Abstract:
A sheath introducer for a catheter includes a sheath having a lumen, a hub positioned on a proximal end of the sheath, and a housing positioned on the hub. The hub can include a splittable penetration member having a port in fluid communication with the sheath lumen. The housing can include a valve having a closed upper surface and a channel surrounding the splittable penetration member. Movement of the housing with respect to the hub can expose the port of the splittable penetration member for insertion of the catheter.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 11/288,959, filed Nov. 29, 2005, now U.S. Pat. No. 9,597,483, which claims priority to U.S. Provisional Application No. 60/631,397, filed Nov. 29, 2004, each of which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to medical devices and methods for manufacturing such medical devices. In particular, the invention relates to introducers for catheters, methods for making such introducers, and methods for using such introducers. More particularly, the invention relates to self-sealing sheath introducers (both tear-away and non-tear-away), methods for manufacturing such introducers, and methods of using such introducers in medical procedures. 
       BACKGROUND OF THE INVENTION 
       [0003]    Tear-away sheath introducers (“sheath introducers” or “introducers”) and their use as medical devices are well known in the art. See, for example U.S. Pat. Nos. 6,814,718; 6,808,520; 6,808,509; 6,796,991; 6,740,101; 6,712,791; 6,712,789; 6,695,810; 6,641,564; 6,632,234; 6,623,460; 6,599,302; 6,361,559; and 5,558,652; as well as U.S. Patent Publication Nos. 2004/0260243, 2004/0254534, 2004/0176781, 2004/006330, 2004/097863, and 2002/072789, the disclosures of which are incorporated herein by reference. These introducers are used in medical procedures to insert a catheter into the body, thereby providing vascular access to the vessel of a patient. The catheters are inserted via the introducers by first using a needle to create an access site. A dilator is then used to dilate the access site to allow a larger-diameter sheath introducer to be introduced into the vessel through the access site. The catheter is then inserted through the sheath introducer and into the vessel. After the catheter has been inserted, the sheath introducer is removed, leaving the catheter in the vessel. 
         [0004]    As shown in  FIG. 19 , conventional tear-away (or split) sheath introducers  100  usually contain four major components: (1) a dilator  140 ; (2) a tear-away sheath hub  111 ; (3) a tear-away valve  113 ; and ( 4 ) a tear-away sheath  130 . The dilator  140  facilitates insertion of the sheath introducer  100  into the vascular system and maintains the inside diameter of the sheath  130  during insertion. The dilator  140  is normally locked into the hub  111  in order to keep it seated within the sheath  130 . The dilator  140  typically contains a tapered tip to facilitate insertion into the vascular system with the proximal end  144  of the dilator  140  containing a standard medical luer hub  146 . Both the distal end  142  and the proximal end  144  of the dilator  140  are usually manufactured of a rigid polymer. 
         [0005]    The tear-away hub  111  provides a means to contain the valve  113  while connecting the valve  113  and the sheath  130 . The hub  111  typically has a “T” shape with the opposing ends of the “T” being grasped and pulled to split both the valve  113  and sheath  130 . Thus, the hub  111  provides a mechanism to split the sheath  130  into two portions and allow the introducer to be split and removed from around the catheter. The hub  111  is also often manufactured of a rigid polymer. 
         [0006]    The tear-away valve  113 , however, is typically made of a flexible material (such as silicone) that provides a self-sealing slit. The valve  113  may be designed as one piece that tears in half during the splitting procedure, or as two (or more) pieces that separate from each other during the splitting procedure. With conventional introducers, the valve  113  is encapsulated by the hub  111 . 
         [0007]    The tear-away sheath  130  is normally manufactured as a thin-walled structure, often as an extrusion. The extrusion contains splitting means, i.e., score lines that facilitate splitting or a self-splitting propagating material (such as linearly-directional extrusion). The proximal end  132  of the sheath  130  is attached to the hub  111  using over-molding or any other known attachment mechanism. The distal end  134  of the sheath  130  can be tapered to provide a smooth transition at the dilator/sheath interface. 
