Abstract:
A system, method and apparatus are provided for administering medical liquids to a patient. The invention is particularly apt for use in the intravenous administration of multiple doses of a flush solution over an extended period of therapy. In certain aspects of the invention methods and apparatus are directed to the provision and utilization of a packaged syringe filled with a medical liquid and having a tubing length interconnected thereto, wherein the volume of pre-filled medical liquid is sufficient to allow for multiple administrations to a given patient. By way of primary example, where the syringe is pre-filled with a flush solution, a volume of at least about 40 ml. is preferred. In other aspects, methods and apparatus are directed to the administration of medical liquids from a pre-filled syringe utilizing an apparatus that is particularly adapted for administering a medical liquid in successive increments over a plurality of separated time intervals.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a system for dispensing flowable materials, and more particularly to methods and apparatus for use in connection with the intravenous administration of medical liquids to a patient. The inventive aspects are particularly apt for use in applications entailing vascular catheter flushing on multiple occasions over an extended period of patient care.  
         BACKGROUND OF THE INVENTION  
         [0002]    Numerous techniques are employed for the administration of “medical liquids” (e.g. liquid medication and flush solutions) to a patient. In particular, where repeated medication infusions are required, medical liquids are often administered via the use of a vascular access catheter that is fluidly interconnected or interconnectable to one or more medical liquid sources via an associated tubing line set. Typically, the catheter is inserted into the vein of a patient and left there for multiple intravenous (IV) infusions during an extended course of medication therapy. By way of example, the time period between IV drug infusions may be between about 4 to 24 hours, wherein the IV liquid medication source is typically replaced after each dose infusion. In the course of extended medication therapy a given tubing line set may be repeatedly employed, and a number of tubing line sets may be successively employed. For example, it is typical to replace a given tubing line set every two or three days.  
           [0003]    During extended therapy applications, a desirable practice is to disconnect the vascular catheter from a medical liquid source and tubing line set between infusions. In this regard, most patients receiving IV medication therapy are ambulatory to some degree and benefit from not being continuously connected.  
           [0004]    In conjunction with the repeated connection/disconnection of a vascular catheter and liquid medication source and tubing line set, it is usual practice to purge the vascular catheter with a flush solution (e.g. a saline solution) prior to and at the completion of a given liquid medication infusion. Pre-infusion flushing verifies that the vascular catheter is primed and clear of obstructions. Post infusion flushing not only flushes through any remaining liquid medication to achieve the desired therapeutic effect, but also reduces any chance that the vascular catheter may become blocked in-between infusions, e.g. by a blood clot that may otherwise form in the vascular catheter. In relation to infusion procedures, it is also common practice to verify the proper functioning of a vascular catheter via aspiration. This is typically done prior to pre-infusion flushing and after liquid medication infusion. The procedure entails using the flush solution syringe or liquid medication syringe to drain a small amount of a patient&#39;s blood through the vascular catheter, thereby permitting visual verification of proper vascular catheter functionability, then advancing the blood back through the vascular catheter using the syringe. By way of example, such procedure assures that the vascular catheter is not blocked by a blood clot and is otherwise properly inserted into a patient&#39;s vascular system.  
           [0005]    A number of approaches are currently utilized for the noted flushing procedures. Such techniques generally entail the usage of flush solutions packaged in large volume, multi-dose reservoirs (e.g. about 250 ml. or more) or pre-filled unit dose syringes (e.g. having volumes of 2, 3, 5 or 10 ml.).  
           [0006]    Where a unit dose syringe is utilized, medical personnel must generally remove the syringe from packaging, remove a cap from the syringe, remove any air in the syringe, swab a vascular catheter access port with an antibacterial material, interconnect the syringe to a vascular catheter access port, optionally aspirate the vascular catheter, advance the syringe plunger to infuse the flush solution (e.g. at a rate of about 5 to 10 ml. over about 15 to 30 seconds), remove the syringe from the vascular catheter access port and discard the used syringe with its wrapper. As may be appreciated, such steps may need to be repeated numerous times over the course of extended medication therapy, e.g. after each infusion and vascular catheter access port reconnection, thereby entailing significant medical personnel time and resulting in substantial medical waste. Further, while unit dose syringes provide good sensitivity for aspiration purposes they are not particularly pressure sensitive for flushing purposes.  
           [0007]    Where multi-dose flush solution reservoirs are employed, medical personnel typically utilize an empty unit dose syringe to draw the flush solution from the reservoir, then follow the same basic procedure noted above in an administering the flush solution. Again, such procedure may be followed a number of times during a medication therapy. Further, contamination concerns may arise when a unit dose syringe is filled from a multi-dose reservoir at the point of use. To address such concern, unit dose syringes are often filled from a multi-dose reservoir within a pharmacy department of a medical care facility utilizing a hepa-filter air hood. However, significant syringe handling is required. Moreover, labeling becomes a further need when a delay is expected between the filling of a unit dose syringe and the usage of the filled syringe.  
         SUMMARY OF THE INVENTION  
         [0008]    In view of the foregoing, primary objectives of the present invention are to reduce the number of steps, complexity and associated time required by medical personnel for the infusion of medical liquids, and in particular flush solutions, in conjunction with IV procedures. More particularly, a specific objective is to reduce the number of connections/disconnections made for flushing purposes in relation to each liquid medication infusion.  
           [0009]    An additional objective of the present invention is to provide one or more of the noted medical liquid administration benefits in a manner that also enhances the maintenance of sterility, thereby reducing any risk of infection.  
           [0010]    Yet another objective of the present invention is to reduce medical waste associated with the IV administration of flush solutions.  
           [0011]    The above objectives and additional advantages are met by various aspects of the present invention. Such aspects comprise methodology and apparatus directed to the repeated administration of a medical liquid from a single source to a patient.  
