Patent Publication Number: US-2022233816-A1

Title: Catheter hub adapted to be used with multiuse blood control valve

Description:
This is a US National stage application of PCT Application No. PCT/US2020/039134, filed Jun. 23, 2020, which in turn claims priority from U.S. Provisional application No. 62/866,951 filed Jun. 26, 2019. The contents of the &#39;134 and &#39;951 applications are fully incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The instant invention relates to intravenous catheter assemblies and other vascular access devices including peripheral intravenous catheter (PIVC) assemblies and, more particularly, to an improved catheter hub adapted to be used with a resealable valve to control the blood flow of the catheter assemblies. 
     BACKGROUND OF THE INVENTION 
     Catheter assemblies typically have a catheter hub that has a catheter tube extending from a distal end of the catheter hub. A needle cannula or simply needle slidably extends through the lumen of the catheter so that the sharp tip of the needle extends beyond the distal end of the catheter. The catheter is guided into the appropriate vasculature for example a vein or artery of a patient by the sharp tip of the needle inserting into the patient and then the vasculature. Once the catheter is in place, the needle is removed from the catheter and the catheter hub. Thereafter, a fluid store device such as a syringe or pump would be coupled to the catheter hub so that a fluid path is established between the vasculature of the patient for example a vein and the fluid store device by way of the catheter and the interior space of the catheter hub. 
     To ensure that the catheter is correctly positioned into the vein, or artery, of the patient, the needle may have a side opening that allows blood to seep into the space between the internal surface of the catheter and outer circumferential surface of the needle. This blood along the catheter may act as an indication to the clinician that the catheter is correctly placed. However, after the removal of the needle from the catheter but before the coupling of the fluid store device to the catheter hub, pressured blood may undesirably back flow into the catheter hub via the unobstructed lumen of the catheter. 
     To prevent the blood back flow, the prior art discloses an elastomeric septum or seal member provided in the catheter hub. The stationary seal member is responsive to the insertion movement of a probe for example the male luer taper into the cavity of the catheter hub and opens when the luer lock or end connector of the fluid store device is firmly coupled to the luer end of the catheter hub. The fluid store device may be a syringe, an administration set or a pump for example. 
     Patents and applications assigned to the assignee of the instant invention describe a compressible valve that is biased by the inserted luer taper against an actuator fixedly attached to the interior of the catheter hub. The actuator is a separate component that has an eyelet portion. To attach the actuator and the catheter to the catheter hub, the eyelet portion is press fitted into the aperture at the distal end of the catheter along with the proximal end of the catheter. In order to be able to press fit into the aperture, at least the eyelet portion of the actuator is made of a metallic material. Thus, in addition to requiring separate components, catheter assemblies having the actuator press fitted catheter hub may not be safely used in magnetic resonance imaging (MRI). The patents and applications assigned to the assignee of the instant application that describe a catheter hub that has the compressible valve and the fixedly attached actuator include: U.S. Pat. Nos. 8,652,104, 9,399,116, 9,545,495, 10,080,867 and U.S. application Ser. Nos. 16/110,051 and 16/110,111. The respective disclosures of the &#39;104, &#39;116, &#39;495 and &#39;867 patents and the &#39;051 and &#39;111 applications are incorporated by reference herein to the disclosure of the instant application. 
     SUMMARY OF THE PRESENT INVENTION 
     The instant invention is directed to an improved catheter hub for use with a catheter assembly. Instead of a separate actuator, in a first embodiment of the instant invention, the catheter is used to form both the catheter and the actuator of the catheter hub. To that end, a catheter is fittingly threaded through the aperture at the distal end of the catheter hub so that a distal portion extends distally away from the catheter hub and a proximal portion extends proximally into the internal cavity of the catheter hub. The portion of the catheter sandwiched by the distal and proximal portions is fixedly bonded to the aperture by any of the conventional methods including for example chemical adhesive bonding, melt bonding, plastic insert molding, among others. The proximal portion of the catheter may be configured to be structurally rigid and has the appropriate columnar strength so that its probe end is adapted to open the resealable partition or membrane of a multiuse valve. This may be achieved by injection molding the catheter so that the thickness of the circumferential wall of the proximal portion is greater than the thickness of the circumferential wall of the distal portion. alternatively, the proximal and distal portions of the catheter may be extruded with different material, or have particles added to the proximal portion to add columnar strength and rigidity thereto. The proximal portion of the catheter that extends into the cavity of the catheter hub may be referred to as the catheter actuator or simply the actuator. 
