Abstract:
A luer activated device includes an inlet adapted to receive a male luer, an outlet associable with a fluid flow system, and a fluid flow path therebetween. The flow path is defined by an elastomeric flow controller extending between the inlet and outlet and maintained in a tensioned state. When a male luer is inserted into the inlet, some of the tension in the flow controller is relieved, allowing the flow path to deform and change in volume. The flow path is adapted such that the change in volume results in no net fluid displacement or minimal positive fluid displacement when the male luer is inserted into the inlet. Other aspects include tensioned flow controllers having a plurality of sealing layers for the inlet and methods of manufacturing valves having a tensioned fluid flow controller.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to luer activated devices or valves that allow for the bi-directional transfer of fluids to and from medical fluid flow systems. 
     BACKGROUND OF THE INVENTION 
     Luer activated devices (LAD) or valves (LAV) are commonly used in association with medical fluid containers and medical fluid flow systems that are connected to patients or other subjects undergoing diagnostic, therapeutic or other medical procedures. A LAD can be attached to or part of a fluid container or a medical fluid flow system to simplify the addition of fluids to or withdrawal of fluids from the fluid flow system. 
     Within the medical field there are a wide variety of medical fluid flow systems, serving a variety of functions. One of the more common uses of LADs are in association with fluid flow systems that are used for the intravenous administration of fluids, such as saline, antibiotics, or any number of other medically-related fluids, to a patient. These flow systems are commonly referred to as intravenous or “IV” fluid administration sets, and use plastic tubing to connect a phlebotomized subject to one or more medical fluid sources, such as intravenous solution or medicament containers. 
     Typically, such intravenous administration sets include one or more LADs providing needless access to the fluid flow path to allow fluid to be added to or withdrawn from the IV tubing. The absence of a needle for injecting or withdrawing fluid has the important advantage of reducing the incidence of needle stick injuries to medical personnel. A LAD typically includes a tapered female luer component, such as the inlet into a valve housing, that accepts and mates with a tapered male luer of a medical infusion or aspiration device, such as a needleless syringe or a administration set tubing brand. 
     There are certain characteristics and qualities of LADs that are highly desirable. For example, the LAD should provide a sufficient microbial barrier for the full service life of the valve. It is desirable that the microbial barrier be conducive to the application of standard aseptic techniques preformed by clinicians during the use of the device. For example, the geometry of the LAD should be such that it is easily swabbable and reduces the potential of entrapping particulates or contaminants that cannot be cleanly swabbed clear prior to use. In addition, the LAD should not permit cross contamination between the male luer and the surfaces of the aseptic fluid path. 
     Furthermore, it is highly desirable that the LAD be substantially devoid of any interstitial space or any other “dead space” that cannot be flushed, or that such interstitial space be physically isolated from the fluid flow path. Such interstitial space has the potential of providing an environment for undesired microbial growth. In addition, the LAD should have a geometry that allows it to be sufficiently flushed so as to clear the dynamic fluid path and adjacent areas of residual blood or intravenous fluids to prevent undesired microbial growth. 
     LAD&#39;s are commonly used with intravenous catheters that provide access to a patient&#39;s vascular system. In such systems, another desirable feature of a LAD is minimal displacement of fluid during insertion and removal of the male luer. In certain situations, it is preferable that the LAD be a neutral/neutral device in that there is zero or only a very slight displacement of fluid during both insertion and removal of the male luer. In other situations it can be desirable for the LAD to produce a positive displacement of fluid from the valve housing during the insertion and removal of the male luer. The LAD also preferably prevents blood reflux into the catheter. Reflux is known to reduce the efficiency of the catheter, contribute to catheter clotting and also contribute to catheter related bloodstream infections. 
