Abstract:
A connector is described which includes a valve housing comprising a valve housing base and a valve cap, the valve housing defining an inlet port, and an outlet port, the valve housing further including a fluid path from the inlet port to the outlet port, the fluid path including a channel formed in an inner wall of the valve housing. A valve insert in the valve housing defines a bowl sealed by a diaphragm, such that the sealed bowl forms an inner volume in the valve housing. A valve plug operable seals the inlet port when the connector is in an unactuated state thereby closing the fluid path through the connector. Upon actuation of the connector the valve plug deforms the diaphragm into the inner volume thereby unsealing the inlet port and opening the fluid path through the connector. Because of the arrangement of the valve plug, valve insert and diaphragm, the connector has a low priming volume and has positive fluid displacement characteristics upon actuation.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to medical connectors used in fluid delivery applications, and more specifically to connectors having a low priming volume and low positive displacement on disconnection. 
       BACKGROUND OF THE INVENTION 
       [0002]    Medical connections are widely used in fluid delivery systems such as those used in connection with intravenous fluid lines, blood access, hemodialysis, peritoneal dialysis, enteral feeding, drug vial access, etc. Many prior art aseptic medical connections has been to puncture an elastomeric diaphragm or septum, which has one side in contact with the fluid, with a sharpened hollow hypodermic needle. The use of such hypodermic needles has been gradually decreasing as a result of both safety and cost considerations associated with infectious disease acquired from needle sticks. These connectors have been replaced with luer activated connectors which don&#39;t require hypodermic needles, but instead use an activator such as a luer on the end of a syringe or IV line to create a fluid path though a valve in a connector. The removal of the connector causes the valve to close when the line is disconnected. Such a system is described in U.S. Pat. No. 5,569,235 to Ross et al. 
         [0003]    Typical connectors and valves of this type, such as described by Ross, have many attributes that are not ideal in medical applications for fluid delivery. First, such devices can have large priming volumes, that is the connector can have a large chamber associated with the valve element that must be filled with the fluid being delivered before that fluid is actually delivered into the patient line and the patient. For very low flow rates (for example, 0.1 milliliter per hour or 0.05 milliliters per hour), as is common for neonatal or infant care as well as other types of care, such a large priming volume can cause a delay of as much as several hours before the intended therapy reaches the patient. A connector having a low priming volume would allow an introduced therapy to reach the patient more quickly, even at low flow rates. 
         [0004]    Second, fluid displacement can occur whenever a connection is made between two closed fluid systems. When a connection, such as a luer or hypodermic needle, is inserted into an intravenous connector or fluid tubing, fluid displacement occurs. Because the intravenous fluid is incompressible, a volume of fluid equal to the luer or needle volume is displaced out of the intravenous tubing and into the patient&#39;s blood vessel. This displacement of fluid from the intravenous tubing into the patient&#39;s blood vessel is referred to as antegrade flow. Similarly, when the connection is withdrawn, an equivalent volume of blood will be drawn back, usually through the catheter, into the intravenous tubing. This retrograde flow can be harmful when the blood drawn into the end of the catheter remains stagnant for a long period of time. The stagnant blood tends to settle, and may begin to clot, thereby restricting flow through the catheter and possibly requiring insertion of a new intravenous catheter into the patient. Connector systems providing for negative, or retrograde, displacement on insertion and positive, or antegrade flow on removal, are much more desirable in medical applications. 
         [0005]    Third, most connectors use a septum, or permeable membrane at the connection site. These membranes must be penetrated on the insertion of the connector and therefore promote bacteria growth inside the connector. This septum is also susceptible to leaking when there is back pressure in the system. Connector systems that have swabable surfaces to allow for cleaning and which prevent leakage under backpressure are preferable. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    An embodiment of a connector is described having a valve housing defining an inlet port, and an outlet port, the valve housing further including a fluid path from the inlet port to the outlet port. The connector further includes a valve plug operable to seal the inlet port when the connector is in an unactuated state thereby closing the fluid path through the connector, and a diaphragm in the valve housing, the diaphragm separating the valve plug from an inner volume in the valve housing and the diaphragm sealing the inner volume, such that upon actuation of the connector the valve plug deforms the diaphragm into the inner volume thereby unsealing the inlet port and opening the fluid path through the connector. 
