Abstract:
A medical device includes a vascular access device with an access port having a septum and a slit. The slit is formed on the inner surface of the body of the septum where the access port receives an access device that is separate from the vascular access device through the slit of the septum. A pivoting member in communication with the access port pivots when the port is accessed by an access device. The medical device may be used to control the volume displacement of a chamber within the medical device by decreasing the volume of the chamber by inserting a substance having a mass into the chamber, pivoting a structure associated with the chamber, and increasing the volume of the chamber simultaneously and commensurately with the mass of the substance inserted into the chamber.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/820,639, filed Jul. 28, 2006, entitled VASCULAR ACCESS DEVICE VOLUME DISPLACEMENT, which is incorporated herein by reference. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    The present disclosure relates to the displacement of volume in medical devices such as vascular access devices to provide infusion or other therapy to patients. Infusion therapy is one of the most common health care procedures. Hospitalized, home care, and other patients receive fluids, pharmaceuticals, and blood products via a vascular access device inserted into the vascular system. Infusion therapy may be used to treat an infection, provide anesthesia or analgesia, provide nutritional support, treat cancerous growths, maintain blood pressure and heart rhythm, or many other clinically significant uses. 
         [0003]    Infusion therapy is facilitated by vascular access devices located outside the vascular system of a patient (extravascular devices). Extravascular devices that may access a patient&#39;s peripheral or central vasculature, either directly or indirectly, include closed access devices, such as the BD Q-SYTET™ closed Luer access device of Becton, Dickinson and Company; syringes; split access devices; catheters; and intravenous (IV) fluid chambers. A vascular access device may be indwelling for short term (days), moderate term (weeks), or long term (months to years). A vascular access device may be used for continuous infusion therapy or for intermittent therapy. 
         [0004]    A common vascular access device is a plastic catheter that is inserted into a patient&#39;s vein. The catheter length may vary from a few centimeters for peripheral access to many centimeters for central access. The catheter may be inserted transcutaneously or may be surgically implanted beneath the patient&#39;s skin. The catheter, or any other extravascular device attached thereto, may have a single lumen or multiple lumens for infusion of many fluids simultaneously. 
         [0005]    The proximal end of a vascular access device commonly includes a Luer adapter to which other medical devices may be attached. For example, an administration set may be attached to a vascular access device at one end and an IV bag at the other. The administration set is a fluid conduit for the continuous infusion of fluids and pharmaceuticals. Commonly, an TV access device is a vascular access device that may be attached to another vascular access device, closes or seals the vascular access device, and allows for intermittent infusion or injection of fluids and pharmaceuticals. An IV access device may comprise a housing and a septum for closing the system. The septum may be opened with a blunt cannula or a male Luer of a medical device. 
         [0006]    Complications associated with infusion therapy may cause significant morbidity and even mortality. One significant complication is catheter related blood stream infection (CRBSI). An estimate of 250,000-400,000 cases of central venous catheter (CVC) associated BSIs occur annually in US hospitals. Attributable mortality is an estimated 12%-25% for each infection and a cost to the health care system of $25,000-$56,000 per episode. 
         [0007]    Vascular access device infection resulting in CRBSIs may be caused by pathogens entering the fluid flow path from refluxed or displaced blood subsequent to catheter insertion. Studies have shown the risk of CRBSI increases with catheter indwelling periods. This may be due, at least in part, to the reflux or displacement of blood from the vascular system of a patient to an extravascular device, such as the catheter. When contaminated, pathogens adhere to the vascular access device, colonize, and form a biofilm. The biofilm is resistant to most biocidal agents and provides a replenishing source for pathogens to enter a patient&#39;s bloodstream and cause a BSI. 
         [0008]    Certain extravascular devices can operate with each other to form a continuous, extravascular system that provides fluid access to the vascular system, yet is entirely sealed from the external surrounding environment. Such a sealed system limits or supposedly prevents unwanted bacteria from entering from the external surrounding environment through the extravascular devices to the vascular system of a patient. 
         [0009]    However, a sealed system of extravascular devices (extravascular system) may function as a closed or sealed vacuum, capable of drawing blood, and consequently a culture for infection, into the extravascular system. As devices are twisted off or otherwise removed from the extravascular system, the volume of the extravascular system is sometimes slightly increased. Because extravascular systems are often less elastic than a patient&#39;s vascular system, when the volume of the extravascular system is increased, the volume of a patient&#39;s vascular system is decreased under a vacuum pressure from the extravascular system. When the volume of the vascular system decreases, blood flows or is sucked from the vascular system to the extravascular system. Further, as pressure in the extravascular system decreases below the vascular pressure of a patient, either as a result of a change in volume in the extravascular system or another event, blood will flow from the vascular system to the extravascular system. 
