Abstract:
A catheter assembly ( 10 ) having an outer catheter ( 12 ) and an inner catheter ( 14 ) extending coaxially through the outer catheter, and a hub ( 16 ). The inner catheter ( 14 ) is axially movable within and with respect to the outer catheter ( 14 ) by use of an actuator assembly ( 130 ) such that the catheter assembly has an opened condition permitting fluid communication with the vasculature of a patient, and a closed condition preventing fluid communication with the vasculature. The opened condition permits the intended use of the catheter assembly such as for hemodialysis of the patient. In the closed condition, locking solution may be maintained in the catheter assembly and later removed therefrom, with essentially no locking solution leaving the catheter assembly or entering the patient. The actuator assembly ( 130 ) is secured to the proximal end portion ( 128 ) of the inner catheter ( 14 ) as it protrudes proximally from the hub ( 16 ), where it is accessible to the practitioner. The actuator assembly ( 130 ) may comprise an adapter sleeve ( 90 ) fixed to the inner catheter ( 14 ), and a swivel sleeve ( 92 ) which is rotatable with respect to both the adapter sleeve ( 90 ) and the hub ( 16 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/937,847 filed Jun. 29, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This relates to the field of medical devices and more particularly to catheters and catheter assemblies. 
       BACKGROUND OF THE INVENTION 
       [0003]    Hemodialysis catheters are implanted into the vasculature of a patient, and have proximal ends that extend from the patient and are connectable to and disconnectable from tubing of a hemodialysis apparatus. Such catheters are provided with a first lumen and a second lumen coextending to respective distal tips that are carefully positioned at a selected site in a particular vessel of the patient, so that undialysed blood may be withdrawn from the patient&#39;s vessel while dialysed blood may be reintroduced into the patient&#39;s vessel simultaneously, at respective distal tip openings of the lumens. The catheter lumens may be coextending separate catheters or may be dual (or more than two) lumens of a single catheter separated by a septum wall. The distal tips of the two lumens are generally staggered along the vessel such that blood being withdrawn does not include any significant amount of dialyzed blood that has been reintroduced into the vessel at the more distal of the two distal tips. 
         [0004]    When a particular dialysis procedure has been completed, the proximal ends of the catheter are disconnected from the tubes of the hemodialysis apparatus, and the lumens are generally inactive until the subsequent dialysis procedure, although fluid medication or saline may be infused into at least one of the lumens, if and when desired, or a blood sample withdrawn. However, blood is highly susceptible to coagulation and clot formation. The addition of a specific agent or locking solution to the catheter or any extracorporeal blood-contacting surface can reduce the incidence of coagulation by interfering and/or inhibiting the hematological chemistry of blood and its interaction with synthetic materials, such as those from which catheters are made. 
         [0005]    It is conventional, then, to introduce anticoagulant locking solutions such as heparin into an implanted catheter between hemodialysis treatments, to prevent clotting of blood within the catheter, and which then is withdrawn for the subsequent dialysis procedure. Between hemodialysis treatments, the catheter is clamped off outside of the patient, creating a pressure gradient that holds the locking solution within the lumens. However, certain amounts of locking solution are known to enter the patient&#39;s blood stream through the open distal tips, especially in areas where side holes are present. The amounts introduced into the patient are generally not at a level to cause toxicity or disrupt a patient&#39;s hematology; however, the leaching of small amounts of locking solution from the distal lumen tips makes the catheter more prone to lumen clot-off. 
         [0006]    One catheter assembly directed to minimizing amounts of locking solution entering the patient&#39;s blood stream is disclosed in U.S. Patent Publication No. US 2006/0253063 A1. In this application, the catheter includes a first lumen having a first distal tip, and a second lumen having a second distal tip, wherein the first and second distal tips having wall sections that are normally disposed in a closed position but are each openable under fluid pressure. While both lumens have openable distal tip wall sections, the first distal tip has a flap openable both inwardly and outwardly when the first lumen is subjected to negative pressure and positive pressure, respectively, relative to the blood pressure of the patient in whom the catheter has been implanted. The second lumen extends a selected distance distally of the first distal tip to a second distal tip that is a generally rounded tip when closed, and the second distal tip is defined by an openable section that is internally concave and may be formed by at least one slit cut into a closed rounded distal tip after extrusion of the lumen, defining at least two generally curved lip portions. 