     In most situations it is preferred that the LAD be ergonomically dimensioned to be completely activated by a wide range of ISO compliant male luer lock adaptors. However, there may some instances when the LAD is specifically designed to be activated by a male luer lock that is not ISO complaint. Another desirable characteristic of a LAD is the ability of the LAD to seal against pressure contained within a fluid system to which the LAD is connected. For example, it is desirable to be leak resistance to positive pressures ranging from 10 to 45 psi and to negative pressures or vacuum from 1 to 5 psi. The LAD also preferably has a geometry that allows for easy priming and flushing that does not require any additional manipulations to remove residual air bubbles from the tubing system. 
     These and other desirable characteristics, which may be used separately or in combination, is preferably present over the full service life of the valve. When used in connection with an IV set or catheter, the LAD may go through many connections and disconnections. It is desirable that the life of an LAD last through upwards to about 100 connections and disconnections or 96 hours of dwell time. 
     As described more fully below, the fluid access devices of the present invention provides important advances in the safe and efficient administration or withdrawal of medical fluids to or from a fluid flow system. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, a medical valve for the bi-directional transfer of fluid is provided with a valve housing having an inlet adapted for receiving a male luer, an outlet and a passageway therethrough. A fluid flow controller is received within the valve housing and has a valve element fixedly attached to the inlet. The valve element has a resealable aperture for receiving a male luer and sealing the inlet. An extending portion extends away from the valve element and is fixedly attached to the outlet to define a fluid flow path in communication with the aperture and the outlet. The fluid flow controller is maintained in a tensioned state within the valve housing, such that insertion of a male luer into the inlet decreases the tension in at least a portion of the fluid flow controller. 
     According to another aspect of the present invention, a medical valve for the bi-directional transfer of fluid is provided with a valve housing having an inlet adapted for receiving a male luer. A fluid flow controller associated with the valve housing has a valve element fixedly attached to the inlet in a tensioned state. The valve element has a first sealing layer defining a first resealable aperture, a second sealing layer defining a second resealable aperture, and a channel therebetween and in communication with both apertures. The channel is substantially closed in the tensioned state and open in an untensioned state. 
     According to yet another aspect of the present invention, a method of manufacturing a medical valve involves providing a fluid flow controller having a valve element and an extending portion defining a fluid flow path. The valve element is fixedly attached to an upper portion of a valve housing so as to seal an inlet of the upper housing portion. The fluid flow controller is stretched away from the inlet and a lower housing portion is placed over the extending portion of the fluid flow controller so that the extending portion extends into an outlet of the lower housing portion. The lower housing portion is fixedly attached to the lower housing portion and a section of the extending portion is fixedly attached to the outlet, thereby maintaining the fluid flow controller in a tensioned state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Turning now to a more detailed description of the various embodiments of the present invention illustrated in the attached drawings, of which: 
         FIG. 1  is a cross-sectional view of one embodiment of a luer activated device of the present invention; 
         FIG. 2  is a cross-sectional view of the LAD of  FIG. 1 , with a male luer partially inserted therein; 
         FIG. 3  is a cross-sectional view of the LAD of  FIG. 1 , with a male luer fully inserted therein; 
         FIGS. 4-7  show a method of manufacturing the LAD of  FIG. 1 ; 
         FIG. 8  is a cross-sectional view of another embodiment of an LAD according to the present invention; 
         FIG. 9A  is a cross-sectional view of the LAD of  FIG. 8 , with a male luer partially inserted therein; 
         FIG. 9B  is a cross-sectional view of the LAD of  FIG. 8 , with a male luer fully inserted therein; 
         FIGS. 10-13  show a method of manufacturing the LAD of  FIG. 8 ; 
         FIG. 14  is a cross-sectional view of another embodiment of an LAD according to the present invention; 
         FIG. 15  is a cross-sectional view of the LAD of  FIG. 14 , with a male luer partially inserted therein; 
         FIG. 16  is a cross-sectional view of the LAD of  FIG. 14 , with a male luer fully inserted therein; 
         FIGS. 17-21  show a method of manufacturing the LAD of  FIG. 14 ; 
         FIG. 22  is a cross-sectional view of a variation of the LAD of  FIG. 14 ; 
         FIG. 23  is a cross-sectional view of the LAD of  FIG. 22 , with a male luer fully inserted therein; 
         FIG. 24  is a cross-sectional view of a portion of the LAD of  FIG. 22  incorporated into a T-site; 
         FIG. 25  is a cross-sectional view of the device of  FIG. 24 , with a male luer fully inserted into the T-site; and 
         FIG. 26  is a cross-sectional view of a portion of the LAD of  FIG. 22  incorporated into another T-site. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriate manner. 
