Inner cannula for tracheostomy tube

Abstract

An inner sleeve comprising a domed portion is proposed in which the average wall thickness of at least a longitudinal portion of the sleeve wall extending along an inner arcuate side is at least 40% greater than the average wall thickness of a longitudinal portion of the sleeve wall extending along an outer arcuate side and opposite the longitudinal portion extending along the inner arcuate side.

Description

[0001] The present invention relates to an inner cannula for insertion into an outer cannula or outer tube of a tracheostomy tube, wherein the inner cannula comprises a tubular cannula wall consisting of a flexible plastic material and extending in the longitudinal direction between a proximal end of the inner cannula and an opposite distal end of the inner cannula, wherein the inner cannula comprises a domed portion in its longitudinal direction having an inner and an outer curved side. The present invention also relates to a tracheostomy tube having an outer cannula and an inner cannula of the type described above arranged in the outer cannula, a method for producing such a tracheostomy tube, and the use of an inner cannula of the type described above for replacing a used inner cannula arranged in the outer cannula of a tracheostomy tube.

[0002] Tracheostomy tube (also referred to as tracheostomy cannula) enables long-term ventilation of patients with a tracheal inlet (tracheostomy) formed, for example, by means of a surgical procedure (tracheotomy) through the soft tissue of the neck. In the case of spontaneous breathing in tracheostomy patients, the tracheostomy tube can also be used to keep the stoma open. In addition, the tracheostomy tube can also be used as a connector that can be used for accessories (such as HME or tracheostomy valve). In order to achieve an optimal transition between the tracheostomy and the trachea, the tracheostomy tube typically includes a dome-shaped portion.

[0003] For their intended use, many tracheostomy tubes include an inner cannula (also called an inner tube) that is arranged in an outer cannula (also called an outer tube) and, in many cases, can be locked in the outer cannula, while other tracheostomy tubes are used without an inner cannula arranged therein. There are also tracheostomy tubes that can be used both with and without an inner cannula. In the prior art, the term "tracheostomy tube" is used so that it covers all these variations without explicitly disclosing whether the tracheostomy tube includes an inner cannula.

[0004] Tracheostomy tubes with an inner cannula have the advantage that if the inner cannula becomes clogged, for example, with mucus, it can be replaced very simply, while the outer cannula can remain on the patient. Furthermore, different types of inner cannulas can be quickly and easily exchanged to adapt the tube's functionality to potentially changing requirements. For example, if a patient wishes to speak, an inner cannula with a voice window can be inserted into an outer cannula with a window. In contrast, if the patient requires ventilation, a closed inner cannula without a window can be used again. Replacing the inner cannula is easier and gentler for the patient than completely replacing the outer cannula. This is particularly true for newly formed stomas, where dangerous complications can frequently occur when replacing tracheostomy tubes.

[0005] There is a wide variety of tracheostomy tubes on the market that are implemented in different ways, with attempts to use them to meet various requirements. Given the sometimes very different anatomical structures and physical conditions, tracheostomy tubes differ in terms of length, inner and outer diameter of the cannula, the position of the dome, the radius and bend angle, and the softness of the material used.

[0006] Although there are many types of tracheostomy tubes available, the doctors who use them are generally unable to predict with 100% certainty which tube shape and geometry will be optimal for a particular patient. If the patient moves, the requirements may also change, making this prediction even more difficult.

[0007] Therefore, tracheostomy tubes with a cannula that can be bent flexibly are proposed in the prior art. However, bendability cannot be achieved at the expense of kink resistance, which can be tested according to DIN standard ISO 5366:2017 (kink test). If such tracheostomy tubes can be equipped with an inner cannula, the inner cannula must also meet corresponding requirements with regard to kink resistance. In order to achieve the desired flexibility while also achieving kink resistance, tracheostomy tubes with a spirally reinforced cannula are used, for example, wherein the spiral reinforcement can be made of metal or plastic and is typically integrated into the cannula wall.

