Abstract:
A closed IV catheter system, includes a needle shield assembly positioned proximally of a catheter hub and distally of the needle hub. The needle shield assembly cooperates with the catheter hub on the outer circumferential and peripheral surface of the catheter hub. The needle shield adds additional length and width to the closed IV catheter system. An improved manufacturing process with unique materials is also presented.

Description:
TECHNICAL FIELD 
       [0001]    The present invention pertains to a closed IV catheter system, comprising a needle hub, a catheter hub with a catheter connected distally of an adapter body, said adapter body having an extension tube extending laterally from the adapter body, wherein the extension tube is in fluid communication with an inner adapter body cavity and the lumen of the catheter, and a needle shield assembly. 
       BACKGROUND 
       [0002]    Catheters, particularly intravascular (IV) catheters, are used for infusing fluid, such as normal saline solution, various medicaments and total parenteral nutrition, into a patient, withdrawing blood from a patient or monitoring various parameters of the patient&#39;s vascular system. Peripheral IV catheters tend to be relatively short, and typically are on the order of about two inches or less in length. 
         [0003]    The most common type of IV catheter is an over-the-needle peripheral IV catheter. 
         [0004]    As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. At least the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitates insertion of the catheter into the blood vessel. The catheter and the introducer needle are assembled so that the distal tip of the introducer needle extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient&#39;s skin. 
         [0005]    The catheter and introducer needle assembly is inserted at a shallow angle through the patient&#39;s skin into a blood vessel. There are many techniques for inserting such a catheter and introducer needle assembly into a patient. In one insertion technique, the introducer needle and catheter are inserted completely into the blood vessel together. In another technique, the introducer needle is partially withdrawn into the catheter after the initial insertion into the blood vessel. The catheter is then threaded over the needle and inserted completely into the blood vessel. 
         [0006]    The clinical utilization of a pointed hollow needle mounted inside a flexible catheter tube is well known in the medical art for the introduction of a catheter. In such a medical instrument, the catheter tube is positioned tightly around the needle in such a way as to allow the needle to slide and telescope along the length of the catheter tube. Before use, the tip of the needle is protruding slightly through the opening of the catheter tube to allow facile penetration through the skin. Upon puncturing of the skin and introduction of the needle, the distal end of the catheter tube is simultaneously brought into place inside the desired target body cavity of the patient, such as the inside of a blood vessel, for example a vein. The needle has then done its duty in assisting the introduction of the catheter and is withdrawn by being pulled backwards through the catheter. Upon release of the needle, the catheter is set in its intended working mode extending over a lengthier period of time and including, for example, periodical administration or infusion of fluids or medications in liquid form, the collection of blood samples and the like. 
         [0007]    With regard to over-the-needle catheters, there are mainly two major alternatives. The first one, the open IV catheter system, such as the Venflon®-type, comprises luer through which the needle is withdrawn after insertion of the catheter into the blood vessel, which is connectable to blood withdrawal or infusion means, as well as an optional port for the same purpose. The second one, the closed IV catheter system, such as the Nexiva&#39;-type, comprises a septum in an catheter hub through which the needle is withdrawn after insertion of the catheter into the blood vessel, closing off the “needle channel” from the environment, and instead has an extension tube extending laterally from the catheter hub, wherein the extension tube is in fluid communication with the catheter hub cavity and the lumen of the catheter positioned in the blood vessel. These two alternatives are accompanied with different problems and benefits. 
         [0008]    In recent years, there has been great concern over the contamination of clinicians with a patient&#39;s blood and a recognition that “blood contaminated sharps” must be disposed to avoid an accidental needle stick. This concern has arisen because of the advent of currently incurable and fatal diseases, such as Acquired Immunosuppressive Deficiency Syndrome (“AIDS”), hepatitis, etc., which can be transmitted by the exchange of body fluids from an infected person to another person. 
         [0009]    As a result of the problem of accidental needlesticks by “blood contaminated sharps”, various needle shields have been developed for use in conjunction with intravenous catheters. Due to the difference in configuration between an open and a closed IV catheter system, different needle shields and configurations have been introduced with regard to the two alternatives. 