       FIG. 1  generally illustrates a first embodiment of a luer activated device (LAD) or valve of the present invention, generally designated as  10 . The LAD  10  includes a generally tubular valve housing  12  preferably comprised of a rigid material, such as plastic or other suitable material. The LAD  10  is provided as a combination of a joined upper housing portion  14  and a lower housing portion  16 . The LAD  10  also includes an inlet  18 , an outlet  20 , and a passageway  22  defined therebetween. The terms “inlet” and “outlet” are not to be interpreted as limiting the LAD  10  to applications involving fluid flow in a particular direction, e.g., from the inlet  18  to the outlet  20 , because LAD&#39;s according to the present invention may be used in applications involving fluid flow from the inlet  18  to the outlet  20  or from the outlet  20  to the inlet  18 . 
     The outlet  20  is adapted to be connected to any of a number of fluid flow systems, so the exact configuration of the outlet  20  will vary according to the nature of the fluid flow system to which it is to be connected. For example, the illustrated outlet  20  is suitable for use in connecting the valve  10  to an IV administrative tubing set (not illustrated). In the embodiment of  FIG. 1 , the outlet  20  includes a skirt  24  defining an internal thread  26 , which may be adapted to engage an external thread of the associated fluid flow system (not illustrated). Of course, the outlet  20  may be provided with a different configuration, a different locking system, or without a locking system, depending on the anticipated usage of the valve  10 . 
     The inlet  18  includes an opening  28  adapted to receive a male luer  30  ( FIGS. 2 and 3 ) according to known structure and operation. The inlet  18  and male luer  30  preferably conform functionally to ISO and/or ANSI standards. In general the inlet  18  is unable to conform dimensionally to ISO luer standards as there would be insufficient volume to house the septum displacement upon insertion of a luer tip. 
     The male luer  30  has a hollow channel  32  defined by a generally tubular wall  34 . The wall  34  preferably has a substantially smooth outer surface  36  which is typically cylindrical or conical. The inlet  18  may include external threads  38 , in which case a portion of the luer wall  34  may be surrounded by a collar member  40  ( FIGS. 2 and 3 ) having internal threads  42  adapted to removably lock the male luer  30  to the inlet  18 . Other locking mechanisms may also be incorporated into LAD&#39;s according to the present invention. 
     By way of example, the collar member  40  and luer wall  34  may be configured to provide a tactile feel when the male luer  30  has been fully engaged to the LAD  10 . As shown in shadow in  FIG. 3  the luer wall may include some detents  13  which are placed so as to register with one of cavities or openings  11  formed in the collar member  40 . To allow the LAD to connect with standard male luers, the detents  13  may be placed lower on the luer wall  34  and the collar member  40  extended to provide the registration. 
     The inlet  18  fixedly receives a fluid flow controller  44  having a resealable slit or aperture  46  therethrough. The flow controller  44  acts as a microbial barrier between the internal passageway  22  of the LAD  10  and the atmosphere. The flow controller  44  may include a substantially concave upper surface  48  ( FIG. 1 ), which provides a relatively tight seal of the aperture  46 . Alternatively, the upper surface  48   a  may be substantially flat ( FIG. 7 ), such that it can be easily wiped with antiseptic, which aids in preventing contamination during use. 