[0008] In this respect, metal reinforced tracheostomy tube is not suitable for each patient, because these tubes are incompatible with possible necessary MRI diagnosis due to technical reasons.The tracheostomy tube with spiral reinforcement is obtained by extrusion, thermoforming and / or dip coating method conventionally, compared with injection molding, all these methods are methods associated with relatively large manufacturing tolerances, and this can produce problems in design, particularly in the case of the tracheostomy tube with phonation window and inner cannula.In addition, spiral reinforcement cannula can only be manufactured to have relatively large wall thickness within the scope of typically 1.7mm to 2mm, and this may produce problems at the expense of the cannula cross section that can be used for breathing.Due to the lower rigidity of plastics compared with the metal (as stainless steel or nitinol) typically used, the spiral reinforcement made of plastics causes higher wall thickness conventionally.This probably also is the reason that spiral reinforcement inner cannula is not popular so far on the market.

[0009] EP 3 116 573 A1 describes a method in which an extruded hose piece is blow-molded to produce a pattern of two intersecting oblique grooves. However, the inner surface of the sleeve is also blow-molded, resulting in secretions being more likely to adhere to the inner surface, which is unfavorable from a hygienic point of view.

[0010] WO 2004 / 101048 A3 describes a soft tracheostomy tube having an inner sleeve made of PTFE. However, PTFE is relatively expensive and problematic hydrofluoric acid vapors may occur during manufacture and handling.

[0011] WO 2015 / 118288 A1 describes an inner sleeve comprising a very thin sleeve wall which is supported on its outer side by a structural frame consisting of a plurality of ribs arranged on a longitudinal central strip.

[0012] The inner sleeve described in DE 10 2007 011 930 B3 also consists of a thin plastic layer stabilized by a supporting structure, which in this case consists of a hose-like wire and / or a fiber braid. In both cases, the increased kink resistance is achieved only by a relatively complex and at least two-stage manufacturing process.

[0013] In order to provide an inner cannula for a tracheostomy tube which is not subject to the above-mentioned disadvantages, the present invention proposes an inner cannula of the type mentioned in the introduction, which inner cannula comprises a domed portion, wherein the average wall thickness of the cannula wall at least along a longitudinal portion of the cannula wall extending on the inner arcuate side is at least 40% greater than the average wall thickness of the cannula wall along a longitudinal portion extending on the outer arcuate side and opposite the longitudinal portion extending on the inner arcuate side.

[0014] The inner sleeve proposed according to the invention can be easily manufactured by an injection molding method using corresponding tools, which can be carried out technically without great expenditure, and the desired flexibility is provided by the smaller wall thickness of the outer curved side, while the required minimum kink resistance is also ensured by the larger wall thickness of the inner curved side.

[0015] In the context of the present invention, the terms "distal" and "proximal" are used from the perspective of the physician using the tracheostomy tube, i.e., the proximal end is the end of the ventilation device that remains outside the patient's body after insertion into the trachea (the machine end), while the distal end is inserted into the patient's trachea (the patient end).

[0016] In conjunction with the present invention, the term "arched portion" refers to the curved portion of the inner sleeve. In the embodiment where the inner sleeve is curved over its entire length, the arched portion correspondingly covers the entire length of the inner sleeve.

[0017] The terms "outer arc side" and "inner arc side" respectively refer to the outer part and inner part of the circular arch, wherein the transition portion from the outer arc side to the inner arc side in the circumferential direction is located halfway between the outermost point of the outer arc side and the innermost point of the inner arc side.

[0018] In connection with the present invention, the expression "average wall thickness" means the wall thickness which can be determined from the area of ​​a cross section through the sleeve wall along a longitudinal portion of the sleeve extending on the inner curved side or along a longitudinal portion of the sleeve extending on the outer curved side. If the longitudinal portion under consideration measures, for example, 100 mm in the longitudinal direction of the sleeve and the area of ​​the cross section extending through the sleeve wall over this longitudinal portion is 250 mm 2 , the average wall thickness of the longitudinal section considered is 2.5 mm.

[0019] In some embodiments, the longitudinal portion of the outer arcuate side considered is only the outer arcuate portion that extends through the apex of the arch and extends linearly over at least 30%, at least 50%, at least 75%, at least 90%, or the entire length of the outer arcuate side from proximal to distal in the longitudinal direction of the inner sleeve.

[0020] In some embodiments, the longitudinal portion of the inner arcuate side considered is only the inner arcuate portion that extends through the apex of the arch and extends linearly over at least 30%, at least 50%, at least 75%, at least 90%, or the entire length of the inner arcuate side from proximal to distal in the longitudinal direction of the inner sleeve.