         [0008]    To use the introducer  100 , it is inserted in the desired vessel. Then the dilator  140  is unlocked from the hub  111  and removed to allow room for a catheter (or any similar medical device) to be inserted into the sheath. The valve  113  remains stationary inside the hub  111  and blocks air and/or fluid from flowing through the sheath  130  and hub  111  when they are left behind after the dilator is removed. The valve  113  keeps the passage  105  clear until a catheter is inserted into the passage  105  through the valve. 
         [0009]    The introducer  100  is typically used for larger catheters, i.e., those with a diameter of 12 to 16 French. These larger-diameter introducers are rigid due to their diameter and the material used to construct them. This rigidity allows the large catheters to overcome the frictional forces needed to push the catheter through the valve. 
         [0010]    But inserting smaller catheters into smaller introducers is more difficult. Typical introducers designed for smaller catheters (i.e., those 3 to 12 French in diameter) are made with open communication between the access site and the vascular system once the dilator is removed. This open configuration exists because smaller catheters, due to their smaller diameter and material, are not rigid enough to overcome the frictional forces needed to push the catheter through the valve. In other words, it is like trying to “push” a rope through a hole: the rope does not remain rigid enough for a user to push it through the hole. 
         [0011]    The open configuration between the vascular system and the environment, however, allows two serious clinical problems. First, air embolism into the vascular system which can result in patient injury and/or death. And second, release of potentially infectious bodily fluids (including blood) into the environment, resulting in exposure to the health care provider. 
       SUMMARY OF THE INVENTION 
       [0012]    The invention relates to tear-away and non-tear-away sheath introducers for catheters, methods for making such introducers, and methods for using such introducers. The sheath introducers contain movable valves that are encapsulated in a movable housing unlike conventional valves that are stationary. The movable housing allows the valve to move along the axis of the introducer. As the movable valve and housing travel along the axis, a portion of the hub protrudes past the valve and is exposed. The protruding portion of the hub contains a friction-free pathway for the catheter into the sheath introducer. The introducers can therefore be used with any catheter, regardless of the size or material, because of the reduced or eliminated frictional force between the catheter and introducer. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]    The following description of the invention can be understood in light of  FIGS. 1-19 , in which: 
           [0014]      FIG. 1  is a side perspective view(s) of the introducer assembly in one aspect of the invention; 
           [0015]      FIG. 2  is a side perspective view of a two-piece flexible valve in one aspect of the invention; 
           [0016]      FIG. 3  is a side perspective view of a dilator in one aspect of the invention; 
           [0017]      FIGS. 4 and 5  are section views of a valve housing in one aspect of the invention; 
           [0018]      FIGS. 6 and 7  depict the introducer assembly in another aspect of the invention; 
           [0019]      FIG. 8  is a side view(s) of the sheath introducer in another aspect of the invention; 
           [0020]      FIG. 9  is a side perspective view(s) of the sheath introducer in even another aspect of the invention; 
           [0021]      FIG. 10  is a side perspective view(s) of the sheath introducer in yet another aspect of the invention; 
           [0022]      FIGS. 11-12  show a single-piece valve in another aspect of the invention; 
           [0023]      FIGS. 13-14  depict view(s) of the single-piece valve and sheath hub in another aspect of the invention; 
           [0024]      FIGS. 15-17  depict view(s) of methods of increasing the attachment between the sheath and the sheath hub in another aspect of the invention; 
           [0025]      FIG. 18  shows the operation or the sheath introducer in one aspect of the invention; and 
           [0026]      FIG. 19  illustrates a conventional sheath introducer. 
       
    
    
       [0027]      FIGS. 1-19  presented in conjunction with this description are views of only particular—rather than complete—portions of the devices and methods of making the devices according to the invention. Together with the following description, the Figures demonstrate and explain the principles of the invention. In the Figures, the thickness of layers and regions are exaggerated for clarity. The same reference numerals in different drawings represent the same element, and thus their descriptions will be omitted. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    The following description provides specific details in order to provide a thorough understanding of the invention. The skilled artisan, however, would understand that the invention could be practiced without employing these specific details. Indeed, the invention can be practiced by modifying the illustrated method and resulting device and can be used in conjunction with apparatus and techniques conventionally used in the industry. For example, the invention is described as a micro-introducer for small catheters (3 F-10 F in size), but could easily be adapted for any size of catheter or device regardless of the size or intended use. Further, while the invention is described for use with catheters for vascular access, it could be used with any similar device that is used to grant a physician (or other user) access to a part of the body, whether human or animal. 