         [0007]    A embodiment of a method of operating a connector for medical fluids is also described. The method includes actuating the connector by depressing a valve plug in the connector by inserting a male luer into an inlet port of the connector, the depressing of the valve plug opening a fluid path through the connector, deforming a diaphragm under pressure from the valve plug, the diaphragm defining and sealing an inner volume inside a valve housing of the connector, wherein the deformation of the diaphragm causes the connector to exhibit negative fluid displacement upon actuation, and closing the connector by removing the male luer from the inlet port, wherein the removal of the male luer causes the valve plug to reseal the connector and the diaphragm to return an undeformed state, wherein the return of the diaphragm to the undeformed state causes the connector to exhibit positive fluid displacement upon disconnection. 
         [0008]    In another embodiment of the connector described herein, the connector includes a valve housing having a valve housing base and a valve cap, the valve housing defining an inlet port, and an outlet port, the valve housing further including a fluid path from the inlet port to the outlet port, the fluid path including a channel formed in an inner wall of the valve housing. The connector also includes a valve insert in the valve housing, the valve insert defining a bowl and a diaphragm in the valve housing and sealing the bowl of the valve insert, the sealed bowl forming an inner volume in the valve housing. A valve plug is operable to seal the inlet port when the connector is in an unactuated state thereby closing the fluid path through the connector, and wherein the diaphragm contacts the valve plug and applies a force to the valve plug to maintain the valve plug in the unactuated state. Upon actuation of the connector the valve plug deforms the diaphragm into the inner volume thereby unsealing the inlet port and opening the fluid path through the connector. 
         [0009]    The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: 
           [0011]      FIG. 1  is a perspective view of a luer activated medical connector in accordance with the concepts described herein; 
           [0012]      FIG. 2  is a side view of the medical connector shown in  FIG. 1 ; 
           [0013]      FIG. 3  is a is a exploded side view of the medical connector shown in  FIG. 2 ; 
           [0014]      FIG. 4  is a is a section view of the medical connector shown in  FIG. 2 ; 
           [0015]      FIGS. 5A through 5D  are side views of the medical connector shown in  FIG. 2 , shown in various operational states; and 
           [0016]      FIGS. 6A through 6D  are side views of the medical connector shown in  FIG. 2 , illustrating examples of various alternate embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    According to the concepts described herein, a needleless access medical device that combines, a low priming volume, positive displacement disconnection, and a swabable surface for disinfecting between uses is described. 
         [0018]    Turning to  FIGS. 1 and 2 , an embodiment of a low priming volume luer activated connector  100  according to the concepts described herein is shown in perspective view and side view respectively. The luer activated connector  100  is formed by valve housing  101  and a valve cap  102 . Valve cap  102  is secured to the valve housing  101  using conventional means, such as solvent bonding, ultrasonics, spin welding, etc. A valve inlet port  103  is sealed by the top of valve plug  107  which forms a swabable surface that can be cleaned between uses. Valve inlet port  103  accepts an actuator which pushes valve plug  107  into valve housing  101  to create a fluid path through connector  100  as will be described below. Valve inlet port  103  includes threads which allow connector  100  to be securely connected to a syringe or other fluid dispensing mechanism. 
         [0019]    Housing ribs  106  provide structural support to valve housing  101  and also provide for gripping surfaces to allow connector  100  to be held firmly while attaching another device. As will be described below in a preferred embodiment a channel is formed on the interior of one of the ribs to provide a low priming volume fluid path through connector  100 . Actuator  104  allows the connector to be connected to the inlet port of another device, such as a IV tube or manifold. 