           [0012]    In one aspect, an inventive method is provided that includes the steps of filling a syringe with a medical liquid and providing a tubing length for interconnection to the syringe. The method further includes the step of packaging the pre-filled syringe and tubing length, e.g. for subsequent transport, storage and use. To facilitate use after unpackaging, the tubing length may be interconnected to the pre-filled syringe prior to packaging. Preferably, the tubing length is also provided with at least one outlet connector at its distal end for selective interconnection with a vascular catheter access port to a patient.  
           [0013]    In one embodiment a male luer connector is provided at the distal end of the tubing length. In another embodiment a Y-site member is provided at the distal end, wherein the Y-site member includes a male luer connector outlet and female luer connector inlet (e.g. for selective fluid interconnection to a vascular catheter access port and a liquid medication source, respectively).  
           [0014]    The medical liquid may comprise a volume of medical liquid, e.g. between about 10 ml. and 200 ml. More particularly, the present inventors have recognized that to satisfy vascular catheter flushing needs of a given patient in connection with successive infusions of liquid medication over an extended time period the syringe may be pre-filled with a flush solution volume of at least about 40 ml., and most preferably about 60 ml. Such volume allows for repeated vascular catheter flushing, e.g. both prior and subsequent to liquid medication infusion to insure vascular catheter functionality. In the later regard, vascular catheter flushing prior to drug infusion is particularly desirable in conjunction with procedures where a vascular catheter and liquid medication source are disconnected/reconnected between successive infusions.  
           [0015]    In relation to the noted method, the inventors have further recognized the desirability of maintaining a relatively low flow rate at a vascular catheter during catheter flushing. As such, the noted tubing length is preferably of a “microbore” type (e.g. having an inside diameter of between about 0.75 mm and 1.50 mm).  
           [0016]    The noted method may further include the step of sterilizing the pre-filled syringe and tubing length. In this regard, the sterilizing step may entail exposing the pre-filled syringe and tubing length to gamma radiation. Moreover, the syringe and tubing length may be exposed simultaneously to gamma radiation (e.g. after interconnection). Where gamma radiation is utilized, sterilization may occur either prior to or after the packaging step.  
           [0017]    As will be understood, the inventive apparatus corresponding with the noted method comprises a syringe filled with a medical liquid (e.g. a flush solution) and a tubing length that may be interconnected to the pre-filled syringe prior to packaging. At least one connector may be interconnected to a distal end of the tubing length. Such connector may be adapted and otherwise sized for ready interconnection to and disconnection from a vascular catheter access port. In one embodiment, the connector may be a male luer connector. Correspondingly, a protective screw-on/off cap may be provided on the connector. In another embodiment, a distal Y-site member is provided having both a male luer outlet connector and a female luer inlet connector, each of which may be provided with screw-on/off caps.  
           [0018]    The apparatus may further include an enclosure within which the pre-filled syringe and tubing length are sealably disposed, e.g. prior to transport, storage and use. Such enclosure may comprise a material that facilitates ready heat sealing. Further, the enclosure material may be of a type that accommodates the utilization of gamma radiation for sterilization of the pre-filled syringe and tubing length after placement within the packaging.  
           [0019]    As noted above, the medical liquid may comprise a volume of flush solution that is preferably at least about 40 ml., and most preferably about 60 ml. By way of example, the flush solution may be a saline solution or heparin-containing solution.  
           [0020]    In another aspect of the present invention, an inventive method is provided for use in the administration of medical liquids through a vascular catheter. The method comprises a first step of removing a syringe and tubing length from a sealed package, wherein the syringe is pre-filled with a medical liquid. The tubing length may be pre-connected to the pre-filled syringe, thereby facilitating use upon unpackaging. Alternatively, the tubing length may be interconnected to the pre-filled syringe after unpackaging. Preferably, an outlet connector is interconnected to a distal end of the tubing length for ready interconnection with a vascular catheter access port.  
           [0021]    The method further includes the steps of fluidly interconnecting the tubing length to an access port to a vascular catheter inserted in a patient (e.g. via use of the noted connector), and administering medical liquid from the syringe to the patient through the tubing length and vascular catheter. For extended therapy applications the administering step may include the dispensing of successive increments of the medical liquid over a plurality of separated time intervals. In this regard, the administration of the medical liquid may entail the progressive advancement of a plunger into the barrel of the syringe over the course of the separated time intervals.  
           [0022]    In primary applications, the medical liquid comprises a catheter flush solution, wherein the administering step may provide for the administration of between about 2 ml. and 10 ml. of flush solution, per occasion. In this regard, the method may also include the further step of infusing a liquid medication to the patient via the vascular catheter between each of the noted time intervals during which the flush solution is administered. In particular, the inventive method may provide for the flushing of a vascular catheter from the pre-filled syringe after and/or prior to each liquid medication infusion that is administered through the vascular catheter. Of note, when a Y-site member is provided at the distal end of the tubing length the flush solution administration and liquid medication infusion steps may each be repeated a plurality of times while advantageously maintaining the interconnections between the pre-filled syringe and the Y-site member and between the liquid medication source and the Y-site member.  
           [0023]    In another aspect of the present invention, an administration apparatus is provided for administering a medical liquid from a syringe, such as the pre-filled syringe noted above, when interconnected to a vascular catheter. The apparatus includes a first holder member for restrainably engaging one of a plunger and cylinder of a syringe, and a second holder member for restrainably engaging the other of the plunger and cylinder of a syringe. Additionally, the second holder member may be spring-loaded towards the first holder member, and the apparatus may include a drive means for mechanically driving the first holder member towards the second holder member along a travel path. As will be further described, the combination of a mechanical drive means and an opposed spring-loading yields an easy to use apparatus capable of administering successive increments of a medical liquid (e.g. a flush solution) from a syringe over an extended time period.  
