Patent Publication Number: US-5891096-A

Title: Medicament infusion device

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to medical devices, and more particularly to a medicament infusion device which is adapted to facilitate the metered delivery of fluid from a standard, off-the-shelf partial fill bag without requiring any transfer of fluid from the bag. 
     BACKGROUND OF THE INVENTION 
     There is currently known in the prior art various devices and methodologies for infusing therapeutic fluids directly into an anatomical passage (e.g., a vein or artery) of a patient. Medicaments or therapeutic fluids are typically sold to hospitals in flexible, transparent partial fill bags which are often referred to as &#34;minibags&#34;. These partial fill bags are generally provided with a first outlet port for allowing a tubular fluid line to be fluidly connected thereto, and a second outlet port which serves as an injection site for allowing a needle or other type of piercing tip to be extended into the interior of the bag. 
     One of the most common methods of accomplishing direct fluid infusion into an anatomical passage is through the use of a conventional intravenous (IV) drip unit. Such drip units comprise a fluid filled IV bag which is suspended from a portable hanger assembly. Fluidly connected to the bag and extending therefrom is a tubular fluid line, the distal end of which typically includes an introducer needle connected thereto. In these prior art units, the fluid &#34;drips&#34; from the bag into the tube connected thereto, with the drip rate being adjustable to control the rate at which fluid is introduced into the anatomical passage. The bag is suspended well above the level of the introducer needle, with flow through the fluid line being facilitated by gravity. 
     Though these prior art IV drip units accomplish their intended objective of infusing therapeutic fluids into the anatomical passage of a patient, they posses certain deficiencies which detract from their overall utility. Foremost of these deficiencies is the inability to accurately control or meter the rate at which fluid is infused into the patient. As such, prior art IV drip units are frequently only employed when large volumes of a therapeutic fluid are to be infused into a patient, with the rate of infusion not constituting a critical parameter. 
     In recognition of the deficiencies associated with conventional IV drip units, there has been developed in the prior art various mechanical and electromechanical infusion devices which are adapted to provide a more controlled rate of infusion of a medicament or therapeutic fluid into an anatomical passage. 
     One such prior art device which is marketed and sold by the HealthTech Corporation comprises a spring biased syringe having a flow control orifice. The syringe comprises a plunger member which includes an elongate stem releasably attached to a two-part plunger head having a biasing spring extending between the parts thereof. The stem is pulled relative to the syringe body (which defines the flow control orifice) to facilitate the drawing of a therapeutic fluid into the body. Once the syringe body has been filled to a desired level, the rotation of the stem facilitates the detachment thereof from one part of the plunger head, with such detached part thereafter being biased toward the outlet orifice of the syringe body by the biasing spring. The force applied to the detached part of the plunger head by the biasing spring facilitates a controlled rate of flow of the fluid from the syringe body via the orifice. 
     However, this spring biased syringe also possesses certain deficiencies in relation to the controlled rate of flow of the therapeutic fluid therefrom. In this respect, the force exerted against the detached part of the plunger head by the biasing spring is not constant throughout its entire length of travel. Rather, as the compressed biasing spring is extended, the biasing force exerted against the detached part of the plunger head thereby proportionally decreases. As such, the flow rate of therapeutic fluid from the syringe body typically decreases as the fluid volume within the syringe body decreases. 
     In addition to the foregoing, the prior art spring biased syringe must be disposed of after each use, thereby increasing the costs associated with its use. Moreover, the use of the spring biased syringe necessitates that the therapeutic fluid be transferred from the partial fill bag into the syringe body. As will be recognized, this transfer procedure increases the risk of inadvertent fluid contamination, and requires additional, undesirable handling of the therapeutic fluid. 