         [0020]    Referring now to  FIG. 3 , an embodiment of connector  200  according to the concepts described herein is shown in an exploded side view illustrating the various components of connector  200 . The embodiment of connector  200  shown herein includes valve housing  201 , valve cap  202 , valve plug  207 , valve insert  208 , and diaphragm  209 . As described with respect to  FIGS. 1 and 2 , valve cap  202  has inlet port  203  with threads  205  which receives an actuator from a fluid dispensing or other device. Internal chamber  222  is formed by valve cap  202  and valve housing  201  when mated together and is designed to receive valve plug  207 . 
         [0021]    Valve plug  207  is of a generally cylindrical shape for slidably fitting within internal chamber  222  formed by valve cap  202  and valve housing  201 . Valve plug includes a primary shoulder seal  219  adapted for abutting against the valve seat  220  of the valve cap  202 . Valve plug  14  also includes wiping seal  218  which engages the internal surface of the throat  217  of valve cap  202 . As will be described below, wiping seal  218  acts to remove any fluid from the throat  217  of valve cap  202  when an actuator is disengaged from connector  200 . Valve plug  207  may also include notch  216 . Notch  216  facilitates the deformation of valve plug  207  when under pressure from a luer actuator. The deformation of valve plug  207  creates a fluid path through connector  200 . 
         [0022]    Preferred embodiments of connector  200  also include valve insert  208  and diaphragm  209 . Valve insert  208  includes bowl  211 . When diaphragm  209  is mated with valve insert  208  an air pocket in formed in bowl  211 . The air pocket in bowl  211  provides a counter pressure to diaphragm  209  during fluid flow and works to ensure a negative fluid displacement during insertion and a positive fluid displacement during disconnection as will be explained. Support ribs  214  provide structural rigidity to valve insert  208  and help support diaphragm  209  the air pocket of bowl  211  when the diaphragm in an extended or stretched position. 
         [0023]    Valve insert  208  and diaphragm  209  perform several functions in connector  200 . First, they occupy space that would otherwise be filled by fluid, thereby minimizing the priming volume required to achieve fluid flow through connector  200 . Second, they provide the mechanism by which connector  200  achieves the proper fluid flow characteristics, namely positive fluid displacement during disconnection. Further, diaphragm  209  deforms under back pressure in the system, deforming to accept fluid inserted into the connector during back pressure and then positively displacing that fluid out of the connector when the back pressure has subsided. Bowl  211  also provides a volume for valve plug  207  to displace into when valve plug  207  is displaced by an actuator inserted into inlet port  203 . Diaphragm  209  stretches into bowl  211  under the force of valve plug  207 , but only to the extent necessary, thereby minimizing priming volume. Diaphragm  209  also provide a counter force against valve plug  207 , helping to push valve plug  207  back into chamber  222  when the actuator is removed, thereby resealing inlet port  203  of connector  200 . 
         [0024]    Stem  215  of valve insert  208  extends into outlet port  223  of valve housing  201  further decreasing the internal volume of connector  200  and thereby minimizing the priming volume for fluids flowing through connector  200 . Valve insert  208  slides tightly into valve housing  201  creating a tight connection between the external walls of valve insert  208  and the internal walls of valve housing  201 . A single flow channel is impeded into one of the ribs  206  on the internal side wall of valve housing  201  and also on the base wall of housing  201 . Stem  215  is sized such that when inserted into the outlet port  223  of connector  200 , the cross sectional flow volume of outlet port  223  will be equivalent to the flow volume through the channel in the side wall of valve housing  201 . 
         [0025]    Valve housing  201  also includes male luer  204  and female threads  224 . The connection creatable by male luer  204  and threads  224  is a standardized connection common to medical fluid delivery devices and is the counterpart to the connection formed by the inlet port  203  and male threads  205 . 