[0021] In some embodiments, the longitudinal portion of the outer arcuate side considered may include, in addition to the longitudinal portion extending around the outermost circumference of the outer arcuate side or around the innermost circumference of the inner arcuate side, a longitudinal portion extending parallel thereto. If the domed portion of the inner sleeve is considered in a cross section relative to its longitudinal axis, then for each longitudinal portion extending in the longitudinal direction in a region that extends in the circumferential direction of the sleeve around the longitudinal portion extending along the outermost circumference of the outer arcuate side over 10% of the total circumference of the pipe wall cross section, and / or for each longitudinal portion extending in the longitudinal direction in a region that extends in the circumferential direction of the sleeve around the longitudinal portion extending along the innermost circumference of the inner arcuate side over 10% of the total circumference of the sleeve wall cross section, according to the present invention, the outer arcuate side has a smaller average wall thickness than the inner arcuate side.

[0022] The greater wall thickness on the inner arcuate side can be achieved in that, at least in the region of the longitudinal portion extending along the inner arcuate side and the longitudinal portion extending along the outer arcuate side, the inner circumference and the outer circumference of the sleeve wall are each circular, elliptical or oval in a cross section perpendicular to the central longitudinal axis of the inner sleeve and are selected and arranged so that the average wall thickness of the longitudinal portion on the inner arcuate side is at least 40% greater than the average wall thickness of the longitudinal portion on the outer arcuate side.

[0023] For example, in an embodiment where the outer and inner circumferences of the casing wall are each circular, the center of the circular cross-section of the inner circumference is arranged to be offset from the center of the circular cross-section of the outer circumference toward the outermost point of the outer arcuate side of the outer circumference. In this manner, the wall thickness of the casing wall increases from the outermost point of the outer arcuate side to the innermost point of the inner arcuate side, resulting in an average wall thickness on the inner arcuate side being greater than the average wall thickness on the outer arcuate side.

[0024] The greater wall thickness on the inner arcuate side can also be achieved by including recesses in the sleeve wall in the region of the longitudinal portion extending along the outer arcuate side, whereby the average wall thickness of the sleeve wall is reduced compared to the opposite longitudinal portion extending along the inner arcuate side. Regardless of whether these recesses are provided on the inner or outer arcuate side, such recesses can be arranged both on the outer side of the sleeve wall and on the inner side of the sleeve wall. Preferably, these recesses are arranged only on the outer side of the sleeve wall.

[0025] In this case, the size and shape of the recess on the inner arcuate side and / or the size and shape of the recess on the outer arcuate side are each selected so that the average wall thickness of the longitudinal portion on the inner arcuate side is at least 40% greater than the average wall thickness of the longitudinal portion on the outer arcuate side.

[0026] Due to the different wall thicknesses, an optimal ratio of flexibility to kink resistance is achieved even with relatively low wall thicknesses. In certain embodiments, the average wall thickness of the cannula wall is in the range of 0.3 mm to 1.7 mm, preferably in the range of 0.3 mm to 1.5 mm. If, in such embodiments, the average wall thickness of the domed portion on the outer arcuate side is, for example, 0.30 mm, then according to the present invention, the average wall thickness on the inner arcuate side must be 0.42 mm or greater. If the average wall thickness on the outer arcuate side is 1.0 mm, then the average wall thickness on the inner arcuate side must be at least 1.4 mm.

[0027] According to the present invention, an optimal ratio of flexibility to kink resistance is achieved by having an average wall thickness on the inner curved side that is at least 40% greater than the average wall thickness on the outer curved side. In certain embodiments, depending on the individual desired profile, it may be desirable for the inner curved side to have a more pronounced reinforcement than the outer curved side. Thus, in some embodiments, the average wall thickness on the inner curved side is at least 50% greater, or even at least 60% greater.

[0028] In the case of the cannula according to the invention, the optimal ratio of flexibility to kink resistance can be further fine-tuned by providing, in certain embodiments, recesses in the cannula wall at least in the domed portion, thereby reducing the wall thickness in these areas. The wall thickness in the recessed area can, for example, be in the range of 0.15 mm to 0.4 mm, while the wall thickness in other areas of the cannula wall can be in the range of 0.3 mm to 1.5 mm.