     An elastomeric resealable multiuse valve that has a partition or membrane that separates the valve into a proximal portion and a distal portion is slidably and non-removably inserted into the cavity of the catheter hub with its membrane proximal to the actuator when the valve is in its natural unbiased state. The membrane has at least one slit to assist in its opening. Multiple slits may be scored to the membrane to provide flaps when the membrane is opened. At the unbiased position, the flexibility of the membrane is such that the membrane remains closed to prevent fluid leak from the portion of the catheter hub closed off by the valve even when the catheter is positioned in the artery of the patient and the blood in the lumen of the catheter is under pressure. 
     The membrane is biased against the actuator to an opened position in the catheter hub when the contact end of the connector (luer taper of the luer lock connector) of an external device for example a fluid store device comes into contact with the proximal end of the valve, as the external fluid store device is coupled to the catheter hub. With the membrane opened, an open fluid communication path is established between the chamber at the proximal portion of the valve, the cavity at the proximal portion of the catheter hub, and the lumen of the catheter, so that fluid may be collected from, or infused to, the patient. When the external fluid store device is removed from the catheter hub, no longer under bias and due to its inherent elasticity, the valve returns to its natural state with the membrane again positioned proximal to the probe end of the actuator in the closed position. 
     Another embodiment of the present invention has an actuator integrally formed as a part of the catheter hub. For this embodiment, the actuator integrally extends from an internal distal end wall inside the catheter hub as a tubular structure having an internal passage that aligns with the aperture at the distal end of the catheter hub. The actuator may have a frusto-conical probe end to assist in the opening of the membrane. The proximal portion of the catheter may extend into and fixedly attach to the aperture at the distal end of the catheter hub. Alternatively, the proximal portion of the catheter may extend through the passage of the actuator so that the lumen of the catheter provides a through passageway between the internal cavity of the catheter hub and the vein or artery of the patient. 
     With the various embodiments of the present invention, there is no need for a separate actuator component and the additional process of installing the separate actuator component into the catheter hub. Cost savings thus result both from the lesser number of components as well as the lesser amount of manufacturing required to produce the catheter hub assembly. Further, by eliminating the metallic actuator, the inventive catheter assembly may be safely used in MRI scans. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The present invention will become apparent and the invention itself will be best understood with reference to the following description of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a semi-transparent perspective rear view of a first embodiment of the catheter hub assembly of the instant invention; 
         FIG. 2  is a semi-transparent perspective front view of the first embodiment of the catheter hub assembly of the instant invention; 
         FIG. 3  is a disassembled view of the catheter hub assembly in the first embodiment of the instant invention; 
         FIG. 4  is a cut away cross-sectional view of the catheter hub of the first embodiment of the instant invention; 
         FIG. 5  is a semi-cut away cut away cross-sectional view of the catheter hub assembly of the first embodiment of the instant invention; 
         FIG. 6  is a semi-cut away of the outer wall perspective view of the catheter hub assembly of the first embodiment; 
         FIG. 7  is a perspective semi-transparent view of the catheter hub assembly and the multiuse valve positioned therein; 
         FIG. 8  is a cross-sectional view of the instant inventive catheter hub assembly and its relationship to the multiuse valve in an unbiased position; 
         FIG. 9  is a cross-sectional view of the first embodiment of the instant inventive catheter hub assembly and the positioning of the multiuse valve relative to the actuator portion of the catheter when the valve is in a biased position; 
         FIGS. 10A and 10B  are cross-sectional views of the inventive catheter hub assembly showing the membrane of the multiuse valve in its natural closed position and its opened position, respectively; 
         FIG. 11  is a cross-sectional view of another embodiment where the actuator portion of the catheter inside the cavity of the catheter hub is flared or enlarged and is located distal to the closed membrane of the multiuse valve; 
         FIG. 12  is a cross-sectional view of the catheter hub of  FIG. 11  showing the multiuse valve being biased to its opened position by the flared catheter actuator; 
         FIGS. 13A and 13B  illustrate the positioning of the multiuse valve relative to the flared catheter actuator with the membrane in a closed position and an opened position, respectively; 
         FIGS. 14A, 14B and 14C  are respective cross-sectional views of different exemplar multiuse valves adapted to be used in the catheter hub assembly of the instant invention; 
         FIG. 15  is a cut away view of a further embodiment of the catheter hub of the instant invention; 
         FIG. 16  is a cross-sectional view showing the catheter hub of  FIG. 15  with a catheter; and 
         FIG. 17  is a cross-sectional view showing an embodiment where the proximal portion of the catheter is extended through the internal passage of the integral actuator of the catheter hub. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For the description below, the terms proximal and non-patient, and the terms distal and patient, when used to denote the direction of the inventive catheter assembly, are interchangeable. For example, the terms distal end and patient end denote the same direction, while the terms proximal end and non-patient end denote the same opposite direction. 
