Patent Publication Number: US-2012035585-A1

Title: Tapered venous access introducer

Description:
TECHNICAL FIELD 
     This embodiments described herein relate to a medical apparatus suitable for percutaneous catheterization of body vessels and methods of use, and in particular, a system for intravenous therapy including at least a catheter and an introducer sheath. 
     BACKGROUND 
     Central venous system access in a patient is an important aspect of administering intravenous therapy, such as drug, chemotherapy, and total parenteral nutrition (TPN). It is desirable that the therapy be administered in the superior vena cava (SVC) of the central venous system. In order to gain access, introducer devices are commonly used, through which other medical devices, such as central venous catheters (CVC), are inserted. One such example of a CVC is a peripherally inserted central catheter (PICC). A PICC typically has one or more tubes, which are externally accessible by a clinician, that converge into a single catheter body that is internally implanted in a vein of the patient. The tubes are adapted to receive therapeutic agents, which are then released through a distal tip of the catheter body into the central venous system of the patient. 
     The most common technique used by the clinician to gain access to the central venous system of the patient with a PICC is a modified Seldinger technique. This technique involves the clinician first inserting a needle through the patient&#39;s skin at a peripheral location and into a vein to form a venotomy. The clinician then inserts the guidewire through the passageway of the needle and into the vein. The distal end of the guidewire may then be translated to the target site. Next, the clinician removes the needle from the proximal end of the guidewire, and following removal of the needle the clinician inserts an introducer device and dilator assembly over the proximal end of the guidewire and into the vein. The introducer device and dilator assembly typically includes a splittable introducer device and a dilator to facilitate the ease of insertion and creation of a larger opening in the venotomy. The clinician then removes the dilator, and may even subsequently remove the guidewire from the lumen of the introducer device, leaving the introducer device inserted in the body. The clinician usually with the use of the guidewire determines a suitable length of the PICC and then trims the PICC accordingly. 
     Next, with reference to  FIG. 1 , a PICC  8  is inserted through introducer device  10  in order to gain access to the vein and eventually the SVC of the central venous system. PICC  8  has a catheter body  9  extending from a manifold  11 , with a portion  12  of catheter body  9  adjacent manifold  11  shown to be tapered. PICC  8  is shown inserted through a constant diameter passageway  13  of introducer device  10 . As can be seen, the constant diameter passageway  13  is only sized to receive most of catheter body  9  of PICC  8 , essentially until the size of the catheter body at tapered portion  12  is greater than the size of passageway  13 . As a result, tapered portion  12  is left dangling external to a handle  14  of introducer device  10 . This arrangement is problematic because the dangling tapered portion  12  (about 10-15 cm) can result in an increase in patient discomfort at the access site. 
     Furthermore, the distal tip of PICC  8  is initially positioned short of its preferred target site by about the same amount as the length of the dangling tapered portion  12 . The preferred target site to position a distal tip of a PICC is the lower one-third of the SVC, close to the junction of the SVC and the right atrium. At this location, it has been found that complications from thrombosis and infection are considerably reduced. One factor for this reduction is the ability of the distal tip of the PICC to float freely within the vein lumen at this location and to lie parallel to the vein wall without impinging on the wall. Any impinging of the vein wall from the PICC is known to cause irritation, if not damage, to the vein wall. 
     Since the distal tip of PICC  8  is not initially positioned at its preferred target site, the clinician must then perform a series of alternating steps of peeling a small part of introducer device  10  away from the implanted PICC  8  and translating the distal tip of PICC  8  closer to the target site until the distal tip of the PICC is at the preferred target site. However, when performing the series of alternating steps, the clinician must manipulate tapered portion  12  of catheter body  9  of PICC  8 , leaving the catheter body along this portion highly susceptible to buckling and kinking. Not until the clinician is satisfied with the location of the distal tip of the PICC does this risk of buckling reduce. Buckling and kinking of PICC  8  is highly undesirable because the PICC becomes essentially useless for its intended purpose. At that point, a new PICC must be inconveniently reinserted into the vein by starting over at the very beginning with the modified Seldinger technique, which can extend the procedure time and further delay the administration of intravenous therapy. 
     Thus, what is needed is an introducer device that is configured to receive a catheter to permit the distal tip of the catheter to reach a target site, e.g., the central venous system, during its initial insertion through the introducer device. Further, what is needed is an introducer device that is configured to receive a catheter to limit, if not eliminate, any external dangling portion of the catheter and its associated risks to buckling and/or kinking during insertion through the introducer device. What is also needed is a catheterization system, and method of use thereof for therapeutic treatment, such as therapeutic treatment of the central venous system, that can cause less discomfort and inconvenience to the patient. 
