Abstract:
Systems and methods to provide an intravenous device having flashback capabilities and features to permit a flashback notch of an introducer needle to bypass a septum of the device without incurring an undesirable contact between the flashback notch of the introducer needle and a related contact surface of the septum.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This present invention relates generally to cannulae and associated methods. More specifically, this disclosure discusses a cannula or needle having a flashback notch that is configured to bypass a septum of an intravascular device without incurring septum damage, preventing proper retraction and shielding of the needle, and/or providing a disconcerting feel to the clinician. Further, the disclosure discusses methods for aligning various features of the needle and the septum to minimize and/or prevent damage to the septum. 
         [0002]    Generally, vascular access devices are used for communicating fluid with the vascular system of patients. For example, catheters are used for infusing fluid (e.g., saline solution, medicaments, and/or total parenteral nutrition) into a patient, withdrawing fluids (e.g., blood) from a patient, and/or monitoring various parameters of the patient&#39;s vascular system. 
         [0003]    Intravenous (IV) catheter assemblies are among the various types of intravascular access devices. Over-the-needle peripheral IV catheters are a common IV catheter configuration. As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. The introducer needle is generally a venipuncture needle coupled to a needle assembly that helps guide the needle and facilitates its cooperation with the catheter. At least the inner surface of the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and, thereby, to facilitate insertion of the catheter into the blood vessel. The catheter and the introducer needle are often assembled so that the sharp distal tip of the introducer needle extends beyond the distal tip of the catheter. Moreover, the catheter and needle are often assembled so that during insertion, the bevel of the needle faces up, away from the patient&#39;s skin. The catheter and introducer needle are generally inserted at a shallow angle through the patient&#39;s skin into a blood vessel. 
         [0004]    In order to verify proper placement of the needle and/or the catheter in the blood vessel, the operator generally confirms that there is a “flashback” of blood into a flashback chamber associated with the needle assembly. Flashback generally entails the appearance of a small amount of blood, which exits the needle through an aperture or notch which is visible within the needle assembly or between the needle and the transparent catheter. 
         [0005]    The operator may then withdraw the introducer needle from the catheter. In some cases, the intravascular device further includes an internal septum having a slit or opening through which the introducer needle passes. The septum generally provides a fluid tight seal around a cross-section of the introducer needle. The septum is positioned within the intravascular device so as to provide a fluid barrier that prevents undesirable exposure to blood during and after the catheterization process. Following insertion of the cannula or catheter, the introducer needle is withdrawn from the intravascular device, whereby the “flashback” aperture or notch must pass through the slit in the septum. As the notch is typically provided by removing a portion of the needle&#39;s wall, the septum can engage or snag on a distal edge of the notch as the introducer needle is retracted past the septum. This engagement can prevent proper retraction and shielding of the needle, be disconcerting to the clinician, or even damage the septum. 
         [0006]    Thus, while methods currently exist for incorporating a septum into an intravascular device having flashback capability, challenges still exist. Accordingly, it would be an improvement in the art to augment or even replace current techniques with other techniques. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    This present invention relates generally to cannulae and associated methods. More specifically, this disclosure discusses a cannula or needle having a flashback notch that is configured to bypass a septum of an intravascular device without incurring septum damage, preventing proper retraction and shielding of the needle, and/or providing a disconcerting feel to the clinician. Further, the disclosure discusses methods for aligning various features of the needle and the septum to minimize and/or prevent damage to the septum. 
         [0008]    In some implementations of the present invention, an intravascular device is provided comprising a catheter adapter having an inner surface and an outer surface, wherein a septum is seated within the inner surface of the catheter adapter and includes an opening defined by a plurality of flaps or leaves, each leaf having a contact surface. The intravascular device further includes a notch for providing a flashback signal to indicate proper insertion of the introducer needle into the vasculature of a patient. Still further, in some implementations a width and/or length of the notch is configured to be less than a width of the contact surface of the leaf, such that the contact surface of the leaf is incapable of substantially penetrating the notch. For example, in some implementations an axial length of the notch is shorter than a related contact surface of the leaf. Further, in some implementations a circumferential width of the notch is narrower that the related contact surface of the leaf. 
         [0009]    In some implementations, an intravascular device is provided comprising a septum having at least three leaves, each leaf having an apex which contacts an outer surface of the introducer needle. In some implementations, the septum is oriented within a catheter adapter of the intravascular device such that the notch of the needle, or cannula and the apex are misaligned. In other implementations, the notch comprises a plurality of notches or holes, wherein the apex of each leaf contacts a portion of the outer surface of the needle which is interposed between the plurality of notches. 