     With reference to  FIGS. 1-5 , a first embodiment of a catheter hub assembly  2  of the instant invention is shown to have an elongated cylindrical body  4  that has an opened proximal end  6 , a distal end  8  and an internal cavity  10  that opens to opening  4   o.  Cavity  10  has a proximal section  4   p  and a slightly larger diameter distal section  4   d  separated by a transition  4   s.  An aperture  12  extends through distal end  8 . Although not required for the embodiment, aperture  12  is shown to have a distal portion  12   a  and a proximal portion  12   b,  with portion  12   b  having a cross section greater than that of portion  12   a.  Proximal end  6  has two tabs  6   c  and  6   b  that enable the proximal end  6  to lockingly couple with a luer connector  14   c  of an external device  14 , shown in  FIG. 5  and represented by directional arrow  14  in other figures. The external device may be a fluid store device including for example a syringe, an administration set or a pump or the like. When thus coupled, the luer taper cone or simply luer taper  14   t  of the external device enters into the cavity  10  of the catheter hub into contact with the proximal end  16   b  of a multiuse valve  16  positioned in the catheter hub, as will be described in greater detail below. Luer taper  14   t  may also be referred to as the connector end of the external device. 
     A catheter  18  extends from the distal end  8  of the catheter hub. As best shown in  FIG. 3 , catheter  18  has a proximal portion  18   p  and a distal portion  18   d  having a distal tip  18   t.  As shown in  FIG. 5 , the proximal portion  18   p  of catheter  18  is extended through aperture  12  into the internal cavity  10  of catheter hub  4 . Once catheter  18  is slidably fitted through aperture  12 , a portion of proximal portion  18   p  is fixedly attached to the inner wall at distal end  8  of catheter hub  4  that defines aperture  12  by any of a number of conventional attachment methods including for example gluing, adhesive bonding, melt bonding, ultrasonic bonding or the like. Aperture  12  may be configured into two sections  12   a  and  12   b  with catheter  18  slidably form fitted through section  12   a  and adhesive provided to section  12   b  to fixedly bond catheter  18  to the catheter hub. The length of the portion of catheter  18  that extends proximally into cavity  10  is designated  18   i  in  FIG. 6 , and may be referred to as the actuator portion of the catheter, the catheter actuator or simply actuator. Actuator  18   i  may be configured to have a frusto-conical probe end  18   e  to assist in the opening of a membrane in valve  16 . The length of actuator  18   i  inside cavity  10  is dependent on the rigidity and columnar strength of at least that portion of the catheter required to act as the actuator to open the membrane or partition of valve  16 , as well as the length and cross dimension of the portion of the valve  16  that prevents fluid leak from the catheter actuator, as will be further described infra. 
     Catheter  18  may be extruded to have different materials or mixture of materials so that the rigidity and columnar strength for the actuator portion is stronger than the rest of the catheter. Catheter  18  may also be formed by injection molding with the material that forms the actuator portion having more rigidity than the material that forms the patient end of the catheter. Materials that may be used for extruding or molding catheter  18  may include polyurethane or nylon, and other conventionally known materials. Air bubbles and other non-metallic particles may also be added to the actuator portion during the extrusion or molding process to provide different columnar strengths for the different portions of the catheter. Also, the wall of the actuator portion may be formed to have a greater thickness than the wall for the patient portion of the catheter. 
     Valve  16 , which may also be referred to as a seal member, is an elongated cylindrical member made of an elastomeric material such as for example silicone or polyisoprene, or other similar materials that have the required flexibility and compressibility characteristics. One exemplar multiuse valve  16 , as shown in  FIGS. 5-7 , has a proximal portion  16   p  and a distal portion  16   d.  Valve  16  has a cross dimension that enables it to slidably fit into the cavity  10  of the catheter hub. A through passage  16   o  extends between a proximal end  16   b  and a distal end  16   e  of valve  16  to form a chamber inside valve  16 . A notch  16   n  at the outer surface of proximal portion  16   p  provides an outlet for air to escape from inside cavity  10  when the distal portion  16   d  is compressed in the catheter hub. Notch  16   n  also provides an inlet for sterilization gas to pass into distal portion of the cavity of the catheter hub to sterilize the catheter hub assembly. The inherent elasticity characteristics of the elastomer material enables the valve to compress inside cavity  10  when it encounters a biasing force along its longitudinal axis, and returns to its natural state when the biasing force is removed. It should be appreciated that distal portion  16   d  may function more as the compressible biasing member of valve  16  since it can more readily compress in response to a biasing force due to the space in cavity  10  that surrounds it, and then decompresses to return the valve to its natural state once the biasing force is removed. 