           [0024]    The spring-loading of the second holder members is preferably established to be at least about 5 psi, and most preferably between about 10 psi and 15 psi. Further, the second holder, member may be provided to permit a user to manually move the second holder member away from the first holder member against the noted spring-loading. More particularly, a least one lever arm may be pivotably disposed to effect movement of the second holder member towards the first holder member. As will be further described, such an arrangement provides a means for highly sensitive aspiration of a vascular catheter that is interconnected to a syringe employed with the apparatus.  
           [0025]    In one arrangement, the inventive apparatus includes a housing to which the second holder member is pivotably interconnected, and at least one spring member for providing the spring-loading of the second holder member towards the first holder. Preferably, the second holder member is pivotable to travel a distance (e.g. relative to the housing) that is at least as great as the distance traveled by the first holder member (e.g. relative to the housing) in conjunction with the administration of a given increment of medical liquid.  
           [0026]    To further facilitate the incremental administration of medical liquid utilizing the inventive apparatus, the apparatus may further include stop means for restricting movement of the first holder member at a plurality of spaced positions along the travel path. By way of primary example, the stop means may include a plurality of stops corresponding with the plurality of stop positions and at least one catch member for restrainably and successively engaging the plurality of stops. Preferably, the plurality of stops may be located along the travel path and the catch member may be interconnected to the first holder member and spring-loaded towards the plurality of stops. In the later regard, the spring-loading of the catch member may be established at between about 2 psi and 5 psi, and most preferably about 3 psi, wherein the catch member may be manually disengaged relative to the stops.  
           [0027]    In one arrangement, the catch member may be a pawl that is pivotably interconnected to the first holder member. In turn, the stop means may further include an actuator member for pivoting the pawl away from the plurality of stops against the spring-loading thereof.  
           [0028]    In one embodiment, the drive means of the inventive apparatus includes a first drive arm pivotably carried by the first holder member to effect movement of the first holder member between successive ones of said plurality of stop positions (e.g. upon being pivoted by a user). Preferably, the first drive arm is provided so that a restricted pivot range, or stroke length, is defined, wherein a full stroke moves the first holder member a first predetermined number of stop positions (e.g. one or more) to effect the administration of a first predetermined increment of medical liquid.  
           [0029]    In the noted embodiment, the drive means may further include a drive shaft rotatably supported by the first holder member and a ratchet means supported by the drive shaft and interconnected to the first drive arm. The ratchet means may function to translate pivotable movement of the first drive arm between first and second positions (e.g. defining a full stroke length therebetween) to rotational movement of the drive shaft. The ratchet means may further function to automatically return the first drive arm from its second position to its first position without rotating the drive shaft.  
           [0030]    The drive means may further include a second drive arm that is also pivotally carried by the first holder member to effect movement of the first holder member between successive ones of said plurality of stop positions (e.g. upon being pivoted by a user). Again, the second drive arm is provided so that a restricted pivot range, or stroke length, is defined, wherein a given full stroke moves the second holder member a second predetermined number of stop positions (e.g. one or more) to effect the administration of a second predetermined increment of medical liquid. Of note, the stroke lengths of the first and second drive arms may be advantageously established to be different, wherein the first and second predetermined number of stop positions moved per stroke are different, as well as the resulting first and second predetermined increments of medical liquid administered from a syringe employed with the apparatus. In one arrangement the first and second increments may be established at 2.5 ml. and 5 ml.  
           [0031]    The second drive arm also may be connected to the ratchet means, wherein the ratchet means functions to translate pivotable movement of the second drive arm between first and second positions (e.g. defining a full stroke length therebetween) to rotational movement of the drive shaft. Again, the ratchet means may further function to automatically return the second drive arm from its second position to its first position without rotating the drive shaft.  
           [0032]    In another embodiment, the drive means may include a drive spring that is activatable to apply a spring force to the first holder member to effect movement thereof across the plurality of stop positions upon a single activation of the drive spring. In one approach, the drive spring may be disposed to be in tension upon activation. In such approach, a negator-type spring may advantageously employed. In another approach, the drive spring may be disposed in compression upon activation. In either case, the spring member may be actuated a single time upon loading of a syringe into the inventive apparatus. Subsequently, the spring member may be successively employed to apply a spring force to effect incremental administration of medical liquid from the syringe by the apparatus.  
           [0033]    In this embodiment, the inventive apparatus may be provided so that the stop means is controllable to provide at least two different spacings between the plurality of noted stop positions. Such control allows at least two different increments of medical liquid administration to be achieved. More particularly, first and second sets of stops may be provided, wherein a first spacing between the first set of stops is different from a second spacing between the second set of stops. In turn, a user may selectively employ the first or second set of stops in use of the inventive apparatus.  
           [0034]    As may be appreciated, one or more of the above-noted aspects may be implemented in an overall system for providing a medical liquid to a patient. In one embodiment, the system may comprise the steps of packaging a syringe filled with a flush solution at a first location (e.g. a location where the syringe is filled with the flush solution), packaging the filled syringe at a second location (e.g. a patient care site), positioning the filled syringe in an administration apparatus at the second location, and utilizing the administration apparatus to control the administration of the flush solution to a patient through a vascular catheter in a plurality of successive increments over a corresponding plurality of separated time intervals.  
           [0035]    As may be appreciated, the system may include the further step of interconnecting a tubing length to the syringe prior to the packaging step. Preferably, an outlet connector is also provided at a distal end of the tubing length. Further, the syringe may be filled with at least about 40 ml. of the flush solution prior to the packaging step. Additionally, the filled syringe and interconnected tubing length may be sterilized (e.g. via exposure to gamma radiation) prior to said unpackaging step (e.g. after said packaging step and prior to transport to a patient care site).  
           [0036]    In conjunction with the utilization of an administration apparatus, the system may employ the administration apparatus to progressively drive the syringe plunger into the syringe barrel over the plurality of separated time intervals. For such purposes, the syringe plunger and syringe barrel may be restrainably positioned in first and second holder members, respectively, comprising the administration apparatus. In turn, at least one of the first and second holder members may be employed to effect relative movement between the syringe plunger and syringe barrel, wherein the syringe plunger is incrementally advance(s) within the syringe barrel to administer the flush solution.  