         [0010]    With regard to closed IV catheter systems, the catheter hub has to be of a material compatible with adhesion of the extension tubing. Such a material is for example polycarbonate, which is a hard and brittle polymer with a high impact strength. Additionally, the septum in the catheter hub takes up the proximal part of the catheter hub. 
         [0011]    WO 2004/087247 discloses a closed IV catheter system, wherein a needle shield assembly is positioned proximally of the catheter hub and distally of the needle hub, and wherein the needle shield assembly cooperates with the catheter hub on the outer circumferential and peripheral surface of the catheter hub. This means that the needle shield adds additional length and width to the closed IV catheter system. Additionally, the needle shield assembly could be reached and perhaps released unintentionally from the catheter hub, and not as envisioned only by withdrawal of the needle hub. 
         [0012]    Hence, a needle shield assembly with improved volume occupying characteristics, as well as decreased risk of undue needle shield assembly release with regard to a closed IV catheter system, is desired. 
       SUMMARY 
       [0013]    It is an object of the present invention, considering the disadvantages mentioned above, to provide a closed IV catheter system with a needle shield, while avoiding unnecessarily adding to dimensions thereof. 
         [0014]    It is another object of the present invention, to provide an IV catheter system which may be produced at low cost. 
         [0015]    These and other objects, which will appear from the following description, have now been achieved by an IV catheter system comprising: a catheter hub, said catheter hub comprising: a tubular catheter attached to a catheter hub body at its proximal end; a catheter hub cavity in fluid communication with the lumen of the tubular catheter; a tube in fluid communication with the catheter hub cavity, said tube extending laterally from the catheter hub body; a septum, proximally of the catheter hub cavity; and an end cavity, proximally of the septum; a needle hub, said needle hub comprising: a needle extending distally from a needle hub body, said needle having a bulge at its distal end zone; a needle shield, said needle shield comprising: at least one resilient arm extending distally from a base plate, said base plate having a through hole for receiving the needle there through; wherein the needle hub is arranged in the catheter hub, such that the needle is slidingly arranged through said septum and in the lumen of said catheter, such that the needle may be withdrawn proximally from the catheter hub; wherein the needle shield is arranged in the end cavity in a retained manner through cooperation between the needle shield and an inner wall of the catheter hub in said end cavity, and onto the needle, such that the at least one arm rests upon and is spring loaded by the needle, and the needle is slidingly arranged within the through hole of the base plate, in an assembled state; and wherein the bulge will interact with the base plate when the needle hub is withdrawn from the catheter hub to release the needle shield from the catheter hub and the at least one arm will cover the tip of the needle, in a released state. 
         [0016]    Further features of the invention and its embodiments are set forth in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    These and other aspects, features and advantages of which the invention is capable will be apparent and elucidated from the following description of non-limiting embodiments of the present invention, reference being made to the accompanying drawings, in which 
           [0018]      FIG. 1  is a cross-sectional view of a catheter hub according to one embodiment of the present invention; 
           [0019]      FIG. 2  is a cross-sectional view of a needle hub, with a needle shield arranged thereon, according to one embodiment of the present invention; 
           [0020]      FIG. 3  is a perspective view of a needle shield according to one embodiment of the present invention, intended to be arranged on a needle of a needle hub according to  FIG. 2  which in turn is intended to be arranged in the catheter hub according to  FIG. 1 ; and 
           [0021]      FIG. 4  is a cross-sectional view of a closed IV catheter system, with a catheter hub, a needle hub, and a needle shield, in assembled state, in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0022]    Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in order for those skilled in the art to be able to carry out the invention. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0023]    Furthermore, the terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. More specifically, the term “proximal” refers to a location or direction of items or parts of items, during normal use of the closed IV catheter system disclosed herein, is closest to the user, i.e. the clinician, and farthest away from the patient receiving the closed IV catheter system. Similarly, the term “distal” refers to a location or direction of items or parts of items, during normal use of the closed IV catheter system disclosed herein, is closest to the patient and farthest away from the clinician. The term “laterally” refers to the direction away from the central axis of the closed IV catheter system, such that at least a vector component perpendicular to the central axis of the closed IV catheter system, wherein the needle and catheter of the assembled closed IV catheter system coincides with the central axis of the closed IV catheter system. 