     Another prior art infusion device which is marketed and sold by Secure Medical, Inc. under the trademark Med Flo and is the subject of U.S. Pat. No. 4,953,753 comprises a hollow housing or reservoir having a fluid inflatable bladder or balloon disposed therein. The balloon is filled with a therapeutic fluid via an inlet check valve communicating therewith. Fluidly connected to the end of the balloon opposite the inlet check valve is a tubular fluid line which includes a fixed orifice flow control fluidly coupled therewithin. The filling of the balloon with the therapeutic fluid causes the resilient expansion thereof within the housing. In this respect, the resiliency of the balloon forces the fluid into the fluid line, with the rate of flow through the fluid line being regulated by the fixed orifice flow control therewithin. 
     This infusion device, like the spring biased syringe previously described, also possesses deficiencies which detract from its overall utility. In this respect, this prior art device must also be disposed of after each use, thereby increasing the costs associated with the utilization thereof. Additionally, the use of this device also requires that the medicament or therapeutic fluid be transferred from a partial fill bag into the inflatable balloon via a separate transfer procedure. As previously indicated, such transfer procedure increases the risk of fluid contamination 
     Another prior art infusion device is sold by the I Flow Corporation under the trademark SideKick 100 and comprises a hollow housing having a cap including a spring biased plate threadably engaged thereto. Disposed within the housing is a circularly configured bladder which is inflatable with a therapeutic fluid. Subsequent to the placement of the filled bladder within the interior of the housing, the cap is engaged thereto which facilitates the application of compressive pressure to the bladder via the spring biased plate of the cap. 
     However, as in the previously described prior art syringe, the pressure applied to the bladder by the spring biased plate of the cap threadably engaged to the housing is not constant, but rather decreases as the fluid volume within the bladder decreases. Additionally, though only the bladder need be disposed of after each use of the device and both the housing and spring plate cap may be reused, the utilization of this device still necessitates that the therapeutic fluid be transferred from the partial fill bag into the bladder. 
     In another prior art electromechanical infusion device, a conventional syringe filled with a therapeutic fluid is placed into a housing, with the plunger member of the syringe being coupled to a movable actuation mechanism. The device is programmable in a manner regulating the speed at which the actuation mechanism forces the plunger into the syringe body, and hence the rate at which fluid is dispensed from the outlet end of the syringe body. However, this particular electromechanical infusion device is extremely expensive, and requires specialized training for its programming and use. Additionally, once again, the therapeutic fluid must be transferred from the partial fill bag into the syringe which is subsequently placed into the device and coupled to the actuation mechanism. 
     As previously discussed, perhaps the largest deficiency associated with the prior art infusion devices is the necessity of having to transfer the therapeutic fluid from the partial fill bag into the device. Additionally, the prior art mechanical and electro-mechanical infusion devices tend to be extremely costly, with current insurance regulations providing for decreased levels of insurance reimbursement associated with their usage. Moreover, these prior art devices typically do not provide for a highly controlled rate of fluid flow, with certain ones of these devices requiring specialized training for their use thus further increasing the costs associated therewith. 
     The present invention overcomes the deficiencies of prior art mechanical and electromechanical infusion devices by providing a device which is adapted to accommodate standard, off-the-shelf partial fill bags, thus eliminating the necessity of having to conduct a separate fluid transfer operation. Additionally, the infusion device constructed in accordance with the present invention is substantially less costly to manufacture than those known in the prior art, and provides an extremely accurate, controlled rate of fluid flow. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided an infusion device which comprises a generally rectangular housing. Rigidly attached to the housing is a hanger member for facilitating the suspension thereof from a support fixture. Disposed within and releasably attached to the housing is a base plate which is slidably moveable between first and second positions. The base plate includes an integral latch member for facilitating the releasable attachment thereof to the housing. Attached to the base plate and the housing is a biasing mechanism for biasing the base plate to the second position. The biasing mechanism facilitates the movement of the base plate to the second position when the base plate is detached from the housing. 
     In the preferred embodiment, the biasing mechanism comprises a negator spring assembly which itself comprises a negator hub attached to the base plate. Rotatably connected to the negator hub is a spring drum. In addition to the negator hub and spring drum, the negator spring assembly comprises an elongate negator spring having a first end wound about the spring drum and a second end attached to the housing. The negator spring is sized and configured to apply approximately sixteen (16) pounds of load to the base plate. 