         [0029]    The invention includes a tear-away or non-tear-away sheath introducer that contains a movable valve and housing that when moved, allows a portion of the hub to protrude through a valve and be exposed. The protruding portion of the hub contains a friction-free pathway for the catheter. Any inducer having these properties can be used in the invention, including the sheath introducer described below and illustrated in the Figures. 
         [0030]    The sheath introducer of the invention contains several primary components. First, dilator means used to dilate the vascular system and create a pathway for the catheter. Second, means for sheathing the dilator means to protect it from the vascular system. And third, valve means for keeping the pathway created by the dilator closed until the catheter needs to be inserted. 
         [0031]    One example of the sheath introducer is illustrated in  FIG. 1  where the introducer  10  contains dilation means comprised of a dilator hub  1  and a dilator shaft  2 . The dilation means is configured to fit within the sheath means comprised of a sheath hub  7  and a sheath  8 . The introducer  10  also contains valve means comprised of a valve with left and right halves ( 4  and  5 ) contained within a valve housing having left and right halves ( 3  and  6 ) that is attached to the sheath hub  7 . 
         [0032]      FIGS. 2-5  illustrate detailed views of each of these components.  FIG. 2  depicts one half of the valve  4 ,  FIG. 3  illustrates the dilator hub  1 , and  FIGS. 4-5  show the different views of one half of the valve housing  3 . In  FIG. 2 , the valve contains retention means for retaining the valve to the valve housing. Any retention means known in the art can be used, including retention member  12  which seats into a corresponding structure in the valve housing such as the valve retention slot  15 . The valve has a size and shape substantially the same as the inner part of the valve housing to which it is retained. Accordingly, the valve half  4  depicted in  FIG. 2  is substantially circular and with a size that fits within the corresponding inner surface of the valve housing  3  shown in  FIGS. 4-5 . The valve can be manufactured from any suitable medical material, including flexible materials like silicone or polyurethane. 
         [0033]      FIG. 3  depicts one example of a dilator of the introducer  10 . The dilator  31  can contain any standard medical luer hub, including a dilator hub  1  with a gripping mechanism (such as finger grips  11 ) and locking mechanism (such as locking ears  9 ) as shown in  FIG. 3 . The locking mechanism  9  locks the dilator  31  into the valve housing by using, for example, the locking channel  16  contained in the valve housing  3  and  6 . The dilator  31  also contains a shaft  2  with a tapered section for dilating the vessel into which it is inserted. The dilator  31  can also be manufactured from any suitable medical material, but should be made fairly rigid, yet flexible enough that it can be maneuvered into the desired vessel by a user. 
         [0034]      FIGS. 4 and 5  depict one example of the internal geometry of the valve housing  3 . The valve housing  3  contains any means for securing the valve housing to the sheath hub  7 . In  FIGS. 4 and 5 , the securing means comprises snap features  13 , which secure the valve housing  3  to the sheath hub  7  using the mating snap feature  21  (shown in  FIG. 6 ). Using the securing means keeps the valve housing (and therefore the valve) in a closed position until it is needed to be opened (i.e., such as when the catheter is inserted). 
         [0035]    The valve housing  3  also contains any known means for positioning it with the sheath hub  7 . An example of this positioning means is depicted in  FIGS. 4 and 5 , where a guide slot  15  and stop post  20  mate with the guidepost  22  of the sheath hub  7  (shown in  FIG. 6 ). The exterior of the valve housing  3  contains grips  14  that can be employed by the user in the splitting procedure. The valve housing  3  is constructed of any suitable medical material that provides the desired rigidity, such as rigid polymeric materials. 
         [0036]    The valve housing  3  can also contain any known interlock mechanism between the two halves of the valve housing. An example of this interlock mechanism is lock  19  that, when the halves are assembled together, serves to maintain uniform travel between both halves of the valve housing. This interlock mechanism can be supplemented with any known mechanism, including the detachable interlock features  17  and  18 . 