         [0024]    In accordance with  FIG. 1 , one embodiment of a catheter hub  100  of a closed IV catheter system is illustrated. The catheter hub  100  comprises a longitudinal and tubular catheter  101  at its distal end. The catheter is, in accordance with above, intended to be inserted into a blood vessel of a patient. The catheter  101  is attached to a catheter hub body  102  at its proximal end, such that the catheter extends distally from the catheter hub body  102 . The lumen of the catheter  101  is in fluid communication with a catheter hub cavity  103 . The catheter hub body  102  is preferably made through injection molding, and then of a rigid plastic material suitable for injection molding and connection and interaction with other parts of the system. Such a suitable material is polycarbonate or a copolymer of polycarbonate and polyester. 
         [0025]    From the catheter hub body  102  a tube connector  104  is provided. The tube connector  104  extends laterally from the catheter hub body  102 . The tube connector  104  has a lumen in fluid communication with the hub cavity  103 , such that a tube  105  may be connected to the tube connector  104  to allow for infusion from the tube  105  into the tube connector  104 , further into hub cavity  103  to catheter  101 , and finally into the blood stream of the patient. The tube connector  104  may for example be tubular. A suitable material for the tube  105  is polyvinyl chloride or ethylene vinyl acetate. 
         [0026]    The catheter hub cavity  103  ends proximally in a septum  106 . This septum  106  has a central through channel, which may be penetrated by a needle  201  of a needle hub  200 , in accordance with  FIG. 2 . When the needle  201  has been withdrawn from the catheter hub  100 , the septum  106  will close said through channel, such that the hub cavity  103  is marked off from the surroundings in the proximal direction. For this reason, the septum  106  is preferably of a suitable rubber material or silicone. 
         [0027]    On the proximal side of the septum  106  a proximal end cavity  107  is located. The end cavity  107  is formed by the tubular wall of the catheter hub body  102  and a distal end wall in form of the proximal end wall of the septum  106 . This end cavity  107 , extending distally into the catheter hub body  102 , is adapted in size and shape to house the needle shield  300 , as disclosed in  FIG. 3 . 
         [0028]    The needle shield  300  is thus intended to be arranged on the needle  201  of the needle hub  200 , which in turn is intended to be arranged in the catheter hub  100 . In such assembled state, in accordance with  FIG. 4 , the needle  201  penetrates the septum  106 , and extends through the catheter  101 . Preferably, the needle  201  extends just beyond the distal end of the catheter  201 , such that skin and blood vessel penetration is facilitated. In that position, the needle shield  300  is arranged in the end cavity  107 , with arms  301  thereof forced laterally by needle  201 . The needle shield  300  preferably does not extend proximally of the proximal end of the catheter hub  100 , but is instead entirely housed in the end cavity  107  of the catheter hub  100 . In this way, the needle hub body  202  of the needle hub  200  may cooperate with the catheter hub body  102  of the catheter hub  100 , without intermediary structures, such as the needle shield  300 . This may be accomplished through a distal connective flange  203  on the needle hub  200 . The distal connective flange  203  may then house the distal end of the catheter body  102  of the catheter hub  100 . This connection may be a snap fit. Alternatively, the needle hub body  202  has a distal cavity for housing a part of the needle shield  300 , while still being adapted to be connectable to the catheter hub body  102 . In this position the needle shield  300  is held in place in the proximal end cavity  107  through interaction between a needle shield base plate  302  and the inner tubular wall of the catheter hub body  102 . This may be accomplished by tongues  303 , extending laterally of the base plate  302 , being flexed somewhat inwardly to exercise a lateral pressure on the inner tubular wall of the catheter hub body  102  inside the end cavity  107 . To further increase the cooperation between the periphery of the needle shield  300  and the catheter hub  100  a circumferential ridge  108  may be formed at the opening of the end cavity  107 . The base plate  302  is provided with a centrally arranged through hole, such that the needle  200  may run freely therein. 