         [0007]    With respect to the above-discussed catheter system of Publication No. US 2006/0253063 A1, the several lip portions are openable outwardly under positive pressure applied to the distal end of the second lumen, and a closable together under negative pressure applied to the second lumen. Near the second distal tip, in the side wall of the second lumen are side port sections that are openable inwardly upon application of negative pressure to the proximal end of the second lumen. The closable and openable sections of the first and second distal tip sections of the first and second lumens operate thusly: during hemodialysis, negative pressure is applied to the first lumen and blood is drawn from a patient&#39;s vessel into the first distal tip and through the first lumen; positive pressure applied to the second lumen when blood enters the proximal end of the second lumen and separates the several lip portions at the second distal tip to re-enter the vessel. Were the reverse of the pressures to be caused by an incorrect hemodialysis connection, blood traveling into the first lumen would open the flap to enter the vessel, while negative pressure on the second lumen would close the several lip sections but open the side ports for blood to enter from the vessel. Between dialysis procedures, locking solution injected under low pressure into the catheter would fill both lumens since the distal tips would be in their closed, undeflected conditions, and when removed, blood from the vessel would enter both distal tips due to negative pressure on both lumens. 
         [0008]    It is desired to provide a catheter that will minimize or eliminate the small amounts of locking solution entering a patient&#39;s blood stream from an implanted catheter between dialysis treatments. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    The present invention is a closable and openable catheter assembly of first and second catheters having respective first and second lumens, first and second distal portions, first and second proximal portions, first and second distal end portions, and first and second proximal end portions; first and second distal openings defined into the first and second distal end portions of the first and second catheters for fluid communication between the first and second lumens with vasculature of a patient when the distal portions of the first and second catheters are implanted in the vasculature; and an actuating assembly in operative association with respect to the first and second catheters, wherein actuation of the actuating assembly actuates at least one of the first and second distal end portions between opened and closed conditions wherein the first and second lumens are in fluid communication with the vasculature of the patient in the opened condition and the first and second lumens are not in fluid communication with the vasculature of the patient. 
         [0010]    The present invention also includes an actuator assembly for a closable and openable catheter assembly where the catheter assembly includes a first and second catheter wherein one of the first and second catheters is axially movable with respect to the other to close and open distal openings of the first and second catheters, including a first actuator portion rotatably affixed about one of the first and second catheters, and a second actuator portion nonrotably affixed to the one of the first and second catheters, wherein relative rotation of the first actuator portion with respect to the second actuator portion and between first and second angular stops, permits and prevents respectively, axial movement between first and second axial positions of the second actuator portion with respect to the first actuator portion and also with respect to the other of the first and second catheters, wherein when the second actuator portion is in the first axial position, the distal openings of the first and second catheters are open and when the second actuator is in the second axial position, the distal openings are closed. 
         [0011]    Also, the present invention includes a closable and openable catheter assembly, including a first catheter and a second catheter respectively having first and second distal end portions and having respective distal openings to vasculature of a patient when the catheter assembly is implanted within the patient; and each of the first and second distal end portions having respective closure structures to occlude the distal openings of the other when the catheter assembly is actuated to a closed condition, and which do not occlude the distal openings of the other when the catheter is actuated to an opened condition. 
         [0012]    In a preferred embodiment, the catheter assembly comprises a dual lumen catheter wherein a first lumen is defined in a separate, generally coaxial inner catheter within an outer catheter and that is movable axially with respect to the second or outer lumen by manipulation remote from the distal end, of a proximal inner catheter end section extending proximally from a hub outside of the patient and separate from the proximal outer catheter end section, all while the assembly remains sealed. The first distal tip of the inner catheter extends at least to some extent distally of the second distal tip of the outer catheter and includes an enlargement, such as a closure cap assembly, sufficiently large in diameter to close off the distal opening of the outer catheter when positioned thereagainst in the closed catheter assembly position. While it is preferred that the enlargement include an aperture therethrough for guide wire placement, a valve traverses the aperture and allows for passage of the guide wire, where upon guide wire removal, the aperture seals closed. 