     The infusion device further comprises an actuator plate which is disposed within the housing and slidably movable between inner and outer positions. The actuator plate is cooperatively engaged to the base plate in a manner wherein the movement of the base plate toward the second position facilitates the movement of the actuator plate toward the outer position, with the movement of the base plate toward the first position facilitating the movement of the actuator plate toward the inner position. The base and actuator plates each include ramped camming surfaces which cooperate with each other such that the direction of movement of the actuator plate between its inner and outer positions is perpendicular relative to the direction of movement of the base plate between its first and second positions. In the preferred embodiment, these ramped camming surfaces are adapted to provide approximately a four to one cam action against the actuator plate during the movement thereof from the inner position to the outer position. 
     Slidably attached to the housing in spaced relation to the actuator plate is a lid member which is movable between open and closed positions, and is preferably fabricated from a piece of transparent plastic material. The lid member, the actuator plate and the housing define a medicament chamber when the lid member is in the closed position. This medicament chamber is partially defined by the outer surface of the actuator plate which is preferably ramped at an angle of approximately 0.2 degrees and includes a neoprene pad member applied thereto. 
     The infusion device constructed in accordance with the present invention is used by placing a standard, off-the-shelf partial fill bag (i.e., a &#34;mini-bag&#34;) into the medicament chamber. The movement of the actuator plate toward the outer position narrows the distance separating the actuator plate from the lid member, thus reducing the volume of the medicament chamber and facilitating the compression of the bag therewithin. Conversely, the movement of the actuator plate toward the inner position widens the distance separating the actuator plate from the lid member, thus increasing the volume of the medicament chamber and allowing a new partial fill bag to be placed thereinto subsequent to the removal of the empty bag from therewithin. The base plate preferably includes graduation markings applied thereto which protrude from the housing as the base plate moves toward the second position and correspond to the gradually decreasing fluid volume of the partial fill bag during the progressive movement of the actuator plate to the outer position. 
     Further in accordance with the present invention, there is provided a variable rate flow control valve which is used in combination with the infusion device. The flow control valve comprises a housing which defines an inlet passage, an outlet passage, and a flow path fluidly connecting the inlet and outlet passages to each other. The inlet and outlet passages are defined by inlet and outlet portions of the housing, respectively, each of which has an elongate, tubular configuration. The inlet portion of the housing preferably includes a spiked distal end and a retainer barb formed thereon, with the outlet portion of the housing including a Luer/tubing adaptor formed thereon. The flow path itself preferably comprises a groove which is formed within the housing and has a generally V-shaped cross-sectional configuration of decreasing depth as it extends toward the outlet passage. Additionally, the flow path may be formed to have a tortuous, serpentine configuration, or alternatively a generally U-shaped configuration. 
     Disposed within the housing adjacent the flow path is a resilient disc member which is preferably fabricated from silicone having a durometer hardness of approximately 40. Also disposed within the housing and abutted against the disc member is a plunger member. 