         [0029]    When withdrawing the needle hub  200  from the catheter hub  100 , after the catheter  101  has been securely placed inside the blood vessel of the patient, the needle hub  200  will firstly be disconnected from the cooperation between the catheter hub body  102  and the needle hub body  202 , such as through release of the connective flange  203  from the circumference of the catheter body  102 . Then the needle  201  travels proximally within the catheter  101 , until the needle tip of the needle  201  exits the catheter  101  and enters the catheter hub body  102 . When entering the catheter hub body  102 , the needle tip of the needle  201  will continue proximally into the catheter hub cavity  103  and further through the septum  106 . While the needle tip of the needle  201  travels proximally through the septum  106 , the septum  106  will continuously seal off the catheter hub cavity  103  from the surroundings in the proximal direction. When the needle tip of the needle  201  exits the septum on the proximal side thereof, the needle tip of the needle  201  enters the proximal end cavity  107  of the catheter hub  100 , wherein the needle shield  300  is positioned and is securingly interacting with the inner tubular wall of the catheter hub body  102 . When the needle tip of the needle  201  passes proximally of the arms  301 , the arms  301  will snap centrally to cover the needle tip of the needle  200 . This may be further facilitated by hooked tips  304  on the arms  301 . Just subsequently to the snapping of the arms  301  in front of the tip of the needle  201 , a bulge  204  on the needle  201  hits the base plate  302 . The bulge  204  has a width that is greater than the central lumen of the base plate  302 . Thus, the withdrawal of the needle hub  200  further proximally will pull out the needle shield  300  from the end cavity  107 . This is accomplished by adapting the retaining action from tongues  303 , such that the retaining force from these is overcome by a suitable withdrawal force. Then the needle hub is separated from the catheter hub, and the needle shield  300  is securely arranged on the tip of the needle  200  to prohibit and prevent accidental needle stick. 
         [0030]    The needle shield  300  may comprise one, two, three or more tongues  303 , which extend proximally from the lateral circular periphery of the base plate  302 . The tongues  303  are, in accordance with above, resilient, whereby they are resiliently striving from a compressed state towards an expanded state. In the assembled state within the end cavity  107 , the tongues  303  are somewhat compressed, to exercise a force on the inner walls of the catheter hub  100 . The needle shield  300  is thereby held therein, i.e. a constant spatial relationship between the needle shield  300  and the catheter hub  100  is provided. A plurality of tongues  303  may be evenly spread at the periphery of the base plate  302 , whereby each tongue  303  is contacting the inner surface of the catheter hub  100  with essentially the same force. 
         [0031]    The tongues  303  may comprise a protuberance  305  extending in a direction essentially perpendicular to the central axis or laterally of the needle shield  300 . When the tongues  303  are provided with protuberances  305 , the diameter of the base plate  302  in a transversal plane intersecting the protuberances  305  may be greater than the diameter of the end cavity  107 , and specifically the proximal opening thereof, along a transversal plane. Then the needle shield  300  may be compressed, due to the flexibility of the tongues  303 , such that it may be inserted into the end cavity  107  in a compressed state. In the inserted position, the protuberances  305  on the tongues  303  then exerts a retaining radially outwards directed pressure on the inner wall of the end cavity  107 . The ridge  108  of at the opening of the end cavity  107  then maintains the needle shield  300  within the cavity, until the needle  201  pulls the needle shield proximally, whereby the pressure of the protuberances  305  on the inner walls of the end cavity  107  is overcome and the also the protuberances  305  are pressed inwardly beyond the ridge  108  to release the needle shield  300  from the end cavity  107 . To facilitate interaction between the needle shield  300  and the end cavity  107 , the ridge  108  is somewhat slanting distally and/or proximally. The protuberances  305  are in the same way slanting distally and/or proximally. Preferably the slanting of the protuberances is sharper in the proximal direction than in the distal direction, whereby the needle shield  300  may be smoothly inserted into the end cavity  107 , retained with a snap action when the proximal side of the protuberances pass distally beyond the ridge  108 , and also maintained more securely due to the sharper slanting at the proximal zone. 
