beyond the end of the stent.

[0012] If the end of the cannula is at least partially embedded in the stent, this end of the cannula is compressed by the stent when the stent is crimped. The cannula is therefore flexible or suitably compressible and preferably self-expandable when the stent expands.

[0013] One possible design may provide for the stent to be covered with a foil over all or part of its length. The coating can be applied externally, internally, or on both sides of the stent. A foil, preferably on the inside, ideally provides a seamless connection or transition into the more proximal inner lumen of the cannula. The foil thus preferably merges into the inner surface of the cannula.

[0014] If an external foil is provided, this ideally represents a seamless connection to the outer surface of the cannula.

[0015] Such an inner or outer film can be formed, for example, by a reduced-thickness end region of the cannula. The film and cannula can thus be made of the same material, preferably in one piece. The stent can also be embedded in the thickness of the cannula in another design.

[0016] One possible embodiment preferably provides that the outer diameter of the stent in the crimped state is smaller than or equal to the outer diameter of the cannula, particularly compared to the area of ​​the cannula not covered by the stent. Further preferably, the inner diameter of the stent in the expanded state is larger than or equal to the inner diameter of the cannula. This provides the advantage that elements that also fit through the cannula can be moved through the stent. Such elements can be, for example, removable elements of the cannula assembly.

[0017] In preferably all embodiments of the invention, the cannula forms a structural unit with the stent, ie stent and cannula are connected, in particular inseparably connected when used as intended.

[0018] In a first possible embodiment, the cannula assembly of the invention can be a single-piece assembly, particularly at least with regard to its components: insertion region, stent, and cannula. In this case, the tapered insertion region, which is arranged distally next to the stent arranged on the cannula, is a component of the preferred unit consisting of stent and cannula.

[0019] In a second possible embodiment, the cannula arrangement can also be designed in several parts, in particular in the sense that the tapered insertion region is formed separately from the unit comprising cannula and stent, in particular on a separate element that is preferably removable from / from the cannula arrangement, e.g. after insertion into the umbilical cord, in particular through the expanded stent and the cannula. With regard to the first aforementioned possible embodiment, the invention can thus provide that the tapered insertion region is preferably formed at least in regions by the stent itself at the distal end region of the cannula, for which purpose the stent, in the crimped state, tapers distally at least in regions. The stent does not have to taper over its entire extent, but at least in its distal region.The stent can therefore have a non-tapered section and a distally adjacent tapered section. The stent can also be tapered throughout.

[0020] In this first embodiment, the stent thus assumes, on the one hand, the function of supporting the dilation of the umbilical cord during the insertion process of the cannula assembly due to its tapered shape in the crimped state, and, on the other hand, the further function of overcoming the vascular spasm after its expansion and keeping the umbilical cord open.

[0021] In a preferred embodiment, the stent can have a constant cross-section in its expanded direction, in particular an inner free cross-section that is greater than or equal to the inner cross-section of the cannula. From such an expanded state with a constant cross-section, the stent can be converted into the crimped state by increasing the strength of the crimp distally.

[0022] Another embodiment of the first embodiment of a one-piece cannula assembly can also provide for a distally tapered insertion region to be fixedly arranged distally next to the crimped and expandable stent. This insertion region is connected to the stent. This insertion region can be formed, for example, by a portion of the cannula that is passed through the stent and protrudes distally from it, or by a tapered component that is attached distally to the stent.

[0023] In the second possible embodiment, which is preferred for the invention, it can also be provided that the tapered insertion region is formed by the end of a rod-shaped or tubular insertion aid, which end is thickened in cross section and tapers distally, onto which the cannula with the stent is pushed or at least can be pushed pointing towards the thickened end.

[0024] In a cannula assembly in which the stent and cannula unit is pushed onto such an insertion aid, the stent is preferably located proximally next to the thickened end, in particular adjacent to it, preferably at a distance, in particular between the thickened end and the cannula, or at least in front of its proximal end region. Viewed from distal to proximal, the stent is thus located behind the thickened end.

[0025] The thickened end of the insertion aid is preferably tapered distally and proximally, preferably with the distal taper having a smaller gradient than the proximal taper. In the case of a tubular insertion aid, the thickened end can be tapered in both directions to a cross-section that is identical both in front of and behind the thickened end. The tubular design of the insertion aid has the advantage that additional elements can be passed through it, or it can also be used for medication delivery during the insertion process.