         [0010]    As recognized in conjunction with the present invention, even a temporary presence of blood within an extravascular system can cause future operational challenges for that extravascular system. For example, blood that clots in the end of a catheter of an extravascular system can block future fluid flow between the extravascular system and a vascular system. If drugs and other fluid substances are forced through the extravascular system causing the blood clot to dislodge from the extravascular system, the blood clot will enter the vascular system causing a dangerous embolism within the patient. Finally, as discussed above, even the rapid entry and exit of blood into the catheter tip of an extravascular system will leave a residue of protein, bacteria, and other pathogens on the inner wall of the catheter. This residue may become a breeding ground for bacteria to grow, and after a given period of time, will cause the formation of a harmful biofilm that is difficult to remove or bypass during extravascular system operation. 
         [0011]    Therefore, a need exists for systems and methods that avoid or limit the reflux or displacement of blood from a patient&#39;s vascular system into an extravascular system that is connected to the patient&#39;s vascular system. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The present invention has been developed in response to problems and needs in the art that have not yet been fully resolved by currently available extravascular systems, devices, and methods. Thus, these developed systems, devices, and methods provide an extravascular system that may be connected to a patient&#39;s vascular system and will limit or prevent the flow, reflux, or displacement of blood from the vascular system to the extravascular system. 
         [0013]    A medical device may include a vascular access device with an access port having a septum and a slit. The slit is formed on the inner surface of the body of the septum. The access port may receive an access device that is separate from the vascular access device through the slit of the septum. A pivoting member in communication with the access port pivots when the port is accessed by an access device. 
         [0014]    The pivoting member may be one of the following types of devices: a T-bone shaped rigid structure, a T-bone shaped rigid structure on the outer surface of the septum, an L-shaped rigid structure, a gate held under the tension of a torsion spring, a rib, a wedge, a split wedge, a four-bar mechanism, a semi-rigid or rigid buckling member, a rigid member displaced by a disturbed air pressure chamber, a rigid member displaced by a disturbed pressure sensitive chemical, and/or a spring finger. The pivoting member may articulate upon a bistable spring, a torsion spring, or other spring or tension creating member. The pivoting member may form a curved or other structure. 
         [0015]    A method of employing the medical device may be used to control the volume displacement within a chamber of the medical device. The method may include decreasing the volume of a chamber of an extravascular system by inserting a substance having a mass into the chamber, pivoting a structure within the extravascular system, and increasing the volume of the chamber simultaneously and commensurately with the mass of the substance inserted into the chamber. The substance may be either a fluid or a mechanical structure of a medical device, such as the tip of a syringe. 
         [0016]    These and other features and advantages of the present invention may be incorporated into certain embodiments of the invention and will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. The present invention does not require that all the advantageous features and all the advantages described herein be incorporated into every embodiment of the invention. 
     
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0017]    In order that the manner in which the above-recited and other features and advantages of the invention are obtained will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only typical embodiments of the invention and are not therefore to be considered to limit the scope of the invention. 
           [0018]      FIG. 1  is a perspective view of an extravascular system connected to the vascular system of a patient. 
           [0019]      FIG. 2  is a cross section view of a vascular access device with pivoting T-bone members. 
           [0020]      FIG. 3  is a cross section view of the vascular access device of  FIG. 2  taken along lines  3 - 3   
           [0021]      FIG. 4  is a cross section view of the vascular access device of  FIG. 2  shown with the tip of a separate device inserted. 
           [0022]      FIG. 5  is a cross section view of the vascular access device of  FIG. 4  taken along lines  5 - 5 . 
           [0023]      FIG. 6  is a cross section view of a vascular access device having an alternative embodiment of a pivoting member. 
           [0024]      FIG. 7  is a cross section view of a vascular access device having a further embodiment of a pivoting member. 
           [0025]      FIG. 8  is a partial cross section view of a vascular access device with an external pivoting member. 
           [0026]      FIG. 9  is a cross section view of a vascular access device with a bistable spring pivoting member 
           [0027]      FIG. 10  is a partial cross section view of the vascular access device of  FIG. 9  with the bistable spring pivoting member actuated in an open position. 
           [0028]      FIG. 11  is a partial cross section view of a vascular access device with a rigid pivoting member. 
           [0029]      FIG. 12  is a partial cross section view of the vascular access device of  FIG. 11  with the tip of a separate device inserted. 
           [0030]      FIG. 13  is a partial cross section view of a vascular access device with a rigid pivoting member. 
           [0031]      FIG. 14  is a partial cross section view of the vascular access device of  FIG. 13  with the tip of a separate device inserted. 
           [0032]      FIG. 15  is a partial cross section view of a vascular access device and closed spring loaded valve. 
           [0033]      FIG. 16  is a partial cross section view of the vascular access device of  FIG. 15  with the spring loaded valve open. 
           [0034]      FIG. 17  is a partial cross section view of a vascular access device with a spring loaded valve. 