     The flow control valve further comprises a cap member which is rotatably connected to the housing and cooperatively engaged to the plunger member in a manner wherein the rotation of the cap member in first direction facilitates the movement of the plunger member toward the flow path and the compression of the disc member. Conversely, the rotation of the cap member in a second direction opposite the first direction facilitates the movement of the plunger member away from the flow path and the resilient return of the disc member to an uncompressed condition. The compression of the disc member resulting from the application of compressive force thereto by the plunger member causes the resilient deformation of the disc member into the flow path. In the preferred embodiment, the plunger member and the cap member each include camming surfaces which are cooperatively engaged to each other such that the rotational movement of the cap member facilitates the axial movement of the plunger member relative thereto. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These, as well as other features of the present invention, will become more apparent upon reference to the drawings wherein: 
     FIG. 1 is a top perspective view of the infusion device of the present invention; 
     FIG. 2 is a bottom perspective view of the infusion device of the present invention; 
     FIG. 3 is an exploded view illustrating the components of the infusion device of the present invention; 
     FIG. 4 is a perspective view of the variable rate flow control valve of the infusion device of the present invention; 
     FIG. 5 is an exploded view illustrating certain components of the flow control valve shown in FIG. 4; 
     FIG. 6 is a cross-sectional view of the flow control valve shown in FIG. 4; 
     FIG. 7 is a cross-sectional view taken along line 7--7 of FIG. 6; 
     FIG. 8 is a cross-sectional view illustrating an alternative manner of forming the portion of the flow control valve shown in FIG. 7; 
     FIG. 9 is a cross-sectional view of the infusion device shown in FIGS. 1 and 2 as in a first, uncompressed position; and 
     FIG. 10 is a cross-sectional view of the infusion device shown in FIGS. 1 and 2 as in a second, compressed position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings wherein the showings are for purposes of illustrating a preferred embodiment of the present invention only, and not for purposes of limiting the same, FIGS. 1 and 2 perspectively illustrate the medicament infusion device 10 constructed in accordance with the present invention. Referring now to FIGS. 1-3, the infusion device 10 comprises a rectangularly configured housing 12 including opposed, laterally extending top and bottom walls 14, 16, and opposed, longitudinally extending sidewalls 18. As seen in FIGS. 9 and 10, in addition to the top, bottom and sidewalls 14, 16, 18, the housing 12 includes a back wall 20. Rigidly attached to the outer surface of the top wall 14 in approximately the center thereof is a hanger member 22 which is used to suspend the housing 12, and hence the infusion device 10, from a support fixture. The preferred method of attaching the hanger member 22 to the top wall 14 is via a sonic welding process, though alternative attachment methods may also be employed. 
     Disposed within the housing 12 and releasably attached thereto is a generally rectangular base plate 24. In the infusion device 10, the base plate 24 is slidably moveable between a first position (shown in FIG. 9) and a second position (shown in FIG. 10). As seen in FIGS. 9 and 10, the base plate 24 is positioned within the housing 12 such that the generally planar back surface thereof is abutted against and slidably movable along the inner surface of the back wall 20. To facilitate its releasable attachment to the housing 12, the base plate 24 includes an integral latch member 26 extending from the approximate center of the top edge thereof. 
     As seen in FIGS. 1 and 9, the base plate 24 is releasably attached to the housing 12 by extending its latch member 26 through a complementary slot 28 disposed within the top wall 14. After being extended through the slot 28, the latch member 26 is engaged to the top edge of the back wall 20. When the latch member 26 is engaged to the housing 12, and in particular to the back wall 20 thereof, the base plate 24 is in its first position. When in the first position, the base plate 24 is disposed almost entirely within the interior of the housing 12. In this respect, only the bottom edge of the base plate 24 slightly protrudes from the housing 12 via an elongate slot 30 disposed within the bottom wall 16, as seen in FIGS. 2 and 9. 
     Extending perpendicularly from the front surface of the base plate 24 in opposed relation to each other is an identically configured pair of wedge-shaped camming members 32, the outer surfaces of which are substantially continuous with respective ones of the longitudinal side edges of the base plate 24. The camming members 32 extend from the top edge of the base plate 24, and terminate inwardly from the bottom edge thereof. The camming members 32 each define an inclined or ramped camming edge 34 which slopes downwardly toward the bottom edge of the base plate 24. 
     Referring now to FIGS. 2, 3, 9 and 10, to facilitate the movement of the base plate 24 to the second position (shown in FIG. 10) when the latch member 26 thereof is detached from the housing 12, attached to the front surface of the base plate 24 between the camming members 32 is a biasing mechanism 36 which biases the base plate 24 to the second position. The biasing mechanism 36 comprises a negator spring assembly including a cylindrically configured negator hub 38 which is attached to the front surface of the base plate 24. Rotatably connected to the negator hub 38 is a spring drum 40. 