[0029] The shape of the notch in the cannula wall is quite variable, as long as the requirements for different average wall thicknesses are met. In certain embodiments, the notch in the cannula wall extends in a ring-like, buckle-like, or spiral-like manner on the cannula wall in the circumferential direction. The notch can be designed to be continuous or interrupted in certain sections. This allows for greater optimization of the ratio of flexibility to kink resistance and maximum freedom in adapting the cannula to the specific needs of the respective patient.

[0030] The shape of the recess in the sleeve wall can also be designed differently in different parts and regions to optimize the ratio of flexibility to kink resistance. As an example, in some embodiments, the shape of the recess on the outer arcuate side is different from the shape of the recess on the inner arcuate side.

[0031] In some embodiments, the maximum depth of the notch on the inner curved side is greater than the maximum width of the notch. By way of example, in some embodiments, the maximum depth of the notch on the inner curved side is 10% to 70% greater than the maximum width of the notch. In certain embodiments, the maximum depth of the notch on the inner curved side is in a range of 0.5 mm to 1.2 mm, and / or the maximum width of the notch on the inner curved side is in a range of 0.3 mm to 8 mm.

[0032] Since the depth of the notch is greater than its width, the kink resistance is significantly increased, since the upper ends of the sides of the notch bear against each other with a certain degree of bending, thereby supporting each other.

[0033] Some embodiments of the present invention having a notch on the outer arcuate side are characterized in that the maximum depth of the notch on the outer arcuate side is less than the maximum width of the notch. In certain embodiments, the maximum depth of the notch on the outer arcuate side is 10% to 70% less than the maximum width of the notch. In specific embodiments, the maximum depth of the notch on the outer arcuate side is 0.3 mm to 0.5 mm, and / or the maximum width of the notch on the outer arcuate side is 0.5 mm to 1.5 mm.

[0034] In the above embodiment in which the depth of the recess on the outer arcuate side is smaller than its width, a particularly good flexibility of the outer arcuate side is ensured, which is particularly advantageous when introducing the tracheostomy tube into the trachea and at the same time contributes to a relatively high wearing comfort.

[0035] In a particular embodiment of the invention, the recess extends in an annular manner over the entire circumference of the sleeve wall, wherein the individual rings are designed such that on the inner arcuate side the maximum depth of the recess is greater than its maximum width and on the outer arcuate side the maximum depth of the recess is less than its maximum width.

[0036] In an alternative embodiment of the invention, the recess extends annularly over the entire circumference of the cannula wall, wherein between two of these rings, the plastic material of the cannula wall is embodied as a sealing ring having a circular outer circumference 5% to 15% larger than the circular outer circumference of the inner side of the cannula wall of the outer cannula in which the inner cannula is intended to be arranged. The thickness of the sealing ring is preferably <0.5 mm so that when the inner cannula according to the invention is inserted into the outer cannula of the tracheostomy tube, the sealing ring has the necessary flexibility to yield slightly and seal against the inner wall of the outer cannula.

[0037] While the above embodiments provide for a single sealing ring, they already achieve an ideal seal between the inner and outer sleeves. However, in certain embodiments, it may be advantageous to provide two or three such sealing rings directly alongside one another (i.e., separated only by respective intervening notches) or spaced apart by a plurality of notches.

[0038] The region of at least one sealing ring of the aforementioned type can be provided in the domed portion, in the region between the domed portion and the distal end, or in the region between the domed portion and the proximal end. Preferably, the region of at least one sealing ring of the aforementioned type can be provided in the region between the domed portion and the distal end of the inner cannula. In such an embodiment, the inner circumference of the outer cannula particularly preferably tapers toward the distal end.

[0039] Since the center of the dome of the sleeve according to the present invention may be particularly susceptible to kinking, in certain embodiments of the present invention, reinforcing elements are provided on both sides of the sleeve wall at least at or around the apex of the dome, at the periphery of the sleeve wall where the outer side of the dome transitions to the inner side of the dome, and the sleeve wall thickness is increased at this location. This further enables bending not only to be achieved in the center of the sleeve, but also to be distributed over a larger area.

[0040] The above-mentioned reinforcement elements can be embodied such that they protrude slightly beyond the circumference of the sleeve wall in the reinforcement area, wherein a protrusion in the range of 0.05 mm to 0.30 mm is particularly preferred, as a result of which the tendency to kink in the central area of ​​the sleeve is further reduced, firstly due to the greater material thickness in this area and secondly because the inner sleeve can be better supported on the inner wall of the outer sleeve by the protruding reinforcement elements.