           [0037]    As will be appreciated, the system may also include the steps of interconnecting and disconnecting an outlet connector provided at the distal end of the tubing length a vascular catheter access port. For example, a male luer connector allows for easy connection/disconnection.  
           [0038]    In relation to the noted system, a liquid medication may be infused to a patient through a vascular catheter between the plurality of separated time intervals of flushing. In conjunction with liquid medication infusion, the system may further include the steps of: (i) first administering an increment of the flush solution prior to liquid medication infusion, and (ii) second administering an increment of the flush solution after liquid medication infusion. Of note, the steps of infusing a liquid medication and administering a flush solution through the vascular catheter may be repeated a plurality of times while conveniently maintaining the noted positioning of the syringe in the administration apparatus.  
           [0039]    Further, in one arrangement, liquid medication infusion may be completed via selective interconnection of a liquid medication source to a Y-site member provided at the distal end of the above-noted tubing length. In turn, the flush solution administration and liquid medication infusion steps may each be repeated a plurality of times while advantageously maintaining the interconnections between the pre-filled syringe and the Y-site member and between the liquid medication source and the Y-site member. The maintenance of such interconnections simplifies the procedure and enhances the maintenance of sterility.  
           [0040]    In later regard, the noted system and methods may also provide for the sterile docking of a male inerconnector provided at the distal end of the tubing length attached to the pre-filled syringe. By way of example, a docking apparatus and method may be employed as taught in a U.S. patent application entitled “STERILE DOCKING APPARATUS AND METHOD”, filed on Aug. 22, 2002, the entirety of which is hereby incorporated by reference.  
           [0041]    Additional aspects and advantages of the present invention will become apparent to those skilled in the art upon consideration of the further description provided hereinbelow. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0042]    [0042]FIG. 1A illustrates one embodiment of a pre-filled syringe assembly comprising the present invention.  
         [0043]    [0043]FIG. 1B illustrates the embodiment of FIG. 1A as packaged for transport and storage.  
         [0044]    [0044]FIG. 2A illustrates another embodiment of a pre-filled syringe assembly comprising the present invention.  
         [0045]    [0045]FIG. 2B illustrates the embodiment of FIG. 1B as packaged for transport and storage.  
         [0046]    [0046]FIG. 3. illustrates one embodiment of a method for providing a pre-filled syringe assembly according to the present invention.  
         [0047]    [0047]FIG. 4 illustrates one embodiment of a method for use in the administration of a medical liquid to a patient.  
         [0048]    [0048]FIG. 5 illustrates further optional steps for use in connection with the method embodiment of FIG. 4.  
         [0049]    [0049]FIG. 6 illustrates one embodiment of an apparatus for use in administering medical liquid from the syringe assembly embodiment of FIGS. 1A and 11B.  
         [0050]    [0050]FIG. 7 is another view of the apparatus and syringe assembly embodiments shown in FIG. 6.  
         [0051]    [0051]FIG. 8 is a cross-section side view of the apparatus and syringe assembly embodiments shown in FIG. 6.  
         [0052]    [0052]FIGS. 9A, 9B,  9 C and  9 D are perspective, top, front and rear views of the apparatus and syringe assembly embodiments shown in FIG. 6.  
         [0053]    [0053]FIG. 10 illustrates another embodiment of an administration apparatus for use with the syringe assembly embodiments of FIGS. 1A and 1B.  
         [0054]    [0054]FIG. 11 is another view of the apparatus and syringe assembly embodiments as shown in FIG. 10.  
         [0055]    [0055]FIG. 12 is a cross-sectional side view of the apparatus and syringe assembly embodiments as shown in FIG. 10.  
         [0056]    [0056]FIG. 13 is a cross-sectional side view of the dispenser assembly embodiment and syringe assembly embodiment as shown in FIG. 6.  
     
    
     DETAILED DESCRIPTION  
       [0057]    [0057]FIGS. 1A, 1B and  2 A,  2 B illustrate alternate embodiments of a pre-filled syringe assembly  10  comprising the present invention. In each embodiment, the assembly  10  includes a syringe  20  filled with a medical liquid  30 , and a tubing length  40  interconnected with or interconnectable to the pre-filled syringe  20 . The assembly  10  further includes a packaging enclosure  50  for sealably receiving the pre-filled syringe  20  and tubing length  40 .  
         [0058]    The syringe  20  includes a barrel  22  and plunger  24  slidably disposed therewithin. As shown in FIG. 1, plunger  24  is located in a retracted position and barrel  22  is filled with medical liquid  30  as packaged. Consequently, assembly  10  may be readily employed by medical personnel when unpackaged. Barrel  22  may be provided with volumetric gradation indicators thereupon and/or a contents description provided thereupon (e.g. via printing and/or labeling). Plunger  24  and barrel  22  may be sized to accommodate a relatively large volume of medical  2  liquid  30 , e.g. in one arrangement plunger  24  presents a liquid interface of about 1 in.  
         [0059]    In primary applications, medical liquid  30  may comprise a relatively large volume of a vascular catheter flush solution. More particularly, a volume of at least about 40 ml. of flush solution, and most preferably about 60 ml. of flush solution is provided for use in successive flushing procedures over the course of extended patient care. By way of primary example, the flush solution may be a saline solution or heparin-containing solution.  