           [0035]      FIG. 18  is a partial cross section view of a vascular access device having a rigid member. 
           [0036]      FIG. 19  is a partial cross section view of the vascular access device of  FIG. 18  with the tip of a separate device inserted. 
           [0037]      FIG. 20  is a partial cross section view of a vascular access device and a rotational clip. 
           [0038]      FIG. 20A  is a partial cross section view of the vascular access device illustrated in  FIG. 20  with a separate device inserted. 
           [0039]      FIG. 21  is a perspective view of a vascular access device. 
           [0040]      FIG. 22  is a perspective view of a vascular access device including the septum with a reservoir. 
           [0041]      FIG. 23  is a perspective view an annular member with spring fingers. 
           [0042]      FIG. 24  is a cross section view of a vascular access device with a collapsed reservoir. 
           [0043]      FIG. 25  is a cross section view of the vascular access device of  FIG. 24  showing the reservoir full. 
           [0044]      FIG. 26  is a partial cross section view of a vascular access device with a split wedge. 
           [0045]      FIG. 27  is a partial cross section view of the vascular access device of  FIG. 26  with the split wedge in open position. 
           [0046]      FIG. 28  is a partial cross section view of a vascular access device with two curved pivoting members. 
           [0047]      FIG. 29  is a partial cross section view of the vascular access device of  FIG. 28  the tip of a separate device inserted. 
           [0048]      FIG. 30  is a partial cross section view of a vascular access device with a four-bar mechanism. 
           [0049]      FIG. 31  is a partial cross section view of the vascular access device of  FIG. 30  with the tip of a separate device inserted. 
           [0050]      FIG. 32  is a cross section view of a vascular access device with a rigid member. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0051]    The presently preferred embodiments of the present invention will be best understood by reference to the drawings, wherein like reference numbers indicate identical or functionally similar elements. It will be readily understood that the components of the present invention, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description, as represented in the figures, is not intended to limit the scope of the invention as claimed, but is merely representative of presently preferred embodiments of the invention. 
         [0052]    Referring now to  FIG. 1 , a vascular access device (also referred to as an extravascular device, intravenous access device, and/or access port)  10  is used to introduce a substance via a catheter  12  across the skin  14  and into a blood vessel  16  of a patient  18 . The vascular access device  10  includes a body  20  with a lumen and a septum  22  placed within the lumen. The septum  22  has a slit  24  through which a separate extravascular device  26 , such as a syringe, may introduce a substance into the vascular access device  10 . 
         [0053]    The device  10  also includes a member (discussed with reference to the figures below) capable of creating a volume within the vascular access device  10  and/or the extravascular system  28  to which the vascular access device  10  is connected. The member capable of creating this volume creates the volume when a tip  30  of the separate device  26  is inserted into the vascular access device  10  through the slit  24  of the septum  22 . Normally, when the tip  30  is inserted into the device  10 , the volume of the extravascular system  28  is decreased, causing fluid to flow from the system  28  into the blood vessel  16 . Conversely, under normal conditions, when the tip  30  is removed from the device  10 , the volume of the extravascular system  28  is increased, causing blood to flow from the blood vessel  16  into the system  28  by entering through the end  32  of the catheter  12 . 
         [0054]    As mentioned throughout this description, even a temporary presence of blood within an extravascular system  28  can cause future operational challenges for that extravascular system  28 . These problems may include blood clots, fluid flow barriers, embolisms, and the production of harmful biofilm. Thus, the devices disclosed herein are provided to avoid reflux or drawback of blood from the blood vessel  16  into the catheter  12 . The devices may include a member capable of creating a volume when the separate device  26  is inserted into the vascular access device  10  and will permit the created volume to decrease to its original size. When the volume decreases to its original size, the decrease in volume will offset any volume displaced such that upon removal of the separate access device  26 . The volume offset will either result in no net displacement of fluid between the system  28  and the vessel  16  or will result in fluid being forced distally from the vascular access device  10  or other medical device toward the vascular system of a patient. This further avoids creation of a vacuum or a pressure differential between the system  28  and the vessel  16  that would cause blood to flow or be sucked from the blood vessel  16  into the catheter  12 . 
         [0055]    Referring now to  FIG. 2 , a vascular access device  10  includes at least one rigid, pivoting member  34  within the wall of the septum  22 . The pivoting member  34  is rigid in relation to the materials of its surrounding environment. In this embodiment, the septum  22  is formed of silastic or other pliable, elastic material. Thus, the pivoting member  34  may be formed of hardened rubber, plastic, metal, alloy, or other relatively rigid material. The pivoting member  34  is shaped as a T-bone structure with a first end  36  of the top of the “IT” extending towards the slit  24  of the septum. A second end  38  of the top of the “T” extends towards the edge of the body  20  of the vascular access device  10 . The base  40  of the “T” extends into a separation of an outer chamber  42  and an interior chamber  44  of the device  10 . 