     In addition to the negator hub 38 and spring drum 40, the negator spring assembly includes an elongate negator spring 42 having a first end which is secured to and wound about the spring drum 40, and a second, distal end which is attached to the housing 12. In this respect, the distal end of the negator spring 42, which includes an aperture 44 disposed therein, is extended through a slot 46 which is disposed in the bottom wall 16 and extends in perpendicular relation to the slot 30. Subsequent to the extension of the distal end of the negator spring 42 through the slot 46, a retaining pin 48 is advanced through the aperture 44. Due to the tension exerted thereon by the negator spring 42, the pin 48 is maintained in direct engagement to the outer surface of the bottom wall 16, as seen in FIGS. 2, 9 and 10. It will be recognized by those of ordinary skill in the art that alternative methods may be employed to facilitate the attachment of the negator spring 42 to the housing 12. 
     As previously explained, the movement of the base plate 24 to its second position (shown in FIG. 10) is facilitated by the detachment of the latch member 26 thereof from the housing 12. As seen in FIGS. 1, 2, 9 and 10, as the base plate 24 is moved from its first position toward its second position, the same is gradually advanced from the slot 30 disposed within the bottom wall 16 of the housing 12. In the infusion device 10, the negator spring 42 is sized and configured to apply approximately sixteen (16) pounds of load to the base plate 24 to facilitate the movement thereof to its second position. 
     The return of the base plate 24 to its first position is accomplished by applying pressure to the bottom edge thereof in an amount sufficient to overcome the negator spring 42. Such pressure is applied until such time as the latch member 26 re-engages the housing 12, and in particular the top edge of the back wall 20 thereof. The movement of the base plate 24 back toward its second position is accomplished by pushing the latch member 26 toward the hanger member 22 so as to facilitate its disengagement from the housing 12. As seen in FIG. 3, the front surface of the base plate 24 adjacent the bottom edge thereof includes graduation markings 50 applied thereto. As will be recognized, these graduation markings 50 progressively protrude from the housing 12 as the base plate 24 moves toward its second position. The use of these graduation markings 50 will be discussed in more detail below. 
     The infusion device 10 constructed in accordance with the present invention further comprises a generally rectangular actuator plate 52 which is also disposed within the housing 12, and is slidably moveable between an inner position (shown in FIG. 9) and an outer position (shown in FIG. 10). In this respect, the actuator plate 52 is cooperatively engaged to the base plate 24 in a manner wherein the movement of the base plate 24 toward its second position facilitates the movement of the actuator plate 52 toward its outer position. Conversely, the movement of the base plate 24 toward its first position facilitates the movement of the actuator plate 52 toward its inner position. 
     As best seen in FIGS. 3, 9 and 10, the actuator plate 52 includes an opposed pair of identically configured camming members 54 which extend perpendicularly relative to the back surface thereof. The outer surfaces of the camming members 54 are continuous with the longitudinally extending side edges of the actuator plate 52. The camming members 54 each define an inclined or ramped camming edge 56 which is sloped downwardly toward the top edge of the actuator plate 52. As such, the camming edges 34, 56 of the base and actuator plates 24, 52 slope in opposite directions, though the inclination angles thereof are identical. 
     As further seen in FIGS. 9 and 10, the actuator plate 52, and in particular the front surface 58 thereof, does not extend in parallel relation to the back wall 20 of the housing 12 when the actuator plate 52 is disposed therein. Rather, the front surface 58 is preferably ramped at an angle of approximately 0.2 degrees, with the top edge of the actuator plate 52 being spaced furthest from the back wall 20. Additionally, formed within the front surface 58 of the actuator plate 52 and extending to the bottom edge thereof is a cavity 60, the use of which will be discussed below. Further, attached to the front surface 58 is a rectangularly configured pad member 62 which is preferably fabricated from neoprene. In the infusion device 10, the pad member 62 is sized such that the top and longitudinally extending side edges thereof are substantially flush with the top and side edges of the actuator plate 52, with the bottom edge of the pad member 62 extending to but not beyond the cavity 60 formed within the front surface 58. 
