WO2025098991A1 - Indwelling cannula - Google Patents

Abstract

The invention relates to an indwelling cannula having a puncture needle for puncturing a hollow body, the indwelling cannula comprising at least one catheter with a tubular catheter tube in which the puncture needle is longitudinally movably guided, and the catheter is designed such that, after puncturing the wall of the hollow body to be punctured, it can be shifted across at least part of the length of the catheter tube through the opening created by the puncture needle in the wall of the hollow body to be punctured and dwells there for a period of time.

Description

Indwelling cannula

The invention relates to an indwelling cannula with a puncture needle for puncturing a hollow body, wherein the indwelling cannula has at least one catheter with a tubular catheter tube in which the puncture needle can be guided in a longitudinally displaceable manner, wherein the catheter is designed, after a puncture of a sheath of the hollow body to be punctured, to be pushed over at least part of the length of the catheter tube through the opening created by the puncture needle through the sheath of the hollow body to be punctured and to remain there for a period of time.

Such an indwelling cannula can be designed, for example, as a venous cannula. The hollow body to be punctured can be the hollow body of a living being or the hollow body of an object. As far as the indwelling cannula is concerned, the hollow body can be, for example, a blood vessel such as a vein or artery.

The terms "puncturing" and "puncture" are to be understood in the medical sense. "Puncture" refers to the insertion of a puncture needle into the hollow body in such a way that the puncture needle penetrates the shell of the hollow body to be punctured.

The near-hollow section of parts of the indwelling cannula is defined as those parts that, from the user's perspective, are located at the distal end of the indwelling cannula and thus close to the punctured hollow body. Accordingly, far-hollow sections are located at the proximal end of the indwelling cannula from the user's perspective, i.e., further away from the punctured hollow body. In the context of medical applications of the indwelling cannula, the terms "near-vein" or "near-patient" or "far-user" are used synonymously with the term "near-hollow body." For the term "far-hollow body," the terms "far-vein" and "far-patient" and "far-user" are also used.

Components close to the vein tend to be located inside the patient, while those far from the vein tend to be located outside. This is not always mandatory, but is intended to further clarify the terms. The additions are generally self-explanatory, and the context is crucial.

An indwelling cannula is known from WO 2022/263550 A1.

The goal is to create an improved puncture system in the sense of a general puncture system. In principle, the improved indwelling cannula makes it possible to effectively puncture all body cavities and interbody spaces, as well as all anatomical and pathological structures that are to be punctured, and to insert a catheter into them. The improved puncture system can also be used to create access to anatomical structures, and then, upon reaching these structures, to guide another, longer catheter/catheter tube through the puncture needle and/or through the catheter/catheter tube of the improved puncture system toward these anatomical structures. This can be used in particular in regional anesthesia and all other interventional procedures when the additional, longer catheter/catheter tube is intended to remain in the organism for a longer time than the improved puncture system. In such a case, the improved puncture system can also be used solely as an improved access system and removed again immediately after access to the desired anatomical structures has been created.

In principle, components of the improved indwelling cannula can be combined with all known puncture and catheter systems or used as standalone products.

The term "indwelling cannula" will be retained in the following, but has a broader meaning, as a general puncture system that can be used for more than just veins. The terms "vein" and "veins" therefore essentially encompass all blood vessels and, more generally, all body cavities and interbody spaces, as well as all anatomical and pathological structures that are to be punctured and catheterized.

For example, the indwelling cannula can also be used to puncture the trachea, pleural space, abdominal cavity, stomach, intestines, renal pelvis, bladder, structures of the central and peripheral nervous system, cerebrospinal fluid space, and bones. In addition, pathological structures such as abscesses in and on the patient can be punctured. Arterial blood vessels can also be punctured advantageously.

The term "patient" herein encompasses all living beings of all ages and genders. Applications in technical fields and in and on all objects and structures, e.g., in and on reservoirs, containers, cavities, expandable materials, and in and on pump, hose, tube, and port systems, are also explicitly possible.

When the word “or” is used below, possible alternatives are shown, but combinations of the characteristics or characteristics separated by “or” are also explicitly possible.

All described components can be used singly or multiple times on an indwelling cannula, independently of such a cannula, on/in other products, or completely independently. Various features of different components can also be freely combined, and features of certain components can also be used on other components without this being explicitly stated. In principle, all components and features can be used inside and outside a patient.

Indwelling catheters, and in particular venous catheters, are specialized medical devices in that they must have specific diameter and length dimensions to be applied to the usual venous access sites in human or animal patients. This also requires a certain degree of flexibility or elasticity of the catheter tube. Such catheters are therefore not comparable to catheter systems for other applications, such as urinary catheters, because completely different requirements apply. The object of the invention is to provide an indwelling cannula that is easier and safer to use.

This object is achieved by an indwelling cannula according to claim 1. Advantageous further developments are specified in the subclaims.

According to an advantageous embodiment of the invention, the indwelling cannula has a gripping area that is designed to allow the user to grip the indwelling cannula in the gripping area during handling. The gripping area of the indwelling cannula can be an area in which no other functions or functional elements of the indwelling cannula are present, but which is only provided for manual gripping of the indwelling cannula. This has the advantage that the user intuitively grasps the indwelling cannula in the correct place, thereby avoiding unnecessary contact at other points, e.g., at points on the indwelling cannula that must remain sterile. In this way, unnecessary contamination of certain points on the indwelling cannula can be avoided. For example, the gripping area can be formed on the housing of the catheter, for example, formed integrally with the housing. The gripping area can be realized, for example, by appropriately designing areas of the outer surface of the housing.

For example, the grip area may have ribbing, nubs, or other surface texture. Likewise, the grip area may be at least partially made of, or coated with, a material that increases frictional resistance. This prevents the user's fingers from accidentally slipping. The grip area may also be made of, for example, an elastomer, such as rubber or silicone, or any other material that is softer than the rest of the housing of the indwelling cannula.

The grip area can also be made of or coated with at least one antimicrobial material. It can also exhibit particularly hydrophobic properties. Properties similar to or similar to a lotus effect are also conceivable.

The handle area can also be designed, at least in part, in a different color than the other components of the IV catheter, e.g., green. Areas of the IV catheter that must not be touched under any circumstances can be designed, at least in part, in red. The color "yellow" is also conceivable, at least in part, in areas that should not be touched, but which can still be touched in special situations. This is intended to remind the user of the colors of a traffic light. Highly luminous or fluorescent colors are also particularly conceivable.

In a further advantageous embodiment, the entire indwelling cannula is transparent so that fluid/blood flow can be directly detected. The puncture needle can also be transparent, provided the material properties allow it.

Special patterns in the grip area are also possible, such as cross- or arrow-like patterns. This area can also be numbered or generally labeled. It is also conceivable that the grip area is initially covered by an adhesive structure, such as a film, which can be removed after the puncture procedure.

The features explained for the grip area can also be implemented individually or in combination on one or more of the grip surfaces explained below.

According to an advantageous embodiment of the invention, the indwelling cannula has a needle assembly to which the puncture needle is attached, and a catheter assembly separate from the needle assembly to which the catheter tube is attached, wherein the needle assembly is designed to be removed from the catheter assembly after the puncture procedure has been carried out. Accordingly, the indwelling cannula can consist of just two separate and separable assemblies, namely the needle assembly and the catheter assembly. It is also possible for the indwelling cannula to have one or more additional assemblies. The assemblies enable simple operation by the user. In particular, the user can use the indwelling cannula in the initial state to puncture the hollow body. Once the puncture procedure is complete, i.e. the catheter tube has been pushed through the opening created by the puncture needle through the sheath of the hollow body to be punctured and is positioned there as desired, the needle assembly can be removed from the catheter assembly. The puncture needle is also removed in the process. Only the catheter assembly then remains on the patient, which, in an advantageous embodiment, has no sharp edges or elements that could cause injury.

According to an advantageous embodiment of the invention, the indwelling cannula has a manually operable advance mechanism with a manual control element, the manual actuation of which automatically generates a relative movement between the catheter tube and the puncture needle, through which a puncture needle tip protruding from the catheter tube at the end closest to the patient can be received in the catheter tube. This achieves several advantages when using the indwelling cannula. With conventional indwelling cannulas, they are applied to the patient, e.g., to a vein, in such a way that the vein is first punctured with the puncture needle tip protruding beyond the catheter tube. After puncturing the vein, the catheter tube is manually advanced over the puncture needle, which can also be at least partially retracted into the catheter tube. These steps are at the discretion and skill of the user. Inexperienced people or in particularly difficult situations may make mistakes, for example by advancing the catheter tube too far or not advancing it far enough, so that part of the puncture tip still protrudes from the catheter tube.

The manually operable advance mechanism present in the indwelling cannula according to the invention ensures defined handling by the user and, accordingly, a defined relative movement between the catheter tube and the puncture needle, which is predetermined by the design of the indwelling cannula. In particular, the design of the advance mechanism ensures that the puncture tip is completely accommodated in the catheter tube and thus cannot cause further injuries during further insertion of the indwelling cannula into the hollow body.

The puncture needle located inside the catheter tube also supports, i.e. splints, the relatively elastic or flexible catheter tube.

Materials for the puncture needle can be metal, in particular stainless steel or generally metal alloys. The puncture needle can also be made of a plastic material. It can also be lightweight or made of at least one absorbable material/material that is easily soluble in blood and infusion solutions, e.g., a sugar or a salt, e.g., in the area of the puncture tip. Magnesium can also be used. Likewise, the puncture needle can advantageously be further developed with at least one sensor and/or at least one optical component, e.g., in the area of the puncture tip. This sensor and/or this optical component can be designed such that it indicates the correct position of the puncture tip. The design of the advancement mechanism also ensures that the puncture needle is not retracted too far into the catheter tube, allowing the catheter tube to be splinted essentially along its entire length. This is not possible with conventional indwelling cannulas, as the extent to which the puncture needle is retracted is at the discretion of the user.

According to an advantageous embodiment of the invention, the advance mechanism allows the catheter tube to be pushed over the puncture needle tip and/or the puncture needle tip to be retracted into the catheter tube. This allows for great flexibility in the design of the manually operable advance mechanism. Thus, the catheter tube can be advanced relative to the puncture needle, or the puncture needle can be retracted relative to the catheter tube, or a combination thereof.

According to an advantageous embodiment of the invention, one, several, or all operating elements of the manually operable advancement mechanism are arranged in the handle area and/or form parts of the handle area. This has the advantage that the indwelling cannula is particularly easy and hygienic to handle by the user and is particularly suitable for one-handed operation during the entire process of applying the indwelling cannula to the patient. This has the further advantage that the improved indwelling cannula can be gripped by technical equipment/handling devices, e.g., a robot. The improved indwelling cannula can therefore be part of a system for robot-assisted venipuncture, which can be designed to simplify both vein detection and correct puncture itself, or to have only the latter functionality. For this purpose, it can be advantageous if the improved indwelling cannula or individual components thereof, e.g., components of the needle assembly, can be inserted and/or plugged into at least one component of a handling device, e.g., a robot arm.