         [0010]    In some implementations, a needle feature is provided having a width greater than an outer diameter of the needle, the needle feature forming a portion of an outer surface of the needle and being positioned between the notch and a tip of the cannula. In other implementations, an intravenous device is provided comprising a notch shield having an inner diameter greater than the outer diameter of the needle and less than the width of the needle feature, such that a portion of the needle feature binds on a distal surface of the needle shield. The notch shield is further positioned within the opening of the septum, wherein the notch shield further includes an opening though which a shaft portion of the needle or cannula is slidably positioned, wherein upon withdrawing the needle in a proximal direction, the notch is drawn into the notch shield, whereafter the needle feature contacts a distal surface of the notch shield thereby displacing the notch shield from the opening of the septum in a proximal direction. 
         [0011]    In some implementations, an intravascular device is providing which includes a catheter adapter having an inner surface and an outer surface, a septum seated within the inner surface of the catheter adapter thereby dividing a lumen of the catheter adapter into a proximal chamber and a distal chamber, the septum having an opening defined by a plurality of leaves, and the needle having a notch for providing a flashback signal. In some implementation, the intravascular device further includes a feature for preventing a portion of the plurality of leaves from substantially penetrating the notch. For example, in some implementations the feature comprises a contact surface of each of the septum having a width that is greater than a width of the notch. Further, in some implementations the feature comprises a misaligned position of the notch relative to a misaligned position of an apex surface of the septum. Still further, in some implementations the feature comprises a notch shield positioned within an opening of the septum. 
         [0012]    Some implementations of the present invention include a method for preventing septum damage in an intravascular device, assisting in proper retraction and shielding of the needle, and/or eliminating a disconcerting feel to the clinician, wherein the method includes the steps of providing a catheter adapter having an inner surface and an outer surface, seating a septum within the inner surface of the catheter adapter thereby dividing a lumen of the catheter adapter into a proximal chamber and a distal chamber, the septum having an opening defined by a plurality of leaves, providing a cannula having a notch for providing a flashback signal, and providing a feature for preventing a portion of the plurality of leaves from substantially penetrating the notch. Further, in some implementations the method includes a step for misaligning a position of the notch relative to a position of the apex. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0013]    In order that the manner in which the above-recited and other features and advantages of the invention are obtained and will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not, therefore, to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
           [0014]      FIG. 1  illustrates a perspective view of a representative embodiment of a cannula comprising a notch feature in accordance with a representative embodiment of the present invention. 
           [0015]      FIG. 2A  illustrates a cross-section view of a notch feature of a cannula in accordance with a representative embodiment of the present invention. 
           [0016]      FIG. 2B  illustrates a front plan view of a septum having a tri-leaf slit in accordance with a representative embodiment of the present invention. 
           [0017]      FIG. 3  illustrates a cross-section perspective view of an intravascular device in accordance with a representative embodiment of the present invention. 
           [0018]      FIG. 4  illustrates a cross-section perspective view of an intravascular device and partially withdrawn introducer needle in accordance with a representative embodiment of the present invention. 
           [0019]      FIG. 5  illustrates a cross-section perspective view of an intravascular device and partially withdrawn introducer needle, wherein a notch feature of the introducer needle is positioned within a tri-leaf slit of a septum in accordance with a representative embodiment of the present invention. 
           [0020]      FIG. 6  is a cross-section distal view of an intravascular device and partially withdrawn introducer needle, wherein a notch feature of the introducer needle is positioned within a tri-leaf slit of a septum in accordance with a representative embodiment of the present invention. 
           [0021]      FIG. 7  is a cross-section distal view of an intravascular device and partially withdrawn introducer needle, wherein a notch feature of the introducer needle is positioned within a tri-leaf slit of a septum in accordance with a representative embodiment of the present invention. 
           [0022]      FIG. 8  is a cross-section side view of an intravascular device and partially withdrawn introducer needle, wherein a notch feature of the introducer needle is positioned within a tri-leaf slit of a septum in accordance with a representative embodiment of the present invention. 
           [0023]      FIG. 9  is a cross-section distal view of an intravascular device and partially withdrawn introducer needle, wherein multiple notch features of the introducer needle are positioned within a tri-leaf slit of a septum in accordance with a representative embodiment of the present invention. 
           [0024]      FIG. 10  is a cross-section distal view of an intravascular device and partially withdrawn introducer needle, wherein multiple notch features of the introducer needle are positioned within a tri-leaf slit of a septum in accordance with a representative embodiment of the present invention. 
           [0025]      FIG. 11  is a cross-section side view of an intravascular device having a notch shield in accordance with a representative embodiment of the present invention. 