         [0056]      FIG. 3  is a cross-section view of the vascular access device  10  of  FIG. 2  taken along lines  3 - 3 . Device  10  includes the base  40  of the “T” of the pivoting member  34  embedded within a silastic material. This silastic material is an extension of the septum  22  and has been manufactured, extruded, molded, heat-treated, or otherwise formed to include at least one fold  46  along its cross section. The fold  46  remains until a separate device  26  is placed within the slit  24  of the septum  22  causing the rigid member  34  to open. When the rigid member  34  opens, the base members  40  move from a first resting position shown in  FIG. 3  to a second opened position to be shown in  FIG. 5 . When the base members  40  are moved from a first resting position to a second opened position, the at least one fold  46  straightens causing the volume of the outer chamber  42  to decrease and the volume of the interior chamber  44  to increase. 
         [0057]    Referring now to  FIG. 4 , a vascular access device  10  of  FIG. 2  is shown with the tip  30  of the separate device  26  inserted within the septum  22 . As the tip  30  is inserted into the septum, the walls of the septum begin to move downward and outward in a direction  48 . As the walls of the septum  22  are moved in a direction  48  under the influence of the tip  30 , rigid members  34  pivot outward causing the first ends  36  to move downward and the base members  40  to move outward towards the body  20  of the vascular access device  10 . 
         [0058]    The first ends  36  move downward, away from the direction of the advancing tip  30  as the second ends  38  pivot against a fulcrum  50  placed within the body  20  of the vascular access device  10 . As the base members  40  are moved outwards towards the body  20  of the device  10 , the volume of the outer chamber  42  decreases while the volume of the interior chamber  44  increases. At least one channel  52  may need to be placed within the body  20  of the vascular access device  10  in order to permit the air within the outer chamber  42  to escape the outer chamber  42  when the base members  40  are moved into the space of the outer chamber  42 . The at least one channel  52  will permit the volume of the outer chamber  42  to decrease without any pressure buildup that would require an increase in insertion force during tip  30  insertion. 
         [0059]      FIG. 5  is a cross-section taken along lines  5 - 5  of  FIG. 4 . The vascular access device  10  includes the base member  40  extended towards the body  20  of the vascular access device  10 . With the base members  40  extended, the silastic material no longer includes at least one fold  46 . Rather the folds  46 , as show in  FIG. 3 , have been extended to form a straight section of the silastic member such that the volume of the outer chamber  42  has been decreased and the volume of the interior chamber  44  has been increased. 
         [0060]    When the tip  30  of a separate device  26  is removed from the slit  24  of the septum  22 , the rigid member  34  closes under the force of the formed silastic material that is an extension of the septum  22 . As mentioned earlier with reference to  FIG. 3 , the silastic material has been manufactured or otherwise formed to include at least one fold ( FIG. 3 ) along its cross-section. These folds  46  exist when the silastic material is in its resting position. Thus, when the silastic material is stretched as shown in  FIG. 5 , once the tip  30  of the separate device  26  is removed, the natural force of the formed silastic material will cause the silastic material to return to its original position as shown in  FIG. 3 . When the formed silastic material returns to its original position, the base members  40  will likewise return to its original position causing the volume of the outer chamber  42  to increase while the volume of the interior chamber  44  decreases. This decrease of volume within the interior chamber  44  will result in either no net volume displacement within the interior chamber  44  or will result in a volume that is displaced from the interior chamber  44  downstream through the extravascular system  28  and into the vascular system of a patient. 
         [0061]    Referring now to  FIG. 6 , a vascular access device  210  includes at least one rigid, pivoting member  234  within the wall of the septum  222 . The pivoting member  234  is rigid in relation to the materials of its surrounding environment. As with embodiments previously discussed, the septum  222  is formed of silastic or other pliable, elastic material. Thus, the pivoting member  234  may be formed of hardened rubber, plastic, metal, alloy, or other relatively rigid material. The L-shaped member may be encased in the silastic as illustrated in  FIG. 6 , or may be bonded or attached to the silastic by means well known to those of skill in the art. 
         [0062]    In this embodiment, the pivoting member  234  is shaped as an L-shaped structure with a first end  236  of the top of the “L” extending towards the slit  224  of the septum. The base  240  of the “L” extends downwardly along the channel through the septum  210 . Thus, when a separate extravascular device  26  is inserted into the septum, the rigid L-shaped pivoting member  234  causes the channel  238  through the septum to increase in volume. When the extravascular device  26  is removed and the channel  238  returns to its original configuration, the volume within the channel  238  is reduce, thus preventing blood or other fluid from being drawn up into the extravascular system  28 . 