     An integral membrane or partition  16   m  of valve  16  separates proximal portion  16   p  and distal portion  16   d.  Distal end  16   e  of valve  16  is in contact with an inside distal wall  4   w  of catheter hub  4 . Distal wall  4   w  defines the distal end of the internal cavity  10  of catheter hub  4 . As best shown in  FIG. 4 , wall  4   w  encircles aperture  12 . Although wall  4   w  is shown to be flat in the exemplar embodiment, it should be appreciated that wall  4   w  has a counterpart configuration adapted to reflect the particular or given configuration of distal end  16   e  of valve  16 , so as to ensure that the maximum contact area is provided between wall  4   w  and distal end  16   e  to enable optimal compression by valve  6  under a biasing force and the return of valve  6  to its natural position when the biasing force is removed. For example, if the distal end  16   e  has a rounded configuration, then wall  4   w  would have a counterpart grooved configuration to receive distal end  16   e.  Or if the distal end  16   e  is flat, then distal wall  4   w  likewise is flat. Even though the distal portion for the exemplar valve embodiment may be considered as the biasing member, It should be appreciated that, as noted above, due to the inherent elasticity of the elastomer material, the entire valve may act as one biasing member, as will be described later with respect to the embodiment shown in  FIG. 14B . 
     As shown in  FIG. 7 , valve  16  is slidably inserted into cavity  10  of catheter hub through opening  4   o  at proximal end  6  of catheter hub  4 . Cooperating means for example cooperating groove(s) and flange(s), not shown, may be provided at the outer surface of valve  16  and the inner circumferential surface of catheter hub  4 , respectively, to maintain valve  16  inside but slidable within catheter hub  4 . 
     With reference to  FIG. 1 , in a ready to use position, a needle cannula, or simply needle  20 , extending from a needle hub or a needle insertion device or assembly  22 , is inserted into cavity  10  of catheter hub  4 , through membrane  16   m  of valve  16 , and slidably extends through lumen  18   a  of catheter  18  with its sharp tip  20   a  extending beyond the distal end  18   t  of catheter  18 . 
       FIGS. 8 and 9  are illustrations of another exemplar multiuse valve adapted to be used with the catheter assembly of the instant invention. Components that are the same as the exemplar valve described above are labeled with the same reference numbers. As shown, the distal section  16   d  of the multiuse valve  16  of the  FIGS. 8-9  embodiment has an outer circumferential surface that is a substantial continuation of the outer circumferential surface of proximal section  16   p,  while its inside surface is unevenly formed to define a chamber  16   f  that houses catheter actuator  18   i.  Distal portion  16   d  is the biasing portion of the exemplar valve  16  as it can compress inwardly into chamber  16   f.  Valve  16  shown in  FIGS. 8-9  is similar to the seal member described in the afore-noted incorporated by reference patents and publications, for example U.S. Pat. No. 8,652,104.  FIG. 8  shows valve  16  in its natural state where membrane  16   m  is proximal of probe end  16   e  of actuator  18   i.    