     BRIEF SUMMARY 
     In a first embodiment, an introducer sheath for vessel catheterization is provided. The sheath can include a sheath body and a handle. The sheath body has a proximal end and a distal end, and a passageway extending longitudinally therethrough. The handle can be attached to the proximal end of the sheath body. The handle can include an opening extending from a proximal end to a distal end. The opening can be in communication with the passageway of the sheath body, which together define an access lumen of the introducer sheath. A first tab and a second tab may be disposed on opposite sides of the opening. A weakened region can be oriented in the longitudinal direction so that the handle is capable of being split when the first and second tabs are pulled apart from one another. The access lumen can have a tapered portion that is sized to receive a tapered outer surface of a catheter. Preferably, the tapered portion has a continuously smooth taper. The body of the introducer sheath disposed about the tapered portion of the access lumen can also be tapered, preferably at the same tapering rate as the tapered outer surface of the catheter. An introducer sheath having a tapered body to define a tapered portion of the access lumen can more quickly provide hemostasis at the puncture site, can provide enhanced strain relief along the introducer sheath body, and/or can be easier to split along the weakened portion of the introducer sheath due to mechanical advantage from the tapered body. 
     In a second embodiment, a system for vessel catheterization is also provided. The system can include an embodiment of a catheter assembly in addition to one of the embodiments of an introducer sheath, as described herein. The catheter assembly is preferably a central venous catheter, such as a peripherally inserted central catheter, for insertion and access to a central venous system of a patient. The catheter assembly can include a catheter body, a hub assembly, and at least one tube. The catheter body can have a tapered outer surface along a length thereof. The catheter body can have one or more lumens extending longitudinally therethrough, with the body extending distally from the hub assembly. The tube can have a lumen extending longitudinally therethrough, with each tube extending proximally from the hub assembly. The hub assembly can have a body adapted to provide a fluid transition from the lumen of the tube(s) to the lumen(s) of a single catheter body. The catheter body preferably has a tapered outer surface along the length thereof, preferably adjacent the hub assembly. The catheter body may also include an antimicrobial drug coating along a portion of at least one of an outer surface or a luminal surface along at least one of the lumen(s). A system with an introducer sheath having an access lumen with a tapered portion and a catheter with a tapered portion can provide a reduced risk of buckling and kinking of the catheter&#39;s tapered portion during insertion and translation of the catheter into the body vessel and/or can facilitate a closer initial tip position relative to the target site. 
     In a third embodiment, a method of vessel catherization, for example to provide intravenous therapy to a patient, is provided. The method can include one or more of the following steps: creating an entry opening in a body vessel; introducing a distal end of one of the embodiments of the introducer sheath described herein through the entry opening to inside the body vessel; introducing a catheter body of one of the embodiments of a catheter assembly described herein to inside the body vessel, through an access lumen of the introducer sheath; translating the catheter body in the body vessel until confronting surfaces of a tapered outer surface of the catheter body and a tapered portion of the introducer sheath contact one another. This method can significantly reduce the number of steps, and time associated therewith, when gaining percutaneous access to a body vessel for treatment such as to administer intravenous therapy more quickly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view of a prior art system for vessel catheterization, depicting a catheter introduced within an introducer device, with a portion of the catheter dangling external to the introducer device. 
         FIG. 2  is a side elevation view of a catheter used in a system for vessel catheterization. 
         FIG. 3  is a side elevation view of an introducer sheath with a dilator that is used in a system for vessel catheterization. 
         FIG. 3A  is an end view of the introducer sheath of  FIG. 3 , with the dilator removed therefrom. 
         FIG. 4  is a cross-sectional view of the introducer sheath of  FIG. 3 , with the dilator removed therefrom. 
         FIG. 4A  is a cross-sectional view of the introducer sheath of  FIG. 3 , with the catheter of  FIG. 2  introduced in the place of the dilator, depicting a system for vessel catheterization. 
         FIGS. 5A-5D  are side elevation views, depicting various steps of a method of using a system for vessel catheterization of a body vessel of a patient. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     In the following discussion, the terms “proximal” and “distal” will be used to describe the opposing axial ends of inventive devices, as well as the axial ends of various component features. The term “proximal” is used in its conventional sense to refer to the end of the device (or component thereof) that is closest to the clinician during use of the device. The term “distal” is used in its conventional sense to refer to the end of the device (or component thereof) that is initially inserted into the patient, or that is closest to the patient during use. 