         [0063]      FIG. 7  illustrates an alternative embodiment of the device in which the L-shape pivoting member  234  is replaced by a rigid wedge member  250 . Wedge member  250  can be made of rigid plastic or other similar materials. Once again, wedge member  250  provides sufficient rigidity to cause the channel  230  to expand in volume as a separate extravascular device  26  is inserted into the device  210 . Thus, when the extravascular device  26  is removed, the volume decreases to its original state, preventing blood or other fluids from being drawn into the extravascular system  28 . 
         [0064]    Referring now to  FIG. 8 , a partial cross-section view of a vascular access device  10  shows a rigid, folding member  54  located on the external surface of a silastic septum  56 . The silastic septum  56  includes a knob  58  on its exterior surface to which the pivoting member  54  is attached. The pivoting member  54  also includes an elbow  60  housed within a fulcrum  62  of the body  20  of the vascular access device  10 . The elbow  60  houses a flap  64  that extends from the body  20  of the septum  56 . In use, when a separate device  26  is placed within the slit  24  of the septum  56 , the body  20  of the septum  56  is biased downward and outward in a direction  48 , causing the knob  58  and/or any portion of the entire structure of the pivoting member  54  to bias downward and outward in the direction  48 . As the pivoting member  54  pivots in the direction  48 , the volume of the interior chamber  44  is increased while the volume of the outer chamber is decreased. 
         [0065]    Referring now to  FIG. 9 , a vascular access device  10  includes a rigid, pivoting member  66  embedded within the material of a silastic septum  22 . The pivoting member  66  includes a bistable spring  68  along the top of the “T” of the pivoting member  66 . 
         [0066]      FIG. 10  is a partial cross section view of the device  10  of  FIG. 9 . As illustrated in  FIG. 10 , the bistable spring  68  of the pivoting member  66  is a beam that snaps open after a predetermined amount of pressure has been applied to the bistable spring  68 . In use, as the tip  30  of a separate device  26  is advanced through the slit  24  of the septum  22 , the septum  22  begins to open in an outward direction causing pressure to build upon the bistable spring  68 . After a given amount of pressure has been placed on the bistable spring  68 , the beam of the bistable spring  68  will snap open causing the pivoting member  66  to pivot upon a fulcrum  70  of the body  20 , which in turn causes the base  72  of the pivoting member  66  to move downward and outward in a direction  48 . When the base member  72  of the pivoting member  66  moves toward the body  20 , the volume of the interior chamber  44  is increased and the volume of the outer chamber  42  is decreased. 
         [0067]    A bistable spring may be used with any of the above illustrated embodiments or with any of a number of the following embodiments described throughout this detailed description. The properties of the bistable spring may preferably be employed when a rapid increase in volume within an interior chamber is desired when a separate device  26  is introduced into the vascular access device  10 . Similarly, the properties of the bistable spring may also preferably be employed when a rapid decrease in volume of an interior chamber is desired upon retraction and/or removal of a separate device  26  from the vascular access device  10 . 
         [0068]    In some embodiments, a gradual increase in volume of an interior chamber may be desired as a separate device is gradually inserted into the slit of the septum of the device. In these embodiments, as the separate device is gradually inserted, the opening of the septum decreases the volume of the interior chamber, while the opening of a rigid member simultaneously increases the volume of the interior chamber, offsetting the decrease of volume caused by the insertion of the separate device. In this manner, during the initial entry of the separate device into the septum, all the way through full engagement and full removal of the separate device from the septum, there will be no net change in volume of the interior chamber. Thus, with no net change in volume of the interior chamber during use of the vascular access device, any potential displacement of fluid into and out of a patient&#39;s vascular system is avoided. 
         [0069]    Referring now to  FIG. 11 , a vascular access device  10  includes at least one rigid member  74  in the shape of a wedge placed below the slit  24  of a septum  22  when the device  10  is in a resting state. 
         [0070]    Referring now to  FIG. 12 , when the tip  30  of a separate device  26  is inserted into the septum  22 , the rigid members  74  are biased downward and outward in a direction  48  causing an increase in volume within an interior chamber  44 . The increased volume of interior chamber  44  is illustrated as volume  76 . The rigid members  74  may be embedded, or surrounded, by an elastic material, such as silastic. The silastic may be attached at an elbow  78  of the silastic to a fulcrum  80  of the body  20  of the vascular access device  10 . A lower portion  82  of the elastic material will stretch to enable the rigid member  74  to create the additional volume  76  when the tip  30  is inserted into the septum  22 . 
         [0071]    Referring now to  FIG. 13 , a vascular access device  10  includes a rigid member  84  such as a rigid rib having a structure that is continuous with a silastic or other elastic septum  22  and an elastomer  86 . The elastomer  86  is attached to the base of the rib  84  while the septum  22  is attached to the head of the rib  84 . The rib or rigid member  84  may also be embedded or otherwise attached to a continuous elastomer as illustrated throughout the embodiments of this detailed description. As mentioned earlier, one end of the elastomer  86  is attached to the rib  84 , while the other end of the elastomer is fixed at a point  88  within the vascular access device  10 . Because the elastomer  86  is fixed at a point  88  and attached to the base of the rib  84 , when the rib  84  pivots, causing the elastomer  86  to stretch, the elastomer  86  will not be dislodged from its fixed point  88 . 