     The flow controller  44  is comprised of a first portion or valve element  50 , which includes the upper surface  48  and the aperture  46 , and a second portion or extending portion  52  ( FIG. 1 ) that extends away from the valve element  50 . The extending portion  52  is generally tubular and defines a fluid flow path  54  in communication with the aperture  46  of the valve element  50 . The valve element  50  is fixedly attached to the LAD inlet  18 , while the extending portion  52  is fixedly attached to the LAD outlet  20 , preferably by mechanical means, such as a bushing member  56 . The operation of the flow controller  44  is illustrated in  FIGS. 2 and 3 , and will be described in greater detail herein. 
     Preferably, the flow controller  44  is molded as a unitary piece, typically from a deformable elastomeric material, such as silicone or rubber or santoprene. The “as-molded” configuration of the flow controller  44  is shown in  FIG. 4 , with a substantially convex upper surface  48   b  and an extending portion  52  comprised of a wall  58  having a bulb or bulge  60 . The illustrated wall  58  has a generally uniform outer radius, except for the bulge  60 , which has an increased outer radius. The bulge  60  affects the flow dynamics of the LAD  10 , as will be described in greater detail herein. 
     It will be seen that the flow controller  44  is significantly shorter in the “as-molded” configuration of  FIG. 4 , as compared to the condition illustrated in  FIG. 1 . According to a preferred method of manufacturing the flow controller  44 , the flow controller  44  is initially provided in the relatively short “as-molded” condition of  FIG. 4 , along with a separate upper valve housing portion  14 . The valve element  50  is fixedly attached to the LAD inlet  18  to close the opening  28  thereof. This may be done by any of a number of means, which vary according to the materials selected for the flow controller  44  and the upper housing portion  14 . These means include, but are not limited to, adhesion or mechanical attachment (e.g., crimping), although the flow controller  44  is preferably overmolded onto the upper housing portion  14 . The aperture  46  may be formed in the valve element  50  prior to or after the valve element  50  is secured to the LAD inlet  18 . Referring briefly to  FIG. 2 , the overmolded section attaching the controller  44  and the upper housing portion  14 , may be dimensioned to engage the threads of the male luer to provide the desired torque resistance to disengagement per ISO standards. 
     When the valve element  50  has been secured to the inlet  18 , an elongated mandrel or vacuum member  62  is inserted through the aperture  46  and the fluid flow path  54  ( FIG. 5 ). A suction source (not illustrated) is associated with the mandrel  62  and creates a vacuum force that pulls the extending portion  52  inwardly against the mandrel  62 . The mandrel  62  is then moved downwardly (in the orientation of  FIG. 5 ) to push the convex upper surface  48   b  into the LAD inlet  18  and stretch the extending portion  52 . In the “fully stretched” condition of  FIG. 5 , the bulge  60  substantially flattens out against the mandrel  62  and the wall  58  of the extending portion  52  has a generally uniform outer radius. It will be appreciated that the flow controller  44 , and in particular the extending portion  52  is in a state of tension in the “fully stretched” condition of  FIG. 5 . 
     With the mandrel  62  still in place and providing a suction force, the lower valve housing portion  16  is slid over the extending portion  52  and affixed to the upper housing portion  14  ( FIG. 6 ). A portion of the mandrel  62  and the extending portion  52  remains outside of the lower housing portion  16 . A bushing member  56  is affixed to this portion of the extending portion  52 , and the mandrel  62  is removed ( FIG. 7 ). When the mandrel  62  has been removed, the flow controller  44  is free to move into an “assembled” condition ( FIGS. 1 and 7 ). The flow controller  44  as a whole shifts upwardly and the upper surface  48  assumes either a concave condition ( FIG. 1 ) or a flat condition ( FIG. 7 ) depending on the magnitude of the original convex curvature ( FIG. 4 ) and the degree of stretching. Forcing the upper surface  48  to fit within the inlet opening  28  forces the valve element into a state of radial compression, which promotes an improved seal of the resealable aperture  46 , thereby preventing fluid leakage through the inlet  18 . The bushing member  56  constrains the extending portion  52 , thereby maintaining it in a state of tension, and preventing it from returning to the “as-molded” condition of  FIG. 4 . From  FIG. 7 , it will be seen that the fluid flow path  54  is isolated from the surrounding LAD passageway  22  to define the sole path for fluid moving through the LAD  10 . 