         [0060]    The tubing length  40  is preferably of a “microbore” type, e.g. having an inside diameter of between about 0.75 mm and 1.50 mm. Further, for common arrangements the tubing length may be between about 30 in. and  75  in., and most typically about 60 inches. The tubing length  40  may be preferably provided with an outlet connector  42  at a distal end thereof, wherein the outlet connector  42  is adapted for ready interconnection with a vascular catheter access port. For example, outlet connector  42  may be a male luer connector sized for screw-on/off interconnection with a complimentary female luer connector defining a vascular catheter access port. To facilitate the visual inspection of fluids therein, outlet connector  42  and/or tubing length  40  may be at least partially transparent. To maintain the sterility of outlet connector  42 , a protective cap  44  may also be provided. Further, a line clip  46  (e.g. having a key-hole slot) may be included about tubing length  40  for selective occlusive positioning during use.  
         [0061]    As shown, tubing length  40  may be interconnected to barrel  22  prior to packaging. For example, the proximal end of tubing length  40  may be provided with a female luer connector  48  that is rotatably secured to a male luer fitting of syringe  20 . Alternatively, the proximal end of tubing length  40  may be fixedly interconnected to syringe  20  prior to packaging.  
         [0062]    In one arrangement, the tubing length  40  may be both interconnected to syringe  20  and primed prior to packaging. To prime the tubing length  40 , the syringe  20  may be initially overfilled with a volume of medical liquid  30 . Then, with cap  44  removed, plunger  24  may be advanced so that a small portion of the medical liquid  30  is dispensed from syringe  20  to prime tubing line  40 . Thereafter, cap  44  may be placed on connector end  42  prior to packaging of assembly  10  in enclosure  50 .  
         [0063]    In another arrangement, the tubing length  40  may be provided with a proximal female luer connector  48  and protective end cap thereupon (not shown), wherein the tubing length  40  is packaged with the pre-filled syringe  30  in a disconnected state. The syringe  30  may be slightly overfilled with medical liquid  30 , wherein tubing length  40  may be interconnected to and primed from syringe  20  after unpackaging. More particularly, after unpackaging the protective caps on each end of the tubing length  40  may be removed and the proximal female luer connector  48  connected to the complimentary outlet end of syringe  20 . Then, plunger  24  may be advanced so that a small portion of medical liquid  30  is dispensed from syringe  20  to prime the tubing line  40 .  
         [0064]    In the embodiment of FIGS. 2A, 2B a Y-site member  60  is interconnected (e.g. fixedly bonded) to the distal end of tubing length  40 . The Y-site member  60  includes an outlet connector  42  and an inlet connector  62 . More particularly, inlet connector  62  may be a female luer connector employable for ready interconnection with a liquid medication source. For example, inlet connector  62  may be provided for ready interconnection with an outlet connector (e.g. a male luer connector) of a tubing line that is interconnected to a multi-dose reservoir of liquid medication (e.g. either directly for use with an infusion pump or via a gravity-fed drip chamber interposed therebetween), or to a multi-dose syringe of liquid medication that is located in an auto-infuser device. Alternatively, the inlet connector  62  may be readily interconnected directly with a syringe containing liquid medication.  
         [0065]    As may be appreciated, pre-filled syringe assembly  10  may be sterilized prior to transport, storage and use. In a primary approach, such sterilization may be completed by exposing syringe  20  to gamma radiation after filling with the medical liquid  20 . Further, gamma radiation exposure may be utilized for sterilization of tubing length  40 . Where tubing length  40  is connected to syringe  20  prior to packaging, the pre-filled syringe  20  and tubing length  40  may be exposed to gamma radiation simultaneously (e.g. after priming of the tubing length  40  as noted above). As will be appreciated, sterilization via gamma radiation exposure may be completed prior to, or after the sealed disposition of pre-filled syringe  20  and tubing length  40  within the packaging enclosure  50 , as shown in FIG. 2.  
         [0066]    By way of summary, FIG. 3 illustrates steps of an exemplary method  100  for providing the syringe assembly  10  described above. The method  100  optionally provides for the interconnection of a tubing length  40  to syringe  20  (step  102 ), e.g. via female luer connector  48 . The method  100  further includes the step of filling the syringe  20  with flush solution  30  (step  104 ). In conjunction with such filling, the method may optionally include priming of the tubing length  40  with the flush solution  30  (step  106 ). As previously indicated, such priming may be achieved by simply advancing the plunger  24  of syringe  20  so as to dispense a small portion of flush solution  30  through tubing length  40 . After priming, the method may further provide for the optional placement of a protective cap  44  on an outlet connector  42  of the tubing length  40  (step  108 ). The pre-filled syringe with interconnected tubing length  40  may then be inserted into the enclosure packaging  50  (step  110 ). Thereafter, the enclosure packaging  50  may be sealed (e.g. via heat sealing). Then, the assembly  10  may be sterilized via exposure of the packaged assembly to gamma radiation (step  112 ). After sterilization, the packaged assembly  10  is ready for transport, storage and use.  
         [0067]    Assembly  10  yields a number of advantages in use. To facilitate an understanding of such advantages reference is now made to FIGS. 4 and 5 which illustrate steps of one method embodiment in which assembly  10  is utilized by medical personnel at a patient care site (e.g. after transport and storage of assembly  10 ).  
         [0068]    With particular reference to FIG. 4, use of assembly  10  may be initiated by removing the pre-filled syringe  20  and an interconnected tubing length  40  from the sealed enclosure  50  (step  202 ). In embodiments where pre-filled syringe  20  and tubing length  40  are packaged in a disconnected state, the two may be readily interconnected upon removal from enclosure  50  (e.g. via use of a female inerconnector  48  noted above). Next, protective cap  44  may be removed from the outlet connector  42  of tubing length  40  (step  204 ). To prime or otherwise ensure that the tubing length  40  is properly primed with the flush solution  30 , the plunger  24  of pre-filled syringe  20  may be advanced until a small amount of the flush solution  30  is dispensed from the outlet connector  42  (step  206 ). Additionally, when a Y-site member  60  is provided at the distal end of tubing length  40 , the inlet connector  62  thereof may be interconnected to a liquid medication source as noted above. In particular, where such interconnection is made to an outlet connector of a tubing line, such tubing line may be primed from the liquid medication source after interconnection.  