       FIG. 9  shows an external device, designated by arrow  14 , being coupled or connected to proximal luer end  6  of catheter hub  4 . As the external device connects to proximal end  6  with its luer lock, its luer taper  14   t  is inserted into cavity  10  of the catheter hub and its distal connector end  14   e  comes into contact with proximal end  16   b  of valve  16 . Due to its elasticity, when biased by luer taper  14   t,  valve  16 , particularly its distal portion  16   d,  compresses against distal end wall  4   w  inside catheter hub  4 , as described in greater detail in the above-noted incorporated by reference patents and publications, such as for example the disclosure with reference to  FIGS. 9, 10 and 19  in the &#39;104 patent. Further distal movement of the distal connector end  14   e  moves valve  16  in the distal direction relative to catheter hub  4  to bias membrane  16   m  against actuator  18   i,  more particularly its probe end  18   e  until the opening of probe end  18   e  is positioned in through passage  16   o,  which may also be referred to as chamber or proximal chamber  16   o,  of valve  16 . As a result, an open fluid communication passageway is established between the external fluid store device and the vein of the patient through lumen  18   a  of catheter  18 , chamber  16   o  of valve  16  and cavity  10  inside catheter hub  4 . It should be appreciated that since chamber  16   o  and cavity  10  are both inside catheter hub  4 , the term cavity may also define the internal space or cavity of the catheter hub open to proximal probe end  18   e  of actuator  18   i.  When the external device is removed from catheter hub  4  thereby removing the force biasing membrane  16   m  against actuator  18   i,  valve  6  returns to its natural state or unbiased position where membrane  16   m  is closed and is proximal of probe end  18   e,  as per shown in  FIG. 8 . To assist in the opening and closing of membrane  16   m,  as discussed above, one or more slits may be formed in membrane  16   m.    
       FIGS. 10A and 10B  illustrate the distal movement of valve  16  and shows membrane  16   m  in the closed state and the opened state, respectively. 
     With reference to  FIG. 1 , to use the catheter assembly of the instant invention, the clinician pierces into the vasculature for example a vein or a blood vessel of the patient by using the sharp tip  20   a  of needle  20 . Needle  20  is then moved to position catheter  18  that overlays needle  20  in the vein. After catheter  18  is correctly positioned, the needle is removed so that the catheter assembly is as per shown in the cross section view of  FIG. 8 . The clinician may use the number of suture tie down rings  24  at the outer surface of catheter hub  4  and tape to attach the catheter hub assembly to the skin of the patient. A fluid store device for example a syringe may then be connected to the catheter assembly by coupling the luer connector of the fluid store device to the luer end  6  of catheter hub  4 . 
     After the removal of the needle  20  from the catheter hub assembly  2  but before the coupling of the external device to catheter hub  4 , catheter assembly  2  is as per illustrated in  FIG. 8  where valve  16  is in its natural state. As shown, membrane  16   m  is closed and positioned proximal to probe end  18   e  of catheter actuator  18   i.  At this position, membrane  16   m  partitions the proximal chamber  16   o  at proximal portion  16   p  from the distal chamber  16   f  at distal portion  16   d  of valve  16 . With membrane closed, blood back flow from the patient through lumen  18   a  of catheter  18  is prevented from escaping chamber  16   f.    
       FIGS. 11 and 12  illustrate another embodiment that uses a one piece catheter as both the actuator and the patient vasculature conduit is shown. The same reference numbers in  FIGS. 1-10  used to identify the same components in the being discussed figures are repeated. As shown, the actuator  18   i ′ of the catheter  18 ′ is enlarged by a flaring device so that the flared cylindrical catheter actuator  18   i ′ has a bore  26  that tapers to meet lumen  18   a ′ via a tapered section  26   t.  By having a flared actuator, membrane  16   m,  when biased against probe end  18   e ′, has a larger opening. This may lead to more fluid flow through the catheter assembly. Also, the tapered section  26   t  is holdingly supported by the circumferential protrusion  16   h  while the flared portion  18   i ′ is holdingly supported by circular protrusion  16   g  of valve  16  to provide a more stable actuator. The operation and the function of the catheter assembly shown in  FIGS. 11 and 12  are the same as discussed above for the embodiment shown in  FIGS. 1-10 .  FIGS. 13A-13B  show the movement of the valve relative to the catheter hub when the membrane is not biased against the flared actuator and is in its unbiased closed position and when the membrane is biased against the flared actuator and is in its opened position. 
     With reference to  FIGS. 14A-14C , three embodiments of the multiuse valve adapted to be used with the actuator in the catheter hub are shown. The different multiuse valves are shown to be in their unbiased position. Components that are the same as those described in the earlier figures are labeled with the same reference numbers. The multiuse valve  16  shown in  FIG. 14A  is the same valve that is described in the incorporated by reference &#39;104 patent. Cavity  28  in the distal portion  16   d  of valve  16  enables distal portion  16   d  to be readily compressed against distal end wall  4   w  when valve  16  is biased in the distal direction relative to the catheter hub  4 . The circumferential protrusion  16   h  provides support for catheter actuator  18   i.    