           [0026]      FIG. 12  is a cross-section side view of an intravascular device having a notch shield, wherein a notch feature of the introducer needle is positioned within the notch shield in accordance with a representative embodiment of the present invention. 
           [0027]      FIG. 13  is a cross-section side view of an intravascular device following removal of the introducer needle and notch shield in accordance with a representative embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    The presently preferred embodiments of the described invention will be best understood by reference to the Figures, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the present invention, as generally described and illustrated in the accompanying Figures, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of some embodiments of the invention, as represented in the Figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of some presently preferred embodiments of the invention. 
         [0029]    Generally, this disclosure discusses a cannula or introducer needle having a notch feature for providing a flashback communication indicating proper insertion of an intravascular device into the vascular system of a patient. While the described cannula can comprise any suitable component or characteristic,  FIG. 1  illustrates a representative embodiment in which the cannula (e.g., needle  10 ) comprises a notch feature  20 , described below in greater detail. 
         [0030]    Cannula  10  may comprise virtually any rigid tube that both includes a sharpened distal tip and which is configured to puncture an animal&#39;s body, to access an intended space, and to draw off or to introduce fluid from or into the intended space. One example of a suitable cannula comprises a venipuncture needle. In this example, the venipuncture needle may include virtually any suitable venipuncture needle, including an introducer needle for use in an IV catheter assembly (e.g., an over-the-needle peripheral IV catheter assembly), a venous needle, an arterial needle, and the like. For simplicity, however, the cannula  10  with notch feature  20  is described below with reference to an introducer needle. 
         [0031]    The introducer needle  10  may have any component that is suitable for use with an IV catheter assembly. For instance,  FIG. 1  shows a representative embodiment in which the introducer needle  10  comprises a sharpened distal tip  12 , an inner lumen  14 , and an elongated tubular shaft  16 . Moreover, each component of the needle may have any suitable characteristic. For example, the distal tip of the needle may comprise a standard bevel, a short bevel, a true short bevel, a bias grind point, a vet point, a lancet point, a deflected point (anti-coring), or another suitable known or novel needle point. Additionally, the lumen and elongated tubular shaft may be any suitable size. For example, the needle may be any suitable length or any suitable gauge (e.g., from about a 7 to about a 33 on the Stubs scale) that allows it to be used as the introducer needle in an intravascular device assembly. 
         [0032]    As mentioned above, needle  10  also defines a notch feature  20  which provides fluid communication between inner lumen  14  and an exterior environment of needle  10 . This notch feature may serve several purposes, including acting as an aperture through which blood can exit the inner lumen  14  of the needle  10  to provide flashback confirmation when the needle  10  is properly placed in a patient&#39;s vasculature. 
         [0033]    The notch feature may have any orientation with respect to the needle&#39;s bevel that allows the notch feature to fulfill its intended purposes. In some embodiments, the notch feature is defined in the cannula so as to be offset in orientation from the direction in which the needle&#39;s bevel faces. In some instances in which the notch feature is defined in the needle so as to be offset from the direction of the bevel, the notch feature may allow for faster flashback confirmation in instances in which the user&#39;s line of sight includes the side of the needle in which the notch is defined but does not include the side of the needle from which the bevel faces. In other embodiments, the notch feature  20  is defined in the needle  10  so as to face in substantially the same direction as the needle&#39;s bevel  18 , as illustrated. 
         [0034]    Where the notch feature is offset from the direction of the needle&#39;s bevel, the notch feature can be offset in any suitable manner. For instance, the notch feature can be defined in the needle so as to face in an opposite direction to, a perpendicular direction to, or in another suitable direction with respect to the direction in which needle&#39;s bevel faces. 
         [0035]    The notch feature can have any suitable characteristic that allows it to provide the needle with flashback confirmation. In some embodiments, from a face view of the notch feature, the notch feature  20  comprises any suitable shape, including a shape that is substantially elliptical, square, rectangular, triangular, circular, polygonyl, irregular, etc. For instance,  FIG. 2A  illustrates an embodiment in which the notch feature  20  is substantially rectangular. In another example of a suitable characteristic, the notch feature may remove any amount of a cross-sectional area of the needle&#39;s sidewall that allows the notch feature to provide the needle with flashback confirmation while still allowing the cannula feature to have sufficient structural integrity to fulfill its intended purposes. 
         [0036]    Referring now to  FIGS. 2B and 3 , in some embodiments an introducer needle  10  is used in combination with a septum  30 . Septum  30  generally comprises a polymer membrane which is disposed within a catheter adapter  40  of an intravascular device  100 . For example, in some embodiments septum  30  is positioned within catheter adapter  40  so as to divide an inner lumen of catheter adapter  40  into a proximal chamber  42  and a distal chamber  44 . Accordingly, septum  30  acts as a blood barrier to control and/or isolate blood flow between the proximal and distal chambers  42  and  44 . 