         [0072]    Referring now to  FIG. 14 , the vascular access device  10  of  FIG. 13  shows the tip  30  of an external device  26  inserted within the septum  22 . As the tip  30  advances through the septum  22 , the rigid members  84  pivot upon an elbow  90  that communicates with a fulcrum  92  of the body  20  of the vascular access device  10 . When the rigid members  84  pivot, the base of the rigid members  84  moves in an outward direction  94  stretching the elastomer  86  and creating an increased amount of volume  96  within the interior chamber  44 . When the tip  30  of the external device  26  is removed from the septum  22 , the pivoting members  84  return to their original resting position as shown in  FIG. 13 , causing the elastomers  86  to return to their original position and the volume gained  96  to be decreased to an original volume of the interior chamber  44 . A similar decrease in volume occurs with reference to  FIGS. 11 and 12  when the tip  30  is removed from the device  10  of that particular embodiment. 
         [0073]    Referring now to  FIG. 15 , a vascular access device  10  includes a septum  98  that is sealed by a rigid, pivoting member  100  which pivots on a torsion type spring  102 . The tension of the spring  102  biases the pivoting member  100  in a clockwise direction  104 . In its resting state, the pivoting member  100  seals the septum  98  in a closed position. 
         [0074]    Referring now to  FIG. 16 , the vascular access device  10  of  FIG. 15  is shown with the tip  30  of a separate device  26  inserted into the septum  98 . The tip  30  is shown discharging a fluid  106  towards the pivoting member  100 . The force of the fluid  106  and/or the force of the mechanical insertion of the tip  30  against a lower wing  108  of the pivoting member  100  causes the pivoting member  100  to rotate in a counter clockwise direction against the tension of the torsion spring  102 . When the pivoting member  100  rotates counter clockwise, the lower wing  108  extends into the interior chamber  44  and the upper wing  110  of the pivoting member  100  retracts into a cavity within the wall of the septum  98  to create an increased volume  112 . After the fluid  106  has been fully discharged into the interior chamber  44  and the rate of flow has decreased and/or after the tip  30  is removed, the tension of the torsion spring  102  will cause the pivoting member  100  to rotate again clockwise to a position that seals the septum  98  as shown in  FIG. 15 . Once sealed, the pivoting member  100  prevents any backflow of fluid  106  into the septum chamber where the tip  30  is inserted. 
         [0075]    Referring now to  FIG. 17 , a vascular access device  10  includes a septum  112  and a pivoting member  114  placed under tension of a torsion spring  116 . When fluid is infused and/or the tip  30  of a separate device  26  is inserted into the septum  112 , the pivoting member  114  rotates counter clockwise against the clockwise tension of the torsion spring  116 . When the pivoting member  114  rotates counter clockwise, a lower wing  118  moves into an interior chamber  44  to decrease the volume of the interior chamber  44 . Simultaneously, an upper wing  120  is retracted from the interior chamber  44  into a recess of the septum  112  to create a larger volume  122  within the interior chamber  44 . 
         [0076]    Thus, the vascular access device  10  of  FIG. 17  is an alternate embodiment to the vascular access device of  FIGS. 15 and 16  which creates more volume than the volume that is used or depleted when the tip  30  accesses the device  10 . The increased volume  122  is possible because the upper wing  120  is longer than the lower wing  118 , and when the pivoting member  114  rotates counter clockwise a greater amount of volume is created than the amount of volume that is depleted. 
         [0077]    The embodiments shown in  FIGS. 15 through 17  thus reveal a pivoting member that creates a larger volume within an interior chamber  44  when the pivoting member is activated by the insertion of the tip  30  of a separate, external device  26 . Preferably, the length of the various wings and the tension placed on the torsion spring of the pivoting member of the embodiments of  FIG. 15 through 17 , may be adjusted to ultimately produce a mechanically activated valve that avoids any reflux or displacement of fluid. In this manner, the tip  30  of a separate device  26  may be inserted into the vascular access device  10 , fluid may be discharged, and a patient may be treated without the operation of the extravascular system ever resulting in fluid traveling upstream, i.e., from a patient&#39;s vascular system to a catheter of the extravascular system. 
         [0078]    Referring now to  FIG. 18 , a vascular access device  10  includes an elastomeric septum  124  with a rigid spring and pivoting member  126  embedded in the base  128  of the septum  124 . The base  128  of the septum  124  rests upon a fulcrum or pivot point  130 . The device  10  also includes a channel  132  located between the pivot point and the body  20  of the device  10 . 