     In an alternate embodiment, the extending portion  52  may be directly attached to the lower valve housing portion  52  by over-molding. 
     Turning now to the operation of the LAD  10 , a male luer  30  is inserted into the inlet  18  and through the aperture  46  ( FIG. 2 ). If desired, the aperture  46  or the male luer  30  may be lubricated for ease of insertion and removal. The male luer  30  deforms the flow controller  44  and relieves some of the tension in the extending portion  52 . On account of the shape memory of the elastomeric material, this reduction in tension allows the bulge  60  to reemerge and expand outwardly into the surrounding passageway  22 , thereby defining a first volume V of the fluid flow path  54 . 
     The male luer  30  is further inserted into the aperture  46  until the aperture  46  completely opens and allows a portion of the male luer  30  to move into the extending portion  52 . The outer radius of the male luer  30  is larger than the inner radius of the fluid flow path  54 , which causes the portion of the wall  58  between the bulge  60  and the male luer  30  to bend outward into a generally frusto-conical shape defining a fluid reservoir  64  ( FIG. 3 ). When the fluid reservoir  64  has been established and the male luer  30  is fully inserted, a second volume V′ is defined. 
     The difference between the first volume V ( FIGS. 1 and 2 ) and the second volume V′ ( FIG. 3 ) determines the magnitude of the fluid displacement when the male luer  30  is inserted and removed, and that difference is determined by the configuration of the bulge  60 . Reflux of fluid into the male luer  30  can lead to a number of problems, such as contamination, so it may be preferred for the bulge  60  to be adapted such that the difference between the first volume V and the second volume V′ is minimized. In one embodiment, the bulge  60  is adapted such that the first volume V is substantially equal to the second volume V′, which ideally creates a neutral fluid displacement, thereby substantially eliminating fluid reflux when the male luer  30  is inserted or removed. If the volumes V and V′ cannot be practicably equated, then preferably the bulge  60  is adapted such that the second volume V′ is only slightly smaller than the first volume V, which results in a minor positive fluid displacement as the male luer  30  is inserted into the LAD  10  and a minor negative fluid displacement as the male luer  30  is removed from the LAD  10 . 
       FIG. 8  illustrates another LAD  10   a  according to the present invention. The LAD  10   a  of  FIG. 8  generally conforms to the foregoing description of the embodiment of  FIG. 1 , except it includes a restrictor member  66  mounted within the valve housing  12 . The restrictor member  66  acts as a second or auxiliary resealable aperture, as will be described in greater detail herein. 
     As with the embodiment of  FIG. 1 , the flow controller  44   a  is preferably molded as a unitary piece, typically from a deformable elastomeric material, such as silicone or rubber or santoprene. With the flow controller  44   a  in an “as-molded” configuration, the valve element  50  is secured to the LAD inlet  18  ( FIG. 10 ) to close the opening  28  thereof. This may be done by any of a number of means, which vary according to the materials selected for the flow controller  44   a  and the upper housing portion  14 . These means include, but are not limited to, adhesion or mechanical attachment (e.g., crimping), although the flow controller  44   a  is preferably overmolded onto the upper housing portion  14 . In  FIG. 10 , the extending portion  52  of the flow controller  44   a  is illustrated without a bulge, but a bulge may also be provided without departing from the scope of the present invention. 
     When the valve element  50  has been secured to the inlet  18 , an elongated mandrel or vacuum member  62  is inserted through the aperture  46  and the fluid flow path  54  ( FIG. 11 ). A suction source (not illustrated) is associated with the mandrel  62  and creates a vacuum force that pulls the extending portion  52  inwardly against the mandrel  62 . The mandrel  62  is then moved downwardly (in the orientation of  FIG. 11 ) to push the convex upper surface  48   b  into the LAD inlet  18 , stretch the extending portion  52 , and maintain the flow controller  44   a  in a state of tension. 