       FIG. 2  shows an exemplary central venous catheter (CVC)  20 , such as a peripherally inserted central catheter (PICC), for insertion into a body vessel of a patient so that access to a central venous system can be provided. One desirable target site in the central venous system is the superior vena cava (SVC), and preferably, the lower one-third of the SVC, close to the junction of the SVC and the right atrium. At this preferred target site, complications from thrombosis and infection can be minimized. 
     Catheter  20  includes a catheter body  22  extending distally from a hub assembly  24  and having a length suitable to reach the intended target site. For example, the catheter length can be up to about 50-60 cm, although it can be trimmed to suitable size as necessary. Catheter body  22  has a proximal end  26  and a distal tip  28 , and one or more lumens  30  extending through the catheter body. An outer portion  32  corresponding to the proximal end of catheter body  22  tapers down from a first diameter  33  to a second diameter  35  for a predetermined longitudinal distance  37 . Longitudinal distance  37  may be a suitable distance to extend through the body just short of the body vessel, and may even extend into the body vessel. It is desirable to make the first and second diameters as small as possible to limit the amount of space during the indwelling of the catheter body within the body. The difference is sizes for first and second diameters  33 ,  35  can be sized up to about 2-3 French sizes. Longitudinal distance  37  can be any distance necessary but typically in the range of 3-4 cm up to about 10-15 cm. 
     Tapered outer portion  32  of the catheter body is typically larger than the puncture opening and can be used to provide immediate hemostasis when pushed slightly more into the opening for sealing along the edge of the puncture opening. A remaining portion  39  of catheter body  22 , distal to tapered outer portion  32  and extending to distal tip  28 , typically has a constant diameter. Remaining portion  39  is generally the same diameter as second diameter  35  at the end of tapered outer portion  32 . Catheter body  22  can be made of medical grade polymers, such as polyurethane or silicone. Markings can be placed on the catheter body to indicate incremental distances, e.g., every 1 cm or 5 cm, so that the intended length of the catheter body can be easily determined for trimming. 
     Hub assembly  24  includes a first port  34  where the proximal end  26  of catheter body  22  attaches thereto, and one or more second ports  36 . Extending proximally from each second port  36  is a tubular member  38  having a proximal end  40  and a distal end  42 . Hub assembly  24  is a structure that provides a fluid transition from one or more discrete tubular members  38  (e.g., 1, 2, 3, 4, 5 or more tubular members) at one end to typically a corresponding number of separate, noncommunicating lumens  30  (e.g., 1, 2, 3, 4, 5, or more lumens) that are located within a single catheter body  22 . For example,  FIG. 2  shows a first and a second tubular member  38  at one end of the hub assembly, and a single catheter body  22  having a  FIG. 8 , dual lumen  30  on the other side. A connector  44 , e.g., a luer connector, can be attached to proximal end  40  of each tubular member  38 . A clamping device  46  can be disposed around each of tubular members  38  and is capable of shutting off fluid flow through the tubular members and preventing air aspiration due to inadvertent hub dislodgement. Hub assembly  24  may also have one or more attachment wings  48  for facilitating attachment to the body of the patient. 
     One or more coatings may be associated with catheter body  22 . Such coating may comprise a hydrophilic coating, a lubricous coating, and/or a drug coating. The coating can be associated with the catheter body by any suitable manner known in the art, such as dipping, spraying, impregnation, and the like. The drug coating can be an antimicrobial useful in treating catheter-related blood stream infections, such as methicillin-resistant  Staphylococcus aureus  (MRSA), VARS, and vancomycin-resistant  enterococcus  (VRE). One such drug coating that can be beneficial in inhibiting the blood infections can comprise at least one of minocycline and rifampin. One exemplary catheter having a drug combination coating of minocycline and rifampin is the SPECTRUM® Turbo-JeCT™ PICC, which is available at Cook Medical Incorporated in Bloomington, Ind. 