The manually operated advancement mechanism can be fully or partially part of the needle assembly of the indwelling cannula, at least with its predominant elements, such as the manual controls. This has the advantage that the needle assembly and thus also the puncture needle can be held in a stable, ideally static, position by the user upon successful puncture of the vein, often recognizable by blood flow back into the puncture needle. The distal end of the catheter tube can first be precisely advanced over the puncture tip into the vein before the catheter tube, splinted by the puncture needle, is then advanced further into the vein. In this case, the puncture needle, together with the aforementioned parts of the manually operated advancement mechanism, is designed as a single assembly that, once the catheter tube has been correctly positioned on the patient, i.e., in the hollow body to be punctured, can be removed entirely from the assembly connected to the catheter tube, in particular the housing.

The catheter tube can be precisely inserted over the fixed puncture needle. The puncture needle can be withdrawn further back from the catheter tube at any time.

It is advantageous if the user holds the puncture needle/needle assembly with his fingers at all times.

The design of the inventive venous cannula ensures that the user never has to forcibly withdraw the puncture needle. This has the advantage that the user always retains control over the withdrawal of the puncture needle, enabling an optimal combination of technical and user control. According to an advantageous embodiment of the invention, the relative movement between the catheter tube and the puncture needle that can be generated by manual actuation of the advance mechanism is limited to a maximum value. This has the advantage that operation is particularly simple for the user and the design of the advance mechanism ensures that errors when advancing the catheter tube relative to the puncture needle are avoided. Limiting the relative movement to the maximum value can be achieved, for example, by the type of force transmission from the operating elements of the advance mechanism to the assembly connected to the catheter tube. For example, the advance mechanism can have at least one mechanical stop by which the relative movement between the catheter tube and the puncture needle that can be generated by manual actuation is limited to the maximum value. However, limitation to the maximum value can also be achieved without such a mechanical stop.

According to an advantageous embodiment of the invention, the maximum value of the relative movement is at least as large as the length of the puncture tip. This ensures that the feed mechanism provides sufficient relative movement to completely accommodate the sharp-edged puncture tip in the catheter tube.

According to an advantageous embodiment of the invention, the maximum value of the relative movement is less than twice the length of the puncture tip. This ensures that the puncture needle is not retracted unnecessarily far into the catheter tube and that sufficient support in the sense of splinting the catheter tube by the puncture needle is maintained. According to a further advantageous embodiment of the invention, the maximum value of the relative movement is less than three times the length of the puncture tip. According to a further advantageous embodiment of the invention, the maximum value of the relative movement is less than four times the length of the puncture tip.

The puncture tip is defined as the area of the puncture needle closest to the patient that is sharpened, e.g., by a bevel or conical shape. The length of the puncture tip is thus the extension of the puncture tip in the longitudinal direction of the puncture needle.

The puncture tip can be designed in such a way that it can penetrate intact patient skin without significant advancement by the user. In a further design, due to its shape, it cannot penetrate patient skin without significant advancement or even bends before penetrating the skin. The puncture tip is therefore less pointed / more blunt. This allows the invention to be advantageously used directly in very vulnerable/soft anatomical regions to which, for example, surgical access has already been created through the skin. For example, the invention can be used in the area of the central nervous system, in particular in the area of the brain. For example, the invention can also generally be used in the area of the nervous system, including, for example, in the context of regional anesthesiological procedures.

If the puncture tip has the aforementioned bevel, various puncture techniques are possible. In the bevel-up technique, the puncture tip is inserted through the skin in such a way that the bevel, including the inner opening of the puncture needle, points upwards, i.e., away from the patient's skin. In the bevel-down technique, the puncture tip is rotated 180° relative to the catheter tube, so that the bevel, including the inner opening of the puncture needle points downwards, i.e. towards the patient's skin.

The indwelling cannula can, for example, be designed such that the puncture needle or at least the puncture tip can be rotated around its longitudinal axis relative to the catheter tube at any time. The user can then choose to use the bevel-up technique or the bevel-down technique, or even combine both techniques within a puncture procedure. The indwelling cannula can also be designed such that the puncture needle or at least the puncture tip cannot be rotated relative to the catheter tube in at least one specific longitudinal displacement position, for example when the puncture tip protrudes from the catheter tube at the end closest to the patient, or can only be rotated with increased force. For example, the assembly comprising the puncture needle can be positively coupled to the assembly comprising the catheter tube in this longitudinal displacement position, thus preventing the puncture needle from rotating relative to the catheter tube. In this case, the indwelling cannula can be designed, for example, in such a way that the oblique bevel, including the inner opening of the puncture needle therein, points downwards from the outset, i.e. it faces the patient's skin or an underside of the indwelling cannula on which at least one fixation wing of the indwelling cannula is arranged.

According to a further advantageous embodiment of the invention, the puncture tip is rotated/turned about its own longitudinal axis and/or the longitudinal axis of the puncture needle and is preferably adjustable to a circular dimension of 45°, 90°, 135°, 180°, 225°, 270°, 315° or 360° (angles given in degrees relative to a circular dimension of 360 degrees (360°)), with all intermediate stages in terms of the circular dimension being conceivable. In this case, the beveled edge of the puncture tip no longer necessarily points upwards due to the design of the inventive indwelling cannula before use, i.e. it is no longer necessarily facing away from the patient's skin. This can advantageously enable more gentle puncture techniques since, among other things, the puncture/puncture angle can be varied. The puncture needle or the assembly comprising the puncture needle can have holding/travel-limiting elements (hereinafter referred to as "holding elements"), by which the rotation/rotation of the puncture tip/puncture needle is restricted or eliminated, at least in certain longitudinal displacement positions of the puncture tip and/or puncture needle and/or needle assembly relative to the catheter tube. In an advantageous embodiment of the invention, the rotation/rotation of the puncture tip/puncture needle described above is completely eliminated when the puncture tip extends at least partially beyond the catheter tube distally (towards the patient). The holding elements can be designed, for example, as locking elements, notches, grooves, or projections. These can interact with holding elements located on the catheter tube or on other components of the indwelling cannula according to the invention, for example by locking, wedging, or twisting. All holding elements can be at least partially made of a material or coated with at least one such material that increases frictional resistance. The angle information mentioned above can be indicated on a component of the indwelling cannula for the user to easily read the current circular dimension to which the puncture tip and/or puncture needle is set.

For example, circular or semicircular markings with different line thicknesses and, for example, colored markings in the traffic light colors "green," "yellow," and red" are also conceivable. It is also conceivable that the initial puncture and further advancement of the puncture tip and/or puncture needle into the tissue to be punctured takes place in such a way that the puncture tip and/or puncture needle is sequentially set to a different circular dimension, i.e., is turned/rotated around the longitudinal axis of the puncture tip/puncture needle in the temporal sequence of the puncture procedure.

According to an advantageous embodiment of the invention, it is provided that the feed mechanism is locked by means of a locking device in the manually operated position in which the The puncture tip can be fixed in the catheter tube once it has been received in the catheter tube. For example, the advance mechanism can have a first locking mechanism by which at least part of the advance mechanism can be fixed in the manually operated position in which the puncture tip is received in the catheter tube. This has the advantage that the design of the advance mechanism prevents the puncture tip from being accidentally extended out of the catheter tube again. Once the advance mechanism has been manually operated and the puncture tip is received in the catheter tube, the locking or locking mechanism prevents the puncture tip from accidentally moving out of the catheter tube again.

According to an advantageous embodiment of the invention, in the manually operated position of the advance mechanism, in which the puncture tip is received in the catheter tube, at least one operating element of the advance mechanism can be fixed by means of the locking mechanism and/or at least a part of the catheter housing can be fixed to the needle assembly. This allows for a simple implementation of the locking of the advance mechanism in the manually operated position. The operating element of the advance mechanism can, for example, be fixed to another operating element assigned as a counterpart by means of the locking mechanism, or to another part of the needle assembly.

According to an advantageous embodiment of the invention, in the manually operated position of the advance mechanism, in which the puncture tip is received in the catheter tube, at least one operating element of the advance mechanism can be locked by means of the first locking mechanism and/or at least a part of the catheter housing can be locked to the needle device by locking. This allows for a simple implementation of locking the advance mechanism in the manually operated position.

According to an advantageous embodiment of the invention, the first locking mechanism is configured to generate a signaling sound when the operating element is locked. For example, a clicking sound can be generated. This can provide the user with acoustic information about sufficient actuation of the operating element. This has the advantage that the user does not have to visually check the actuation of the operating element, i.e., does not have to look away from the puncture site to know when the operating element has been sufficiently actuated.

According to an advantageous embodiment of the invention, the manual control element is arranged essentially centrally on the indwelling cannula in the longitudinal direction of the indwelling cannula. This enables simple and particularly ergonomic operation of the feed mechanism by the user as well as balanced handling of the indwelling cannula.

According to an advantageous embodiment of the invention, at least one operating element of the advance mechanism is designed as a pivotably mounted actuating lever with at least one lever arm. In this way, a reliably functioning, robust advance mechanism is created that is simple and intuitive to operate by the user. The actuating lever can, for example, have a force arm and a load arm, wherein the actuating lever is pivotally mounted at a position between the force arm and the load arm by means of a bearing element. The load arm is the lever arm that exerts a force on a component connected to the catheter tube, e.g., on the housing of the indwelling cannula. The force arm is the lever arm to which the actuating force is applied by the user, e.g., on a gripping surface of the force arm. The lengths of the force arm and load arm can be the same or different. For example, the load arm can be longer than the force arm. As an actuating element for generating the advancement of the catheter tube relative to the puncture needle, a rotatably mounted wheel can be provided, for example, which transmits a feed force upon rotation of the wheel to the catheter tube or a component connected to it through a force-locking coupling and/or friction. A force-locking coupling between the rotatably mounted wheel and the catheter tube or the component connected to it can be provided, for example, by a slotted/pin guide or by a toothing. Such a rotatably mounted wheel is considered below as a special case of a lever.

The required relative movement between the catheter tube and the puncture needle, which ultimately engages the puncture tip in the catheter tube, can be generated solely by manually applied actuation force. The relative movement can also be additionally supported by spring force, i.e., by the force of a preloaded spring, which completely or partially continues a relative movement manually initiated by the user. For example, the indwelling cannula, as a manual control element, can have only a trigger element for initiating the relative movement, with the further execution of the relative movement then being carried out by spring force.

According to an advantageous embodiment of the invention, the advancement mechanism has at least two gripping surfaces as operating elements, each of which can be used to hold at least one of the user's fingers, with the at least two gripping surfaces being arranged facing away from one another. This has the advantage that the user can very easily grasp the indwelling cannula and can hold and operate it using the same gripping surfaces throughout the entire application process on the patient. This allows one-handed operation without the user having to change the gripping position during the application process on the patient (no changing of grip is necessary). Because the at least two gripping surfaces are arranged facing away from one another, the user can grip these gripping surfaces from two sides and thus hold the indwelling cannula securely. This advantageous embodiment of the invention also achieves hygienic operation of the indwelling cannula, which results not only from safe and one-handed operation. The at least two opposing gripping surfaces can be considered components of a protective box that, during the puncture procedure, surrounds, among other things, the part of the indwelling cannula to which, after the puncture and removal of the puncture needle, for example, an infusion line is sterilely connected. It is repeatedly observed that, due to a lack of suitable gripping surfaces, conventional indwelling cannulas are grasped at the infusion line connection point remote from the patient and thus advanced into the organism. This poses the risk of contamination of the connection point, for example with bacteria, which can trigger bloodstream infections. This can be avoided by the advantageous embodiment of the invention, which features a type of contamination protection box.