     With the mandrel  62  still in place and providing a suction force, the restrictor member  66  is slid over the extending portion  52  and into the position of  FIG. 11 . In the illustrated embodiment, the restrictor member  66  has an annular rim  68  adapted to abut a shoulder  70  of the upper housing portion  14 . A generally tubular portion  72  extends upwardly from the rim  68  and terminates in an inwardly extending upper flange  74 . In a relaxed condition ( FIG. 8 ), the flange  74  defines an opening  76  smaller than the diameter of the extending portion  52  to compress and close the fluid flow path  54 , but the presence of the mandrel  62  widens the opening  76  into an open condition ( FIG. 11 ). The profile of the opening  76  may vary, provided that it is adapted to close the fluid flow path  54  in the relaxed condition of  FIG. 8  and to allow passage of the fluid flow path  54  in the open condition of  FIG. 11 . 
     As described in greater detail herein, the flange  74  has the tendency to resiliently return to the relaxed condition when the mandrel  62  is removed from the LAD  10   a . Accordingly, the flange  74  is preferably comprised of a material more rigid than the elastomeric material of the flow controller  44   a  (to pinch the fluid flow path  54  closed), but sufficiently pliable to move between the relaxed condition of  FIG. 8  and the open condition of  FIGS. 9B and 11 . Suitable materials for the flange  74 , and preferably the entire restrictor member  66 , include rubber, silicone, polyisoprene, HDPE and polyurethane It will be seen from the following description that the restrictor member  66  may be provided in virtually any configuration, provided that it includes means for holding it in place within the LAD  10   a  and means for resiliently compressing a section of the fluid flow path  54  into a closed position ( FIGS. 8 and 9A ). 
     When the restrictor member  66  has been properly positioned within the upper housing portion  14 , the lower valve housing portion  16  is slid over the extending portion  52  and affixed to the upper housing portion  52  ( FIG. 12 ). Preferably, the lower housing portion  16  includes an element, illustrated in  FIG. 12  as an upwardly extending annular lip  78 , which abuts the restrictor member rim  68  and maintains the restrictor member  66  in place. However, other means for maintaining the restrictor member  66  in place within the housing  12  may be used without departing from the scope of the present invention. 
     A portion of the mandrel  62  and the extending portion  52  remains outside of the lower housing portion  16 . A bushing member  56  is affixed to this portion of the extending portion  52  ( FIG. 13 ), and the mandrel  62  is removed ( FIG. 8 ). When the mandrel  62  has been removed, the flow controller  44   a  is free to move into an “assembled” condition ( FIG. 8 ), according to the foregoing description of the embodiment of  FIG. 1 . Additionally, the flange  74  of the restrictor member  66  resiliently returns to its relaxed condition, thereby decreasing the size of the opening  76  and pinching closed a section of the fluid flow path  54 . 
     Turning now to the operation of the LAD  10   a , a male luer  30  is partially inserted into the inlet  18  and through the aperture  46  ( FIG. 9A ). The male luer  30  opens the aperture  46 , but not the opening  76  of the restrictor member  66 , so flow through the LAD inlet  18  remains closed ( FIG. 9A ). Hence, it will be seen that the restrictor member  66  acts as a secondary or auxiliary sealing element that prevents fluid flow through the inlet  18  when the male luer  30  is only partially inserted. As the male luer  30  is further inserted into the inlet  18 , it engages the section of the fluid flow path  54  closed by the restrictor member  66  and forces the restrictor member  66  into the open condition of  FIG. 9B . In the condition of  FIG. 9B , fluid flow through the LAD  10   a  may begin. If the extending portion  52  includes a bulge (not illustrated), the fluid displacement upon inserting and removing the male luer  30  will be governed according to the foregoing description of the embodiment of  FIG. 1 . 