         [0069]    At this point, assembly  10  is ready for interconnection to a vascular catheter, e.g. wherein the catheter is already inserted in a patient (step  208 ). Such interconnection may be made by attachment of the outlet connector  42  to an access port to the vascular catheter (e.g. via a screwon connection between complementary luer connector ends).  
         [0070]    The illustrated method further comprises the step of administering the flush solution  30  from pre-filled syringe  20  to the patient through the tubing length  40  and interconnected vascular catheter (step  209 ). Of note, the administration of flush solution  30  may entail a number of optional steps carried out in connection with multiple liquid medication infusions and corresponding flush solution administrations over an extended period of patient care. Such options will be described with reference to FIG. 5.  
         [0071]    As shown, upon interconnection of assembly  10  to a vascular catheter, medical personnel may want to aspirate the vascular catheter (step  210 ), e.g. to insure that the vascular catheter is properly inserted into the patient. To do so, plunger  22  of pre-filled syringe  20  may be slightly retracted/advanced to draw/infuse a small portion of blood through the vascular catheter (step  212 ). Then, medical personnel may desire to flush the vascular catheter with an increment of flush solution  30  from syringe  20  (step  214 ). To do so, the plunger  24  of syringe  20  may be advanced to dispense the desired increment of flush solution  30  (step  216 ). Next, medical personnel may infuse a liquid medication through the vascular catheter (step  218 ). By way of example, the liquid medication may be passed into an inlet connector  62  of a Y-site member  60  provided on tubing length  40 . After infusion of the liquid medication through the vascular catheter, medical personnel may selectively flush the vascular catheter (step  220 ), e.g. to complete infusion of the desired infusion dosage and otherwise reduce subsequent potential blood clotting in the vascular catheter. To do so, plunger  22  of pre-filled syringe  20  may be further advanced to dispense an increment of the flush solution  30  from the syringe  20  (step  222 ). As may be appreciated, the flushing of vascular catheter as per step  222  may be particularly desirable in situations where the infusion of liquid medication through the vascular catheter is to be repeated (step  224 ).  
         [0072]    When no additional liquid medication infusion is desired, tubing length  40  may be disconnected from the access port to the vascular catheter and assembly  10  properly disposed (step  226 ). Where further infusion of a liquid medication is desired, medical personnel may optionally determine whether tubing length  40  is to be disconnected from the vascular catheter (step  228 ), e.g. to facilitate patient movement in the interim time period before the next infusion of liquid medication. When the tubing length  40  is disconnected, the tubing length  40  will need to be selectively reconnected to the vascular catheter prior to the next liquid medication infusion (step  230 ). However, it should be appreciated that, when a Y-site member  60  is utilized, the interconnections between the Y-site member  60  and syringe  20  and between the Y-site member  60  and a liquid medication source may be maintained, i.e. while outlet connector  42  is disconnected from the vascular catheter access port.  
         [0073]    Prior to the next medical liquid infusion, medical personnel may desire to aspirate the vascular catheter (step  210 ), e.g. to insure that the vascular catheter is properly located and/or to insure that a blood clot has not formed within the vascular catheter. To do so, plunger  22  of syringe  20  may be slightly retracted/advanced so as to draw/return a small portion of blood through the vascular catheter (step  212 ). It should be noted that such aspiration is particularly facilitated by an administration apparatus described hereinbelow.  
         [0074]    Prior to the further infusion of liquid medication through the vascular catheter, medical personnel may again desire to flush the vascular catheter thereof (step  214 ). For such purposes, plunger  22  of syringe  20  may again be advanced to dispense another increment of flush solution  30  from the syringe  20  (step  216 ). Thereafter, medical liquid infusion and further flushing may continue in a repeated fashion as indicated by FIG. 5.  
         [0075]    Reference is now made to FIGS.  6 - 9  and FIGS.  10 - 13  which illustrate alternate embodiments  300  and  400  of an apparatus for use in the administration of flush solution  30  of syringe assembly  10 . As will be appreciated, apparatus embodiments  300  and  400  may be advantageously employed to facilitate and otherwise simplify the execution of the various steps described in relation to FIG. 5 above. In FIGS. 6 and 10, syringe assembly  10  is shown loaded in the administration apparatus  300  and  400 , respectively, with outlet connector  42  positioned for ready, rotatable connection to a female luer access port  500  that is fluidly connected by a tubing line  504  to a vascular catheter  510  inserted into the arm of a patient. Further, an inlet connector  62  of a Y-site member  60  is positioned for interconnection to a liquid medication source such as the illustrated syringe  520 . Of course, other liquid medication source arrangements may also be employed. In particular, multi-dose liquid medication sources may be interconnected via a tubing line having an outlet connector (e.g. a male inerconnector).  
         [0076]    As shown in FIGS.  6 - 9 , administrative apparatus  300  includes first and second holder members  310 ,  320  for holding the plunger  24  and barrel  22  of syringe  20 , respectively. The first and second holder members  310 ,  320  are disposed relative to a housing  330  in a manner that facilitates controlled relative movement therebetween, thereby providing for the metered administration of flush solution  30  from syringe assembly  10 .  
         [0077]    More particularly, the first holder member  310  supports a catch assembly  340  that is adapted to successively engage a plurality of stops  350  provided with housing  330  along a travel path of the first holder member  310 . As best shown by FIG. 8, the plurality of stops  350  may be defined by downwardly angled teeth of a stop member  352  disposed on one side of a housing slot  332  along which first holder member  310  travels during use. Another stop member of common configuration (not shown) may be provided on the other side of housing slot  332 .  
         [0078]    The catch assembly  340  includes a catch member  342  and at least one spring  344  that spring-loads the catch member  342  towards the noted plurality of stops  350 . As such, when catch member  342  is in spring-loaded engagement with one of the plurality of stops  350 , movement of the first holder member  310  away from the second holder member  320  is restricted. Preferably, spring(s)  344  provide a spring-loading of between about 2 psi and 5 psi, and most preferably about 3 psi.  