According to an advantageous embodiment of the invention, at least one of the gripping surfaces is arranged on a lever arm of a pivotably mounted actuating lever of the feed mechanism. This ensures safe operation of the feed mechanism. The user can intuitively place the finger required for operation in the correct position.

According to an advantageous embodiment of the invention, the actuating lever is rotatable about a rotational axis, wherein, at least in the unactuated state of the feed mechanism, the gripping surface arranged on the actuating lever extends from a position that is farther away from the puncture needle than the rotational axis to a position that is closer to the puncture needle than the rotational axis. This has the advantage of preventing unintentional incorrect actuation of the feed mechanism during insertion of the puncture tip of the puncture needle into the hollow body. By appropriately positioning the gripping surface relative to the rotation axis, sufficient torque is not transferred to the lever during the puncture procedure, preventing the advance mechanism from being accidentally activated prematurely. In general, the rotation axis should not be positioned too close to the puncture needle, also to allow sufficient actuation travel for advancing the catheter tube relative to the puncture needle. The gripping surface arranged on the actuating lever can, for example, be located predominantly on the lever's force arm, but it can also extend over at least part of the load arm.

According to an advantageous embodiment of the invention, it is provided that a feed force for advancing the catheter tube relative to the puncture needle is transmitted from the actuating lever to the catheter tube or a component connected thereto at a point which is arranged closer to the distal end of the catheter tube than the axis of rotation about which the actuating lever is pivotably mounted.

According to an advantageous embodiment of the invention, the puncture needle, together with the manually operable advance mechanism, is designed as a single assembly whose components are firmly connected to one another, e.g., such that they cannot be separated without tools. In particular, the pivotably mounted actuating lever can be designed as an integral part of this assembly, which includes the advance mechanism and the puncture needle. If the puncture needle is to be removed after performing a vessel puncture, the entire assembly is always removed, i.e., the puncture needle with the advance mechanism, including the actuating lever.

According to an advantageous embodiment of the invention, the actuating lever can be continuously pivoted from an initial position, in which the tip of the puncture needle protrudes completely from the catheter tube, to an end position in which the puncture needle is completely received in the catheter tube. This allows for very sensitive handling of the venous catheter during application to a patient.

According to an advantageous embodiment of the invention, the advance mechanism has at least one securing element that prevents actuation of the advance mechanism until the securing element is released. For example, the securing element can be designed such that the pivotable actuating lever cannot be pivoted initially, i.e., in the secured state. Only through targeted actuation of a release element or a release mechanism is the safety released and the actuating lever can be pivoted. This can provide protection against unintentional advancement of the catheter tube relative to the puncture needle. For example, the unlocking of the securing element can be carried out such that a specific part of the advance mechanism must first be actuated in a specific direction, in particular in a different direction than the actuating lever is to be actuated for pivoting. For example, to release the safety element, the actuating lever may first have to be pressed down in the direction of the puncture needle, e.g. in a direction substantially orthogonal to the longitudinal direction of the puncture needle, and/or parts of the actuating lever may first have to be pressed together laterally in order to release the safety.

According to an advantageous embodiment of the invention, the actuating lever is rotatable about a rotational axis, wherein the rotational axis is displaceably mounted. This displaceability of the rotational axis allows further functionalities of the indwelling cannula to be realized, for example, a safety function in the unactuated state of the actuating lever, as previously explained. For example, the actuating lever can be displaced in the unactuated state when the rotational axis is at a first displacement position, be blocked against any pivoting movement. Only when the actuating lever is moved so that the axis of rotation is in a second shift position that is different from the first shift position can this blocking be released and pivoting of the actuating lever enabled. In this way, additional security is provided against unintentional advancement of the catheter tube. The axis of rotation can, for example, be displaceable relative to the puncture needle, for example in a direction at a right angle to the longitudinal extent of the puncture needle or at an oblique angle to the longitudinal extent of the puncture needle, for example in the range of +/- 45°.

According to an advantageous embodiment of the invention, the rotation axis is designed to be displaceable relative to the base body. In this way, the actuating lever can first be moved into an unlocked position by a sliding movement, e.g., to unlock the locking element. In this unlocked position, the actuating lever can then be pivoted. In the locked position, pivoting is prevented by the locking element.

Due to a recess on each of the side gripping surfaces, which has a smaller transverse than longitudinal extension (long hole), the actuating lever for unlocking can only perform a precise movement towards the puncture needle, usually a downward movement, without further deflection to the side.

When the actuating lever is pressed down, tabs located on the underside of the indwelling cannula can also be pushed down. This allows the lower edge of the actuating lever to be pushed down slightly further than a rigid stop on the underside of the indwelling cannula would allow.

This in turn allows the upper part of the curved part of the actuating lever to slide proximally, i.e. away from the patient, under the curved surface of the base body of the feed mechanism and thus be pivoted.

The operation of the pivoting operating lever, especially during the release process, can also be accompanied by an acoustic signal, e.g., a click. The operating lever can also engage in a specific position with an acoustic signal.

In an advantageous embodiment, all gripping surfaces have ribbing, nubs, or other surface textures to ensure a particularly secure grip on the indwelling cannula. The gripping surfaces can also be partially or completely magnetic, magnetized, or magnetizable, which, through appropriate interactions, can provide further possibilities for operation by components of handling devices, e.g., robots.

The pivoting operating lever can also contain a spring mechanism or be combined with one. This spring mechanism can be designed in such a way that spring forces must first be overcome in order to bring the pivoting operating lever into a position in which the feed mechanism is triggered, or to move it into the unlocking position. It is also conceivable for the spring to be designed in such a way that a larger force must first be exerted on the spring over a certain distance of actuation of the operating lever and then a smaller force over a further distance in order to trigger the function of the operating lever. This is also possible in the reverse order; i.e. first a smaller force must be exerted on the spring and then a larger one. In an advantageous embodiment, the previously mentioned tabs can perform the functionality of such a spring. The pivoting actuating lever can also contain or be combined with a bimetal element which, upon successful venipuncture, heats up due to blood flowing back into the indwelling cannula and, by changing its shape, automatically releases and/or triggers the actuating lever.

It is also conceivable that the pivoting actuating lever could be operated by a handling device, e.g., a robot. The actuating lever and/or other components, or the entire venous catheter, can be grasped and operated by a robot, e.g., by a gripper of a robotic arm. The aforementioned safety element can also be operated in this way.

It is also conceivable that operating the aforementioned safety element and/or the pivoting operating lever could close an electrical circuit, thus illuminating a diode, for example. This diode can be located in the area of the operating lever and/or surrounded by the gripping surfaces and the cover surface of the operating lever. These surfaces can be fully or partially translucent. This allows the user to determine, even under difficult conditions, whether the operating lever has been correctly released and/or activated, i.e., whether the diode is illuminated.

According to an advantageous embodiment of the invention, the indwelling cannula, in particular its catheter tube, has one or more markings that indicate the relative movement between the catheter tube and the puncture needle generated as a result of the manual actuation of the advance mechanism. In this way, the user can easily visually check whether sufficient relative movement has occurred between the catheter tube and the puncture needle. In particular, the current position generated by the advance mechanism can be visually read.

According to an advantageous embodiment of the invention, the advance mechanism has at least one intermediate position between its end positions that can be detected haptically by the user, for example in the form of a detent position. In this way, one or more intermediate positions of the generated relative movement of the puncture needle with respect to the catheter tube can be structurally predetermined and actively adjustable by the user. Through haptic control, the user can easily recognize which intermediate position they have reached, e.g., by increased resistance occurring in the respective intermediate position when actuating the advance mechanism. In this way, the rigidity of the catheter tube can be varied and adapted to individual anatomical conditions. For example, with fragile blood vessels, it can be advantageous if the catheter tube is designed to be more flexible during insertion into the blood vessel, particularly in the area close to the patient, in order to ensure gentler insertion into the blood vessel.

A characteristic of conventional venous cannulas is the unrestricted longitudinal movement of the inner puncture needle relative to the outer catheter tube, due to their design. This allows the puncture needle to be withdrawn from the catheter tube and removed in the direction of the user after a successful puncture. However, the more flexible catheter tube often requires a splint when advanced into the vein after a successful puncture to ensure stable insertion. This splinting is achieved through the inner puncture needle. With conventional venous cannulas, however, the extent to which the puncture needle is withdrawn is uncertain. If the needle is withdrawn too little, the tip of the puncture needle may still be exposed at the end of the catheter tube near the vein, thus inadvertently damaging anatomical structures. If the needle is withdrawn too far, the catheter tube may not be sufficiently splinted when advanced into the vein. However, the puncture needle may also inadvertently slip back towards the user after withdrawal. This can lead to damage to the catheter tube by the tip of the puncture needle and, for example, to parts of the catheter tube being sheared off into the vein.

With the indwelling cannula according to the invention, the puncture needle is retracted a defined distance longitudinally into the catheter tube after a successful venipuncture. This has the advantage that the user can be sure that the tip of the puncture needle no longer extends beyond the catheter tube in the longitudinal direction toward the vein. In this state, the tip is completely surrounded by the external catheter tube, thus avoiding unintentional injury to anatomical structures.

The inventive indwelling cannula also prevents the puncture needle from being retracted too far from the vein into the catheter tube during the puncture procedure, thus resulting in insufficient splinting of the tube. The puncture needle thus splints the catheter tube over a precisely defined path, precisely stabilizing it as it is advanced into the vein. The path can also be indicated by markings on the indwelling cannula. It can also be precisely varied by the user by adding appropriate ridges/depressions to the indwelling cannula, into which, for example, a handle can be snapped.

Advantageously, a maximum value for the relative movement between the catheter tube and the puncture needle can be specified, which can only be overcome with particular effort by the user in order to be able to remove the puncture needle. This prevents the puncture needle from accidentally slipping completely out of the indwelling cannula. The above is particularly relevant if the catheter tube is very flexible and/or has, for example, a spiral or wave-shaped structure, as can be the case with the indwelling cannula according to the invention. The catheter tube can also contain a spiral or wave-shaped support structure which is loosely arranged in the catheter tube over part or the majority of its longitudinal extent or its entire longitudinal extent. This support structure can, for example, rest loosely on the inside and/or outside of the catheter tube and/or be loosely inserted into a gap/space in the catheter tube. This can improve the kink resistance of the catheter tube.

This can be particularly relevant if the indwelling cannula is very flexible only at the transition point between the catheter tube and/or only in a portion remote from the vein, e.g., at skin level, as described above. The catheter tube may also have a spiral or wave-shaped structure only at areas subject to particularly high mechanical stress and/or contain the loosely arranged support structure mentioned above only there.

Maximum safety against unintentional injury to anatomical structures by the tip of the puncture needle is particularly ensured if the catheter tube is additionally puncture-proof.

A pronounced thermoplasticity of the catheter tube is no longer absolutely necessary, since it can be designed to be very flexible and the rigidity often required for insertion into the vein is mainly ensured by the puncture needle.

