Abstract:
A vascular access device may include a gas chamber housed between a body and a septum, and a receptacle in communication with the gas chamber. A method of displacing gas in a medical device may include transferring gas between a gas chamber of a vascular access device and a receptacle housed within the vascular access device.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/864,113, filed Nov. 2, 2006, entitled VASCULAR ACCESS DEVICE GAS DISPLACEMENT, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present disclosure relates to infusion therapy with vascular access devices. 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 a vascular access device. The vascular access device may access a patient&#39;s peripheral or central vasculature. The vascular access device may be indwelling for short term (days), moderate term (weeks), or long term (months to years). The 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 vascular access device attached thereto, may have a single lumen or multiple lumens for infusion of many fluids simultaneously.  
         [0005]     The 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 intravenous (IV) bag at the other. The administration set is a fluid conduit for the continuous infusion of fluids and pharmaceuticals. Commonly, an IV access device is a vascular access device that may be attached to another vascular access device, closes the vascular access device, and allows for intermittent infusion or injection of fluids and pharmaceuticals. An IV access device may include 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]     When the septum of a vascular access device fails to operate properly, certain complications may occur. 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]     Current vascular access devices prevent complications, such as infection resulting in CRBSIs, by providing a septum that functions properly during attachment and/or access of the vascular access device by other medical devices. Septa that function properly will act, in part, as infection barriers between the internal and external environments of the vascular access device during attachment and/or access by other medical devices. By functioning properly as infection barriers, septa minimize CRBSI&#39;s and other complications.  
         [0008]     In order to function properly, a septum needs to open and close during use without difficulty. Often, the gas in a chamber adjacent a septum, must be vented or otherwise displaced as the septum is actuated during use. If neighboring gas chambers are not vented, a septum will be unable to open without significant force. Once opened, the septum will be reluctant to close as a result of neighboring gas chambers that remain compressed under vacuum pressure. Thus, what are needed are various gas chamber venting and displacement structures and methods capable of maximizing proper septum functionality.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     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 vascular access systems, devices, and methods. Thus, these systems, devices, and methods are developed to provide proper septum functionality by providing gas chamber venting and displacement structures and methods.  
         [0010]     A medical device may include a vascular access device that includes a body and a septum at least partially housed within the body, a gas chamber housed between the body and the septum, and a receptacle within the body for receiving gas from the gas chamber as the septum is actuated. The medical device may also include a vent connecting the gas chamber to the receptacle. The receptacle may be a neighboring gas chamber that is near the gas chamber of the device.  
         [0011]     The vascular access device may include a cavity below the septum of sufficient volume to receive the receptacle as the receptacle is expanded in volume and to simultaneously permit a separate access device to communicate fluid with the cavity of the device. The septum may also include a bottom disk that is thin enough to cause the bottom disk to balloon and create the receptacle as the septum is actuated and the gas chamber decreases in volume.  
         [0012]     The receptacle may be an elastomer in communication with the gas chamber. The elastomer may expand and the receptacle may increase in volume as the gas chamber decreases in volume. The gas chamber may conversely increase in volume as the elastomer contracts and the receptacle decreases in volume.  
         [0013]     A method of displacing gas within a medical device may include providing a vascular access device including a body, a septum housed within the body, and a gas chamber between the body and the septum, providing a receptacle within the body, and transferring gas between the gas chamber and the receptacle. Transferring gas between the gas chamber and the receptacle may also include transferring gas through a vent that connects the gas chamber to the receptacle.  
         [0014]     The method may also include increasing the total effective volume of the gas chamber by placing the gas chamber in communication with the receptacle, which receptacle may include a volume. Further, if the receptacle includes a volume, the method may also include decreasing the pressure required to compress the gas chamber by placing the gas chamber in communication with the volume of the receptacle, thus increasing the overall combined volume of the receptacle and the gas chamber.  
         [0015]     The method may also include ballooning the septum to provide the receptacle. The method may further include providing a cavity capable of receiving the ballooning septum and simultaneously permitting a separate access device to communicate fluid with the cavity. The method may also include expanding the receptacle while decreasing the volume of the gas chamber, and conversely contracting the receptacle while increasing the volume of the gas chamber.  