     Similarly upon withdrawal of the male luer  30 , as the male luer is withdrawn the male luer no longer engages the section of the fluid flow path  54  adjacent the restrictor member  66  and the restrictor member then closes the flow path. Further withdrawal of the male luer will create a vacuum condition in the flow path  54  which pulls fluid from within the male luer. This reduces aersolization of fluid from the male luer tip. 
       FIG. 14  illustrates yet another LAD  10   b  according to the present invention. The LAD  10   b  of  FIG. 14  generally conforms to the foregoing description of the embodiment of  FIG. 1 , except it includes a modified valve element  80 . The modified valve element  80  provides a second or auxiliary resealable aperture  82 , similar to the embodiment of  FIG. 8 , but it may be preferred for some applications because it eliminates the potential non-flushable “dead space” between the upper and lower sealing elements, as described in greater detail herein. 
     As with the embodiment of  FIG. 1 , the flow controller  44   b  is preferably molded as a unitary piece ( FIG. 17 ), typically from a deformable elastomeric material, such as silicone or rubber or santoprene. The modified valve element  80  includes an upper surface or first sealing layer  48  defining a first resealable aperture  46  adapted to receive a male luer  30  ( FIG. 15 ). In the illustrated embodiment, a skirt  84  extends downwardly from the outer perimeter of the first sealing layer  48 . A second sealing layer  86  is spaced from the first sealing layer  48  and includes a rim  88  comparable in structure and operation to the restrictor member rim  68  of the embodiment of  FIG. 8 . The rim  88  defines a second resealable aperture  82  adapted to receive a male luer  30  ( FIG. 16 ) and preferably coaxial with the first aperture  46 . The first and second apertures  46  and  82  are joined by a channel  90 . As shown in  FIG. 17 , the channel  90  is preferably at least partially open in the “as-molded” configuration. The flow controller  44   b  is illustrated in  FIG. 17  with a flat upper surface  48  and a bulge  60 , but it will be appreciated from the following description that the upper surface  48  may be substantially convex in the “as-molded” configuration and/or the extending portion  52  may be provided without the bulge  60 . 
     With the flow controller  44   b  in an “as-molded” configuration, the modified valve element  80  is secured to the LAD inlet  18  ( FIG. 18 ) to close the opening  28  thereof. This may be done by any of a number of means, but is preferably achieved by pushing the upper surface  48  upward through the inlet  18  until the skirt  84  seats within a ledge or shelf  92  of the inlet  18  by a friction fit. Preferably, the upper surface  48  is slightly larger than the inlet  18 , such that the upper surface  48  is seated with an interference fit that results in a radial compression that aids in more tightly sealing the first aperture  46 . 
     When the first sealing layer  48  is securely seated, the rim  88  is positioned to abut a shoulder  70  of the upper housing portion  14 . The rim  88  may be affixed to the shoulder  70  by a variety of means, depending on the material selected for the housing upper portion  14  and the flow controller  44   b . Suitable means may include welding, adhesion, and a press fit with the lower housing portion  16 , as described in greater detail herein. 
     Preferably, the distance between the top of the upper surface  48  and the rim  88  is less than the height of the inlet  18 , such that the channel  90  must be stretched to properly position the first and second sealing layers  48  and  86 .  FIG. 18  shows that a channel  90  in such a state of tension will deform to be substantially closed, along with the first aperture  46  and the second aperture  82 . Stretching the channel  90  may cause the first and/or second sealing layers to assume a generally concave configuration (not illustrated) that imparts a radial compression on the associated apertures and aids in maintaining the inlet  18  in a sealed condition. 
     When the modified valve element  80  has been secured to the inlet  18 , an elongated mandrel or vacuum member  62  is inserted through the apertures  46  and  82 , the channel  90 , and the fluid flow path  54  ( FIG. 19 ). A suction source (not illustrated) is associated with the mandrel  62  and creates a vacuum force that pulls the extending portion  52  and bulge  60  inwardly against the mandrel  62 . The mandrel  62  is then moved downwardly (in the orientation of  FIG. 20 ) to stretch the extending portion  52  and maintain the flow controller  44   b  in a state of tension. 