It is also conceivable that the puncture needle must first be advanced to a position in which the tip of the puncture needle protrudes beyond the catheter tube in the direction of the vein.

The indwelling cannula can also be fixed to the skin with a thread at the concave bulge (see drawings), especially if the bulge has reefs. recesses/depressions/elevations, side cutouts and/or other fastening elements.

The inventive indwelling cannula is also easier to operate with one hand than conventional indwelling cannulas. This allows the user to use the other hand, for example, to stabilize the body part to be punctured and to stretch the skin. This increases the likelihood of a successful puncture.

In contrast to conventional cannulas, the indwelling cannula according to the invention also features defined and intuitively operable gripping surfaces for the user's fingers. The indwelling cannula can thus no longer be accidentally soiled/contaminated, particularly in the area of the entry point into and/or the contact surface on the skin. Furthermore, the area of the entry point into the skin is specially protected from soiling/contamination due to its design. The gripping surfaces themselves are adapted to the user's anatomy and can also be designed to be malleable/deformable.

In addition, the fixation of the indwelling cannula according to the invention is facilitated because the fixation wings are connected to the other components of the indwelling cannula via only a narrow web, thus making it easier to apply plasters, for example. In particular, the wings of a plaster and/or plaster strips can be easily guided under the indwelling cannula. It is also conceivable for the wings to be pivotably attached to the indwelling cannula. It is also conceivable for the wings to be kneadable and/or deformable and thus to be able to adapt optimally to unevenness in the patient's skin. It is also possible for the web to consist of at least one kneadable and/or deformable and/or elastic material. It can also advantageously be further developed with at least one spiral-like and/or spring-like structure. This means that forces/movements acting on loaded components of the venous cannula can be mitigated, e.g. cushioned, in their effect on other components of the venous cannula if a bridge as described above is located between the loaded and the other components.

Any conventional/commercially available, single- or multi-lumen catheter tube can be used. However, according to an advantageous embodiment of the invention, the catheter tube has at least one support structure that increases the bending moment and/or the radial moment of resistance of the catheter tube. The support structure can be designed in the form of one or more reinforcement elements.

The support structure, which, for example, can also be arranged at least partially loosely in/on the catheter tube as described above, can be, for example, a spiral structure extending over a certain longitudinal section of the catheter tube, which can be integrated on the inside and/or outside of the catheter tube and/or partially or completely into the catheter tube wall. Several coaxial support structures of this type can also be present. The spiral structure can also have spring-like properties. Instead of a spiral structure, individual support rings spaced apart from one another can also be present, both on the inside, the outside and/or fully or partially integrated into the catheter tube wall. The spiral structure and/or the rings can be formed from round or flat material, in particular from a metal material. At least one support structure can also be formed by a thin-walled support sleeve or a support braid made of interwoven fibers or fibers joined to form a woven or scrim. The catheter tube can be constructed in a single or multi-layered manner in the radial direction, using either the same or different materials in the individual radial layers. For example, a support structure can be embedded in an inner radial layer, which is covered by an outer radial layer of the catheter tube. Materials such as polyurethane (PU) or FEP can be used for the catheter tube. Materials for the support structure can be metal, particularly stainless steel, and/or metal alloys, particularly nitinol. Nitinol has the advantage of further increasing the desired resistance of the catheter tube to compression or kinking due to its memory effect.

Other materials for the support structure can be plastic materials, in particular fiber-reinforced plastics, e.g. carbon or aramid fiber-reinforced plastics.

In a spiral-shaped support structure, there may be a single spiral or several nested spirals. The coils of the spiral may be spaced at the same distance from one another over the entire length of the support structure, or they may have varying spacing. In an advantageous embodiment of the invention, a spiral support structure may have a smaller spacing between the coils in the region remote from the hollow body than in the region close to the hollow body.

Additional structures can be located between the coils to stabilize the support structure. In an advantageous configuration, these structures expand as the coils move away from each other, thus becoming more rigid. The structures between the coils also ensure that the coils can only be spaced apart to a limited extent. As the coils move toward each other, the structures between them become less rigid. In this configuration, the support structure has a structure similar to an accordion.

In an advantageous embodiment, the structures between the turns can make the support structure at least partially fluid-impermeable if the material is chosen accordingly.

Such a support structure, when using a material visible in medical imaging procedures, particularly a metal material, can improve the visibility of the catheter in patients using medical imaging procedures, e.g., ultrasound examinations. In an advantageous embodiment of the invention, the support structure or the longitudinal sequence of several support structures is designed irregularly along its length. The irregular design enables even more precise position identification of specific areas of the catheter in the patient using medical imaging procedures.

According to an advantageous embodiment of the invention, the catheter tube has several lateral through-holes extending from the inside to the outside. The through-holes can be present along the entire length of the catheter tube or only along one or more longitudinal sections, e.g., in a section closer to the hollow body. The through-holes can be distributed around the circumference of the catheter tube. The through-holes in the catheter tube wall can improve the flow of fluids through the catheter tube.

According to an advantageous embodiment of the invention, one, several, or all of the through-openings are arranged in the area of the catheter tube not covered by the support structure. For example, if the support structure has a spiral shape, through-holes can be arranged between the turns of the spiral. In this way, the flow through the through-openings is not impeded by the support structure.

It is also conceivable that a spiral support structure is not surrounded and/or coated by a fluid-impermeable material over at least part of the catheter tube's length. This allows the indwelling cannula to be inserted in this area without any through-hole. holes are permeable to fluids. In an advantageous embodiment, the turns of the spiral support structure are spaced further apart in this area than in the other areas of the catheter tube. This area can preferably be located close to the hollow body, as described above.

It is also conceivable that a fluid-impermeable material surrounding and/or coating the spiral support structure has gaps and/or interruptions over at least a partial length, thus ensuring fluid permeability of the indwelling cannula in the area of these gaps/interruptions. Side holes are then no longer absolutely necessary.

The indwelling cannula according to the invention has the advantage that the aforementioned fluid-permeable areas, e.g., side holes, can be located only in a region of the catheter tube that is splinted by the puncture needle during the puncture procedure and thus also sealed from the inside. This prevents foreign bodies and/or, for example, punched-out skin components from blocking the side holes during the puncture procedure and/or being inadvertently carried into deeper anatomical structures.

However, with the indwelling cannula according to the invention, it is also advantageously possible to precisely and selectively expose fluid-permeable areas, such as side holes, by positioning the puncture needle at different positions along the longitudinal direction, if these are located at different longitudinal positions on or within the catheter tube. This allows precisely controlled dilution effects to be created, for example, to inject vein-irritating substances more effectively.

In a further advantageous embodiment, the above-mentioned material can also only partially surround the spiral support structure in the longitudinal direction of the indwelling cannula. This can create a type of web that counteracts the support structure from becoming uncoiled. With very dense winding, the support structure can be fluid-impermeable, but with less dense winding, it can also be fluid-permeable. The density of the winding can also determine whether the support structure is, for example, fluid-impermeable but still permeable to gases/vapors. It is also conceivable that the support structure is only permeable to certain fluids. It is also conceivable that the support structure has thermoplastic properties and/or expands due to body heat.

According to an advantageous embodiment of the invention, the catheter has a housing to which the catheter tube is attached. The catheter tube extends from a side of the housing facing the hollow body. According to an advantageous embodiment of the invention, the catheter has, in the area where the catheter tube protrudes from the housing, i.e., in a tube exit area of the housing, an anti-kink structure that completely or at least partially surrounds the catheter tube circumferentially, reducing the risk of the catheter tube kinking in the area where it exits the housing. This prevents unwanted kinking of the catheter tube when handling the indwelling cannula, particularly in the area where it exits the housing. This area is particularly prone to kinking because, in known indwelling venous cannulas, there is an abrupt transition from the relatively robust, inflexible housing to the comparatively thin-walled and correspondingly sensitive catheter tube. The anti-kink structure according to the invention smooths the previously abrupt transition in this area. The anti-kink structure can, for example, include a trumpet-shaped, rounded surface surrounding the catheter tube.

In an advantageous embodiment of the invention, the grip area is designed in such a way that it has two gripping surfaces which are located on opposite sides of the component on which the gripping area is present. This has the advantage that the indwelling cannula can be easily and securely gripped at the gripping area using the thumb and another finger, e.g. the middle finger or the index finger. The gripping surfaces can in particular be predominantly flat gripping surfaces or have at least a predominantly flat part. In their flat areas, the gripping surfaces can be arranged parallel to one another. The gripping surfaces can also be designed in the manner of a depression with a surface that is curved (concave) at least in some areas. The gripping surfaces can have a structure that allows the indwelling cannula to be gripped even better and prevents the fingers from slipping.

For example, the gripping surfaces may have ribbing, nubs, or other surface textures. The gripping surfaces may, in particular, be designed such that their dimensions in the longitudinal direction of the indwelling cannula are larger, e.g., at least twice as large as the dimensions in the transverse direction. A respective gripping surface may be made from the material of the housing of the indwelling cannula or from a different material, in particular from a material with greater elasticity or flexibility. For example, the gripping surface may be designed as an insert, e.g., from an elastomer, e.g., rubber, or silicone, or any other softer material than the material of the housing of the indwelling cannula. Such an insert may then be secured in a corresponding recess in the housing of the indwelling cannula.

According to an advantageous embodiment of the invention, the indwelling cannula has at least one finger stop device on the housing, which is arranged at or near the tube exit area. The finger stop device is thus significantly spaced from the proximal end of the housing. The finger stop device serves to prevent the user's fingers, with which the user grasps the indwelling cannula during application to the patient, from accidentally slipping off the housing in the longitudinal direction of the indwelling cannula, i.e., slipping towards the patient. The finger stop device thus forms an obstacle to the fingers slipping off the housing towards the patient. In this way, contamination of the puncture site on the patient and of parts of the indwelling cannula in the area of the puncture site is avoided. The finger stop device can, for example, be designed as a circumferential enlargement compared to adjacent circumferential areas of the housing, for example in the form of an apron, a bead, or some other thickening. The finger stop device can completely surround the housing circumferentially or only in partial sections, for example only to the right and left of the catheter tube.

According to an advantageous embodiment of the invention, the indwelling cannula is provided with a puncture protection device that minimizes the risk of injury from the puncture needle after the puncture procedure has been performed. The puncture protection device has a receiving body that is designed to completely accommodate the puncture needle withdrawn from the catheter tube and shield it from the environment. The puncture protection device can protect users of the indwelling cannula, in particular medical personnel, from injuries caused by the puncture needle, in particular by the sharp-edged puncture tip of the puncture needle. This is particularly necessary if, after the puncture procedure has been performed, the needle assembly is separated from the catheter assembly and is therefore to be disposed of individually. The puncture protection device according to the invention can advantageously accommodate the entire puncture needle in the receiving body, so that the user is not only protected from the sharp-edged puncture tip, but unwanted contact with other sections of the puncture needle can also be avoided. In this way, protection against unwanted infections caused by accidental contact with the puncture needle can be further improved. The puncture needle can be picked up automatically in the receiving body when the puncture needle is pulled out of the catheter tube, ie after of the puncture procedure. This allows for easy handling by the user.