       FIG. 3  shows an exemplary introducer sheath assembly  50  including an introducer sheath  52  and a dilator  54 . Introducer sheath assembly  50  can be used over a guidewire, and can be adapted to provide external access to a body vessel. Since catheter  20  typically does not have a tip to puncture the skin and/or is not adapted to access the vessel of its own, introducer sheath assembly  50  can be well suited for providing vessel access for catheter  20 , as described in more detail below. Dilator  54  is shown inserted completely through an access lumen  56  of introducer sheath  52  and locked to the introducer sheath. Introducer sheath  52  includes a sheath body  58  extending from a handle  60 . 
     Sheath body  58  is a tubular body having a proximal end  62  and a distal end  64 , with a passageway  66  extending longitudinally therethrough about a longitudinal axis  68 . Sheath body  58  can be made of low friction biocompatible polymers or fabrics. Non-limiting examples of a suitable material for the sheath body includes polytetrafluoroethylene (PTFE), ePTFE, polyethylene terephthalate (PET), polyamides such as nylon, polyether amide (PEBA), polyurethanes, or the like. To increase lubricity, the sheath body can also be coated with a hydrophilic coating as appreciated in the art. 
     According to  FIGS. 3 and 3A , handle  60  is shown attached to proximal end  62  of sheath body  58 . Handle  60  includes an opening  70  extending through a central portion of a handle body  72  along longitudinal axis  68 . Handle opening  70  has a proximal end  74  and a distal end  76  and is positioned such that the handle opening is in fluid communication with passageway  66  of sheath body  58  to define together the entire access lumen  56  of introducer sheath  52 . 
     Handle  60  can further include one or more tabs. A first tab  78 A and a second tab  78 B are shown disposed on opposite sides, preferably diametrically opposite, of handle opening  70 , and extending radially outward away from longitudinal axis  68 . Tabs  78 A,  78 B provide support for the fingers and/or thumb of the clinician and enhanced control and handling of the device during its use. Handle  60  can be formed from any rigid or semi-rigid material having sufficient structural strength for the purposes described herein. Preferably, handle  60  is insert-molded over the proximal end of the sheath body. 
     Handle  60  preferably has a weakened region  80  in a longitudinal direction, so that introducer sheath  52  is capable of being longitudinally split for removal from the patient&#39;s body. Weakened region  80  may facilitate the splitting of at least a portion of sheath body  58  as well. In other words, when tabs  78 A,  78 B are pulled radially apart from one another and downward, handle  60  and at least a portion of sheath body  58  can be readily removed by peeling introducer sheath  52  away from a device that is inserted in its access lumen. Weakened region  80  can include a pair of axial slots  82 , as shown in  FIGS. 3 and 3A , to create a region of relatively thin material. The weakened region may further include a longitudinal region of softer material, a series of perforations, or other structural features to facilitate removing of the introducer sheath as known in the art. The tabs can be a variety of shapes and can even include surface irregularities to improve its gripping when being manipulated and pulled apart. 
     Access lumen  56  is adapted to allow the passage of other medical devices, such as the aforementioned dilator  54  and catheter  20 . As shown in  FIG. 4 , introducer sheath assembly  50  can include a tapered outer portion  51  along its outside surface and a distal portion  53  with a constant diameter, although the entire length of the body can be tapered. The tapered outer portion  51  can provide hemostasis at the puncture site more quickly by increasing the distance of insertion of introducer sheath  52  into the vessel opening to create a tighter seal. Tapered outer portion  51  may also provide enhanced strain relief along sheath body  58 , and a smoother transition from handle  60  to sheath body  58 , to avoid potential stress risers and kinking. Further, tapered outer portion  51  provides material farther away from the axis  68  than conventional introducer sheaths, and at an angle to axis  68 , to provide a mechanical advantage for initially breaking handle  60  along weakened portion  80  and for splitting the handle and the sheath body. 
     Referring back to  FIG. 3 , dilator  54  has a longitudinal body, with a substantial portion  84  thereof having a diameter approximately equal to the diameter of access lumen  56  along distal portion  53  of introducer sheath  52 . Dilator  54  may also have portion that is tapered in a similar manner as a tapered inner portion of the access lumen described below in order to improve the internal fit and inhibit the dilator from being inserted too far into the access lumen. Dilator  54  also has a distal end  86  shown extending beyond distal end  64  of sheath body  58 . Distal end  86  can be tapered to an even smaller diameter in order to facilitate insertion of introducer sheath  52  into the body vessel. Dilator  54  may also have a connector  88 , e.g., a threaded luer connector, which is capable of being attached to handle  60  of the introducer sheath. In one example, dilator connector  88  can be adapted to removably attach with handle  60 , e.g., handle opening  70 , for easy removal from introducer sheath  52 . In addition, dilator  54  may also include a connector  90 , e.g., a luer connector, at its proximal end for attachment to devices used for flushing the system, and may include an injection cap (not shown) that is placed over the proximal end of dilator  54 . 