         [0037]      FIGS. 6 and 7  illustrate the various components of the introducer when assembled together. In  FIGS. 6 and 7 , the sheath hub  7  and the sheath  8  are attached together into an assembly by any attachment means. Examples of suitable attachment means include insert molding or any mechanical attachment, such as a friction fit, locking snap fit, solvent or UV bond. 
         [0038]    The sheath hub  7  also contains a valve penetration means. The valve penetration means operates to penetrate the two halves of the valve  4  and  5 , thereby providing an opening in the valve. Any penetration means known in the art can be used for this function. As depicted in  FIGS. 6 and 7 , the penetration means comprise penetration member  23  that is configured to fit between the two halves  4  and  5  of the valve. The penetration member  23  opens the two halves  4  and  5  of the valve when it is forced between them by any action which pushes the penetration member  23  through the valve. 
         [0039]    The valve penetration means need not physically force (i.e., push) the valve halves  4  and  5  apart to penetrate the valve. In this aspect, the penetration member  23  penetrates the valve halves  4  and  5  when the valve housings are pulled apart to expose the penetration member  23 . The valve housings  3  and  6  can be pulled apart by the mechanisms described below. 
         [0040]    When the penetration member  23  opens the valve in either of these manners, port  24  is exposed. The port  24  is the location where the catheter (or similar device) is inserted. Unlike the conventional introducers where the catheter is forced between the valve (which creates a friction force that must be overcome by a user), the catheter can be inserted in the port  24  of the introducers. The port  24  can be configured to have less friction than that required in conventional devices by providing an inside diameter slightly larger than that of the catheter insertion member. Alternatively, the port can be configured to have substantially no friction (“friction-free”) by providing an inside diameter significantly larger than that of the catheter insertion member. As well, the port  24  can be configured to have less or substantially no friction by providing a coating on the inside of the port  24  and/or the outside of the catheter. 
         [0041]    The sheath hub  7  also contains activation means. The activation means is used to force the penetration member  23  up through the valve halves  4  and  5 , move the valve halves (and housing) down over the penetration member  23 , or to pull the valve halves  4  and  5  apart, to thereby open them and expose penetration member  23  containing port  24 . Any mechanism that operates in this manner can be use as the activation means. In the sheath hub depicted in  FIG. 7 , the activation means pulls the valve halves  4  and  5  apart and comprises a reaction force member  25  that is formed on the bottom edge of the sheath hub  7 . When pressure is applied to the reaction force member  25  by the user, it depresses the valve housings  3  and  6  and forces the valve halves  4  and  5  apart. Of course, any other known mechanism could be used to push or pull the valve apart. 
         [0042]      FIG. 8  depicts the introducer in a position ready to accept a catheter. In  FIG. 8 , the penetration member  23  protrudes out of the valve halves  4  and  5 . The penetration member  23  need only protrude enough so that port  24  is exposed enough for a catheter to be inserted. Typically, the port  24  protrudes from about 0.025 to about 0.05 inches above the valve. In one aspect of the invention, the port  24  protrudes about 0.05 inches above the valve. 
         [0043]      FIG. 9  depicts one part of a method for using the introducer  10 . After the introducer  10  has been inserted into the desired vessel, the catheter (not shown) is inserted through the introducer  10 . Then, the user presses on the grips  14  to cause the valve housing  3  and  6  to separate from each other. As the pressing continues, the valve halves  4  and  5  and the sheath hub  7  then separate from each other. Once this initial separation has occurred, the user can continue pull on the ends of the separated portions to continue separating the introducer  10 . 
         [0044]      FIG. 10  illustrates another part of a method for using the introducer  10 . In step 1, the introducer  10  has been inserted in the desired part of the vascular system, i.e., the desired vessel. Next, as shown in step 2, the dilator is then removed from the introducer  10 . As shown in step 3, removing the dilator still leaves the valve in a closed position. Next, using the actuating mechanism a user makes the penetration member  23  penetrate the valve in any of the methods described above so that valve is opened with the port  24  exposed. Then, the catheter (not shown) is inserted into the introducer as shown in step 4. Finally, the introducer is removed by the splitting procedure as shown in step 5. 