According to an advantageous embodiment of the invention, in an initial state of the indwelling cannula, in which the indwelling cannula is provided by the manufacturer or before a puncture of the hollow body to be punctured has taken place, the puncture needle is arranged predominantly or entirely outside the receiving body. In this initial state, the puncture needle can thus be located predominantly or essentially entirely within the catheter tube, with the puncture tip of the puncture needle protruding from the end of the catheter tube closest to the patient.

According to an advantageous embodiment of the invention, the puncture protection device is configured to automatically detach from the catheter assembly when the puncture needle has reached a predetermined minimum position during withdrawal from the catheter tube. This allows for easy handling by the user.

According to an advantageous embodiment of the invention, the puncture protection device has a securing device that prevents the puncture protection device from being separated from the catheter assembly before the puncture needle has reached the predetermined minimum position. This automatically prevents incorrect operation of the indwelling cannula or the puncture protection device. Appropriate components of the securing device automatically ensure that the puncture protection device cannot be separated from the catheter assembly too early, in particular not before the puncture needle is completely received in the receiving body. The predetermined minimum position can be reached, for example, when the puncture needle is completely received in the receiving body.

The puncture protection device may be part of the needle assembly, i.e. an element of the needle assembly that is firmly connected to the puncture needle.

According to an advantageous embodiment of the invention, the receiving body has an outer body and an inner body arranged in the outer body, which can be extended telescopically from the outer body. For example, the inner body can be extended telescopically in a linear direction from the outer body. This allows for a simple, cost-effective, and reliable design of the puncture protection device. The telescopic mechanism also achieves a relatively short overall length of the safety device in the initial state of the indwelling cannula, i.e., before the puncture is performed. Only when the puncture needle is received in the receiving body or in the inner body is the overall length increased, since the inner body is then moved telescopically out of the outer body. For example, in the initial state of the indwelling cannula, the puncture needle can be arranged completely outside the outer body and/or the inner body. After the puncture has been performed, i.e., when the puncture needle is withdrawn from the catheter tube, the puncture needle can be arranged completely inside the inner body.

According to an advantageous embodiment of the invention, the puncture needle is arranged at a fixed position of the indwelling cannula relative to the outer body. For example, the puncture needle can be firmly and permanently connected to the outer body.

In an advantageous embodiment, the outer body can also serve as an aid for holding and/or advancing the puncture needle when puncturing the hollow body. According to an advantageous embodiment of the invention, the puncture protection device is configured to automatically extend the inner body from the outer body when the puncture needle is withdrawn from the catheter tube, thereby accommodating the puncture needle within the inner body. This allows for simple, intuitive handling by the user. Despite the new mechanism, the user does not have to adapt to a different method of use compared to conventional indwelling cannulas.

According to an advantageous embodiment of the invention, the securing device has a first end stop, which limits the extension path of the inner body from the outer body to a maximum value. This ensures that the inner body cannot accidentally detach from the outer body, particularly during the withdrawal movement of the puncture needle from the catheter tube.

According to an advantageous embodiment of the invention, the puncture protection device has a second locking mechanism, by which the inner body can be automatically locked relative to the outer body when the puncture needle is received in the inner body. The second locking mechanism has the advantage that the inner body cannot be pushed back together with the outer body in the opposite direction, which would prevent the risk of the puncture needle becoming accessible from the outside again. The second locking mechanism thus further increases user safety because the puncture needle received in the inner body remains securely in place.

According to an advantageous embodiment of the invention, the puncture protection device has a blocking mechanism that blocks the extension of the inner body relative to the outer body as long as the actuating lever is not moved into the actuated position. In this way, the design of the indwelling cannula automatically guides the user to correctly operate the indwelling cannula. The user must first initiate the desired advancement of the catheter tube by manually actuating the manual control element via the manually actuated advance mechanism so that the catheter tube is pushed over the puncture tip at the end closest to the patient. Only then does the puncture protection device or its blocking mechanism allow the needle assembly to be retracted in order to withdraw the puncture needle from the catheter tube. The blocking mechanism can be implemented, for example, by the actuating lever being initially blocked against any pivoting movement in the unactuated state and must be released by another type of actuation, e.g., a sliding movement. The outer body can be permanently connected to the puncture needle, the outer body, or another part of the needle assembly. Due to this permanent connection, the outer body can only be moved together with the actuating lever.

According to an advantageous embodiment of the invention, the outer body is arranged closer to the end of the indwelling cannula remote from the patient than the actuating lever. The outer body is thus arranged on the side of the actuating lever or the advancement mechanism facing away from the catheter tube.

According to an advantageous embodiment of the invention, the indwelling cannula on the catheter assembly, particularly in the region of the catheter assembly's fixation wings, has at least one elastically deformable pressure-reducing element with at least one manual actuation surface. The pressure-reducing element can be used to reduce or close the inner lumen of the catheter tube by manually applying pressure to the at least one manual actuation surface of the pressure-reducing element. The pressure-reducing element is a practical aid for the user to prevent blood flow from the catheter tube after the catheter tube has been placed on the patient and the needle assembly has been removed. The pressing element can be operated intuitively by the user, e.g. with two fingers pressed against each other on opposite sides of the indwelling cannula in the area of the pressing element.

According to an advantageous embodiment of the invention, the pressure element is designed as a one-piece assembly with fixation wings for the indwelling cannula. This has the advantage that the indwelling cannula can be manufactured with comparatively few individual parts, which simplifies the manufacturing process and the assembly of the individual parts. The fixation wings serve to secure the indwelling cannula to the patient, e.g., using an adhesive strip.

According to an advantageous embodiment of the invention, the pressure element is made of a material with greater elasticity than the catheter tube, in particular a rubber-elastic material. Accordingly, the pressure element can be easily actuated by the user with reasonable force. Due to its elasticity, the pressure element springs back when the user no longer acts on it. This reliably restores flow through the catheter tube, e.g., for the passage of infusions.

According to an advantageous embodiment of the invention, the push-off element is connected to the catheter tube by a material-to-material connection. For example, the push-off element can be glued to the catheter tube. This has the advantage that when the catheter tube rebounds, i.e., when the user releases the actuating force, the push-off element simultaneously returns the catheter tube to its original shape through tensile forces.

The pressure element can have a receiving channel extending longitudinally along the indwelling cannula. The catheter tube can be guided through this receiving channel. The catheter tube can be guided through this receiving channel without interruptions, i.e., continuously and closed. It is also possible for the catheter tube to have an interruption in the area of the receiving channel and to be connected to the receiving channel in a fluid-tight manner, at least in the outward-facing end sections of the receiving channel, so that undesired fluids cannot escape there.

According to an advantageous embodiment of the invention, the indwelling cannula has a blood collection chamber configured to automatically provide a blood sample for analysis purposes after the puncture of the hollow body to be punctured. This has the advantage that the indwelling cannula can be used in a sterile manner for automatically providing a blood sample. After the indwelling cannula is applied to the patient, the blood automatically flows through the puncture needle and/or the catheter tube into the blood collection chamber. The user only needs to wait a moment before disconnecting the needle assembly from the catheter assembly.

According to an advantageous embodiment of the invention, the blood collection chamber is arranged in the puncture protection device, in particular in the outer body. This has the advantage that the puncture protection device can simultaneously serve another function, namely to provide the blood collection chamber. Thus, no separate component or additional installation space needs to be provided for the blood collection chamber. In applications where blood backflow indicates a possible mispuncture because a blood vessel puncture is undesirable, for example, in the field of regional anesthesia, the blood collection chamber can indicate a mispuncture.

According to an advantageous embodiment of the invention, the blood collection chamber has a viewing window for optical inspection of the blood in the blood collection chamber. collected amount of blood and/or to indicate that the blood collection chamber is completely full. The viewing window can, for example, be a transparent window. It is also possible for the entire blood collection chamber or at least the outer body to be designed as a transparent component. The viewing window allows easy visual control of the amount of blood collected in the blood collection chamber or to determine whether the blood collection chamber is sufficiently filled. The viewing window can, for example, have a measuring scale that the user can use to read off the amount of blood that has been collected in the blood collection chamber so far. The color of the blood can also provide clues to the puncture site: if the blood is bright red, an arterial puncture is likely.

It is also conceivable that the blood collection chamber is at least partially pre-filled with a liquid, such as sterile water, and is also additionally sealed against fluid leakage from the patient at least until the puncture begins. In such a case, the puncture needle connected to the blood collection chamber can also be additionally sealed against fluid leakage from the patient. If the indwelling cannula is used to puncture spaces filled with air and/or steam, for example to relieve a pneumothorax in the chest area, the correct puncture site can be identified by the formation of bubbles in the area of the blood collection chamber after the seal near the patient has been broken, for example by an overpressure situation occurring at the sealing site, as can occur in the case of a tension pneumothorax.

A measuring device for detecting and displaying the pressure in the blood collection chamber can be located in or on the blood collection chamber. Likewise, the blood collection chamber can contain at least one display element that indicates the inflow of gases, vapors, and/or fluids into the blood collection chamber, for example, at least one spherical element that is set in motion by inflowing gases, vapors, and/or fluids.

According to an advantageous embodiment of the invention, the indwelling cannula has an absorbent element that allows the puncture needle to be automatically cleaned, at least on its outer surface, when withdrawn from the catheter tube. This further improves the infection protection of the indwelling cannula.

The indwelling cannula can, for example, have the described puncture protection device, but can also be designed without the described advancement mechanism. In this case, the indwelling cannula is applied to the patient in a known manner, i.e., by the user manually advancing the catheter assembly relative to the needle assembly, without the need for a special manual control element. For example, the user can hold the needle assembly with one hand and advance the catheter assembly slightly with the other hand so that the catheter tube is pushed over the puncture tip. The needle assembly can then be moved away from the catheter assembly with the first hand, i.e., the puncture needle is withdrawn from the catheter tube. The puncture needle is automatically received in the receiving body of the puncture protection device, as described above.

The indwelling cannula can also be designed without a puncture protection device and/or without a manually operated advancement mechanism, but with the aforementioned push-off element. In this case, the beneficial effects achieved by the push-off element can also be achieved with an otherwise conventionally designed indwelling cannula. This also applies to all other puncture systems. This is especially true for puncture systems for regional anesthesia. This also applies in particular to puncture systems that can be used to puncture the trachea, the space between the lungs and the chest (pneumothorax relief), and the abdominal cavity (ascites puncture). The puncture systems used for this purpose are partly very similar to indwelling cannulas for blood vessel puncture (veins, arteries).

The indwelling cannula can be designed, for example, as a peripheral venous catheter (peripheral venous catheter) or as a central venous catheter (CVC).

Further advantages:

• Intuitive operation

• Simple production, e.g. through two-component injection molding

• No valve or multiple components in the cannula, thus avoiding congestion or accumulation of blood

• Easy handling when changing the infusion line

The above-mentioned pressure relief element can also be used independently of an indwelling catheter. For example, it can be combined with or attached to other catheter systems or infusion lines, or possibly even to other components of the indwelling catheter. Its use on tubes, such as ventilation tubes (endotracheal tubes), is also conceivable.