[0041] Preferably, the reinforcing elements extend over a larger area in the longitudinal direction of the sleeve than in the transverse direction, wherein the area particularly preferably tapers from its center in the distal direction and / or in the proximal direction so as to provide as little resistance as possible when the corresponding reinforced inner sleeve is introduced into the outer sleeve. In embodiments with annular, buckled, or spiral recesses in the sleeve wall, the thicker sleeve wall portions extending between the recesses of one or more adjacent recesses are connected to each other. Preferably, the reinforcing elements are positioned laterally, i.e. in the region of the transition between the inner side of the dome-shaped portion and the outer side of the dome-shaped portion.

[0042] In some embodiments, one or more guide strips may be provided in the cannula wall, the guide strips extending continuously or interrupted in the longitudinal direction from proximal to distal along certain portions of the outer wall of the inner cannula. In some embodiments, at least one such guide strip extends in the longitudinal direction along the outer side of the dome-shaped portion, and / or at least one such guide strip extends in the longitudinal direction along the inner side of the dome-shaped portion, and / or at least one such guide strip extends in the longitudinal direction along the transition between the inner side of the dome-shaped portion and the outer side of the dome-shaped portion.

[0043] Preferably, the guide strips have a width in the range of 0.5 mm to 2.0 mm and protrude slightly beyond the outer circumference of the sleeve wall, wherein a protrusion in the range of 0.05 mm to 0.30 mm is particularly preferred, thereby facilitating the introduction of the inner sleeve into the outer sleeve.

[0044] When selecting the plastic material for inner sleeve, basically any material that provides required stability and flexibility and patient can tolerate is suitable.In certain embodiments, the flexible plastic material of sleeve wall is selected from the following: polyurethane, polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, SEBS (polystyrene-polyethylene-polybutylene-polystyrene), SBS (polystyrene-polybutadiene-polystyrene), SIS (polystyrene-polyisoprene-polystyrene), IR (polyisoprene), silicone or the mixture of described polymer, such as polypropylene / polystyrene-polyethylene-polybutylene-polystyrene.Typically, employed plastic material has the Shore A hardness of<95, thereby realizes required flexibility.

[0045] According to one aspect of the present invention, an inner cannula according to the present invention is combined with an outer cannula to form a tracheostomy tube by placing the inner cannula according to the present invention within the outer cannula. According to another aspect of the present invention, a tracheostomy tube according to the present invention is manufactured by inserting the inner cannula according to the present invention into the outer cannula of a conventional tracheostomy tube. Therefore, the inner cannula according to the present invention can also be used to replace a used inner cannula in a tracheostomy tube comprising an outer cannula and an inner cannula disposed within the outer cannula.

[0046] In certain embodiments of the invention, the connector for connecting to a mechanical ventilation device is located at the proximal end of the outer sleeve of the tracheostomy tube.In alternative embodiments, the connector for connecting to a mechanical ventilation device is located at the proximal end of the inner sleeve.

[0047] For the purposes of original disclosure, it is pointed out that all features that a person skilled in the art can gather from the present description, the drawings and the claims, even if they are only specifically described in conjunction with certain further features, can be combined individually and in any desired combination with other features or groups of features disclosed herein, as long as this is not expressly excluded or such a combination is impossible or meaningless for technical reasons. Here, for the sake of brevity and readability of this description, a comprehensive and explicit presentation of all conceivable feature combinations has been omitted.

[0048] Various specific embodiments of the present invention are schematically illustrated in the drawings and the associated descriptions of the drawings. These specific embodiments are merely examples of possible combinations of features. However, the present invention is in no way limited to these specific embodiments, but rather encompasses all embodiments covered by the scope of protection of the patent claims, even if they are not explicitly illustrated or described.

[0049] Figure 1 : Figure 1 A schematic diagram shows a longitudinal cross section of a conventional inner casing.

[0050] Figure 2 : Figure 2 A section through the longitudinal axis of a conventional inner cannula (left) and a section through the longitudinal axis of an inner cannula according to the invention (right) are respectively shown, which are highly schematically illustrated.

[0051] Figure 3 : Figure 3 A plan view showing a schematic diagram of one embodiment of an inner sleeve according to the present invention is shown.