[0026] An introducer of this design can therefore be used temporarily in the cannula assembly, specifically to facilitate the insertion of the cannula and stent unit into the umbilical cord. For this purpose, this unit is pushed onto the introducer assembly, e.g., until the stent reaches the proximal side of the thickened end, in particular, until it comes into contact with the stent. The entire cannula assembly thus formed can be inserted into the umbilical cord with the thickened and distally tapered end of the introducer assembly leading.

[0027] A preferred embodiment provides that the maximum outer diameter of the introducer at the thickened end is smaller than the inner diameter of the cannula and / or the expanded stent. This makes it possible for the introducer to be removed from the cannula assembly in a proximal direction after the stent has been expanded and passed through the stent and through the cannula.

[0028] It is further preferred that the outer diameter of the crimped

[0029] The diameter of the stent is smaller than the maximum outer diameter of the introducer. This ensures that the cannula and stent unit cannot be accidentally guided over the thickened end during insertion.

[0030] All possible embodiments, in particular the first and second embodiments of the type described, can provide that the cannula and the stent arranged in its distal end region are surrounded by a sheath that can be pulled proximally over the cannula and that holds the stent in a crimped state. After removal, preferably after retraction of the sheath, the stent is automatically expandable, in particular into an expanded state in which the stent has a constant cross-section in its direction of extension. Such a sheath can thus assume the function of a retaining element that holds the stent in a crimped state. Such a sheath can be provided in addition to the aforementioned outer sheath or can form said sheath.

[0031] In particular, in the aforementioned type of the first embodiment, the cross-section of the sheath can be provided to taper distally. However, this is also possible in the other embodiments.

[0032] When providing such a sheath, the sheath can preferably further comprise at least one weakening line extending in the axial direction of the cannula / sheath, along which the sheath can be torn open. Such a weakening line is preferably arranged at least in a region of the sheath that tapers distally in cross-section, if such a region is provided.

[0033] Particularly if the stent is not designed to be self-expanding, the invention can provide, in another preferred development, that an expandable balloon is arranged below the stent on the rod-shaped or tubular introduction aid, the inner volume of which balloon can be filled with a fluid, wherein the stent can be converted into the expanded state by applying internal force to the balloon. For this purpose, the introduction aid has such a balloon proximally next to the thickened end, e.g. an inflatable sleeve which surrounds an area proximal to the thickened end over 360 degrees and is inflatable from the inside. By pushing on the unit consisting of cannula and stent, the balloon gets under the stent, so that the inflation of the balloon converts the stent into the expanded state. It is preferably provided that the balloon is fastened to the introduction aid, oraround it, and whose inner volume can be filled with a fluid through a channel in the insertion aid, in particular a channel within the wall thickness of a tubular insertion aid.

[0034] The insertion aid is preferably designed in such a way that it can be removed from the cannula arrangement with the balloon in the unfilled or deflated state through the stent and the cannula in a proximal direction.

[0035] As already mentioned, the insertion aid can preferably be tubular. In such a case, a connection element, preferably a Luer lock, is preferably arranged at the proximal end of the insertion aid for the supply and / or removal of fluids from a vessel with a corresponding connection element.

[0036] A connecting element, e.g. a Luer-Lock, can also preferably be provided on the cannula, in particular at its proximal end.

[0037] Furthermore, the cannula, in particular a proximal end region of the cannula, preferably which is not inserted into the umbilical cord, can preferably have an anti-kink protection which is designed, for example, as a spiral reinforcement.

[0038] In a further development, the cannula assembly according to the invention can also comprise, as a further component, a rigid or flexible core, which is designed such that it can be inserted into the tubular insertion aid, or conversely, such that the insertion aid, preferably with the cannula and stent unit pushed onto it, can be pushed on. Such a core preferably has a consistent cross-section, in particular a round cross-section, over its entire length.

[0039] It can be used in such a way that the core is first inserted into the umbilical cord as a guide. For example, the core can straighten the umbilical cord. The introducer, with the cannula and stent unit worn on it, can then be pushed onto the core while it is still in the umbilical cord and pushed toward the umbilical cord until the introducer, with its tapered, thickened end, penetrates the umbilical cord and expands it, allowing the stent and cannula to penetrate. After this, the core can be removed, and once the stent has expanded, the introducer can also be removed.