The invention is explained in more detail below using exemplary embodiments and drawings. In the drawings:

Figure 1 shows a first embodiment of an indwelling cannula in perspective view,

Figure 2 shows a base body of a feed mechanism in a perspective view, Figure 3 shows a lever of the feed mechanism in a perspective view, Fig. 4-6 shows the indwelling cannula according to Fig. 1 in a side view in a first sectional plane,

Fig. 7-9 the indwelling cannula according to Fig. 1 in side view,

Fig. 10-12 the indwelling cannula according to Fig. 1 in side view in a second sectional plane,

Figure 13 shows a second embodiment of an indwelling cannula in perspective view,

Figure 14 shows the indwelling cannula according to Fig. 13 in a perspective sectional view,

Fig. 15-18 the indwelling cannula according to Fig. 13 in a lateral sectional view in different operating states,

Fig. 19-21 a part of the indwelling cannula according to Fig. 13 in a sectional plan view in different operating states,

Figure 22 shows a needle assembly of the indwelling cannula according to Fig. 13 in a perspective view in a first sectional plane,

Figure 23 shows the needle assembly of the indwelling cannula according to Fig. 13 in a perspective view in a second sectional plane,

Figure 24 shows a third embodiment of an indwelling cannula in perspective view,

Fig. 25, 26 the indwelling cannula according to Fig. 24 in plan view in sectional plan view in different operating states.

Figures 1, 4, 7, and 10 show the indwelling cannula with the advancement mechanism completely unactuated, i.e., in an initial state. In Figures 5, 8, and 11, the advancement mechanism is moved to a released position, in which a safety element is in an unlocked position. In Figures 6, 9, and 12, the advancement mechanism is moved to a fully actuated position of the pivotable lever.

The indwelling cannula 1 shown in Figure 1 comprises a catheter assembly 3 and a needle assembly 2. The catheter assembly 3 comprises a catheter 23 with a housing 24, on which a tube outlet area 7 is provided on a side facing the patient. is present, at which a catheter tube 9 emerges from the housing 24 and protrudes therefrom. The catheter tube 9 is comparatively flexible and serves as an application option for the intravenous introduction of fluids, in particular infusion solutions, blood products, and medications. The catheter tube 9 is then located with its distal part in a hollow body, e.g., in a patient's vein.

The needle assembly 2 has a puncture needle 30 (visible from Fig. 14 onwards), which, in the initial state of the indwelling cannula 1, is located largely in the housing 24 and the catheter tube 9, with the puncture tip 10 of the puncture needle 30 protruding from the distal end of the catheter tube 9. The needle assembly 2 is displaceable in the longitudinal direction L relative to the catheter assembly 3.

Fixing wings 8 are arranged on the housing 24 for manual handling and for securing the catheter 23 to the patient. On the side facing away from the tube exit area 7, the housing 24 has a needle opening through which the puncture needle 30 can be placed in the housing 24 and the catheter tube 9. After the indwelling cannula 1 has been placed on the patient, the needle assembly 2 is removed. The needle opening then serves as a connection option for, for example, an infusion line or an aspiration element, e.g., a syringe.

The housing 24 may also have an injection port, which protrudes from the housing 24, for example, on the side facing away from the fixing wings 8. The injection port is used for injecting medication. It is otherwise closed by a cap.

The needle assembly 2 also has a closure element 6 with a plug and, if applicable, a handling element at the proximal end of the puncture needle 30. In the basic state, the needle opening is closed by the closure element 6.

Figures 1 to 12 show an indwelling cannula 1 with a manually operable advance mechanism 5 for generating a relative movement between the catheter tube 9 and the puncture needle 30. The advance mechanism 5 has a base body 51, which is attached to a housing body or another part of the needle assembly 2. A pivotably mounted actuating lever 53 is connected to the base body 51 via a joint, which forms an operating element 4 of the manually operable advance mechanism 5. The actuating lever 53 is pivotally connected to the base body 51 via the joint. The joint can form a rotation axis 18 about which the actuating lever 53 is pivotally or rotatably mounted.

A gripping surface 50 for the user's finger is provided on the base body 51. A gripping surface 54 is provided on the lever 53, e.g., in the form of an outwardly curved surface with a ribbing. The gripping surfaces 50, 54 are arranged on opposite sides of the respective components so that they can be gripped, for example, between the user's thumb and index finger. For example, the user's middle finger can be placed for support on the underside 72 of the base body 51. The gripping surfaces 50, 54 can, for example, have a ribbing in the transverse direction.

Figure 2 shows the base body 51 as a separate component. It can be seen that a rotation stop 13 is located inside the base body 51. In addition, on the inside of each side wall of the base body 51, there is a groove 16, which runs, for example, in the longitudinal direction L and serves to insert the actuating lever 53, as explained below. On the base body 51, on the underside 72, i.e. the side facing the fixing wings 8, there is also at least one elastically deflectable tab 11, wherein it is shown that one such tab 11 can be located symmetrically on the left and right. The tabs 11 can be made in one piece from the material material of the base body 51 and obtain their elastic deflectability through a lateral cutout, through which they are freed from the side walls of the base body 51. Elongated holes 17 are also formed on both side walls of the base body 51. The base body 51 also has a securing element 14.

Figure 3 shows the pivotable actuating lever 53 as a separate component. The manual grip surface 54 of the actuating lever 53 can be seen. In addition, the actuating lever 53 has one or more locking elements 15 on a rear side facing the interior of the base body 51 and pointing in the direction of the closure body 6. The actuating lever 53 also has pins projecting to the left and right on lateral surfaces, which form the axis of rotation 18 of the actuating lever 53 when pivoting. On a side of the actuating lever 53 facing the underside 72 of the base body 51, projecting cams 22 are formed, which are designed to interact with the elastically deflectable tabs 11. The actuating lever 53 is inserted with the laterally projecting pins 18 through the grooves 16 into the base body 51 and then engages in the slots 17 when it reaches them.

The rotation stop 13 ensures a maximum possible rotational movement of the actuating lever 53, e.g. the rotational movement can include a pivoting angle in the range of 30° to 60°.

Figures 1, 4, 7, and 10 show the indwelling cannula 1 in its initial state with the advance mechanism 5 still completely deactivated. Accordingly, the puncture tip 10 protrudes from the catheter tube 9.

Figures 5, 8, and 11 show the indwelling cannula with the locking element 14 released, i.e., the protection against further actuation of the advance mechanism 5 for performing the relative movement between the catheter tube 9 and the puncture needle 30 is now removed. In the initial state, the actuating lever 53 is still secured against pivoting by the locking element 14, i.e., the advance mechanism 5 cannot yet be fully actuated. This is achieved by the fact that a rear side of the actuating lever 53 facing the closure plug 6 is at the same height as the locking element 14 and accordingly strikes there when an actuating force is applied to pivot the actuating lever 53. To release this safety device, the operating lever 53 must first be moved slightly downwards by manually pressing on the gripping surface 54 in the direction of the underside 72 of the base body 51, i.e., towards the tabs 11. At this point, no pivoting movement of the operating lever 53 can be carried out. The rotation axis 18 in the elongated hole 17 moves from an upper position to a lower position. The cams 22 in the base body 51 hit the tabs 11 and deflect them slightly downwards, i.e., the user must overcome a certain spring force. If the manual actuation at the gripping area 54 is canceled, the operating lever 53 is moved upwards again by the spring force of the tabs 11, i.e., into the secured position.

In the unlocked position, the actuating lever 53 can now be pivoted so that the relative movement between the catheter tube 9 and the puncture needle 30 is carried out, during which the puncture tip 10 is ultimately covered by the catheter tube 9. In the final position of this pivoting movement of the actuating lever 53, the puncture tip 10 is thus located within the catheter tube 9.

Figures 6, 9, and 12 show the indwelling cannula 1 with the advancement mechanism 5 fully activated. Accordingly, the puncture tip 10 is accommodated in the catheter tube 9. One or more locking devices may be provided to lock the advance mechanism 5 in the fully manually actuated position. By way of example, it is shown that at least one locking edge 12 is formed on the base body 51, e.g. in the form of bilateral fixing webs 12 on the inside of the base body 51, which interacts with a locking element 15 arranged on the actuating lever 53. The locking element 15 can be designed, for example, as one or more locking wings. In the manually actuated position, as shown in Figure 6, the locking element 15 locks behind the locking edge 12, so that this manually actuated position, in which the puncture tip 10 is received in the catheter tube 9, is not inadvertently changed again, so that the puncture tip 10 is not released again. This also prevents the catheter tube 9 from moving back inadvertently relative to the puncture needle 30. The locking by the locking element 15/locking edge 12 can become effective, in particular, after the actuating lever 53 has been rotated up to a rotation stop 13. In this rotational position, further rotation of the actuating lever 53 is prevented by the rear side of the actuating lever 53 coming into contact with the rotation stop 13.

At least one of the locking devices can be configured such that an acoustic signal, such as a click, is generated upon manual actuation of the feed mechanism 5 and the corresponding engagement of the locking element 15/locking edge 12. In this way, the user can be given acoustic feedback regarding the complete actuation of the feed mechanism 5.

Additional gripping surfaces 71 can also be formed on each side of the base body 51. These gripping surfaces can be arranged laterally in such a way that one can no longer "see through" the base body 51 from the side. These gripping surfaces can be intuitively grasped, for example, with the right thumb (left) and the right middle finger (right), whereby the right index finger can then operate the actuating lever 53.

In Figures 1, 4, 7, and 10, the indwelling cannula 1 is in its initial state, in which the puncture tip 10 protrudes from the catheter tube 9. In this state, as with conventional indwelling cannulas, the puncture of the hollow body to be punctured is performed. Once the puncture has been performed, i.e., once the puncture tip 10, together with the end of the catheter tube 9 closest to the patient, is within the hollow body, the advance mechanism 5 can first be manually actuated to release the safety catch. The advance movement of the catheter tube 9 can then be carried out by pivoting the actuating lever 53. For this purpose, a force is transmitted to the actuating lever 53 via the gripping surface 54, whereby the hand can be supported, for example, via the thumb, on the opposite gripping surface 50. It can be seen in Figures 6, 9, and 12 that the puncture tip 10 is now received in the catheter tube 9. The puncture needle 30 remains stationary when the advance mechanism 5 is actuated.

In this case, the indwelling cannula 1 can advantageously be gripped and operated with one hand, e.g. by placing the thumb of the user's hand on the gripping surface 50, the index finger on the gripping surface 54 and optionally, in addition to the support, another finger, e.g. the middle finger, on the underside 72 of the base body 51.

After the relative movement generated by the advancement mechanism 5 has been carried out, the catheter tube 9, which is splinted at least substantially over its entire length by the internal puncture needle 30, can now be pushed further into the hollow body until a desired position is reached. Thereafter, as with conventional indwelling cannulas, the needle assembly 2 is removed from the catheter 23, whereby the advancement mechanism 5 can also be removed at the same time. The pivotable actuating lever 53 is arranged in a base body 51 that is largely closed at least laterally and is mounted on a rotation axis 18. The base body 51 surrounds the actuating lever 53 at least laterally and partially also at the rear, so that the lever 53 is largely concealed from the surroundings and the gripping surface 54 for manual actuation is mainly located on the outside. In particular, the locking mechanism with the locking element 15 and the locking edge 12 can be arranged within the area surrounded by the base body 51. In this way, the parts of the feed mechanism 5 and the needle opening are even better protected against contamination. In addition, it is avoided that, for example, parts of the user's glove can become caught in the area of the locking elements 12, 15.