[0052] Figure 4 : Figure 4 An embodiment of an inner sleeve according to the invention is shown schematically in longitudinal section.

[0053] Figure 5 : Figure 5 A plan view showing a schematic diagram of a specific embodiment of an inner sleeve according to the present invention is shown.

[0054] Figure 1A schematic diagram illustrates a longitudinal cross-section of a conventional inner cannula 1, which extends longitudinally from its proximal end 3 to its distal end 4. A connection 14 for connecting to a ventilation device is provided at the proximal end 3. Straight longitudinal sections are located at the proximal end 3 and the distal end 4, respectively. A curved, domed portion 5 is located in the region between two dashed lines and has an inner arcuate side 6 and an outer arcuate side 7. On the outer arcuate side 7, the longitudinal section extending along the outer arcuate side 7 is located between the two dashed lines, while on the inner arcuate side 6, the longitudinal section extending along the inner arcuate side extends between the two dashed lines. The apex of the domed outer arcuate side 7 is located at the position marked with the letter S.

[0055] Figure 2 The left figure shows a cross section through the domed portion of a conventional inner sleeve. Here, the tubular sleeve wall 2 is defined by a circular inner periphery 8 and a circular outer periphery 9. The right figure shows an embodiment of an inner sleeve according to the present invention, in which the sleeve wall 2 is also defined by a circular outer periphery 9 and a circular inner periphery 8. Unlike the conventional design shown in the left figure, the outer and inner peripheries are arranged eccentrically rather than concentrically. That is, the center of the inner periphery 8 is offset relative to the center of the outer periphery 9. According to the present invention, this eccentric arrangement is provided at least in certain portions of the domed portion of the inner sleeve. In the embodiment shown here, this eccentric arrangement is designed so that the center of the inner periphery is offset toward the outer arcuate side 7 of the domed portion 5, resulting in a significantly greater average sleeve wall thickness on the inner arcuate side 6 than on the opposing outer arcuate side 7.

[0056] Figure 3 A plan view showing a schematic diagram of an embodiment of an inner sleeve according to the present invention, wherein the embodiment in which the inner arcuate side is thicker than the outer arcuate side is achieved by arranging the circular inner periphery eccentrically with respect to the circular outer periphery, as in Figure 2 In the embodiment shown here, a notch 11 is provided on the outer arcuate side. In addition, a notch 10 is also provided on the inner arcuate side.

[0057] Figure 4A schematic diagram illustrates a longitudinal cross-section of one embodiment of an inner sleeve according to the present invention. In the embodiment illustrated here, the sleeve wall on the outer curved side has a reduced average sleeve wall thickness compared to the sleeve wall on the inner curved side. This is because the width of the recess provided on the outer curved side is significantly greater than its depth. In contrast, the recess 10 provided on the inner curved side is designed to be significantly deeper than its width. Because the recess on the outer curved side is relatively wide, the outer curved side achieves greater flexibility than the inner curved side. Because the recess on the inner curved side is relatively narrow in width and deeper, the side faces of the wall portion between which the recess is located can abut against each other when the inner sleeve bends more significantly, achieving a relatively high degree of kink resistance.

[0058] Figure 5 A plan view showing a schematic diagram of a specific embodiment of an inner sleeve according to the present invention is shown, wherein, as already described in Figure 4 As schematically shown in FIG, the recesses 11 on the outer arcuate side are a relatively wide embodiment. However, at the transition to the inner arcuate side, these recesses are narrower and at the same time deeper, which also corresponds to Figure 4 In the embodiment shown here, the guide strip 13 is provided at the outermost periphery of the outer arcuate side as an additional reinforcement means, and the lateral reinforcement element 12 (at Figure 5 Only one is visible in the figure) is arranged on both sides of the transition from the outer side of the arch to the inner side of the arch.