         [0045]    The introducer described above can be modified and enhanced with several optional features. One of these modifications is a modified valve  30  as depicted in  FIGS. 11 and 12  that comprises a base  32 , extensions  34 , and channel portion  36 . The base  32  of the valve  30  is configured with a size and shape substantially similar to the valve housing in which the valve  30  rests. The valve  30  can optionally contain an indentation  35  of any shape and size that will help the valve split. 
         [0046]    The extensions  34  are designed to extend upwards from the valve  30  towards the dilator of the introducer. Like the base  32 , the extensions  34  will abut the valve housing, but the sides rather than the bottom. Accordingly, the size and shape of the extensions  34  are selected to substantially match the inner surface of the valve housing which will enclose the valve  30 . The extensions  34  contain a notch(es)  38  that correspond to the notches  50  provided in the protruding member  41  (as described below). 
         [0047]    The channel portion  36  of the valve  30  also extends in an upward direction toward the dilator of the introducer. As shown in  FIG. 12 , the inner surface  37  of the channel portion  36  will abut the outer surface of the outside of the protruding member  41  and is accordingly given a size and shape substantially matching the protruding member  41 . The length of the channel portion  36  is also selected to substantially match the protruding member  41  so that port  44  can be exposed when desired. 
         [0048]    The upper surface  42  of the channel portion contains a slit  40 . The slit  40  does not extend the entire way across the channel portion  36  and so is a non-tear away slit. The slit  40  is held in a closed or sealed position (position A in  FIG. 13 ) by the valve housing and sheath hub. The slit  40  moves into an open position B when the protruding member  41  moves upward through the channel portion  36  and then up through the slit  40  (or the valve  30  moves downward over the member  41 ) as depicted in  FIG. 13 . Of course, as described above, the valve  30  can be pulled apart to expose the protruding member  41  rather than forced apart. 
         [0049]    The channel portion  36  of the valve  30  can also operate as a sealing means around the protruding member  41 . The sealing means helps provide a seal between the vascular system and the environment when the protruding member  41  has forced the slit  40  open. This sealing function is illustrated in  FIG. 13  where the protruding member  41  is shown in its extended state, i.e., protruding above the valve  30 . The channel portion  36  fits snugly around protruding member  41  so that it provides a seal. Optionally, a coating can be added to the inside of the channel portion  36  and/or the outside of the protruding member  41  to increase this sealing function. As shown in  FIG. 12 , the channel portion  36  can optionally contain a ring sealing member(s)  39  to increase the sealing function. 
         [0050]    The advantage of valve  30  is that it can also serve as a flash-back chamber. If the valve  30  (and associated parts of the hub sheath) is made from a translucent or transparent material, it allows the user to view the inside of the valve  30 . If sheath introducer  10  is placed in the proper location (i.e., in the venous system), blood will enter the valve chamber resulting in a red color as an indication that the sheath introducer is placed correctly. Using a translucent or transparent material for the valve  30  therefore allows the user to look through the valve and determine whether this red color is showing. 
         [0051]    As mentioned above, a seal can be formed between the channel portion  36  and the protruding member  41 . To help improve the seal between these two components, the protruding member  41  can be modified by providing stress risers ( 45  and  46 ) on the inside  40  and the outside  41  of the protruding member  41  as shown in  FIG. 14 . The internal stress riser  46  provides a smooth surface at the interface with the valve ring sealing member  39 . As noted above, the valve ring sealing member  39  can provide a seal as the valve translates along the stem. Moving from the bottom to the top of the protruding member  41 , the riser(s)  45  begin on the outside and then move to the inside  46 , allowing the splitting mechanism (crack) to progress while maintaining a smooth outer surface between the valve ring sealing member  39  and the protruding member  41 . 