         [0016]     A medical device may include a means for accessing the vascular system of a patient including a body, a septum at least partially housed within the body, and a gas chamber between the body and a portion of the septum. The medical device may also include a means for receiving gas from the gas chamber, and the means for receiving gas from the gas chamber may reside within the means for accessing the vascular system of a patient. The means for receiving gas from the gas chamber may increase the overall effective volume of the gas chamber. The septum may also balloon to create the means for receiving gas from the gas chamber. Further, the means for receiving gas from the gas chamber may be an elastomer in communication with the gas chamber.  
         [0017]     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  
       [0018]     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.  
         [0019]      FIG. 1  is a perspective view of an extravascular system connected to the vascular system of a patient.  
         [0020]      FIG. 2  is a cross section view of a vascular access device with a gas chamber, vent, and receptacle.  
         [0021]      FIG. 3  is a cross section view of a vascular access device with a ballooning septum before insertion of a separate access device.  
         [0022]      FIG. 4  is a cross section view of a vascular access device with a ballooning septum.  
         [0023]      FIG. 5  is a cross section view of a vascular access device with a resting elastomer.  
         [0024]      FIG. 6  is a cross section view of the vascular access device of  FIG. 4  with the elastomer expanded.  
         [0025]      FIG. 6A  is a partial cross section view of a vascular access device with an elastomer in an alternate location. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]     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.  
         [0027]     Referring now to  FIG. 1 , a vascular access device (also referred to as an extravascular device, intravenous access device, access port, and/or any device attached to or functioning with an extravascular system)  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 .  
         [0028]     The device  10  and all structures used in combination therewith may form a larger extravascular system  28 . As part of the system  28 , a tip  30  of the separate device  26  may be inserted into the device  10  through the slit  24  of the septum  22 . The tip  30  will serve to communicate fluid through the device  10  and the end  32  of the catheter  12  when the device  10  is in use. In an embodiment of the invention, as the tip  30  penetrates the device  10 , the two opposing slit  24  surfaces of the septum  22  will separate in opposing lateral directions and will stretch the slit  24  surfaces of the septum  22  in an axial direction, thus increasing the overall height of the septum  22 . In this particular embodiment, as the height of the septum is increased, the seal between the device  10  and the tip  30  is rendered more effective.  
         [0029]     Referring now to  FIG. 2 , a vascular access device  10  includes a body  20 , a septum  22  at least partially housed within the body  20 , at least one gas chamber  34  housed between the body  20  and the septum  22 , and a receptacle  36  within the body  20  for receiving gas from the gas chamber  34  as the septum  22  is actuated. A vent  38 , also housed within the body  20 , connects the gas chamber  34  to the receptacle  36 . The receptacle  36  may be a neighboring gas chamber that is close in proximity to the gas chamber  34 . The purpose of the receptacle  36  is to increase the total effective volume of the gas chamber  34  by placing the gas chamber  34  in communication with the receptacle  36  by means of the vent  38 . By increasing the total effective volume of the gas chamber  34 , the septum  22  will be able to function properly.  
         [0030]     In traditional vascular access devices that have no vent through the body  20  of the device  10 , as the septum  22  is actuated or opened by the insertion of the tip  30  of a separate access device  26 , pressure would build within the gas chamber  34  of the device  10 . In the current embodiment described with reference to  FIG. 2 , the increased overall combined volume of the gas chamber  34 , the vent  38 , and the receptacle  36  provides an increase in overall volume that reduces the percentage of volume that is compressed as the septum  22  is actuated.  
         [0031]     Thus, as the tip  30  of a separate access device (not shown in  FIG. 2 ) is inserted into the slit  24  of the septum  22 , the volume of the gas chamber  34  decreases, sending gas through the vent  38  and into the receptacle  36 . While the total combined volume decreases during septum actuation and access, the percentage of gas within the volume that is compressed is much smaller in relation to the total combined volume than it would otherwise be if the gas chamber  34  was not connected to any other neighboring gas chamber. Thus, in previous vascular access devices without septum vents, the chamber  34  would reach a compression ratio of greater than 90 to 95 percent, causing only 5 to 10 percent of the total volume of the chamber  34  to remain during septum  22  access.  
         [0032]     However, under the present embodiment, because the total overall volume of the gas chamber  34 , vent  38 , and receptacle  36  is much larger than a conventional gas chamber, when the gas chamber  34  is nearly fully compressed, a large amount of volume, i.e., about 40 to 70 percent, remains uncompressed. The volume of the neighboring gas chamber or receptacle  36  may be increased in order to further increase the overall volume and reduce the percentage of volume compressed when the gas chamber  34  is collapsed upon septum  22  access. The receptacle  36  may reside at any point within the device  10 , so long as the receptacle  36  is in communication with the gas chamber  34 .  