         [0026]    Referring now to  FIG. 4 , a cross-section of an embodiment of connector according to the concepts described herein is shown assembled. A preferred embodiment of connector  300  again includes valve housing  301 , valve cap  302 , valve insert  308 , valve plug  307  and diaphragm  309 . Valve insert  308  and diaphragm  309  fit tightly into valve housing  301  and held in place by valve cap  302  which is securely attached to valve housing  301  by welding or other means. A flange  313  on diaphragm  309  fits into a grove  312  created by valve cap  302  and valve insert  308 . Flange  313  and groove  312  hold diaphragm  309  securely in place and prevent diaphragm  309  from moving when it deforms into bowl  311 . 
         [0027]    Valve plug  307  fits into chamber  322  formed when valve cap  302  is fitted to valve housing  301  with valve insert  308  and diaphragm  309  inserted. In the closed position shown, shoulder seal  319  of valve plug  307  abuts tightly against the valve seat  320  preventing any fluid flow though connector  300 . Additionally, wiping seal  318  seals the entrance to inlet port  303  by providing a seal around the internal wall of throat  317  of valve cap  302 . Wiping seal  318  also acts to remove any fluid from the throat  317  by forcing any fluid in throat  317  up and out of connector  300  when valve plug  307  transitions from an open position to the closed position shown in  FIG. 4 . Notch  316  of valve plug  307  is used to control the deformation of valve plug  307  under pressure from an actuator (not shown) inserted into connector  300 . 
         [0028]    Though the connector  300  is shown in the closed position in  FIG. 4  with the top portion of the fluid path closed by wiping seal  318  and particularly by shoulder seal  319 , the lower portion of the fluid path  310  through connector  300  is shown. Fluid path  310  includes chamber  325  formed by open portion of valve cap  302  and diaphragm  309 . Chamber  325  is in communication with the channel impeded in one of the ribs  306  of valve housing  301 . While connector  300  is shown with a single channel fluid path, channels in other ribs of valve housing  301  may be used in connector  300  to increase flow volume. Also the size of the channel for fluid path  310  can be altered to alter the flow characteristics of the device. It should be noted that increasing channel size or adding additional channels could increase the priming volume of the device. 
         [0029]    The fluid path  310  continues from the channel in rib  306  into a channel in the base of valve housing  301 . The fluid path then enters outlet port  323  in male luer  304  of valve housing  301 . Stem  315  is sized such that the remaining open space in outlet port  323  is matched to the flow characteristics of fluid path  310  through the rest of valve housing  301 . As stated, stem  315  occupies space in outlet port  323  that would otherwise be part of the priming volume for connector  300 . 
         [0030]    Male luer  304  of valve housing  301  allows connector  300  to be inserted into another device such as a manifold, IV line connector or any other device with a universal type female connector. Threads  324  allow connector  300  to be secured in place when connected via male luer  304 . As described, top surface  326  of valve plug  307  sits flush with the top of valve cap  302 , and wiping seal  318  removes fluids from inlet port  303  of connector  300  when the connector is disengaged from another device. This arrangement provides connector  300  with a swabbable inlet surface that can be cleaned and disinfected between uses. Other connector devices that use a slit in a septum allow fluids to collect underneath the septum and are not able to be easily disinfected between uses. 
         [0031]    During use the male luer portion of another device forces valve plug down into connector  300 . Diaphragm  309  is deformed into bowl  311  by valve plug  307  and shoulder seals  319  separates from valve seat  320 , thereby opening fluid path  310  through connector  300 . Notch  316  in valve plug  307  controls the deformation of valve plug  307  and allows it to fold down into connector  300  ensuring that valve plug  307  depresses far enough into connector  300  to allow a good connection with the device being inserted. Diaphragm  309  and the air pocket in bowl  311  provide a positive pressure on valve plug  307 , thereby ensuring that valve plug  307  reseats property upon removal of the actuating device. 
         [0032]    Further, upon actuation the depression of valve plug  307  on diaphragm  309  creates a larger open volume inside connector  300  thereby drawing downstream fluid into connector  300  providing the desired negative displacement on connection. The return of the valve plug  307  and diaphragm  309  back into the unextended position after disconnection reduces the internal volume of connector  300 . As shoulder seal  319  of valve plug  307  prevents fluid from being pushed out inlet port  303 , the fluid in bowl  311  is pushed out outlet port  323  upon removal of the actuating device, thereby providing the desired positive displacement on disconnection. 