         [0052]    The stress riser  45  begins on the bottom of the sheath hub  47  and continues along the outside of the sheath hub until the stress riser  45  reaches a point below the initial location of the valve ring sealing member  39 . At that point, the stress riser  46  moves to the inside of the protruding member  41  and then continues to the notch  50 . The depth and width of the stress risers  45  and  46  are selected depending on the required separation force. 
         [0053]    Another function of the stress risers  45  and  46  are to act as an initiator in the splitting process. By their nature, the stress risers are the beginning of a split in the hub sheath  47  and, therefore, can be used to make the splitting process easier. Accordingly, the stress risers  45  and  46  are located substantially on the axis where the introducer  10  will be split. 
         [0054]    Another optional modification that can be made to the sheath introducer comprises notches  50  in the upper portion of the protruding member  41  that remain above the valve  30  in the extended position. The notches  50  give the protruding member  41  additional length to extend past the valve  30  while at the same time not adding additional length to the stress risers  45  and  46 . Such a configuration adds length to the protruding member  41  without increasing the cracking force needed to split the introducer  10 . 
         [0055]    As shown in  FIG. 14 , the notches  50  are generally made to correspond with the same location as the stress risers  45  and  46 , i.e., substantially along the axis of the expected split. The notches  50  can have any shape that results in a concentration of the stress force. Examples of such shapes include substantial “V” shape or the substantial rectangular shape shown in  FIG. 14 . 
         [0056]    The sheath hub  47  can also be optionally modified to increase the attachment between the sheath hub  47  and the sheath  53 . One manner to increase this attachment is depicted in  FIGS. 15 and 16 . In  FIG. 15 , the sheath has been modified to contain a sheath cap  57  with an interlocking fit between the sheath  53  and the sheath cap  57 . The sheath cap  57  contains grooves  58  which provide a location for the split ends  55  of the sheath  53  when the sheath is inserted though the sheath cap  57 . The ends of the split sheath fold around the sheath retention cap  57  with their location maintained in the grooves  58 . Once the sheath retention cap  57  is assembled into the mating geometry of the sheath hub  47  as shown in  FIG. 16 , it locks the ends  55  of the split sheath tightly into the hub  47 . The sheath cap  57  is then affixed to the sheath hub  47  by means of a thermal, solvent or UV bond. 
         [0057]    Alternatively, another method to increase this attachment is depicted in  FIG. 17 . In  FIG. 17 , the sheath hub  47  has been modified to encapsulate an end portion of the sheath  53 . This encapsulation is performed so that ridges  59  overly the end  56  of the sheath  53 , thereby retaining the end of the sheath underneath the ridges. 
         [0058]    In yet another modification, the sheath introducer can be provided with means for separating the valve housing  33  away from the sheath hub  47 . Any known means for forcing these two components apart can be used in the invention, including leaf spring, coil spring, hinge, and/or a mechanical lever. As depicted in  FIG. 18 , the forcing means comprises a spring  65 . In its compressed state, the valve housing  33  and the sheath hub  47  are attached to each other by any mechanism, such as the snap features  13  and  21  mentioned above and/or the lever  66 . When the valve housing  33  and the sheath hub  47  are attached, the valve  30  remains closed. The moment the user separates the sheath hub  47  from the valve housing  33  by pressing on the grip section  52  (and/or disengaging the lever  66 ), the spring  65  is released from its compressed state and these two components separate from each other. 
         [0059]    One result of the separation of these two components is the movement of valve  30  relative to the protruding member  41 . When these two components are attached to each other, the spring is compressed and the valve  30  slides down the protruding member which then opens the slit  40  of the valve  30 . When these components are separated, the pressure of the spring  65  is released and it returns to the uncompressed state, sliding the valve  30  back up the protruding member and closing the slit  40 . 
         [0060]    In another modification, the valve housing of the introducer could be engaged by means of a rotary movement along the axis of a threaded member or any other mechanical means to translate the valve housing along the desired path. For example, a mechanical lever, push button, or threaded member could be used in this modification. 
         [0061]    In addition to any previously indicated variation, numerous other modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention and appended claims are intended to cover such modifications and arrangements. Thus, while the invention has been described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred aspects of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications, including but not limited to, form, function, manner of operations and use may be made without departing form the principles and concepts set forth herein.