       FIG. 4  further depicts access lumen  56  of introducer sheath  52  including a tapered inner portion  57  that has been exaggerated for clarity. Tapered inner portion  57  tapers from a first diameter  92  to a second diameter  94 . First diameter  92  can be located at some point along handle opening  70  and/or near the proximal end of sheath body  58 . Second diameter  94  can be located along a portion of passageway  66  of sheath body  58  at a pre-determined longitudinal distance  96  from first diameter  92 . Tapered inner portion  57  preferably is sized to be at least approximately the size of tapered outer portion  32  of catheter  20 . In other words, first diameter  92  of access lumen  56  is sized to be at least as large as first diameter  33  of catheter body  22 . Further, second diameter  94  of access lumen  56  is sized to be at least as large as second diameter  35  of catheter body  22 . To minimize the amount of space in the body during indwelling the introducer sheath, first diameter  92  of access lumen  56  can be sized to match first diameter  33  of catheter body  22  and second diameter  94  of access lumen  56  can be sized to match second diameter  35  of catheter body  22 . However, to more easily facilitate the receiving of the catheter body, first diameter  92  of access lumen  56  may be sized 0.5 to 1 French greater than first diameter  33  of catheter body  22  and second diameter  94  of access lumen  56  may be sized 0.5 to 1 French greater than second diameter  35  of catheter body  22 . Further, along the distal portion  53  of the introducer sheath assembly  50 , access lumen  56  preferably is of a constant diameter sized to be at least as large as distal portion  39  of the catheter, although the entire length of the lumen can be tapered. The tapered portion of the access lumen can be tapered at approximately the same rate as the tapered outer surface of the catheter, e.g., a tapering rate in the range of 1/1.5 French size/cm to about 1/7.5 French size/cm. 
     As depicted in  FIG. 4A , when inserted into access lumen  56  of introducer sheath  50 , catheter body  22  of catheter  20  is translated in the body vessel until tapered outer surface  32  of the catheter body confronts tapered inner portion  57  of access lumen  56 . This arrangement may even be sized to permit hub assembly  24 , to contact handle  60  to indicate to the clinician that distal tip  28  of catheter  20  is positioned at its preferred target site. To this end, tapered inner portion  57  of access lumen  56  receives substantially the entire tapered outer surface  32  of catheter  20  up to hub assembly  24  to reduce the risks associated with portions of the catheter dangling external to the access site. This arrangement can provide a reduced risk of buckling and/or kinking of the catheter external to the introducer sheath during initial translation of the catheter. Further, the luminal walls that define access lumen  56  can provide a guiding surface to further inhibit buckling and/or kinking of the catheter disposed internally within the introducer sheath during the final translation of the last portion of the catheter to the target site. This arrangement can also permit distal tip  28  of catheter  20  to be positioned initially closer to (e.g., up to about 10-15 cm), if not at, the target site when compared to conventional devices as shown in  FIG. 1 . 
     With reference now to  FIGS. 5A-5D , a method of vessel catherization will now be described with specific reference to intravenous therapy using the central venous system of a patient with introducer sheath  52  and catheter  20 . One skilled in the art can appreciate that the method described herein can be used for other treatments and therapies for other types of body vessels and lumens, other than intravenous therapy. 
     A clinician can gain central venous system access by using a standard or modified Seldinger technique. After prepping the access site, an access needle (not shown) is inserted through skin  100  of a patient to create an opening or venotomy in a body vessel, such as a vein  102 , where external access to inside of vein  102  is gained. For intravenous therapy, one of the basilic vein, cephalic vein or brachial vein is typically used. The use of ultrasound may be helpful to determine the suitability for venous access and patency. A guidewire  104  is inserted through the access needle and is translated a distance, e.g., 15-20 cm into vein  102 , generally using fluoroscopic guidance. The access needle is then removed, leaving guidewire  104  in place. 