         [0037]    In some embodiments, septum  30  further comprises an opening or slit  32  to accommodate passage of introducer needle  10 . Slit  32  may include any shape or configuration to permit passage of needle  10 . In some embodiments, slit  32  is provided by advancing the sharpened distal tip  12  of needle  10  through septum  30 , whereby the distal tip  12  creates an opening in the septum  30 . In other embodiments, septum  30  is manufactured to include a slit  32  configured to permit passage of needle  10 . Further, in some embodiments slit  32  provides a fluid tight seal between septum  30  and an outer surface of needle  10 . As such, when needle  10  is positioned within septum  30 , blood flow from the distal chamber  44  to the proximal chamber  42  is prevented. 
         [0038]    In some embodiments, septum  30  comprises a tri-leaf slit, wherein slit  32  provides three septum flaps or leaves  50 ,  52  and  54 . For example, in some embodiments slit  32  comprises three slits or branches  60 ,  62  and  64  that are spaced approximately 120° apart. Branches  60 ,  62  and  64  each comprise a corner  66 . Further, each leaf  50 ,  52  and  54  comprises an apex  56 , the positions of which form a center of the slit  32 . 
         [0039]    In general, leaves  50 ,  52  and  54  of slit  32  are biased into an opened or expanded position by the interposed presence of elongated tubular shaft  16  of needle  10 . As previously mentioned, in some embodiments leaves  50 ,  52  and  54  maintain a close tolerance with the outer surface of tubular shaft  16 , thereby providing a fluid tight seal between septum  30  and needle  10 . 
         [0040]    Following insertion of the intravascular device  100  into a patient, introducer needle  10  is withdrawn from the device  100 , as shown in  FIG. 4 . In some embodiments, the axial orientation of septum  30 , as positioned within catheter adapter  40 , is rotated such that notch feature  20  is in axial alignment with a corner  66  of tri-leaf slit  32 , as shown in  FIGS. 5 and 6 . In other words, in some embodiments a feature is provided wherein the axial orientation of septum  30 , as positioned within catheter adapter  40 , is rotated such that notch feature  20  is misaligned with apexes  56  of flaps  50 ,  52  and  54 . Accordingly, as notch feature  20  is withdrawn through slit  32 , apexes  56  are axially positioned approximately 60° from notch feature  20 , thereby preventing apexes  56  from entering into, or catching on notch feature  20 . As such, needle  10  is able to be removed from intravascular device  100  without damaging the septum  30 . Further, some embodiments of the present invention permit proper retraction and shielding of needle  10  by eliminating any undesirable interactions between notch feature  20  and septum  30 . Still further, some embodiments of the present invention eliminate any disconcerting feelings that the clinician may feel through needle  10  as a result of an undesirable interaction between notch feature  20  and septum  30 . 
         [0041]    In some embodiments, notches  20  comprises a plurality of small notches having sufficient size to still allow blood flow and visualization by the clinician, yet be small enough to prevent an undesirable interaction between the notches and a surface of the septum  30 . Referring now to  FIG. 7 , in some embodiments a feature is provided wherein the axial orientation of septum  30 , as positioned within catheter adapter  40 , is rotated such that notch feature  20  is in axial alignment with an apex  56  of leaf  50 . Accordingly, in some embodiments a width  22  of notch feature  20  is decreased so as to minimize the amount of apex  56  capable of entering notch feature  20 . 
         [0042]    Further, in some embodiments a length  24  of notch feature  20  is configured to be less than a thickness  34  of flap  58 , as shown in  FIG. 8 . As such, the thickness  34  of flap  58  prevents substantial penetration of flap  58  into notch feature  20 , thereby avoiding any of the aforementioned undesirable interactions between notch feature  20  and septum  30 . For example, in some embodiments a width and/or length  24  of notch  20  is configured to be less than a width  34  of a contact surface of the leaf  58 , such that the contact surface of the leaf  58  is incapable of substantially penetrating the notch  20 . In some embodiments, width  24  comprises an axial length of the notch  20 , wherein the axial length is shorter than a related contact surface of leaf  58 . As such, the contact surface of leaf  58  is prevented from substantially penetrating notch  20 . Further, in some embodiments width  24  comprises a circumferential width of the notch  20 , wherein the circumferential width is narrower that the related contact surface of leaf  58 . As such, the contact surface of leaf  58  is prevented from substantially penetrating notch  20 . Still further, in some embodiments width and/or length  24  comprises a surface area of notch  20 , wherein the surface area of notch  20  is less than a surface area of the related contact surface of leaf  58 . As such, the related contact surface of leaf  58  is prevented from substantially penetrating notch  20  thereby eliminating any undesirable contact between notch  20  and septum  30 , as discussed previously. 
