Abstract:
Disclosed is a catheter insertion assembly that includes an arterial lumen having a first stylet embedded therein and a venous lumen having a second stylet embedded therein, The stylets extend beyond the proximal and distal ends of each of the lumens. The second stylet of the venous lumen includes an aperture near the distal end thereof so as to receive the distal end of the first stylet of the arterial lumen therethrough, thereby connecting the venous and arterial lumens temporarily together when the catheter is being inserted into a patient. In this way, the stylets increase column strength for dual-tip catheters.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 62/340,000, filed May 23, 2016, which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to medical devices, namely, catheters. More particularly, the present invention is directed to a catheter insertion assembly for dual-tip catheters. 
       BACKGROUND OF THE INVENTION 
       [0003]    Dialysis catheters are generally inserted into the blood vessels using two different techniques: percutaneously (i.e., over a guide wire), and using a tearaway sheath. Catheters with a hard durometer can be easily inserted percutaneously because they have excellent column strength and do not kink easily during the insertion procedure. However, catheter with soft durometers cannot be easily inserted unless a stylet is fitted into the lumens to strengthen the create column. 
         [0004]    Additionally, it is even more difficult to insert a catheter with a split tip because both lumens are separated and need to be properly attached together in order to be inserted easily. In this regard, the invention described herein addresses these problems. 
       SUMMARY OF THE INVENTION 
       [0005]    The following discloses a simplified summary of the specification in order to provide a basic understanding of some aspects of the specification. This summary is not an extensive overview of the specification. It is intended to neither identify key or critical elements of the specification nor delineate the scope of the specification. Its sole purpose is to disclose some concepts of the specification in a simplified form as to prelude to the more detailed description that is disclosed later. 
         [0006]    Some embodiments of the present invention comprise a venous lumen that is in a side-by-side configuration with an arterial lumen, wherein the two lumens are held together via a catheter hub. Each of the lumens comprises a stylet therein, further wherein the stylets extend beyond the proximal and distal ends of each of the lumens. The stylet for the venous lumen comprises an aperture near the distal end thereof so as to receive the distal end of the stylet for the arterial lumen therethrough, thereby connecting the venous and arterial lumens together. In this way, the stylets are configured to create column strength for dual-tip catheters such as split tip and step tip catheters. 
         [0007]    It is, therefore, an objective of the present invention to provide a new and improved catheter insertion assembly for use with catheters with separated distal ends or dual-tips (e.g., split tip and step tip catheters). 
         [0008]    It is another objective of the present invention to provide a new and improved catheter insertion assembly that increases the ease of inserting dialysis catheter with soft durometers. 
         [0009]    It is still another objective of the present invention to provide a new and improved catheter insertion assembly that can temporarily attach the distal ends of split tip or step tip catheter together in order for the catheter to be inserted easily into the body. 
         [0010]    It is still yet another objective of the present invention to provide a new and improved catheter insertion assembly that can properly attach the distal ends of split tip or step tip catheter together without requiring an additional fastening mechanism. 
         [0011]    A final objective of the present invention to provide a new and improved catheter insertion assembly that can be retroactively installed in existing split tip or step tip catheters. 
         [0012]    In the light of the foregoing, these and other objectives are accomplished in accordance with the principles of the present invention, wherein the novelty of the present invention will become apparent from the following detailed description and appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying exemplary drawings, in which like reference characters refer to like parts throughout, and in which: 
           [0014]      FIG. 1  depicts a close-up side cross-sectional view of an exemplary embodiment of the catheter insertion assembly of the present invention. 
           [0015]      FIG. 2  depicts a close-up top-down view of the exemplary embodiment of the catheter insertion assembly. 
           [0016]      FIG. 3  shows an overall side view of the exemplary embodiment of the catheter insertion assembly. 
           [0017]      FIG. 4  shows a close-up cross-sectional view of the distal end of the catheter insertion assembly from the front. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The present invention is directed towards a catheter insertion assembly. For purposes of clarity, and not by way of limitation, illustrative views of the present invention are described with references made to the above-identified figures. Various modifications obvious to one skilled in the art are deemed to be within the spirit and scope of the present invention. 