     According to  FIG. 5A , introducer sheath assembly  50  with introducer sheath  52  and dilator  54  is then inserted over guidewire  104  and into vein  102 . Introducer sheath assembly  50  may need to be twisted in order to be advanced farther into vein  102  in order to implant a substantial portion of sheath body  50  within the subcutaneous portion of skin  100 . When the initial guidewire is not long enough to access the desired target site, it can removed, and another longer and/or stronger guidewire can be introduced through introducer sheath assembly  50  into vein  102  and translated to the desired target site. The longer guidewire, also referred to as reference numeral  104 , is typically marked at 1 cm or 5 cm increments to indicate the distance from the access site to the target site. Catheter  20  can then be trimmed to suitable size according to the measured distance. Leaving introducer sheath  52  and the guidewire  104  in place, dilator  54  can then be removed from introducer sheath  52  by unlocking connector  88  from handle  60  of introducer sheath  52 . It can be appreciated by those skilled in the art that the longer guidewire  104  can also be removed, leaving only the introducer sheath in place. 
     According to  FIG. 5B , catheter  20  is then inserted over guidewire  104 , through introducer sheath  52 , and then translated over guidewire  104  within vein  102  to the target site. Again, the catheter can be inserted through the introducer sheath and translated to the target site after removal of the guidewire. According to  FIG. 5C , catheter  20  is inserted into access lumen  56  of introducer sheath  52 . Catheter  20  is translated distally until confronting surfaces of the tapered outer surface of catheter body  22  and the tapered inner portion of access lumen  56  contact one another, and preferably until distal end  34  of catheter hub assembly  24  contacts handle  60  of introducer sheath  52  (as shown in  FIG. 4A ). Distal portion  39  of catheter  20  is shown extending distally past the end of introducer sheath  52 . Tapered portion  32  of catheter  20  can be advantageously inserted entirely into the access lumen  56  of introducer sheath  52 . Further, while introducer sheath  52  is in place, the distal tip of catheter  20  is preferably translated to the target site. 
     Before removal of introducer sheath  52 , the location of the catheter distal tip can be radiographically verified with imaging equipment to ensure the distal tip is at its intended location. To remove introducer sheath  52  that is implanted within the subcutaneous portion of the skin, the tabs of handle  60  are pulled radially apart from one another and downward to snap or break the handle along the weakened region. Stabilizing catheter  20  in place, introducer sheath  52  while in the subcutaneous portion can then be split apart by continuously pulling the tabs radially apart until the introducer sheath is entirely removed from the catheter. This can be generally performed without affecting the position of catheter  20  within vein  102 , as shown in  FIG. 5D . Preferably, the clinician can remove the introducer sheath from the catheter by avoiding the series of alternating steps of peeling a small part of introducer sheath away from the catheter and translating the distal tip of the catheter closer to the target site. The tip position of the catheter may again be verified. Even when a small portion (e.g., 0.5-1 cm) of the catheter is translated proximally, the clinician can translate the tapered outer portion of the catheter farther in the venotomy for inhibiting blood loss. 
     As can be appreciated by those skilled in the art, a source of therapeutic, nutritional, and/or imageable agents, such as syringe or an intravenous (IV) bag, can then be coupled to the connectors of the one or more tubes of catheter  20  ( FIG. 2 ). The therapeutic agent is pressurized in a manner to travel through the tubes and lumens of catheter  20  and to be released to the target site. Catheter  20  can provide short-term or long-term vessel pressure monitoring, blood sampling, administration of drugs and fluids, such as total parenteral nutrition (TPN), chemotherapeutic agents or other therapeutic drugs, and delivery of contrast in computed tomography (CT) studies with power injectors as known in the art. 
     In one example, a catheter includes a tapered outer surface that tapers from a first diameter of 7 French that is adjacent the hub assembly to a second diameter of 5 French for a longitudinal distance of about 10 cm. An introducer sheath includes an access lumen having a tapered portion that is tapered from a first diameter of 8 French at the proximal end of the handle opening to a second diameter of 5.5 French for a longitudinal distance of about 10 cm from the proximal end of the handle opening. Other introducer sheaths may be proportionally sized in a similar fashion with respect to the different sizes of catheters. 
     Drawings in the figures illustrating various embodiments are not necessarily to scale. Some drawings may have certain details magnified for emphasis, and any different numbers or proportions of parts should not be read as limiting, unless so-designated in the present disclosure. Those skilled in the art will appreciate that embodiments not expressly illustrated herein may be practiced within the scope of the present invention, including those features described herein for different embodiments may be combined with each other and/or with currently-known or future-developed technologies while remaining within the scope of the claims presented here. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting. And, it should be understood that the following claims, including all equivalents, are intended to define the spirit and scope of this invention