         [0013]    The inner catheter includes at least one side port proximally of the enlargement for fluid communication between the first lumen and the vessel when the inner catheter is in the open position, and the inner catheter side ports are closed by the surrounding outer catheter when the inner catheter is in the closed position. Further, the inner catheter includes a barrier section that blocks and closes all outer catheter side ports preferably from within the outer catheter when the inner catheter is in the closed position, whereby no side ports in either the first lumen or the second lumen are open to the blood vessel when the catheter assembly is closed. Locking solution is successfully kept within the catheter assembly when in the closed position, and fluid flow successfully permitted when the catheter assembly is in the open position. 
         [0014]    In a preferred embodiment of distal tip arrangement, the side ports of the outer catheter comprises a pair of elongate slots on opposite sides while the barrier section of the inner catheter comprises a pair of outwardly projecting ribs that are disposed in the respective slots and are movable therealong between forward or open, and rearward or closed, positions with respect thereto when the inner catheter is moved between open and closed positions. 
         [0015]    The proximal end section of the inner catheter extends proximally through the hub of the assembly and is movable axially therewithin, and may have secured thereto an extension tube proximally of the hub by a connecting arrangement that is part of the present invention; the outer catheter proximal end may be joined to a respective extension tube within the hub, as is conventional. 
         [0016]    Manipulation of the inner catheter between open and closed positions is preferably attained by controlled and limited axial movement of the inner catheter with respect to the assembly and the outer catheter. The proximally disposed actuator assembly for the inner catheter may comprise an adapter sleeve and a swivel sleeve, and the actuator assembly may also serve to connect the inner catheter to a respective extension tube. The swivel sleeve is located adjacent to the proximal hub exit for the inner catheter and provides an inner cylindrical wall surface having defined thereinto a pair of opposed first and second slots spaced axially therealong coextending circumferentially from respective opposed axial slots extending therebetween, defining first and second, or open and closed, positions, with the open position provided by the more distal first slot and the closed position provided by the more proximal second slot. The swivel sleeve is manually rotatable with respect to the assembly about the inner catheter proximally of the hub. 
         [0017]    The adapter sleeve of the inner catheter is positioned proximally of the swivel sleeve but has a distal portion extending into the proximal end of the swivel sleeve, which distal portion includes a pair of detents on opposite sides of the distal portion and projecting radially outwardly. The adapter sleeve is movable axially with respect to the swivel sleeve and the hub only when the swivel sleeve has been rotated to an “open” position in which the axial slots are moved into alignment with the detents, which can then move axially along the axial slots and then circumferentially along either the first or second slot portion relative to the swivel sleeve. A pair of stabilizing posts may preferably extend distally from the distal end of the cylindrical body of the adapter sleeve and extend through the swivel sleeve adjacent to its inner surface to stabilize the coaxial orientation of the sleeves when in the closed position, when the adapter sleeve is relatively proximally spaced from the swivel sleeve. Visual indicators preferably are provided on both the adapter sleeve and the swivel sleeve, for the practitioner to determine the location of the slot followers with respect to the first and second slot portions to indicate the open or closed positions. 