         [0019]    Moreover, the word “exemplary” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to disclose concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” 
         [0020]    Additionally, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” or “at least one” unless specified otherwise or clear from context to be directed to a singular form. Similarly, the terms “plurality” and “a plurality” as used herein includes, for example, “multiple” or “two or more.” For example, “a plurality of items” includes two or more items. 
         [0021]    Referring now to  FIGS. 1 and 2 , there is shown a cross-sectional side view and a top-down view of the catheter insertion assembly, respectively. The catheter insertion assembly comprises a catheter having an arterial lumen  101  and a venous lumen  102 , wherein each of the lumens  101 ,  102  comprises a substantially D-shaped cross section having a flat side opposite a rounded side. The flat side of the arterial lumen  101  can directly contact the flat side of the venous lumen  102  such that the arterial lumen  101  and the venous lumen  102  are in a side-by-side configuration to form a substantially circular cross section. 
         [0022]    Each of the lumens  101 ,  102  comprises an open distal end  105 ,  106  and an open proximal end, wherein each of the distal end  105 ,  106  is tapered such that the diameter of the cross-section of the distal end  105 ,  106  is less than the diameter of the cross-section of the proximal end. The distance between the distal end  105  and the proximal end of the arterial lumen  101  defines the length of the arterial lumen  101 . Similarly, the distance between the distal end  106  and the proximal end of the venous lumen  102  defines its length. The length of the arterial lumen  101  is less than the length of the venous lumen  102 . 
         [0023]    Preferably, the catheter comprises a split tip (as depicted in  FIG. 1 ) or step tip catheter (as depicted in  FIG. 2 ). The split tip catheter comprises lumens having distal ends that are apart and separate. The step tip catheter comprises a venous lumen having a distal end that extends beyond a distal end of an arterial lumen. In both embodiments, the venous lumen  102  and the arterial lumen  101  can comprise separate lumens. Said another way, each of the lumens comprises a separate structure and are bonded or held together, for example, via a sleeve. 
         [0024]    Alternatively, the lumens may be substantially unitary in structure and split or separated in half via a septum to define two separate lumens—a venous lumen and an arterial lumen. In some embodiments, the catheter can comprise other types of catheters, including catheters comprising lumens with high durometer or lumens that tend to easily bend or flex when being inserted. 
         [0025]    Each of the lumens  101 ,  102  further comprises a stylet embedded therein. It is noted that the term “stylet” or “stylets” may be used interchangeably with the terms “mandrel” or “mandrels.” In the illustrated embodiment, the arterial lumen  101  comprises a first stylet  103  therein. Similarly, the venous lumen  102  comprises a second stylet  104  therein. The stylets  103 ,  104  can be shaped and dimensioned to fit within the interior of the lumens  101 ,  102 . 
         [0026]    Accordingly, some embodiments of the first and second stylets  103 ,  104  also comprises a substantially D-shaped cross section. Each of the first and second stylets  103 ,  104  comprises an open proximal end and an open distal end  107 ,  108 . The first stylet  103  comprises a tapered distal end  107 . In the illustrated embodiments, the distal end  107  of the first stylet  103  comprises a substantially round or circular cross section. Preferably, the distal end  107  of the first stylet  103  is configured to fit over a guide wire. 
         [0027]    The first stylet  103  comprises a sufficient length such that the distal end  107  of the first stylet  103  extends beyond the distal end  105  of the arterial lumen  101 , and the proximal end of the first stylet  103  extends beyond the proximal end of the arterial lumen  101 . Similarly, the second stylet  104  also comprises a sufficient length so that the distal end  108  of the second stylet  104  extends beyond the distal end  106  of the venous lumen  102 , and the proximal end of the second stylet  104  extends beyond the proximal end of the venous lumen  102 . 