         [0033]     By providing a higher level of air pressure within the gas chamber  34 , vent  38 , and receptacle  36  during use of the device, the septum  22  and other portions of the device  10  may be secured under pressure in order to prevent leakage of fluid within the device or microbial ingress within the device from a surrounding environment.  
         [0034]     Referring now to  FIGS. 3 and 4 , a vascular access device  10  includes a body  20  and a septum  22  at least partially housed within the body  20 . A gas chamber  34  resides between the septum  22  and the body  20 . The septum  22  includes a bottom disk  40  that is thin enough to cause the bottom disk  40  to balloon and create a receptacle  36  as the septum  22  is actuated and the gas chamber  34  decreases in volume upon insertion of the tip  30  of a separate access device  26 .  
         [0035]     As illustrated in  FIG. 3 , before the tip  30  is inserted into the device  10 , the gas chamber  34  is in full volume. After the tip  30  of a separate access device  26  is inserted into the septum  22 , as illustrated in  FIG. 4 , the volume of the gas chamber  34  is transferred downward into the ballooning portion of the bottom disk  40  of the septum  22 . The device  10  includes a cavity  42  below the bottom disk  40  of the septum  22 . The cavity  42  is of sufficient volume to receive the receptacle  36  and simultaneously permit the tip  30  of the separate access device  26  to communicate fluid with the cavity through a fluid transfer channel  44 .  
         [0036]     The bottom disk  40  of the septum  22  is thinned and optimized to allow the bottom disk  40  to balloon into the base and chamber  42  of the device  10 . The septum  22  need not necessarily balloon in order for the volume of the gas chamber  34  to be fully transferred into the receptacle  36 , so long as the volume of the cavity  42  is large enough to receive the receptacle  36 . The volume of the cavity may be increased by either lengthening the cavity  42  or widening the walls of the body  20  surrounding the cavity  42  in a lateral direction  46 . The bottom disk  40  of the septum  22  may be thinned or otherwise structured or replaced with a material capable of ballooning to a point at which a user will be able to easily access the septum  22  by inserting the tip  30  of a separate access device  26  with minimal force. However, the ballooning bottom disk  40  should be sufficiently resilient in order to provide the force necessary to return the septum  22  to its original position upon retraction of the tip  30  from the septum  22 . Thus, the resiliency of the bottom disk will cause the volume of the receptacle  36  to decrease as the volume of the gas chamber  34  is increased, returning to its original gas chamber  34  position.  
         [0037]     Referring now to  FIG. 5 , a vascular access device  10  includes a body  20 , a septum  22  at least partially housed within the body  20 , and at least one gas chamber  34  housed between the septum  22  and the body  20 , and an elastomer  48  in communication with the gas chamber  34 . In its resting state as shown in  FIG. 5 , the gas chamber  34  resides at maximum volume and the elastomer  48  is not expanded.  FIG. 6  illustrates the functionality of the elastomer  48  upon insertion of the tip  30  of a separate access device  26  into the septum  22 .  
         [0038]     Referring now to  FIG. 6 , the vascular access device  10  of  FIG. 5  is shown in cross section view with the elastomer  48  expanded, causing an increase in volume within the elastomer. The increase in volume within the elastomer is a receptacle  50  for receiving gas from the gas chamber  34 . The elastomer  48  expands and the receptacle  50  increases in volume as the gas chamber  34  decreases in volume. Conversely, as the tip  30  of a separate access device  26  is removed from the septum  22 , the resilient nature of the elastomer  48  causes the elastomer  48  to contract, consequently causing the gas chamber  34  to increase in volume as the receptacle  50  decreases in volume and the elastomer  48  returns to its original resting position as shown in  FIG. 5 . Thus, during insertion of a separate access device  26  into the septum  22 , or during any other actuation of the septum  22 , air may be displaced or otherwise transferred from the gas chamber  34  into a receptacle  50  that is in communication with the gas chamber  34 .  
         [0039]     The elastomer  48  and receptacle  50  may be located at any functional or non-functional area of the device  10 . For example, the elastomer may be placed upon the shoulder of the body  20  as shown in  FIG. 6A .  
         [0040]     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.