         [0018]    A method of the present invention comprises the steps of providing a catheter having an outer catheter and an inner catheter to which a hub is secured along the proximal portions thereof, the inner and outer catheter having respective distal portions extending to respective distal tip portions, and the inner catheter being movable axially within and along the outer catheter and the hub by an actuator assembly of the inner catheter to move a distal tip of the inner catheter relative to the distal tip portion of the outer catheter to open and close both catheters; and actuating the actuator assembly to move the inner catheter axially with respect to the outer catheter and the hub to move the inner catheter distal tip portion between open and closed positions relative to the outer catheter distal tip portion, to open and close the distal openings of both the inner and outer catheter lumens. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0019]    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: 
           [0020]      FIGS. 1 and 2  are elevations view of the catheter assembly of the present invention in the closed and open positions, respectively; 
           [0021]      FIGS. 3 and 4  are longitudinal cross-sectional views of the catheter assembly of  FIGS. 1 and 2 , with the catheter assembly in the closed and opened positions, respectively; 
           [0022]      FIGS. 5 and 6  are enlarged cross-sectional views of the distal end portion of the assembly of  FIGS. 3 and 4  in the closed and opened positions, respectively, taken along lines  5 - 5  and  6 - 6  thereof, respectively; 
           [0023]      FIGS. 7 and 8  are elevation and top views of the outer catheter&#39;s distal end portion, respectively, with an outer sleeve exploded therefrom in  FIG. 7 ; 
           [0024]      FIGS. 9 to 11  are top, elevation and cross-sectional views of the inner catheter&#39;s distal end portion, respectively, with the closure cap exploded therefrom in  FIG. 9  and the cross-sectional view taken along lines  11 - 11  of  FIG. 9 ; 
           [0025]      FIG. 12  is an enlarged isometric view of the inner catheter&#39;s distal end portion; 
           [0026]      FIGS. 13 and 14  are enlarged cross-sectional views of the inner catheter distal end with the closure cap components, in the exploded and assembled relationships, respectively; 
           [0027]      FIGS. 15 and 16  are isometric views of the adapter sleeve and the swivel sleeve, respectively that comprise the actuator assembly for the inner catheter; 
           [0028]      FIG. 17  is a diagrammatic view of the interior surface of the swivel sleeve of  FIG. 16 ; 
           [0029]      FIGS. 18 and 19  are enlargements of the hub of the assembly of  FIGS. 3 and 4 , in cross-section, in the closed and opened positions, taken along lines  18 - 18  and  19 - 19  of  FIGS. 3 and 4 , respectively; and 
           [0030]      FIGS. 20 and 21  are exploded cross-sectional views of the proximal end of the hub showing the components that will be secured to the catheter assembly at the proximal end of the hub and with respect to the inner catheter, respectively, that will enable remote movement of the distal tip of the inner catheter, with  FIG. 21  showing the adapter and swivel sleeves of  FIGS. 15 and 16 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]    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 term “distal” is meant to describe the portion of a catheter according to the present invention that is inserted into a patient, and the term “proximal” is meant to describe the portion of a catheter according to the present invention that remains exterior of the patient. 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. 
         [0032]      FIGS. 1 to 4  illustrate a catheter assembly  10  of the present invention in a closed condition and an open condition, respectively. The length of the catheter assembly has been shortened from its desired actual length. Catheter assembly  10  includes an outer catheter  12 , an inner catheter  14  ( FIGS. 3 and 4 ), a hub  16 , a first extension tube assembly  18  affixed to the proximal end  20  of the catheter assembly  10  in fluid communication with the inner catheter  14 , and a second extension tube assembly  22  affixed to the hub  16  to be in fluid communication with outer catheter  12  within hub  16 . The first and second extension tube assemblies are shown to include clamps therealong and luer fittings or connectors at proximal ends thereof, as is conventional. Preferably, the hub is insert-molded about the proximal end portion of the outer catheter. Through the use of mandrels and/or core pins (not shown), the hub  16  is molded to include an angled passageway  24  ( FIGS. 3 ,  4  and  20 ) providing fluid communication between the lumens of the outer catheter and its extension tube assembly  22 ; the hub also is molded to include a linear passageway  26  therethrough into which a proximal end portion  128  (see  FIG. 19 ) of the inner catheter  14  will extend as it exits from the proximal end  28  of the outer catheter to be joined to a steel cannula  29  such as by being expanded to extend over a distal end portion of the steel cannula forming a tight, sealed grip thereto, defining an inner catheter/steel cannula subassembly. Steel cannula  29  will continue through linear passageway  26  and protrude from hub  16 ; the inner catheter/steel cannula subassembly  14 , 29  is axially movable with respect to the outer catheter  12  and the hub  16 . 