         [0079]    Referring now to  FIG. 19 , the vascular access device  10  of  FIG. 18  is shown with the tip  30  of a separate device  26  inserted into the septum  124 . With the tip  30  fully inserted into the septum  124 , the rigid spring member  126  is forced to bend or otherwise buckle in order to create a cavity  134  in which fluid is stored. The fluid enters the created cavity  134  through the flow channel  132  as the rigid spring member  126  is bent in an upward arched shape. As the tip  30  is removed from the septum  124 , the pressure placed on the spring member  126  is removed causing the spring member  126  to return to its original position as shown in  FIG. 18 . When the spring member  126  returns to its original position, the cavity  134  disappears as the fluid that was once stored within the cavity  134  travels through the flow channel  132  and into the interior chamber  44 . 
         [0080]    Thus, the embodiment described with reference to  FIGS. 18 and 19  includes a spring member which gradually increases the overall volume of the interior chamber  44  as a tip  30  of a separate device  26  is inserted into the septum  124  of a vascular access device  10 . The spring member  126  may, in other embodiments, take any form, shape, or size. For example, in one embodiment, the spring member may be a bistable spring as mentioned earlier. When actuated by a Luer or other tip  30  of an external or separate device  26 , a bistable spring member will rapidly change shape, or otherwise buckle, in order to create or increase the overall volume of the interior chamber  44 . Subsequently, when the tip  30  of a device  10  is removed, the bistable spring will rapidly resume its posture to its original position, causing the chamber beneath it to collapse and the overall volume of the interior chamber  44  to decrease. 
         [0081]    Referring now to  FIG. 20 , a septum  136  of a vascular access device  10  includes a knob  138  attached to a metal clip  140  that rotates or otherwise pivots upon a pin  142 .  FIG. 20  shows a vascular access device  10  that is not yet engaged or is disengaged with a separate device  26 .  FIG. 20A  shows the vascular access device  10  as engaged with a separate device  26 . In  FIG. 20A  the tip  30  of the separate device  26  is fully inserted into the septum  136  causing the metal clip  140  to rotate in a counter clockwise direction  144  around the pin  142 . The counter clockwise rotation of the metal clip  140  causes the metal clip  140  to raise the knob  138 , thus creating an increased volume  146  within an interior chamber  44 . When the separate device  26  is later removed, the metal clip  140  which is placed on a pre-loaded spring, restores the base, or diaphragm,  148  of the septum  136  to its original position. When the base  148  is returned to its original position, the internal fluid volume of the interior chamber  44  is decreased, causing fluid to flow from the extravascular system (to which the device  10  and separate device  26  are attached) to the vascular system of a patient. 
         [0082]    Referring now collectively to  FIGS. 21 through 23 , a vascular access device  10  includes a septum  150  with a slit  152  and at least one clearance slot  154  through which at least one spring finger  156  may articulate. The septum  150  includes a reservoir  158  at its base. An annular structure  160  may include at least one spring finger  156 . The annular structure  160  includes a lumen through which the septum  150  may be placed. 
         [0083]    Referring now to  FIG. 24 , a cross-section of the vascular access device  10  of  FIG. 21  is shown engaged with the septum  150  of  FIG. 22  and the annular member  160  of  FIG. 23 . The combination of the body  20  of the vascular access device  10 , the septum  150 , and the annular member  160  is shown in resting position, prior to access by the tip  30  of a separate device  26 . In its resting state, the spring fingers  156  of the annular member  160  force the septum  150  closed, which in turn causes the reservoir  158  to be compressed. When the reservoir  158  is compressed, an interior chamber  44  has a relatively smaller internal volume. 
         [0084]    Referring now to  FIG. 25 , the vascular access device  10  of  FIG. 24  is shown fully engaged with the separate device  26  such that the tip  30  is fully inserted into the septum  150 . Upon full insertion, the tip  30  causes the spring fingers  156  to separate outwards through the clearance slots  154  which are shown in  FIG. 21 . With the spring fingers  156  extending outwards through the clearance slots  154 , the base or bottom of the septum  150  has more room to expand just above the reservoir  158 . When the base of the septum  150  expands just above the reservoir  158 , the reservoir also expands causing an increased amount of volume within the interior chamber  44 . Subsequently, when the tip  30  is removed from the device  10 , the spring fingers  156  will move inwardly from the clearance slots  154  towards the septum  150 , causing the septum  150  to close the body of the septum  150  to compress upon the reservoir  158  and the reservoir to collapse to its original starting position as shown in  FIG. 24 . This action of moving the reservoir  158  from a decompressed to a compressed state will cause the internal volume of the interior chamber  44  to decrease, which in turn causes fluid to flow from the interior chamber  44  through the extravascular system and into the vascular system of a patient. This flow of fluid will prevent any unwanted reflux of blood or other fluid from a patient&#39;s vascular system into the extravascular system. 
