Abstract:
An introducer sheath assembly ( 10 ) having a sheath tube ( 12 ), a hub ( 16 ), a valve ( 30 ) and a valve-retaining cap ( 50 ) on the proximal end of the hub. The cap ( 50 ) is so secured to the hub ( 16 ) as to have a closed, locked position and also an open position permitting access to the interior of the hub and the valve ( 30 ) while the cap ( 50 ) remains secured to the hub ( 16 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application Ser. No. 61/007,613, filed Dec. 13, 2007. 
    
    
     FIELD OF THE INVENTION 
     This relates to the field of medical devices, and more particularly to catheter introducer sheath assemblies. 
     BACKGROUND OF THE INVENTION 
     Catheters are often used for the delivery and withdrawal of fluids to and from a blood vessel in a patient, respectively. The fluids may be medication that is administered to the patient, or blood that is withdrawn from the patient. The catheter may also be used for hemodialysis, in which blood is withdrawn from the patient, purified and returned simultaneously through respective lumens of the catheter, and much of the catheter remains within the patient&#39;s vasculature for an extended period of time for repeated treatments. 
     Typically, to insert a catheter into a blood vessel, the blood vessel is located by known methods. An aspirating needle is inserted into the vessel to confirm placement within the vessel. A guide wire is then inserted through a proximal end of the aspirating needle and into the vessel. The aspirating needle is withdrawn by sliding the needle proximally over the guide wire, leaving the guide wire within the vessel. If a catheter with a sufficiently hard wall is being used, the catheter may be slid over the guide wire, directly into the vessel. 
     However, for some catheters, particularly soft walled catheters, a dilator is required to dilate the vessel at the insertion point in order to accommodate the insertion of the catheter. The dilator is typically inserted into a sheath and initially used as a dilator and sheath assembly. The assembly is inserted into the vessel over the guide wire, and the dilator is used to dilate the insertion opening in the vessel wall to permit catheter insertion thereinto. After the insertion opening is dilated, the dilator is removed proximally from the sheath. The sheath remains in the vessel to accommodate insertion of the catheter through the sheath and into the blood vessel, after which the sheath is removed from around the catheter, and the guidewire is withdrawn from the patient. 
     Conventional assemblies provide one-way valves within the introducer hub for hemostasis, that is, preventing blood flow from the patient&#39;s vasculature from the incision made for eventual catheter insertion; the valve seals the passageway while permitting insertion therethrough by a guidewire and a dilator and a catheter. Commonly, proximal caps are affixed to the proximal end of the introducer hub to retain the valve therewithin. 
     It commonly happens that blockages occur within introducer assemblies due to clotting of blood egressing the vascular incision formed for insertion of the catheter into the vasculature. Upon such an occasion, the introducer must be removed and replaced by another, a procedure that greatly extends the time needed and complicating the procedures followed by the practitioner to implant the catheter, thereby exposing the patient to greater risk of infection due to bleeding from the incision. 
     It is desired to provide an introducer assembly facilitating access by the practitioner to the passageway within the introducer hub to clear a blockage that may occur within the introducer. 
     BRIEF SUMMARY OF THE INVENTION 
     Briefly, the present invention provides an introducer assembly having a sheath, a hub, a valve disposed transverse to the passageway extending between the proximal and distal ends of the sheath and hub, and a cap for retaining the valve in proper position within the hub. The cap is attached to the hub at one side thereof by a pivot arrangement whereby the cap can be rotated by the practitioner between a closed position and an open position all while remaining secured to the assembly. A latch on the opposite side of the cap from the pivot arrangement latchingly secures to a catch on the opposite side of the hub to secure the cap in its closed position. When the cap is in the open position, the valve is removable by the practitioner permitting access to the introducer&#39;s passageway for clearance of a blockage whereafter the valve, or a replacement valve, if necessary, can be reinserted into position in the hub and the cap can be returned to its closed position, eliminating the necessity of removing the entire introducer assembly from the patient and replacing it with another. 