[0040] The core itself preferably also has a tapered tip or a tapered distal end. The distal end of the core can be pointed, particularly as a cutting edge, or blunt, preferably convex. A cutting edge offers the advantage of allowing the core to more easily penetrate the umbilical cord wall.

[0041] The invention can preferably also provide a set with a cannula assembly of the type described above, in particular comprising a unit consisting of a cannula and stent, a tubular insertion aid, and at least two cores with different distal end configurations. Thus, using such a set, a user can adapt to various possible conditions, in particular the course of the umbilical cord, by selecting a suitable core from the several cores in the set.

[0042] Preferably, the invention provides that the separate elements of the invention are all arranged or can be arranged around a common central axis. These separate elements include a) the cannula and stent unit, b) the introducer, and c) the core.

[0043] Embodiments of the invention are described in more detail with reference to the figures.

[0044] Figure 1 shows the aforementioned first embodiment in a possible variant.

[0045] The cannula arrangement 1 according to the invention has at the distal end (here above) an insertion region 2 which tapers distally and a crimped, expandable stent 4 located proximally in front of it, which is connected to a cannula 3.

[0046] Here, the distal region of the stent 4 itself forms the tapered insertion region 2, e.g. because the stent 4 is more strongly crimped in its distal region than in the proximal region in front of it.

[0047] The stent 4 is further covered by a foil 5, which can preferably also lie at least partially over the cannula 3. This foil 5 can also serve to hold the stent 4 in the crimped state, for which purpose the foil then tapers distally in cross-section.

[0048] The stent 4 can thus be self-expanding when the film 5 is removed. For this purpose, the film 5 can be pulled proximally, for example. To facilitate this, the film 5 can have a linear weakening 6, so that the film 5 tears open more easily.

[0049] The left illustration of Figure 1 shows the cannula assembly 1 with the stent 4 still crimped, i.e., prior to insertion into the umbilical cord. The right illustration shows the same cannula assembly after the film 5 has been removed, resulting in the expansion of the stent 4. This is the state the cannula assembly assumes when inserted into the umbilical cord. The tapered crimped stent 4 facilitates insertion into the umbilical cord, with the expanded stent 4 keeping the umbilical cord open and overcoming vascular spasm.

[0050] In this first embodiment, the cannula assembly 1 concerning the components insertion area 2, cannula 3 and stent 4 is a one-piece assembly.

[0051] Figure 2 shows the second aforementioned embodiment, in which the insertion area 2 is formed on a separate element, namely on an insertion aid 10.

[0052] As in Figure 1, the cannula 3 and the stent 4 are formed as a connected unit. The stent 4 can be covered with a foil on the inside, outside, or on both sides, but this is not mandatory. Figure 2 shows the stent 4 in its crimped state in all partial images.

[0053] The insertion aid 10 essentially represents a tube 10a with preferably consistently identical inner and outer cross-sections. Distally, the tube 10a or the insertion aid 10 has a thickened end region 10b, which tapers distally and forms the insertion region 2, which facilitates insertion into the umbilical cord. Proximally in front of or next to the thickened end region 10b, an inflatable balloon 10c is provided. The balloon 10c can be filled through a line in the wall thickness of the tube 10a. The design is selected such that the unit comprising cannula 3 and stent 4 can be pushed onto the insertion aid so that the balloon 10c comes to rest beneath the crimped stent. This forms the cannula arrangement 1 in a possible variant of the second embodiment.

[0054] A further variant may provide that the cannula assembly 1 comprises another separate component, namely a core 20 made of a flexible or rigid element, in particular a rod-shaped element with a tapered distal end, which may be designed, for example, as a cutting edge. The core may be hollow or solid.

[0055] This core 20 is designed so that it can be inserted into the assembled cannula arrangement comprising the cannula / stent unit and introducer, in particular into the interior of the tube 10a of the introducer 10.

[0056] The cannula assembly 1 according to the invention can thus be formed, shown on the far right in Figure 2. In practice, it may be provided that the core 20 is first pierced and inserted into the umbilical cord and then the insertion aid 10, with the cannula / stent unit carried thereon, is slidably pushed along the core.

[0057] Once the appropriate position has been found, the core 20 can be removed or left in place for the time being. The balloon 10c is inflated, expanding the stent 4. The introducer 10 (and, if necessary, the remaining core 20) can then be pulled proximally out of the cannula 3 / stent 4 unit.