         [0079]    Administrative apparatus  300  also includes a drive assembly  360  supported by first holder member  310  and having first and second drive arms  361 ,  362  for driving the first holder member  310  towards the second holder member  320 , as will be further discussed. Further, the second holder member  320  is spring-loaded towards the first holder member  310 . More particularly, the second holder member  320  includes opposing, U-shaped bottom and top members  321 ,  322 , respectively. The side arms of the bottom member  322  are configured to define side shelves, or seats, which together with the top member  321  combinatively define a slot that is configured to support and retain a complimentary flange located at the top end of the barrel  22  of syringe  20 . In this regard, the outside of each side arm of the bottom member  322  may be notched to slidably engage guide tracks (not shown) on the housing  330  and may be spring-loaded towards the top member  321  by one or more coil spring(s)  324  to assume a biased “home” position as shown in FIGS.  6 - 9 . At the home position movement of the top member  322  away from the spring-loading may be restricted by the housing  330 . Preferably, coil spring(s)  324  apply a spring force of between about 5 psi and 15 psi to the second holder when attached. Further, such spring force is preferably relatively constant across the intended actuation range.  
         [0080]    When one of the drive arms  361 ,  362  of drive assembly  360  is employed to advance the first holder member  310  and plunger  24  towards the second holder member  320  and barrel  22 , the second holder member  320  and barrel  22  may move downward and away from the first holder member  310  and plunger  24  against the noted spring-loading. Such movement of the second holder member  320  allows the catch assembly  340  to engage one of the plurality of stops  350 . Then, second holder member  320  moves back into its home position in response to coil spring(s)  324  as plunger  24  moves towards barrel  22  to effect the metered administration of flush solution  30  from the outlet of barrel  22 .  
         [0081]    In this regard, it should be appreciated that the amount of flush solution 30 metered will be a direct relation to the amount of linear travel of the first holder member  310  between the different locations, or stop positions, at which catch assembly  340  restrainedly engages different ones of the plurality of stop members  350 . As such, the first and second drive arms  361 ,  362  may be provided to effect differing amounts of linear travel of the firsts holder  310  when pivoted. In turn, differing increments of flush solution administration may be realized.  
         [0082]    Of further note, the top member  322  of the second holder number  320  may be pivotably connected along its back to housing  330  and may include lever arms on each side that extend outward beyond housing  330  for convenient control by a user. Specifically, such lever arms may be manually pivoted towards the bottom member  322  by a user against the noted spring-loading, wherein the coil spring(s)  324  is compressed. As may be appreciated, this feature allows a user to selectively aspirate a vascular catheter  520  that is interconnected to a pre-filled syringe  20 . For example, a user may slightly pivot the top member  322  against the spring-loading, wherein the second holder member  320  moves the barrel  24  of syringe  20  away from the plunger  22  held by the first holder member  310 . Such movement may be controlled with a high degree sensitivity to draw blood from a patient through a vascular catheter  520  connected to pre-filled syringe  20 . In turn, upon release of the lever arms, the spring-loaded second holder member  320  will assume its home position as the blood is returned to the patient.  
         [0083]    Reference is now made to FIGS. 9A, 9B,  9 C and  9 D which illustrate in greater detail the first holder member  310 , catch assembly  340  and drive assembly  360 . For purposes of illustration, the second drive arm  362  of drive assembly  360  is shown in phantom lines.  
         [0084]    First holder member  310  includes a bottom portion  311  having a slot  312  configured to receive a complimentary at the top end of plunger  24  of pre-filled syringe  20 . Additionally, the first holder member  310  includes an upstanding yoke portion  314  to which the catch assembly  340  and drive assembly  360  are supportably mounted. The first holder member  310  also includes arms  326  extending on each side and configured for sliding receipt within slots  337  provided on each side of the housing  330  (see FIG. 8).  
         [0085]    Drive assembly  360  includes a shaft member  363  that is rotatably carried by the yoke portion  314  of the first holder member  310 . Each end of the shaft member  363  is configured for sliding receipt positioning within the slots  337  of the housing  330 . Further, toothed drive wheels  364  are interconnected near each end of shaft member  363  and disposed to rotatably engage corresponding drive tracks  335  disposed within housing  330  along the travel path of the first holder member  320 .  
         [0086]    Drive assembly  360  further includes a central ratchet member  365  interconnected to shaft member  363  for co-rotation therewith. Additionally, outer ratchet members  366  are rotatably carried by shaft member  363  on opposing sides of central ratchet members  365 . Each of the outer ratchet members  366  are interconnected to a corresponding one of the drive arms  361 ,  362 , respectively, for co-rotation therewith. The outer ratchet members  366  are also disposed in spring-loaded engagement with central ratchet member  365  by corresponding coil springs  367  mounted on shaft member  363 . For example, one end of each coil springs  367  may be interconnected to a corresponding, adjacent outer ratchet member  366  while the other end of the coil spring  367  is retainably positioned within a slot of the corresponding drive arm  361  or  362 .  
         [0087]    Catch assembly  340  includes support arms  342  which are rotatably interconnected to and supported by shaft member  363 . The above-noted spring member(s)  344  is disposed between catch member  342  and the yoke portion  314  of the second holder member  320 .  
         [0088]    The pivot range of drive arms  361 ,  362  is restricted to define a corresponding maximum, or full stroke length for each, wherein such full stroke lengths may be established to be different. In turn, differing predetermined increments or amounts of flush solution  30  may be administered from syringe  20  when drive arms  361 ,  362  are separately pivoted. For example, in one arrangement the full stroke lengths may be set to provide for selective administration increments of 2.5 ml. and 5 ml.  