As can be seen in Figure 7, the gripping surface 54 extends from the puncture needle 30 from a position below the rotation axis 18, i.e. a position arranged closer to the puncture needle 30 than the rotation axis 18, to a position arranged above the rotation axis 18.

In the variant shown, the operation of the indwelling cannula 1 and its advancement mechanism 5 during application to the patient can be further improved by arranging lateral gripping surfaces 71 on both sides of the base part 51. Additionally, a lower gripping surface can be located on the underside 72 of the base body 51, i.e., the side facing the patient. The lateral gripping surfaces 71 and/or the lower gripping surface 72 can also have a corresponding structure, as already explained for the gripping surfaces 50, 54.

The base body 51, to which the actuating lever 53 is attached, can be formed with a housing of the needle assembly 2 as a one-piece unit, e.g. as a plastic injection-molded component.

The base body 51 can, for example, be designed as a largely closed housing that accommodates the actuating lever 53. For example, the base body 51 can have at least two opposing side walls, a bottom wall, and a rear wall facing the proximal end. A side of the base body 51 that is open toward the distal end can then be largely closed by the lever 53.

The actuating lever 53 may have side walls that are arranged parallel to the side walls of the base body 51 and that at least partially overlap with the side walls of the base body 51. In this way, the arrangement of the base body 51 and the actuating lever 53 also provides good contamination protection in the lateral direction.

The actuating lever 53 can be pivotally mounted on the base body 51 via its rotational axis 18. To design the pivotal bearing, a projecting pin can be formed, for example, on one of the actuating lever 53 and base body 51, which engages into a recess on the respective other component.

Due to the various gripping surfaces, the user has a variety of options for holding and operating the indwelling cannula 1. An advantageous variant of operation, in which the indwelling cannula 1 is operated with three fingers, consists in the user grasping the indwelling cannula 1 at the opposite lateral gripping surfaces 71 with the thumb and middle finger and placing the index finger on the gripping surface 54 of the actuating lever 53. In this way, the hollow body can first be punctured with the puncture tip 10 and then, without having to change the position of the hand 6, the feed mechanism 5 can be actuated with the index finger via the gripping surface 54. In the initial position, the actuating lever 53 cannot rotate, but can only be moved downwards in a vertical direction through the housing slot 17. The tabs 11 prevent an uncontrolled downward movement of the actuating lever 53.

Figure 4 illustrates the indwelling cannula 1 in its initial position. In this configuration, uncontrolled rotation of the actuating lever 53 is prevented, thus preventing unintentional advancement of the catheter 3, since the actuating lever 53 is supported with its rear side on a housing edge 14 of the base body 51, which forms a securing element.

Figure 10 shows how the catheter 23 is held in the starting position. This is achieved by guide grooves 19 on the actuating lever 53, which fix the catheter 23 to its guide pins 20 so that the catheter 23 cannot be moved relative to the needle assembly 2. The guide pins 20 can, for example, be attached to the housing 24.

By actuating the actuating lever 53 in a vertical downward direction, the cams 22 are pressed against the tabs 11 on the base body 51. In this position, the actuating lever 53 is capable of rotating because it is no longer supported by the housing edge 14. The vertically displaceable travel of the actuating lever 53 is limited by the elongated hole 17.

The design of the cams 22 ensures that the actuating lever 53 is only under tension when pressed and no longer during the subsequent rotational movement. This is intended to ensure that the actuating lever 53 can rotate smoothly within the base body 51.

Figure 11 shows the deflection of the tabs 11 by pressing the cams 22 when the actuating lever 53 is activated in the vertical direction downwards.

Due to the rotational movement of the actuating lever 53, the guide pins 20 slide along the guide grooves 19 on the actuating lever 53, whereby the catheter 23 is advanced in the longitudinal direction L.

Figure 12 shows the indwelling cannula 1 with the catheter 23 advanced. The opening plane 21 allows the catheter 23 to be decoupled from the needle assembly 2. In this rotational position, the guide grooves 19 no longer block movement of the catheter 23 in the longitudinal direction L relative to the needle assembly 2.

The rotational movement of the actuating lever 53 is limited by the rotation stop 13 to prevent over-rotation of the actuating lever 53. This is intended to prevent pinching of the finger or the catheter 23.

Figures 13 to 23 relate to a second embodiment of an indwelling cannula 1 which, in addition to the features explained above, has a puncture protection device 31 and a pressing element 28. The pressing element 28 is structurally integrated into the housing 24 of the catheter 23 and is also designed in the form of a one-piece unit with the fixing wings 8. In this way, the fixing wings 8 are attached to the housing 24. The pressing element 28 is made of a softer and/or more elastic material than the housing 24 and/or the catheter tube 9. As can be seen, for example, in Figures 19 to 21, the catheter tube 9 passes through the pressing element 28 through a channel ^A formed inside the pressing element 28 and extending in the longitudinal direction L. The housing 24 and/or the catheter tube 9 can be made of a relatively hard plastic material, e.g., ABS or PC (polycarbonate). The pressure element 28 can be made of a soft material, e.g., silicone or thermoplastic polyurethane.

The puncture protection device 31 is located on the side of the housing 24 facing away from the catheter tube 9 or the puncture tip 10. The puncture protection device 31 is structurally connected to the advancement mechanism 5 or another component of the needle assembly 2. In particular, the puncture protection device 31 is located on the side of the indwelling cannula 1 facing away from the patient.

The puncture protection device 31 has a receiving body 32, 33 in which the entire puncture needle 30 can be received after the puncture procedure has been performed. The receiving body 32, 33 has an outer body 32 and an inner body 33 arranged within the outer body 32. The inner body 33 is mounted displaceably relative to the outer body 32 in the longitudinal direction L and can be extended from the outer body 32 to receive the puncture needle 30, as illustrated in Figures 17 and 18. Figure 22 also shows the inner body 33 fully extended from the outer body 32.

If the indwelling cannula 1 according to the second embodiment is applied to the patient, it is initially operated as previously described for the first embodiment. In the initial state, the actuating lever 53 is still secured against pivoting by the securing element 14, i.e., the advance mechanism 5 cannot yet be fully actuated. In this state, the puncture protection device 31 is still blocked, i.e., the inner body 33 cannot yet be extended from the outer body 32. Only when the actuating lever 53 is released from the securing element 14 can the desired advance of the catheter tube 9 relative to the puncture needle 30 be generated via the advance mechanism 5 by pivoting the actuating lever 53. The puncture protection device 31 is also automatically activated, i.e., the inner body 33 can now be extended from the outer body 32.

Figures 13 to 15 initially show the indwelling cannula in its initial state before actuation of the advance mechanism 5. According to Figure 16, the advance mechanism 5 is now actuated, so that the puncture tip 10 is located within the catheter tube 9. The actuating lever 53 is pivoted and rests with its rear side against the rotation stop 13. In this manually actuated position, the locking element 15 locks behind the locking edge 12, so that the actuating lever 53 cannot be accidentally moved back.

Guide bars 46 are also arranged on the actuating lever 53, which, in this manually actuated position, are aligned horizontally, i.e., parallel to the puncture needle 30. In this position, the retraction of the puncture needle 30 from the catheter tube 9 is enabled.

The user can now withdraw the puncture needle 30 from the catheter tube 9 in a direction away from the end closest to the patient by retracting the outer body 32, while simultaneously withdrawing the inner body 33 from the outer body 32. The inner body 33 has a holding head 40, which extends with a widened end through a fixing sleeve 41 arranged on the catheter assembly 3 or the housing 24. When the puncture needle 30 is withdrawn, this mechanism automatically withdraws the inner body 33 from the outer body 32. As a result, the inner body 33 is telescopically extended from the outer body 32, while at the same time the puncture needle 30 is received in the inner body 33. During this withdrawal process, the feed mechanism 5 is retracted together with the actuating lever 53. In the process, the guide Webs 46 are received and guided in associated guide grooves 34 of the inner body 33. This ensures reliable telescopic guidance of the inner body 33 relative to the outer body 32 throughout the entire withdrawal movement.

The linear travel of the inner body 33 relative to the outer body 32 is limited by the guide webs 46 when the guide webs 46 reach the end of the guide grooves 34 remote from the patient. Additional sliding webs 36 reduce the sliding friction between the inner body 33 and the outer body 32 during the withdrawal process. Once the maximum withdrawal path of the inner body 33 from the outer body 32 is reached, further relative movement between the inner body 33 and the outer body 32 is prevented by locking a locking lug 43 in a locking groove 37, as shown in Figure 17. This secures the puncture protection device 31 and prevents the inner body 33 from sliding back into the outer body 32.

The puncture needle 30, with its puncture tip 10, is now located far enough within the inner body 33 that, from the patient's perspective, the puncture tip 10 is located behind the locking point between the holding head 40 and the fixing sleeve 41. If the needle assembly 2 is now pulled further backward, i.e., away from the patient, as shown in Figure 21, the blockage between the holding head 40 and the fixing sleeve 41 can be overcome by slightly compressing the holding head 40 at the free end, where the holding head 40 is slit-shaped by means of a release slot 39, using the fixing sleeve 41, thereby reducing its circumference so that the holding head 40 can be pulled through the opening of the fixing sleeve 41. The needle assembly 2 can now be completely separated from the catheter assembly 3, as shown in Figure 21.

Before the state shown in Figure 21 is reached, the release of the holding head 40 from the fixing sleeve 41 is prevented by the fact that the puncture needle 30 is still located inside the holding head 40 and thus prevents the explained compression process of the holding head 40, which is necessary to release the holding head 40 from the fixing sleeve 41, as shown in Figures 19 and 20. Thus, detachment of the needle assembly 2 from the catheter assembly 3 is not possible in this position, since the holding head 40 is prevented by the puncture needle 30 from bending inward into the release slot 39 and escaping through the fixing sleeve 41.

Figure 20 shows a sectional view in which the puncture needle 30 is fully retracted in a linear direction. In this position, the needle assembly 2 can be decoupled from the catheter assembly 3, as the retaining head 40 can bend inward and slide through the fixation sleeve 41.

The indwelling cannula 1 also has a blood collection chamber 44, which is configured to automatically provide a blood sample for analysis purposes after puncturing the hollow body to be punctured. After the indwelling cannula is applied to the patient, the blood automatically flows through the puncture needle 30 and/or the catheter tube 9 into the blood collection chamber 44. Advantageously, the blood collection chamber 44 is arranged in the puncture protection device 31, in particular in the outer body 32. The blood collection chamber 44 has a first viewing window 27 for visually checking the amount of blood collected in the blood collection chamber 44. The first viewing window 27 can be designed as a viewing window elongated in the longitudinal direction L, e.g., as a blood viewing window groove, through which the blood flow into the blood collection chamber 44 can be visually checked. The blood collection chamber 44 has a second viewing window 38 at the end of the blood collection chamber 44 remote from the patient, which serves to signal that the blood collection chamber 44 is completely filled.