         [0043]    The various notches of the present invention may be provided by any technique known in the art, including mechanical grinding, Electro-Chemical Grinding (ECG), laser oblation, and Electrical Discharge Machining (EDM). In some embodiments, notch features are provided which comprise different geometry and patterns for a notch or notches. For example, in some embodiments a laser, water jet, or similar technology is used to produce one or more small holes in the wall of the needle, thereby preventing septum leaf engagement while providing improved structural integrity and/or blood flow visualization when compared to a single large mechanical, ECG or EDM notch, as discussed below. 
         [0044]    Referring now to  FIG. 9 , in some embodiments introducer needle  10  further comprises multiple notch features  20   a,    20   b,  and  20   c.  Accordingly, in some embodiments intravascular device  100  comprises a feature wherein the axial orientation of septum  30 , as positioned within catheter adapter  40 , is rotated such that notch features  20   a,    20   b,  and  20   c  are axially aligned with corners  66 . Accordingly, as notch features  20   a,    20   b,  and  20   c  are withdrawn through slit  32 , apexes  56  are axially positioned approximately 60° from notch features  20   a,    20   b  and  20   c  thereby preventing apexes  56  from entering into, or catching on the notch features. 
         [0045]    With reference to  FIG. 10 , in some embodiments introducer needle  10  further comprises multiple notch features  20   d  and  20   e.  Accordingly, in some embodiments intravascular device  100  comprises a feature wherein the axial orientation of septum  30 , as positioned within catheter adapter  40 , is rotated such that notch features  20   d  and  20   e  are axially misaligned with apex  56  of leaf  50 . Accordingly, as notch features  20   d  and  20   e  are withdrawn through slit  32 , apex  56  is axially positioned between notch features  20   d  and  20   e  thereby preventing any portion of apex  56  from entering into, or catching on the notch features. 
         [0046]    In some embodiments, introducer needle  10  further comprises a needle feature  70 , as shown in  FIGS. 11-13 . Needle feature  70  may serve any suitable purpose. For example, in some embodiments needle feature  70  provides the needle with a proximal engagement, or a surface that is configured to interact with a notch shield  80  of the intravascular device  100  (described hereinafter). 
         [0047]    The needle feature may comprise any suitable component that has at least one surface that extends laterally past the needle&#39;s OD and which is adapted to act as a proximal engagement. Some examples of suitable cannula features comprise one or more crimp features, ferrule features, protuberances, one-way barbs, laterally extending members (e.g., a ring), and other components that have a laterally extending surface. By way of non-limiting illustration,  FIG. 11  shows an embodiment in which the needle feature  70  comprises a crimp. 
         [0048]    In some embodiments, intravascular device  100  further comprises a notch shield  80  which is at least partially positioned within slit or opening  32  of septum  30 . Notch shield  80  generally comprises a tubular structure having an inner lumen through which a portion of the elongate tubular shaft  16  of needle  10  is slidably positioned. In some embodiments, an inner diameter of notch shield  80  is configured to be greater than an outer diameter of shaft  16 , yet less than the outer diameter of needle feature  70 . Accordingly, as needle  10  is drawn through needle shield  80  in a proximal direction  90 , a proximal surface  72  of needle feature  70  makes contact with needle shield  80  thereby positioning notch feature  20  within the inner lumen of notch shield  80 , as shown in  FIG. 12 . Upon further withdrawal of needle  10  in the proximal direction  90 , needle feature  70  displaces needle shield  80  from opening  32  of septum  30 , thereby entirely removing notch shield  80  and needle  10  from septum  30 , as shown in  FIG. 13 . 
         [0049]    In some embodiments, needle feature  70  is provided in a position proximate to needle notch  20  and interposed between needle notch  20  and needle tip  12 . Accordingly, at the point in which proximal surface  72  contacts needle shield  80 , notch feature  20  is entirely positioned within needle shield  80 . Thus, notch shield  80  prevents contact between notch feature  20  and septum  30 . In other words, in some embodiments a feature is provided wherein a notch shield is provided for preventing a portion of the septum (such as one or more of the septum leaves) from substantially penetrating the notch feature. Further, in some embodiments notch shield  80  prevents exposure to liquids (such as blood) which may leak from notch feature  20  following a catheterization procedure. 
         [0050]    The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. All of the described embodiments and examples are to be considered in any and all respects as illustrative only, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.