         [0028]    The distal end  108  of the second stylet  104  comprises an aperture or an opening  109  at an angle so as to receive the distal end  107  of the first stylet  103  therethrough. Because the aperture  109  is drilled at an angle relative to the axis perpendicular to the length of the second stylet  104 , the aperture is substantially oblique or oval in shape instead of a circle. In one embodiment, the aperture  109  is disposed approximately 5 mm from the distal end  108  of the second stylet  104 . It is contemplated, however, that the exact location and shape of the aperture  109  can vary depending upon embodiments. 
         [0029]    In operation, the distal end  107  of the first stylet  103  is inserted through the aperture  109  and exited through the open distal end  108  of the stylet  104  so as to keep the two lumens  101 ,  102  together when being inserted. Preferably, the distal end  107  of the first stylet  103  extends slightly beyond the distal end  108  of the second stylet  104 . Thus, the diameter of the cross section of the tapered distal end  107  of the first stylet  103  is less than the diameter of the cross-section of the distal end  108  of the second stylet  104 . It is noted, however, that the first stylet  103  fills the interior of the second stylet  104  to fill the entire arterial and venous lumen so that there is no gap for tissue to get caught within the gap. 
         [0030]    Referring now to  FIG. 3 , there is shown an overall side view of the catheter insertion assembly  100 . The proximal ends of the lumens  101 ,  102  are connected to the distal ends of a venous extension  115  and an arterial extension  114 , respectively, via an insert molding process, and attached at a catheter hub  116 . 
         [0031]    In some embodiments, the catheter  100  further comprises a sleeve or a cap for holding the lumens  101 ,  102  together, wherein the sleeve is biased toward the hub  116  so as to leave the distal ends of the lumens  101 ,  102  free. It is contemplated, however, that the sleeve can travel along the length of the lumens  101 ,  102  before being secured to the hub  116 . In some embodiments, the sleeve comprises interior threads that mate with exterior threads disposed on the hub  116  so as to secure the sleeve in place. 
         [0032]    The venous extension  115  and the arterial extension  114  extend through the hub  116 . The proximal end of the venous extension  115  is connected to a first catheter female luer  111 , and the proximal end of the arterial extension  114  is connected to a second catheter female luer  110 . The luers  111 ,  110  are configured to connect to blood lines. In some embodiments, the venous extension  115  and the arterial extension  114  further comprise clamps  113 ,  112  thereon. 
         [0033]    The first and second stylets  103 ,  104  extend through the venous extension  115  and the arterial extension  114  such that the proximal ends of the stylets  103 ,  104  exit the luers  111 ,  110 . The proximal ends of each of the stylets  103 ,  104  can comprise a male luer fitted with a spin lock connector  123 ,  124 . The male luer  123  at the proximal end of the first stylet  103  is attached to a first catheter female luer  111  via a spin connector and the male luer  124  at the proximal end of the second stylet  104  is attached to a second catheter female luer  110  via another spin connector. Each of the male luers at the proximal ends of the stylets  103 ,  104  can be attached via insert molding or solvent molding, depending upon embodiments. 
         [0034]    To temporarily secure the first and second stylets  103 ,  104  together as depicted in  FIG. 4  and still allow for the insertion of a guide wire, each of the two stylets  103 ,  104  is embedded within or inserted through each of the respective lumens  101 ,  102 . In operation, the desired blood vessel is accessed with a needle (e.g., an 18 G needle). A guide wire is inserted into the needle and pushed until the guide wire is positioned into place by using fluoroscopy guidance or a similar guidance method. A dilator is then inserted over the guide wire to dilate the blood vessel so that the catheter can be inserted with ease. 
         [0035]    Once the dilator is removed, the distal end  107  of the first stylet  103  is inserted over the wire and gradually pushed into place by, for example, using fluoroscopy guidance. The guide wire is configured to exit the proximal extension of the arterial lumen  101 . Once the catheter is in place, the guide wire is removed and the catheter is sutured in place. The stylets  103 ,  104  can be removed after the catheter is in the proper location by pulling on the back end of the first stylet  103  from the proximal end of the catheter, releasing it from the aperture  109  of the second stylet  104 . Once the two stylets  103 ,  104  are separated, both stylets  103 ,  104  are removed from the lumens  101 ,  102 . 
         [0036]    It is therefore submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
         [0037]    Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.