     In the infusion device 10, the base and actuator plates 24, 52 are cooperatively engaged to each other within the housing 12 in the manner shown in FIGS. 9 and 10. In this respect, the base and actuator plates 24, 52 are oriented such that the camming edges 34, 56 thereof are in direct, sliding contact with each other. Due to the configuration of the camming members 32, 54, and hence the camming edges 34, 56, the direction of movement of the actuator plate 52 between its inner and outer positions is perpendicular relative to the direction of movement of the base plate 24 between its first and second positions. In the preferred embodiment, the camming edges 34, 56 which are cooperatively engaged to each other are adapted to provide approximately a four to one cam action against the actuator plate 52 during the movement thereof from the inner position (shown in FIG. 9) to the outer position (shown in FIG. 10). The significance of this cam action ratio will also be discussed in more detail below. 
     Referring now to FIGS. 1-3, 9 and 10, the infusion device 10 of the present invention further comprises a generally rectangular lid member 64 which is slidably attached to the housing 12 in spaced relation to the front surface 58 of the actuator plate 52. The lid member 64 is preferably fabricated from a transparent piece of plastic material, though other transparent or semi-transparent materials may also be utilized. The slidable attachment of the lid member 64 to the housing 12 is facilitated by the receipt of a pair of flange portions 66 extending along the longitudinal side edges of the lid member 64 into respective ones of a complementary pair of channels 68 extending along the front edges of the sidewalls 18 of the housing 12. When slidably attached to the housing 12, the lid member 64 is selectively moveable between open and closed positions. When in the closed position, the lid member 64, along with portions of the housing 12 and the front surface 58 of the actuator plate 52, collectively define a rectangularly configured medicament chamber 70 which is shown in FIGS. 9 and 10. 
     In view of the manner in which the base and actuator plates 24, 52 move relative to each other, when the lid member 64 is in the closed position and partially defines the medicament chamber 70, the movement of the actuator plate 52 toward its outer position narrows the distance separating the front surface 58 thereof from the lid member 64, thus reducing the volume of the medicament chamber 70. Conversely, the movement of the actuator plate 52 toward its inner position widens the distance separating the front surface 58 thereof from the lid member 64, thus increasing the volume of the medicament chamber 70. The significance of this selective narrowing and widening of the medicament chamber 70 will be discussed in more detail below as well. 
     Referring now to FIGS. 3, 9 and 10, the infusion device 10 constructed in accordance with the present invention is adapted to be used in conjunction with a standard, off-the-shelf partial fill bag 72, often referred to as a &#34;mini-bag&#34;. The bag 72 is fabricated from a flexible, transparent material, and is filled with a particular therapeutic fluid. Formed within the bag 72 is a first outlet port 74 which is sized and configured to facilitate the fluid connection of the bag 72 to a tubular fluid line. In addition to the first outlet port 74, the bag 72 is formed to include a second outlet port 76 which comprises an injection site adapted to permit a piercing tip to be advanced therethrough into fluid communication with the contents of the bag 72. As will be recognized, the first outlet port 74 is typically utilized when the contents of the bag 74 are infused directly into a patient via a tubular fluid line, with the second outlet port 76 being utilized when the contents of the bag 72 are to be transferred to another infusion device. 
     In the infusion device 10, the bag 72 is placed into the medicament chamber 70 subsequent to the movement of the lid member 64 to the open position. However, prior to the placement of the bag 72 into the medicament chamber 70, the second outlet port 76 thereof is preferably interfaced (i.e., fluidly connected to) a variable rate flow control valve 78, the structure of which will now be described with particular reference to FIGS. 3-8. 
     As included in the infusion device 10, the variable rate, flow control valve 78 comprises a housing 80 which includes an elongate, tubular inlet portion 82, an elongate, tubular outlet portion 84, and a hollow, generally cylindrical body portion 86 which defines an interior chamber. As seen in FIG. 6, one end of the interior chamber of the body portion 86 is defined by a circularly configured interior surface 88 of the housing 80. Extending longitudinally through the inlet portion 82 is an inlet passage 90, while extending longitudinally through the outlet portion 84 is an outlet passage 92. The inlet and outlet passages 90, 92 each communicate with the interior chamber of the body portion 86 via respective ones of a pair of apertures 94 disposed within the interior surface 88 of the housing 80. 