         [0085]    Referring now to  FIG. 26 , a vascular access device  10  includes a body  20  and an elastomeric slit septum  162 . A split wedge  164  resides within a lower chamber  44  of the septum  162 . The split wedge is capable of separating its bottom angled surface when coerced by the tip  30  of a separate device  26  against a rigid base member  166  that resides beneath the split wedge  164 . Referring now to  FIG. 27 , the vascular access device  10  of  FIG. 26  is shown with the tip  30  of a separate device  26  fully engaged within the septum  162 . When the tip  30  places force upon the top surface  168  of the split wedge  164 , the bottom angled surfaces  170  of the split wedge  164  are pressed against the surface of the rigid structure  166 , causing the split wedge  164  to separate. When the split wedge  164  separates, the elastic walls of the septum  162  also separate causing the internal volume of the interior chamber  44  to increase. The internal volume of the interior chamber  44  increases both between the legs of the split wedge  164  and on the sides of the rigid structure  166 . 
         [0086]    Referring now to  FIG. 28 , a vascular access device  10  includes a septum  172  with a slit  174  and at least one curved, rigid, pivoting member  176 . The pivoting members  176  are fixed to a pivot point  178  against the body  20  of the vascular access device  10 . 
         [0087]    Referring now to  FIG. 29 , the vascular access device  10  of  FIG. 28  is shown with the tip  30  of a separate device  26  fully engaged with the septum  172 . When the tip  30  is fully inserted into the slit  174 , the pivoting members  176  that are embedded within the septum  172  are forced outward against the walls of the body  20  of the device  10 . In their outward position, the pivoting curved members  176  open to increase the amount of internal volume within the interior chamber  44  beneath the closure of the septum  172 . The space  180  that is created during tip  30  insertion is later eliminated when the tip  30  is removed from the device  10 . As this volume is eliminated, the fluid residing therein is forced from the extravascular system toward the vascular system of a patient. 
         [0088]    Referring now to  FIG. 30 , the vascular access device  10  includes a septum  22  and a four-bar mechanism  182  that is separate and resides on an exterior surface of and in communication with the septum  22 . The four-bar mechanism  182  is anchored to the outer wall of the body  20  of the device  11 . 
         [0089]    Referring now to  FIG. 31 , the vascular access device  10  of  FIG. 30  is shown with the tip  30  of a separate device  26  inserted into the septum  22 . With normal slit septums that do not include a four-bar mechanism as that shown in  FIGS. 30 and 31 , when a tip  30  is inserted into a slit septum, only that portion of the septum that is in direct contact with the tip is biased open with a minimal amount of material of the septum  22  in front of the end of the tip  30 . However, the four-bar mechanism  182  of  FIG. 31  permits the septum  22  to open along its entire length when the tip  30  is initially inserted into the top portion of the septum  22 . As the four-bar mechanism  182  opens the entire length of the septum  22 , a volume  184  is created within the septum  22  as the tip  30  is initially advanced. The increased volume  184  is added to the volume beneath it in the extravascular system, and when the tip  30  is removed from the device  10 , the four-bar mechanism  182  collapses causing the volume  184  to be eliminated. When the volume  184  is eliminated, fluid is expelled from that volume through the extravascular system and into the vascular system of a patient. 
         [0090]    Referring now to  FIG. 32 , a vascular access device  10  includes a septum  22  and a rigid member  186  capable of being displaced by an air pressure chamber  188  that may be disturbed when the tip  30  of a separate device  26  is inserted into the septum  22 . The rigid member  186  may be a bistable spring capable of flexing in alternating directions under the influence of opposing force exerted upon the body of the spring. 
         [0091]    As the tip  30  is inserted into the septum  22 , an upper chamber  190  decreases in size, forcing air through a channel  192  in the septum  22 , to an air pressure chamber  188  neighboring the rigid member  186 . As the pressure within a neighboring chamber  188  increases, the bistable spring of the rigid member  186  will flex in a direction  194  into an expansion chamber  196 . As the rigid member  186  flexes in a direction  194 , the vacuum existing in the neighboring chamber  188  will pull an internal wall  198  in the direction  194 , causing the volume of an interior chamber  44  to increase. 
         [0092]    As the tip  30  is retracted from the septum  22 , the upper chamber  190  will increase in size, pulling air from air pressure chamber  188  through the channel  192  into the upper chamber  190 . As the pressure within the air pressure chamber  188  decreases, the bistable spring of the rigid member  186  will flex in a direction opposite direction  194  to return to its original position, causing the internal wall  198  to also return to its original position, and causing the volume of the interior chamber  44  to decrease to its original volume prior to tip  30  insertion. The stress placed upon the bistable spring is such that only minimal force or pressure is required to engage the bistable spring in either direction. 
         [0093]    The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.