         [0033]    In accordance with the present invention and referring primarily to  FIGS. 1 to 4 , a closure cap assembly  30  containing therewithin a valve is secured to the distal tip section  32  of inner catheter  14  and closes off the distal end opening  34  (see  FIG. 12 ) of the lumen of the inner catheter. Closure cap assembly  30  is also sufficiently large in diameter to close off the distal tip opening  36  ( FIGS. 7 and 8 ) of the lumen of outer catheter  12  when the catheter assembly is in the closed position. Preferably, a containment sleeve  38  is affixed about, and is conterminous with, a distal end portion  40  of outer catheter  12  and having a distal sleeve end  42  that abuts a proximal surface  44  of closure cap assembly  30  when the catheter assembly is in the closed condition. 
         [0034]    Seen in  FIGS. 1 to 4 , outer catheter  12  of the present invention preferably includes a pair of elongate side slots  46  along the distal end portion  40 , permitting fluid communication of the lumen with the vasculature of the patient (when the catheter assembly is in the open condition). Side slots  46  are shown to extend to the distal tip of outer catheter  12 , at distal tip opening  36  (see  FIG. 8 ); this is not required for operation of the invention, but is practical from a manufacturing and assembly standpoint. Inner catheter  14  also includes side slots  48  along its distal end portion  50 , extending proximally from proximal surface  44  of closure cap assembly  30 , establishing fluid communication with the vasculature of the patient when the catheter assembly is in the open condition. 
         [0035]    Portions  52  of the inner catheter side wall appear in  FIGS. 2 and 4  to  6  between the side slots  48 , joining the closure cap assembly  30  to the main portion of the inner catheter  14 . Inner catheter  14  further includes a pair of elongate ribs  54  along opposite sides of distal end portion  50 , best seen in  FIGS. 9 to 12 , extending proximally from side wall portions  52 ; elongate ribs  54  are associated with elongate slots  46  of outer catheter  12  and are disposed therein and therealong upon assembly of the catheter assembly. Elongate ribs  54  are movable axially within elongate slots  46  during axial movement of the inner catheter with respect to the outer catheter  12  during actuation of the assembly between its opened and closed conditions, to open the outer catheter for fluid transmission therethrough. Distal tip section  32  of inner catheter  14  is defined distally of side slots  48  and side wall portions  52 , and becomes part of the closure cap assembly  30 . It is preferable for the distal end portion  50  of inner catheter  14  to undergo an insert molding manufacturing procedure for defining the elongate ribs  54  and the distal tip section  32 , which preferably includes formation of a surrounding sleeve  56  that serves to block communication between the inner catheter  14  and the outer catheter  12 , which is best shown in  FIG. 12 . 
         [0036]    Now referring to  FIGS. 7 and 8 , distal end portion  40  of outer catheter  12  is seen to have a pair of opposed elongate slots  46  extending to the distal end thereof, in communication with the lumen of outer catheter  12  for fluid transmission with the vasculature of the patient when the catheter assembly of the present invention is in the opened condition. Containment sleeve  38  is affixed to the distal end portion  40  after assembly of the inner catheter within the outer catheter, and may be prepositioned along the outer assembly proximally of the distal end portion during assembly and then slid into position, acting to seal the outer catheter by covering most of the length of the elongate slots  46 , and also the elongate ribs  54  of the inner catheter, except for preselected proximal slot portions as seen in  FIGS. 1 and 2  which are open to the vasculature when the elongate ribs  54  therein are in their distalmost positions when the catheter assembly is in the opened condition. 
         [0037]    In  FIGS. 9 to 12 , the distal end portion  50  of inner catheter  14  is shown, having sleeve  56  molded thereonto and including elongate ribs  54  and distal end section  32 . Cap member  58  is shown in  FIG. 9  positioned to be affixed onto distal end section  32  of inner catheter  14 . Sleeve  56  is best shown in  FIGS. 11 and 12 . 
         [0038]    The structure of closure cap assembly  30  will now be described in detail with respect to  FIGS. 13 and 14 . Cap member  58  includes a domed distal face  60  and includes a small diameter hole therethrough and centered with respect to domed distal face  60 ; hole  62  permits insertion and implantation of the catheter assembly into the vasculature of a patient through the use of a small diameter guide wire (not shown), as is conventional, facilitating the various curves and bends in the vasculature in order to precisely position the distal tip of the catheter assembly in position. Hole  62  is aligned with a corresponding hole  64  into distal end section  32  of inner catheter  14 , which in turn is centered with respect to the lumen of the inner catheter when cap member  60  is assembled to distal end section  32 . Cap member  60  further includes a shaped proximal cavity  66  having a capture flange  68  complementary to a capture recess  70  of distal end section  32  to physically secure the cap member to the distal end section; an annular groove  72  is formed into capture flange  66  for placement of a bead of adhesive to bond cap member  58  to distal end section  32 . Cap member  58  further preferably includes a capture recess  74  distally of capture flange  68 , into which becomes seated a distalmost flange  76  of distal end section  32 . 