         [0032]    According to one embodiment, the needle shield  300  may be made of a plastic material. Preferably, the plastic material has a suitable combination, for its intended purpose, of tenacity, rigidity, fatigue resistance, elasticity, and creep deformation resistance. A suitable plastic material has a high creep deformation resistance, i.e. it has a low tendency to slowly move or deform permanently under the influence of an applied external pressure. Hence, a catheter system of the present invention, comprising needle shield  300 , may be stored in the assembled ready mode for a prolonged time without extensive creep deformation of the arms  301  or the tongues  303 . Advantages of a plastic needle shield  300  include the highly reduced tendency, in comparison to metal, of release of e.g. microscopic plastic chips by the scraping of the plastic catheter hub  100 , when the needle shield  300 , is ejected from the former upon withdrawal of the needle  201 . Accordingly, the tendency for formation of scrape marks, which may result in leakage through the affected connector, is greatly reduced. In addition, a plastic needle tip shielding device may be easily color coded or transparent, depending on its particular application. 
         [0033]    The needle shield  300  is a monolithic or homogenous injection molded needle shielding  300 , made of a molded plastic material. Due to the specific configuration of the different parts of the needle shield  300  according to the embodiments of the present invention, the needle shield  300  may be molded, such as injection molded, into one homogenous, i.e. monolithic, piece and/or one integral unit, without interfaces in between the different parts thereof. Advantages of a monolithic needle shield  300  include a lower production cost in comparison to other devices made of more than one part that has to be assembled. The needle shield  300  may in this respect be made of a thermoplastic polymer. The thermoplastic polymer could be crystalline, amorphous, or comprising crystalline and amorphous alternating regions. A creep resistance of the thermoplastic polymer of choice may preferably be at least 1200 MPa (ISO 527, ASTM D638). Suitable plastics for the needle shield  300  may be selected from the group comprising of polyoxymethylene (POM), polybutylen terephthalate (PBTP), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), styrene acrylonitrile (SAN), acrylonitrile styrene acrylate (ASA), polystyrene (PS), styrene butadiene (SB), liquid crystal polymer (LCP), polyamide (PA), polysulfone (PSU), polyetherimide (PEI), polycarbonate (PC), polyphenylene oxide (PPO), and/or PPO/SB, and co- and terpolymers thereof. These polymers have specifically the advantages of providing enhanced storing capacity, even in strained state, and excellent cooperation abilities with regard to the catheter hub, due to the excellent structure memory of these polymers. 
         [0034]    Contacting smooth shapes of two bodies, such as a needle shield  300  mounted in a catheter hub  100 , may result in a significant attraction between these bodies, especially if the contact area is large and they are pressed together. The underlying basis for this type of attraction include intermolecular attraction between the molecules of the two bodies, in which molecular van der Waals interactions and surface tension of the two bodies are important factors. Covalent bond formation between closely interacting surfaces may also contribute to the attraction. Such covalent bond formation, and other types of attraction between two surfaces, may also result upon radiation treatment, such as radiation treatment of e.g. catheter instrument to sterilize these. This type of attraction may become noticeable when the needle shield  300  is about to be released from the catheter hub  100 . The force needed to release the needle shield  300  from the catheter hub  100  then becomes significantly higher than expected. This effect, which may be referred to as “the attraction effect”, may even adventure the intended function of the needle tip shielding device if relying on e.g. an automatic release of a part of the device, such as a spring biased arm or the like, from a part of the catheter hub. The needle shield  300  is kept in contact with the catheter hub  100  in the assembled state via at least one interface surface between the needle shield  300  and the catheter hub  100 . Thus, in one embodiment the surface of the needle shield  300  being in contact with the inner lumen of the catheter hub is of a different polymeric material than the polymeric material of the catheter hub. 
         [0035]    At the other end of the tube  105  a unit with branches (not shown) may be attached to the tube  105 . The branches may in turn be provided with standard Luer slip® or Luer lok® connections and corresponding lids, for allowing infusion into the tube  105 . 
         [0036]    In the claims, the term “comprises/comprising” does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms “a”, “an”, “first”, “second” etc do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.