[0059] List of reference numerals:

[0060] 1 Inner casing

[0061] 2 Casing wall

[0062] 3 Proximal end

[0063] 4 distal end

[0064] 5 Arched part

[0065] 6 Inner curved side

[0066] 7 Outer curved side

[0067] 8 inner week

[0068] 9 periphery

[0069] 10 Notch on the inner curved side

[0070] 11 Notch on the outer curved side

[0071] 12 Reinforcement components

[0072] 13 Guide Bar

[0073] 14 Connectors

[0074] S vertex

Claims

1. An inner cannula (1) for insertion into an outer cannula of a tracheostomy tube, wherein: The inner sleeve (1) comprises a tubular sleeve wall (2) consisting of a flexible plastic material and extending in the longitudinal direction between a proximal end (3) of the inner sleeve (1) and an opposite distal end (4) of the inner sleeve (1), wherein the inner sleeve (1) comprises a domed portion (5) in its longitudinal direction, the domed portion having an inner arcuate side (6) and an outer arcuate side (7), characterised in that the average wall thickness of the sleeve wall (2) at least along the longitudinal portion of the sleeve wall extending along the inner arcuate side (6) is at least 40% greater than the average wall thickness of the sleeve wall (2) along the longitudinal portion extending along the outer arcuate side (7) and opposite the longitudinal portion extending along the inner arcuate side (6).

2. The inner sleeve (1) according to claim 1, characterized in that At least in the region of the longitudinal portion extending along the inner curved side (6) and the longitudinal portion extending along the outer curved side (7), the inner periphery (8) and the outer periphery (9) of the sleeve wall (2) are each circular, elliptical or oval in a cross section perpendicular to the central longitudinal axis of the inner sleeve and are arranged so that the average wall thickness of the longitudinal portion on the inner curved side is at least 40% greater than the average wall thickness of the longitudinal portion on the outer curved side (7).

3. The inner sleeve (1) according to any one of claims 1 and 2, characterized in that The sleeve wall (2) comprises a notch (10) in the sleeve wall (2) at least in the region of the longitudinal portion extending along the inner curved side (6) and / or a notch (11) in the sleeve wall (2) at least in the region of the longitudinal portion extending along the outer curved side (7).

4. The inner sleeve (1) according to any one of claims 1 to 3, characterized in that The size and shape of the notch (10) on the inner arcuate side (6) and / or the size and shape of the notch (11) on the outer arcuate side (7) are selected so that the average wall thickness of the longitudinal portion on the inner arcuate side is at least 40% greater than the average wall thickness of the longitudinal portion on the outer arcuate side (7).

5. The inner sleeve according to any one of claims 3 and 4, characterized in that On the inner arcuate side (6), the maximum depth (T) of the notch (10) is greater than the maximum width (B) of the notch.

6. The inner sleeve according to claim 5, characterized in that On the inner arcuate side (6), the maximum depth of the recess (10) is 10% to 70% greater than the maximum width of the recess.

7. The inner sleeve according to any one of claims 3 to 6, characterized in that On the outer arcuate side (7), the maximum depth of the recess (11) is smaller than the maximum width of the recess.

8. The inner sleeve according to claim 7, characterized in that On the outer arcuate side (7), the maximum depth of the recess (11) is 10% to 70% smaller than the maximum width of the recess.

9. The inner sleeve according to any one of claims 3 to 8, characterized in that The notch (11) in the sleeve wall (2) extends continuously in a ring-like, buckle-like, or spiral-like manner in the circumferential direction or is interrupted at certain portions.

10. The inner sleeve according to any one of claims 1 to 9, characterized in that The flexible plastic material of the sleeve wall is selected from the following: polyurethane, polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, SEBS (polystyrene-polyethylene-polybutylene-polystyrene), SBS (polystyrene-polybutadiene-polystyrene), SIS (polystyrene-polyisoprene-polystyrene), IR (polyisoprene), silicone, or a mixture of the above polymers, such as polypropylene / polystyrene-polyethylene-polybutylene-polystyrene.

11. The inner sleeve according to any one of claims 1 to 10, characterized in that The flexible plastic material of the sleeve wall has a Shore A hardness of <95.

12. A tracheostomy tube having an outer cannula and an inner cannula arranged in the outer cannula, characterized in that The inner sleeve is the inner sleeve according to any one of claims 1 to 11.

13. A method for producing a tracheostomy tube having an outer cannula and an inner cannula arranged in the outer cannula, characterized in that An inner cannula according to one of claims 1 to 11 is introduced into the outer cannula of the tracheostomy tube.

14. Use of the inner cannula according to any one of claims 1 to 11 for replacing a used inner cannula in a tracheostomy tube having an outer cannula and an inner cannula arranged in the outer cannula.

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