[0058] A blood connection to the bloodstream of a newborn can then be established via the hollow interior of the cannula 3 and the stent 4, which keeps the umbilical cord open.

[0059] Figure 3 shows a detailed view of the distal end region of a cannula assembly according to the invention with the previously mentioned construction details.

Claims

Patent claims Cannula arrangement (1) for insertion into the umbilical cord of a newborn, at the distal end region of which an insertion region (2) tapering distally is arranged, next to which a cannula (3) is arranged in the proximal direction, at the distal end region of which a crimped, expandable stent (4) is arranged, preferably the outer diameter of which in the crimped state is less than or equal to the outer diameter of the cannula (3), preferably the inner diameter of which in the expanded state is greater than or equal to the inner diameter of the cannula (3).Cannula arrangement according to claim 1, characterized in that the tapered insertion region (2) is formed at least in regions by the stent (4) at the distal end region of the cannula (3), for which purpose the stent (4) tapers distally at least in regions in the crimped state, in particular wherein the stent (4) has a constant cross-section in its extension direction in the expanded state. Cannula arrangement according to claim 1, characterized in that the tapered insertion region (2) is formed by the end region (10b) of a rod-shaped or tubular insertion aid (10), which end region has a thickened cross-section and tapers distally, onto which the cannula (3) with the stent (4) is pushed or at least can be pushed, pointing in the direction of the thickened end region (2).Cannula arrangement according to claim 3, characterized in that the maximum outer diameter of the insertion aid (10) at the thickened end region (10b) is smaller than the inner diameter of the cannula (3) and / or the expanded stent (4), in particular so that the insertion aid (10) can be removed from the cannula arrangement in a proximally direction after expansion of the stent (4) through the stent (4) and the cannula (3). Preferably, the outer diameter of the crimped stent (4) is smaller than the maximum outer diameter of the insertion aid (10). Cannula arrangement according to one of the preceding claims, characterized in that the cannula (3) and the stent (4) arranged in its distal end region are surrounded by a sheath (5) which can be pulled proximally over the cannula (4) and which holds the stent (4) in a crimped state, wherein the stent (4) is automatically expandable after removal, preferably after retraction of the sheath (5), in particular into an expanded state in which the stent (4) has a constant cross-section in its direction of extension. Cannula arrangement according to claims 5 and 2, characterized in that the cross-section of the sheath (5) tapers distally.Cannula arrangement according to claim 5 or 6, characterized in that the sheath (5) has at least one weakening line (6) running in the axial direction of the cannula (3) / sheath (5), at which line the sheath (5) can tear open, preferably the weakening line (6) is arranged at least in a region of the sheath (5) that tapers distally in cross-section. Cannula arrangement according to one of the preceding claims 3 to 7, characterized in that an expandable balloon (10c) is arranged below the stent (4) on the rod-shaped or tubular insertion aid (10), the inner volume of which balloon can be filled with a fluid, wherein the stent (4) can be transferred into the expanded state by applying internal force to the balloon (10c).Cannula arrangement according to claim 8, characterized in that the balloon (10c) is fastened to the insertion aid (10) and its inner volume can be filled with a fluid through a channel in the insertion aid (10), in particular a channel within the wall thickness of a tubular insertion aid (10), preferably wherein the insertion aid (10) with the balloon (10c) can be removed in the unfilled or deflated state through the stent (4) and the cannula (3) in the proximal direction from the cannula arrangement. Cannula arrangement according to one of the preceding claims 3 to 9, characterized in that the insertion aid (10) is tubular. Cannula arrangement according to claim 10, characterized in that a connection element, preferably a Luer lock, is arranged at the proximal end of the insertion aid (10) for supplying and / or removing fluids from a vessel with a corresponding connection element. Cannula arrangement according to claim 10 or 11, characterized in that it comprises a rigid or flexible core (20) which can be inserted into the tubular insertion aid (10) and / or onto which the cannula arrangement with the tubular insertion aid (10) can be pushed after insertion of the core into an umbilical cord, preferably wherein the core has a tapered tip. Cannula arrangement according to claim 12, characterized in that the distal end of the core (20) is pointed, in particular as a cutting edge, or blunt, preferably spherical.Set with a cannula arrangement according to one of the preceding claims comprising at least two cores with different designs of the distal end.

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