         [0039]    A valve  78  is inserted into cap member  58 , being seated in valve seat  80  in the distal portion of proximal cavity  66 . Valve  78  is shown to include a slit  82  partially transversely thereacross, which slit is normally closed but which is openable to permit passage therethrough of a guide wire. Tapering or funneling surfaces are defined through distal end section  32  and the distal end of cap member  58  to act as lead-ins for facilitating the insertion through the small diameter holes  62 , 64 , of a guide wire in the event that the catheter assembly after initial implantation were to be removed and replaced. Valve  78  remains closed after the catheter assembly has been implanted in the vasculature and the guide wire removed, even when the catheter assembly is in the opened condition since hole  62  is not used for fluid transmission. 
         [0040]    Turning now to  FIGS. 15 to 17 , an adapter sleeve  90  and a swivel sleeve  92  will now be described, that comprise the actuator assembly for axial movement of the inner catheter  14 . Adapter sleeve  90  has a proximal end projection  94  over which will be fitted the distal end of the extension tube assembly  20 , as seen in  FIGS. 1 to 4 ; thus, adapter sleeve  90  serves as the connector of the extension tube assembly  20  to the inner catheter  14 . An annular collar  96  is located proximal to cylindrical body section  98 , and a smaller diameter distal section  100  extends distally from body section  98  to end faces  102 . A pair of detent projections or detents  104  are positioned on opposite sides of distal section  100  adjacent end faces  102 . A pair of stabilizing struts  106  extend distally forwardly from distal section  100 . 
         [0041]    Swivel sleeve  92  is cylindrical, having a proximal end  108  and a distal end  110 . An array of grooves  112  preferably is formed on the exterior side surface thereof to facilitate manual gripping of the swivel sleeve during rotation thereof by the practitioner, during opening and closing the catheter assembly. Referring particularly to the diagram of  FIG. 17 , into and along the interior surface  114  of swivel sleeve  92  is a slot arrangement  116  with which the pair of detents  104  of the adapter sleeve  90  cooperate to move the inner catheter/steel cannula subassembly  14 , 29  to defined fully opened and fully closed positions of the inner catheter  14 . Slot arrangement  116  comprises a pair of opposed axially extending slot portions  118 , circumferentially extending distal slot portions  120  and circumferentially extending proximal slot portions  122  communicating with axially extending slot portions  118 . At the proximal ends of the axially extending slots are seen short slot portions  126  extending to the proximal end  108  that permit positioning of the detents  104  of adapter sleeve  90  into the slot arrangement  116  during assembly of the adapter sleeve and the swivel sleeve to the steel cannula  29  as it projects proximally from the hub  16  (see  FIGS. 3 ,  4 ,  18  and  19 ). 
         [0042]    With respect to  FIGS. 18 to 21 , the structure and operation of the actuation assembly  130  of the catheter assembly of the present invention will now be described. Actuator assembly  130  is affixed to the inner catheter proximal portion  128  in such a manner that adapter sleeve  90  and inner catheter  14  together are able to move axially with respect to swivel sleeve  92 ; detents  104  are able to be moved axially along axial slot portions  118  between the slot portions  120 , 122 . Swivel sleeve  92  is rotatably movable with respect to the adapter sleeve  90  and the inner catheter  14 , with detents  104  able to follow circumferential slot portions  122  at the proximal end of swivel sleeve  92  in an angular direction, or to follow circumferential slot portions  120  at the distal end  110  of the swivel sleeve in an angular direction opposite from that related to slot portions  122 , corresponding to the closed condition and the opened condition, respectively, of the catheter assembly of the present invention. 