     The method of the present invention includes the steps of placing an introducer assembly in position accessing the vasculature of the patient and having a passageway extending therethrough between a distal end and a proximal end, the assembly including a valve-retention cap movably affixed to the assembly&#39;s proximal end between a closed position retaining the valve therein and an open position permitting access to the introducer passageway, moving the proximal cap to the open position, removing the blockage, and moving the cap to its closed position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention. In the drawings: 
         FIG. 1  is an isometric view of an introducer sheath with dilator inserted therethrough and also showing an extension tube extending from a side port of the introducer hub; 
         FIG. 2  is an isometric distal end view of the assembly of  FIG. 1 ; 
         FIG. 3  is an enlarged isometric view of the proximal end of the assembly of  FIG. 1  with the components shown exploded from the introducer sheath&#39;s elongate tube; 
         FIGS. 4 and 5  are elevation and exploded elevation views, respectively, of the hub assembly of the introducer sheath of  FIGS. 1 to 3 , showing the introducer hub, the extension tube and the cap of the present invention; and 
         FIGS. 6 and 7  are, respectively, an exploded isometric view of the proximal end, and an isometric view of the proximal introducer sheath end with the cap attached to the introducer hub and rotated to an open position with the valve exploded outwardly from the hub, exposing the passageway. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the drawings, like numerals indicate like elements throughout. Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. The terms “distal” and “proximal” refer, respectively, to directions closer to and away from the insertion tip of a catheter in an implantable catheter assembly. The terminology includes the words specifically mentioned, derivatives thereof and words of similar import. The embodiments illustrated below are not intended to be exhaustive or to limit the invention to the precise form disclosed. These embodiments are chosen and described to best explain the principle of the invention and its application and practical use and to enable others skilled in the art to best utilize the invention. 
     Introducer assembly  10  is seen in  FIGS. 1 and 2 , and includes an elongate tubular sheath  12  extending to a distal end  14 , a hub  16  affixed to a proximal end of the sheath  12  and having a side port  18  from which extends an extension tube  20  with luer fitting  22 , and a strain relief  24  at a distal end of the hub  16  and around the tubular sheath  12 . A dilator  40  includes an elongate dilator shaft  42  extending from a distal tip  44  to a proximal end onto which is affixed a dilator hub  46 ; the dilator&#39;s distal tip  44  protrudes beyond the distal end  14  of the tubular introducer sheath  12  when the dilator is fully inserted into and through the introducer assembly  10 . 
     With reference to  FIG. 3 , hub  16  defines therethrough a passageway  26  extending to the passageway of the sheath  12 . Recessed into the proximal end of the hub  16  is a valve seat portion  28  into which is placed a valve  30  that preferably includes a slit  32  (see  FIG. 7 ) at the valve center enabling insertion therethrough of dilator shaft  42  and eventually a catheter (not shown). Also, the proximal end of the hub includes on one side a cap capture tab  34  projecting proximally that includes pivot pins  36  projecting laterally from both sides thereof. On the opposite side of the hub proximal end from tab  34  is a catch  38  to which the cap  50  will latch in its closed position. 
     Cap  50  includes a recess  52  (see  FIGS. 5 and 7 ) along its distal surface defining a valve seat portion, and when cap  50  is attached to the hub  16  and in its closed position, retains valve  30  compressed in position within the valve seat  28 ,  52 . Referring to  FIGS. 3 to 7 , cap  50  is seen to have a lift tab  54  depending from one side thereof that will extend alongside the hub when cap  50  is in position but project somewhat outwardly enabling manual grasping thereof to rotate cap  50  to an open position, as shown in  FIG. 7 . Cap  50  will pivot as a result of cooperating tabs  56  on the opposite cap side from lift tab  54 , which tabs includes holes  58  therethrough associated with pivot pins  36  of cap capture tab  34  of hub  16 . A latch ledge  60  is defined on the inner surface of lift tab  54  that latches to catch  38  of hub  16 , to secure cap  50  in its closed position. Proximal aperture  62  of cap  50  permits insertion thereinto of dilator shaft  42  and eventually the catheter (not shown); additionally, proximal aperture  62  may include threads or other features that cooperate with a complementary locking section of the dilator hub  46  to releasably lock the dilator to the introducer sheath assembly. 
     With the present invention, the cap remains secured to the hub not only in the closed position but also in its open position and is thus not a loose piece, if the practitioner must obtain access to the introducer sheath passageway to remove a blockage such as a clot. 
     It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.