         [0089]    A brief summary of the use of administration apparatus with 300 syringe assembly  10  will now be provided. Initially, a user may remove the pre-filled syringe  20  and tubing length  40  from a sealed enclosure  50 , e.g. at a patient care site. Then, the user may locate the first holder member  310  at an appropriate stop position along the plurality of stops  350 , e.g. via manual depression of the catch member  342  and movement thereof with the first holder member  310  in housing slot  332 . Subsequently, the user may load the pre-filled syringe  20  into the administration apparatus  300 . To do so, the flange of barrel  24  is properly oriented and slid into the slot of the second holder member  320  and the flange of the plunger  22  is properly oriented and slid into the slot of the top holder member  310 .  
         [0090]    At this point, it may be pointed out that the administration apparatus  300  may be provided so that when the first holder member  310  is located at a predetermined stop position, e.g. a stop position furthest from the second holder member  320 , the spacing between the first holder member  310  and second member  320  corresponds with the spacing between the flanges of barrel  24  and plunger  22  of pre-filled syringe  20 . Such complimentary design further facilitates use of the syringe assembly  10  and administration apparatus  300 .  
         [0091]    Prior to or after loading of the pre-filled syringe  20  into the administration apparatus  300 , the user may insure the interconnection of tubing length  40  with pre-filled syringe  20  and prime the same. After priming the tubing length  40  may be fluidly interconnected to a vascular catheter  520  inserted into a patient, e.g. via an outlet connector  42  and vascular catheter access port  500 .  
         [0092]    To administer the flush solution  30 , a user simply pivots drive arm  361  or  362 , depending on the desired increment. To aspirate the vascular catheter  520 , a user simply pivots one of the lever arms of the second holder member  320 . Such steps may be repeated as desired to facilitate the various method steps described hereinabove, e.g. in connection with FIG. 5.  
         [0093]    Referring now to FIGS.  10 - 13 , administration apparatus  400  includes first and second holder members  410 ,  420  for holding the barrel  22  and plunger  24  of syringe  20 , respectively, relative to a dispenser housing  430 . The first and second holder members  410 ,  420  are disposed relative to a housing  430  in a manner that again facilitates controlled relative movement therebetween, thereby providing for the metered administration of flush solution  30  from syringe assembly  10 .  
         [0094]    In this regard, the first holder member  410  supports a catch assembly  440  that is adapted to successively engage a plurality of stops  450  provided by housing  430  along a travel path of the first holder member  410 . As best shown by FIGS. 12 and 13, the plurality of stops  450  may be defined by upwardly angled teeth of a stop member  452  disposed parallel to a housing slot  432  along which the first holder member  410  travels during use. The stop member  452  may be selectively moved within housing  430  to present different sets or columns of stops  450 , each having different stop spacings. For example, the stop member  452  may be journaled to housing  430  so that a selection lever  453  may be rotated to rotate the desired column of stops  450  into position for engagement with catch assembly  440 . As will be appreciated, the selected column of stop members  450  will establish the increment or amount of flush solution  30  administered when the first holder member  410  is between successive stop positions.  
         [0095]    The catch assembly  440  includes a catch member  442  in the form of a pawl that is pivotably interconnected to the first holder member  410  and spring-loaded towards the noted plurality of stops  450 , e.g. wherein the spring-loading is preferably between about 2 psi and 5 psi, and most preferably about 3 psi. As such, when catch member  442  is in spring-loaded engagement with one of the plurality of stops  450 , movement of the first holder member  410  towards the second holder member  420  is restricted. As shown, the catch assembly  440  also includes a selectively depressible actuator  444  that functions to pivot the catch member  442  against the spring-loading and out of engagement with the plurality of stops  450 , thereby allowing for movement of the first holder member  410  relative to the second holder member  420 . To help maintain the desired orientation of the first holder member  410 , side arms  411  may be provided on either side to follow complimentary recess tracks  431  provided by housing  430 . As also shown, a toothed track  433  is disposed in opposing relation to the plurality of stops  450  to engage catch member  442  and thereby facilitate controlled movement of the first holder member  410 .  
         [0096]    In this regard, the administration apparatus  400  includes a drive assembly  460  for driving the first holder member  410  towards the second holder member  420 . The drive assembly  460  includes a self-winding spring  461  (e.g. a negator-type spring). More particularly, the spring  461  is anchored to housing  430  at its wound end and interconnected to the first holder member  410  at its free end to pull the first holder member  410  towards the second holder member  420  upon a single activation, i.e. a single unwinding which occurs upon loading of a pre-filled syringe  20 . Preferably, a spring-loading of between 5 and 15 psi is provided by spring  461 .  
         [0097]    As may be appreciated, after loading of a pre-filled syringe  20 , actuator  444  may be pushed to pivot catch member  442  out of engagement with one of the plurality of stops  450  and into engagement with toothed track  433  as the first holder member  410  is pulled toward the second holder member  420 . Upon release of the actuator  444 , the spring-loaded catch member  442  will once again pivot to engage another one of the plurality of stops  450 . Such sequence effects the administration of one increment of flush solution  30 .  
         [0098]    The second holder member  420  of administration apparatus  400  is preferably springloaded towards the first holder member  410 . More particularly, the second holder member  420  is pivotably connected by lever arms  422  to housing  430  and spring-loaded by one or more spring(s) (not shown) located along its pivot axis to assume a “home” position as shown in FIGS.  10 - 13 . Lever arms  422  extend beyond housing  430  and are accessible for manual operation. Further, another arm  425  is pivotably mounted to housing  430  so that it engages, and thereby pivots lever arms  422  when manually pivoted. Such feature may be utilized for vascular catheter  520  aspiration, as previously discussed.  
         [0099]    The embodiments described above are for exemplary purposes only and are not intended to limit the scope of the present invention. Various adaptations, modifications and extensions of the embodiment will be apparent to those skilled in the art and are intended to be within the scope of the invention as defined by the claims which follow.