         [0043]    Actuator assembly  130  is affixed to the hub  16  in the following manner. Two additional components are utilized, preferably along with an o-ring, that are disposed primarily within the hub proximal end portion  132  associated with the inner catheter  14  and steel cannula  29  to which it is joined, in order to permit rotation of swivel sleeve  92  as well as sealing with respect to the inner catheter but which permits axial movement of the inner catheter  14  with respect to the hub. Linear passageway  28  of hub  16  receives thereinto a generally tubular outer sleeve component  134  that is bonded therewithin; outer sleeve  134  includes an external antirotation rib  136  preventing its rotation with respect to hub  16  and also serving as an antirotation strain relief in cooperation with a corresponding slot of the hub thereover ( FIGS. 18 to 21 ). A generally tubular inner sleeve component  138  is disposed within outer sleeve component  134  and around steel cannula  29 , and an o-ring seal  140  is disposed in the distal end  142  of outer sleeve  134  and is abutted by the distal end  144  of the inner sleeve upon assembly; o-ring  140  sealingly engages the outer surface of steel cannula  29  in a manner which permits the inner catheter/steel cannula subassembly  14 , 29  to move axially between opened and closed positions (see  FIG. 21 ) and also defines a seal between the interior passageways of the hub and the proximal exit for steel cannula  29 . Preferably, inner sleeve  138  is bonded to outer sleeve  134 . 
         [0044]    Inner sleeve  138  includes a flange/recess capture section  146  at its proximal end  148 , complementary to a corresponding flange/recess capture section  150  at the distal end  110  of swivel sleeve  92 . The flange/recess capture sections permit relative rotational movement of the swivel sleeve with respect to the hub  16  and, actually, the entire catheter assembly. Also, as seen in  FIG. 20 , inner sleeve  138  includes a pair of strut-receiving slots  152  extending distally from the proximal end  148 , whereinto extend the stabilizing struts  106  of adapter sleeve  90  of the actuator assembly as the struts extend distally beyond the distal end  110  of the swivel sleeve when the catheter assembly  10  is in its opened condition and the inner catheter has been translated to its distalmost position. 
         [0045]    Visual indicators are preferably provided with the catheter assembly  10  of the present invention to provide a clear indication to the practitioner whether the inner catheter is in its closed condition or its opened condition, since the distal portion of the catheter assembly is within the vasculature of the patient while the proximal portion including the hub  16  is external to the patient. A pair of axially extending marker stripes  160  are provided on the external surface of the swivel sleeve  92  at preselected angular locations on opposite sides of the sleeve. The adapter sleeve  90  is provided with two pairs of axially extending marker stripes  162 , 164 : one pair of marker stripes  162  is provided on the external surface of the section  98  and are associated with the opened condition of the catheter assembly, and become aligned with and adjacent to respective ones of the marker stripes  160  of the swivel sleeve when the adapter sleeve is in its distalmost position adjacent the swivel sleeve and fully rotated so that the detents are located at the termini of the distal slot portions  120  in the swivel sleeve; another pair of marker stripes  164  is provided on the external surface of the distal section  100  of the adapter sleeve, angularly offset from marker stripes  162  so that stripes  164  become revealed when the adapter sleeve  90  has been axially translated proximally from swivel sleeve  92 , and become aligned with marker stripes  160  of the swivel sleeve  92  when the swivel sleeve  92  has been rotated so that detents  104  are located at the termini of the proximal slot portions  122  in the swivel sleeve. 
         [0046]    The various components of the present invention may be made from the following materials: inner and outer catheters  14 , 12  may be made for example of silicone, or may be of polyurethane; distal sleeve  56  defining the structure at the distal end of inner catheter  14  is preferably molded of material identical to that of the inner catheter; containment sleeve  38  for outer catheter  12  may be of material identical to that of the outer catheter; cap component  58  may be made of polyurethane; valve  78  may be made of silicone; hub  16  may be made of polyurethane; adapter sleeve  90 , swivel sleeve  92 , outer sleeve  134  and inner sleeve  138  may be made of polyvinyl chloride; o-ring  140  may be made of silicone; and the extension tubes  20 , 22  may be made of polyurethane as is conventional. 
         [0047]    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.