       FIG. 14B  shows a multiuse valve  16 ′ that has a distal portion  16   d ′ formed with a substantially solid elastomeric portion  30  in support of actuator  18   i.  For the embodiment, the elastomeric material that forms portion  30  may be a material that has more elasticity or flexibility such as for example Elastosil that allows portion  30  to be compressed more readily. For the  FIG. 14B  embodiment, even though shown to have the same length as the catheter actuators in  FIGS. 14A and 14B , the length of the catheter actuator  18   i  inside the catheter hub may be varied (shortened or lengthened) as discussed above and the length of distal portion  30  of the valve may also be varied to balance its elasticity against the distance to end wall  4   w  that is needed for the membrane of the valve to be opened by actuator  18   i  under a biasing force. Further, the proximal portion  16   p ′ of the valve may be strengthened with additives, or enforced or replaced for example by a cylindrical ring having a higher shore hardness than the elastomeric material that the valve is made from. 
       FIG. 14C  shows a multiuse valve  16 ″ that was shown in  FIGS. 5-7 . Valve  16 ″ has a distal portion  16   d ″ that tapers from the distal end of the proximal portion  16   p ″ so that distal portion  16   d ″ has a smaller diameter than the diameter of proximal portion  16   p ″. Accordingly, there is a circumferential space  32  surrounding the elongated cylinder  34  of the distal portion  16   d ″ of the valve. In this embodiment, cylindrical cylinder  34  provides support for the entire length of the catheter actuator  18   i  and space  32  provides the room for cylinder  34  to be folded or compressed when the valve is moved distally by a biasing force. 
     Another embodiment of the inventive catheter hub is illustrated in  FIGS. 15-17 . As shown, catheter hub  36  has an elongated cylindrical body and a distal end  40  that tapers from body  38  and a proximal end  39  that is configured to accept a luer connector from an external device as per discussion above. Similar to the earlier discussed embodiments, catheter hub  36  has a proximal end  42  that opens to an internal cavity  44  that has a smaller diameter proximal section  46  and a larger diameter distal section  48  connected by a tapered transition  50 . Instead of utilizing the proximal portion of the catheter to be the actuator, an actuator  52  of this embodiment extends integrally from the inside distal end wall  54  of the catheter hub. In other words, actuator  52  is an integral component of the one piece catheter hub  36  that may be formed from the same mold. As shown, actuator  52  is a cylindrical extension that has a frusto-conical probe end  56  and a passage  58  in alignment with aperture  60  at distal end  40  of catheter hub  36 . Passage  58  and aperture  60  together form a through passageway from distal end  62  to internal cavity  10 . Although shown not to have the multiuse valve, it should be appreciated that the multiuse valve  16  described in the earlier embodiments may be provided in cavity  44  of catheter hub  36  and be utilized in the same manner, i.e., a distal force, designated by arrow  14 , moves the valve in the distal direction relative to the catheter hub so that the membrane  16   m  of the valve is biased against probe end  56  of actuator  52  to its opened position; and when the external distal force is removed, the valve would return to its natural state so that its membrane is proximal to the actuator  52  in its closed position to prevent blood leak. By having an integral actuator, there is no need for the type of support that may be needed for a catheter actuator as described in the earlier embodiment. Manufacturing cost may also be reduced due to the reduction in the manufacturing steps as the actuator and the catheter hub are molded as a one piece component. 
       FIG. 16  shows a catheter  18  slidably fitted into aperture  60 . A step  64  that joins aperture  60  and passage  58  acts as a stop to the proximal end of the catheter. The portion of catheter  18  in aperture  60  is fixedly attached to the inside circumferential surface of the aperture by any of the conventional bonding methods described previously. With the catheter attached to the catheter hub  36 , a fluid communication path is established from the distal end of the catheter to cavity  44  and to the external fluid store coupled to the proximal end of the catheter hub. 
       FIG. 17  is an illustration of an embodiment in which a through aperture  66  extends from distal end  62  of the catheter hub  36  to probe end  56  of actuator  52 . A proximal portion of catheter  18  is slidably form fitted into aperture  60 ′ to probe end  56  of actuator  52 . The catheter may be bondedly attached to aperture  66  as described above, or pressure fitted into aperture  66 . By extending the catheter through to probe end  56  of actuator  52 , a continuous lumen of the same diameter is provided. 
     The invention disclosed above is subject to many variations, modifications and changes in detail. Thus, it is intended that all matters described throughout this specification and shown in the accompanying drawings be interpreted as illustrative only and not in a limiting sense. Accordingly, it is intended that the invention be limited only by the spirit and scope of the hereto attached claims.