     With the mandrel  62  still in place and providing a suction force, the lower housing portion  16  is slid over the extending portion  52  and affixed to the upper housing portion  14  ( FIG. 21 ). Preferably, the lower housing portion  16  includes an element, illustrated in  FIG. 21  as an upwardly extending annular lip  78 , which compresses the second sealing layer rim  88  and maintains the second sealing layer  86  in place. This may be done instead of or in addition to welding or otherwise securing the rim  88  to the shoulder  70  in the condition of  FIG. 18 . However, in comparison to the restrictor member rim  68  of  FIG. 8 , the second sealing layer  86  is relatively flexible, so it may be preferred to use two joinder means (e.g., welding and a compression relationship) to ensure that the second sealing layer  86  is securely maintained within the LAD housing  12 . 
     A portion of the mandrel  62  and the extending portion  52  remains outside of the lower housing portion  16 . A bushing member  56  is affixed to this portion of the extending portion  52  ( FIG. 21 ), and the mandrel  62  is removed ( FIG. 14 ). When the mandrel  62  has been removed, the flow controller  44   b  is free to move into an “assembled” condition ( FIG. 14 ), according to the foregoing description of the embodiment of  FIG. 1 . Additionally, the channel  90  and the second aperture  82  will resiliently close to seal the inlet  18 , along with the first aperture  46 . 
     Turning now to the operation of the LAD  44   b , a male luer  30  is partially inserted into the inlet  18  and through the first aperture  46  ( FIG. 15 ). The male luer  30  opens the aperture  46  and at least a portion of the channel  90 , but not the second aperture  82 , so flow through the LAD inlet  18  remains closed. Hence, it will be seen that the second sealing layer  86  acts as a secondary or auxiliary sealing element that prevents fluid flow through the inlet  18  when the male luer  30  is only partially inserted. 
     As the male luer  30  is further inserted into the inlet  18 , it continues to deform the flow controller  44   b , which causes the bulge  60  to reemerge, and opens the second aperture  82  ( FIG. 16 ). In the condition of  FIG. 16 , fluid flow through the LAD  10   b  may begin. Depending on the nature of the bulge  60  and the resulting fluid reservoir  64 , insertion or removal of the male luer  30  will result in a positive, negative, or neutral fluid displacement, according to the foregoing description of the embodiment of  FIG. 1 . 
     It will be appreciated that the embodiment of  FIG. 8  similarly provides a second sealing element (the restrictor member opening  76 ). However, the embodiment of  FIG. 14 , which provides a substantially closed channel  90  between the upper and lower sealing layers  48  and  86 , may be preferred for certain applications. 
     The flow controller  44   b  of  FIG. 14  may be modified by removing the extending portion  52  and leaving only the valve element  80 , as shown in  FIGS. 22-26 . The resulting flow controller  44   c  may be incorporated as a valve of any of a number of devices, including LAD&#39;s as described herein ( FIGS. 22 and 23 ) and T-sites ( FIGS. 24-26 ). Such a flow controller  44   c  may be preferred to known single or double slit septum-type valves, because there are two separate sealing layers  48  and  86 , along with a channel  90  therebetween that is substantially closed in a relaxed condition ( FIGS. 22 ,  24 , and  26 ) to prevent the creation of a “dead space.” 
     Referring in particular to  FIG. 26 , flow flows through the channel formed by the housing in a path which causes any air present in the injection site to be displaced out of the housing. This provides a self flushing feature to the valve. 
     While the present invention has been described in terms of certain preferred and alternative embodiments for purposes of illustration, it is not limited to the precise embodiments shown or to the particular features, shapes or sizes illustrated. A variety of changes may be made without departing from the present invention as defined by the appended claims.