         [0033]    With the internal volume of connector  300  being occupied by valve insert  308 , diaphragm  309  and valve plug  307 , it can be easily seen that the internal volume, which is also the priming volume of connector  300 , is minimized. Minimizing priming volume can be important in a variety of applications, but can be particularly important in applications involving low dose medications or in neonatal applications where very low flow rates are maintained. In preferred embodiments of a connector according to the concepts described herein, a low priming volume could be considered a priming volume of 70 microliters or less, though greater priming volumes may be appropriate for other applications while remaining within scope of the concepts described herein. 
         [0034]    Referring now to  FIGS. 5A through 5D , various aspects of a preferred embodiment of a connector  400  are described. Each of the connectors shown includes a valve housing  401 , a valve cap  402 , a valve plug  407 , a valve insert  408  and a diaphragm  409  as described with respect to  FIGS. 1 through 4 . 
         [0035]      FIG. 5A  shows connector  400  in its closed position with valve plug  407  sealing connector  400  and preventing any fluid from passing through the connector. Diaphragm  409  is in its normal condition for a closed configuration.  FIG. 5B  illustrates the portion of fluid path  410  after valve plug  407 . As valve plug  407  is in its closed position the fluid path is closed by the valve plug as described with respect to  FIG. 4 . 
         [0036]      FIG. 5C  shows connector  400  under back pressure through outlet port  423 . Fluid entering outlet port  423  travels along fluid path  410  shown in  FIG. 5B  and is blocked by valve plug  407  from exiting connector  400 . Instead the fluid causes diaphragm  409  to expand into bowl  411  creating a space for a volume of fluid between valve plug  407  and diaphragm  409 . Additionally, valve plug  407  is held in place by the back pressure, thereby reinforcing the seals between valve plug  407  and valve cap  402  and ensuring that connector  400  does not leak under back pressure conditions. When the back pressure condition ends the elasticity of diaphragm  409  and the pressure from the air pocket in bowl  411  force the fluid that entered the connector under back pressure to exit through outlet port  423 . 
         [0037]      FIG. 5D  shows connector  400  in an open or actuated state with a male luer compressing valve plug  407  into the body of connector  400 . Valve plug  407  causes diaphragm  409  to expand into bowl  411  creating space for valve plug  407  and opening the fluid path through the device. Diaphragm  409  and the mass of valve pug  407  minimize the volume inside connector  400  in the actuated state, thereby minimizing the priming volume required by connector  400 . 
         [0038]    Referring now to  FIGS. 6A through 6D , various alternative embodiments of the valve plug and diaphragm in a connector are described. Each of the connectors shown includes operates essentially as described with respect to  FIGS. 1 through 5 . 
         [0039]      FIG. 6A  shows a notched valve plug  609   a  in its actuated state with diaphragm  609   a  in its expanded state as described above. The notch allows valve plug  607   a  to deform in a desired manner upon actuation by a male luer.  FIG. 6B  shows a diaphragm  609   b  having a dimple  630  and a corresponding recess  629  in valve plug  607   b.  The dimple and recess again allow diaphragm  609   b  and valve plug  607   b  to deform in a desired manner. 
         [0040]      FIG. 6C  shows a diaphragm  609   c  having a recess  632  and a corresponding dimple  631  in valve plug  607   c.  As before, the dimple and recess allow diaphragm  609   c  and valve plug  607   c  to deform in a desired manner.  FIG. 6D  shows a diaphragm  609   d  having a notch  633  and a corresponding slant  634  in valve plug  607   d.  The slant and notch allow diaphragm  609   d  and valve plug  607   d  to deform in a desired manner. While certain alternate embodiments have been explicitly shown, one skilled in the art would understand that many other alternate embodiments could be envisioned that would have the same or similar function and still be well within the scope of the concepts described herein. 
         [0041]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.