The indwelling cannula has an absorbent element 47, which allows the puncture needle 30 to be automatically cleaned, at least on its outer surface, when withdrawn from the catheter tube 9. This further improves the infection protection of the indwelling cannula 1. The absorbent The absorption element 47 can be arranged, for example, in the form of a sleeve inside the holding head 40 or another part of the inner body 33. When the puncture needle 30 is withdrawn, blood is absorbed by the absorption element 47, thereby preventing uncontrolled splashing of blood drops and cleaning the puncture needle 30. The absorption element 47 can be made of a material that absorbs liquids, such as paper, plastic (sponge, textile), etc. The needle unit 3 is disposed of after use.

Figures 24 to 26 show a third embodiment of an indwelling cannula 1, which is designed, for example, without the advancement mechanism 5 and without the puncture protection device 31. The push-off element 28 is present, which can be designed as previously described.

Figures 25 and 26 explain the function of the pressure element 28, which applies to both the second and the third embodiments of the indwelling cannula 1. In the normal state, as shown in Figure 25, the pressure element 28 is not actuated. This allows free passage of the catheter tube 9 over its entire length, including through the pressure element 28. Accordingly, fluids can flow through the catheter tube 9, as indicated by the dashed arrow. If, for example, an undesired flow of blood through the catheter tube 9 is to be prevented, the pressure element 28 can be subjected to pressure on its outer, oppositely facing actuating surfaces, as illustrated in Figure 26 by the arrows pointing towards one another. As a result, the pressing element 28 or its inner channel is compressed to such an extent that the inner lumen of the catheter tube 9 is also reduced, possibly even closed, so that the undesired blood flow through the catheter tube 9 is prevented. If the force application is removed again according to Figure 26, the pressing element 28 springs back together with the part of the catheter tube 9 located therein, so that the state shown in Figure 25 is achieved again.

The indwelling cannula 1 can additionally have an anti-twist device 26, which is shown, for example, in Figure 24. However, the anti-twist device 26 can be implemented in any embodiment of the indwelling cannula 1. The anti-twist device 26 prevents the catheter assembly 3 in the needle assembly 2 from unintentionally twisting or rotating about the longitudinal axis L. Rotation of the catheter assembly could lead to a malfunction during advancement, which is prevented by the anti-twist device 26.

List of reference symbols 04MO)UW O^WOO(»I^)W^1^^-

1 indwelling cannula 27 first viewing window

Needle assembly 28 Push-off element Catheter assembly 30 30 Puncture needle Operating element 31 Puncture protection device Feed mechanism 32 Outer body Closing element 33 Inner body Tube exit area 34 Guide groove Fixing wing 35 35 Free-running groove Catheter tube 36 Sliding bar Puncture tip 37 Locking groove Tab 38 Second viewing window

Locking edge (e.g. fixing bars) 39 Release slot Rotation stop 40 40 Holding head rear edge 41 Fixing sleeve Locking elements 43 Latch nose Grooves 44 Blood collection chamber Slotted holes 46 Guide bar Rotation axis 45 47 Absorbing element Guide grooves 50 Gripping surface Guide pin 51 Base body Opening level 53 Lever Cam 54 Gripping surface Catheter 50 71 Side gripping surface Housing 72 Lower gripping surface

Anti-twist protection L longitudinal direction

Claims

Claims: 1. Indwelling cannula (1) with a puncture needle (30) for puncturing a hollow body, wherein the indwelling cannula (1) has at least one catheter (23) with a tubular catheter tube (9) in which the puncture needle (30) can be guided in a longitudinally displaceable manner, wherein the catheter (23) is designed, after a puncture of a sheath of the hollow body to be punctured has been carried out, to be pushed over at least part of the length of the catheter tube (9) through the opening created by the puncture needle (30) through the sheath of the hollow body to be punctured and to remain there for a period of time. 2. Indwelling cannula according to claim 1, characterized in that the indwelling cannula (1) has a needle assembly (2) to which the puncture needle (30) is attached, and a catheter assembly (3) separate from the needle assembly (2) to which the catheter tube (9) is attached, wherein the needle assembly (2) is designed to be removed from the catheter assembly (3) after the puncture procedure has been carried out. 3. Indwelling cannula according to one of the preceding claims, characterized in that the indwelling cannula (1) has a manually actuated feed mechanism (5) (5) with a manual operating element (4), by the manual actuation of which a relative movement between the catheter tube (9) and the puncture needle (30) can be generated automatically, wherein by the relative movement a puncture tip (10) of the puncture needle (30) protruding from the catheter tube (9) at the end near the patient can be received in the catheter tube (9). 4. Indwelling cannula according to claim 3, characterized in that the catheter tube (9) can be pushed over the puncture tip (10) of the puncture needle (30) and/or the puncture tip (10) of the puncture needle (30) can be pulled into the catheter tube (9) by the advance mechanism (5). 5. Indwelling cannula according to one of claims 3 to 4, characterized in that the advancement mechanism (5) has a first locking mechanism by which at least a part of the advancement mechanism (5) can be fixed by locking in the manually operated position in which the puncture tip (10) is received in the catheter tube (9). 6. Indwelling cannula according to one of claims 3 to 5, characterized in that in the manually operated position of the advance mechanism (5), in which the puncture tip (10) is received in the catheter tube (9), at least one operating element (4) of the advance mechanism (5) can be fixed by means of the first locking mechanism by locking and/or at least a part of the housing (24) of the catheter (23) can be fixed to the needle device by locking. 7. Indwelling cannula according to claim 5, characterized in that the first locking mechanism is designed to generate a signal noise when the operating element is locked. 8. Indwelling cannula according to one of claims 3 to 7, characterized in that the manual operating element (4) is arranged in the longitudinal direction (L) of the indwelling cannula (1) substantially centrally on the indwelling cannula (1). 9. Indwelling cannula according to one of the claims 3 to 8, characterized in that at least one operating element (4) of the feed mechanism (5) is designed as a pivotably mounted actuating lever with at least one lever arm. 10. Indwelling cannula according to claim 9, characterized in that the actuating lever is rotatable about a rotation axis (18), wherein the rotation axis (18) is displaceably mounted. 11. Indwelling cannula according to one of the claims 3 to 10, characterized in that the feed mechanism (5) is arranged to generate the relative movement between the catheter tube (9) and the puncture needle (30) by manually applied actuating force and/or by spring force. 12. Indwelling cannula according to one of the claims according to one of claims 3 to 11, characterized in that the feed mechanism (5) has as operating elements (4) at least two gripping surfaces (50, 54, 71, 72), on each of which at least one finger of the user can be placed, wherein the at least two gripping surfaces (50, 54, 71, 72) are arranged facing away from one another. 13. Indwelling cannula according to claim 12, characterized in that at least one of the gripping surfaces (50, 54, 71, 72) is arranged on a lever arm of a pivotably mounted actuating lever of the feed mechanism (5). 14. Indwelling cannula according to one of the preceding claims, characterized in that the indwelling cannula (1) has a puncture protection device (31) for reducing the risk of injuries to the puncture needle (30), wherein the puncture protection device (31) has a receiving body which is designed to completely receive the puncture needle (30) withdrawn from the catheter tube (9) and to shield it from the environment. 15. Indwelling cannula according to claim 14, characterized in that in an initial state of the indwelling cannula (1), in which the indwelling cannula (1) is provided by the manufacturer or before a puncture of the hollow body to be punctured has taken place, the puncture needle (30) is arranged predominantly or completely outside the receiving body. 16. Indwelling cannula according to one of claims 14 to 15, characterized in that the puncture protection device (31) is designed to automatically separate the puncture protection device (31) from the catheter assembly (3) when the puncture needle (30) has reached a predetermined minimum position when being withdrawn from the catheter tube (9). 17. Indwelling cannula according to one of claims 14 to 16, characterized in that the puncture protection device (31) has a safety device by which is that the puncture protection device (31) is separated from the catheter assembly (3) before the puncture needle (30) has reached the predetermined minimum position. 18. Indwelling cannula according to one of claims 14 to 17, characterized in that the receiving body has an outer body (32) and an inner body (33) arranged in the outer body (32) which can be moved out of the outer body (32) in a telescopic manner. 19. Indwelling cannula according to claim 18, characterized in that the puncture needle (30) is arranged at a fixed position of the indwelling cannula (1) relative to the outer body (32). 20. Indwelling cannula according to one of claims 18 to 19, characterized in that the puncture protection device (31) is designed to automatically extend the inner body (33) from the outer body (32) when the puncture needle (30) is withdrawn from the catheter tube (9) and to thereby receive the puncture needle (30) in the inner body (33). 21. Indwelling cannula according to one of claims 18 to 20, characterized in that the securing device has a first end stop by which the extension path of the inner body (33) from the outer body (32) is limited to a maximum value. 22. Indwelling cannula according to one of claims 18 to 21, characterized in that the puncture protection device (31) has a locking mechanism by which the inner body (33) can be automatically locked relative to the outer body (32) when the puncture needle (30) is received in the inner body (33). 23. Indwelling cannula according to one of claims 18 to 22, characterized in that the puncture protection device (31) has a blocking mechanism by which the extension of the inner body (33) relative to the outer body (32) is blocked as long as the actuating lever is not moved into the actuated position. 24. Indwelling cannula according to one of claims 18 to 23, characterized in that the outer body (32) is arranged closer to the end of the indwelling cannula (1) remote from the patient than the actuating lever. 25. Indwelling cannula according to one of claims 2 to 24, characterized in that the indwelling cannula (1) has on the catheter assembly (3), in particular in the region of fixation wings of the catheter assembly (3), at least one elastically deformable pressing element (28) which has at least one manual actuating surface, wherein by manually exerting pressure on the at least one manual actuating surface of the pressing element (28), the inner lumen of the catheter tube (9) can be reduced or closed. 26. Indwelling cannula according to claim 25, characterized in that the push-off element (28) is designed as a one-piece assembly with fixing wings of the indwelling cannula (1). 27. Indwelling cannula according to one of claims 25 to 26, characterized in that the pressing element (28) is made of a material with higher elasticity than the catheter tube (9), in particular of a rubber-elastic material. 28. Indwelling cannula according to one of claims 25 to 27, characterized in that the pressing element (28) is connected to the catheter tube (9) by a material connection. 29. Indwelling cannula according to one of the preceding claims, characterized in that the indwelling cannula (1) has a blood collection chamber (44) which is designed for the automatic provision of a blood sample for analysis purposes after the puncture of the hollow body to be punctured has been carried out. 30. Indwelling cannula according to claim 29, characterized in that the blood collection chamber (44) is arranged in the puncture protection device (31), in particular in the outer body (32). 31. Indwelling cannula according to one of claims 29 to 30, characterized in that the blood collection chamber (44) has a viewing window (27, 38) for optically checking the amount of blood collected in the blood collection chamber (44) and/or for indicating that the blood collection chamber (44) is completely filled. 32. Indwelling cannula according to one of the preceding claims, characterized in that the indwelling cannula (1) has an absorbing element (47) on which the puncture needle (30) can be automatically cleaned, at least on its outer side, when it is pulled out of the catheter tube (9).