     As best seen in FIG. 7, formed within the interior surface 88 and extending between the apertures 94 is a flow path 96 which has a generally U-shaped configuration. The flow path 96 preferably comprises a groove which has a generally V-shaped cross-sectional configuration. The groove is also preferably formed to be of decreasing depth as it travels from the aperture 94 communicating with the inlet passage 90 to the aperture 94 communicating with the outlet passage 92. As an alternative to the generally U-shaped flow path 96 shown in FIG. 7, a flow path 96a having a tortuous, serpentine configuration may be formed in the interior surface 88 of the housing 80 between the apertures 94. The use of the flow path 96, 96a will be discussed in more detail below. 
     In the flow control valve 78, the inlet portion 82 of the housing 80 is preferably formed to include a beveled or spiked distal end which defines a piercing tip 98. Formed on the outer surface of the inlet portion 82 in relative close proximity to the spiked distal end thereof is a retainer barb 100. Importantly, the piercing tip 98 is adapted to facilitate the advancement of the inlet portion 82 through the second outlet port 76 of the bag 72 such that the inlet passage 90 communicates with the contents of the bag 72. Subsequent to the advancement of the inlet portion 82 through the second outlet port 76, the same is maintained in engagement to the bag 72 by the retainer barb 100. 
     The distal end of the outlet portion 84 of the housing 80 is preferably formed with a tapered, blunt configuration to facilitate its insertion into and frictional retention within one end of the lumen of a tubular fluid line. Formed about the outer surface of the outlet portion 84 in relative close proximity to the distal end thereof is a Luer connector 102 including Luer threads 104 formed on the interior surface thereof. Formed on and extending radially outward from the outer surface of the Luer connector 102 is a retention tab 106, the use of which will also be discussed below. 
     Referring now to FIGS. 5 and 6, the flow control valve 78 further comprises a cylindrically configured, resilient disc member 108 which is disposed within the interior chamber defined by the body 86. The disc member 108 is preferably fabricated from silicone having a durometer hardness of approximately 40, and is sized having a diameter which is substantially equal to the diameter of the circularly configured interior surface 88. In this respect, as seen in FIG. 6, one end of the disc member 108 is normally abutted against the interior surface 88. Also disposed within the interior chamber defined by the body portion 86 is a plunger member 110 which includes a cylindrically configured stem portion 112 having an enlarged, circularly configured head portion 14 formed on and extending radially outward from one end thereof. 
     The plunger member 110 is positioned within the interior chamber of the body portion 86 such that the generally planar outer surface of the head portion 114 is abutted against the end of the disc member 108 opposite the end abutted against the interior surface 88. As such, the disc member 108 is captured between the interior surface 88 and the head portion 114 of the plunger member 110. Formed on the inner surface of the head portion 114 is an anti-rotation dog 116 which extends into a slot 118 disposed within the inner surface of the body portion 86 (i.e., the sidewall of the interior chamber). As best seen in FIG. 6, the end of the stem portion 112 opposite that including the head portion 114 formed thereon defines an arcuately contoured camming surface 120, the use of which will be discussed below. 
     Rotatably connected to the housing 80, and in particular to the body portion 86 thereof, is a circularly configured cap member 122. As best seen in FIG. 5, the cap member 122 includes an annular, inner flange portion 124, and a peripheral outer flange portion 126. The inner flange portion 124 is concentrically positioned within the outer flange portion 126 and defines a cylindrically configured cavity. In particular, the cavity is defined by the inner surface of the inner flange portion 124 and an end camming surface 128 having a configuration which is complementary to the camming surface 120 of the plunger member 110. 
     The rotatable connection of the cap member 122 to the body portion 86 is facilitated by the engagement of a locking finger 130 formed about the rim of the outer flange portion 126 to an annular flange portion 132 extending radially outward from the body portion 86 in relative close proximity to the distal end thereof. When the locking finger 130 is engaged to the flange portion 132, the stem portion 112 of the plunger member 110 is received into the inner flange portion 124, and in particular the cavity defined thereby. In this respect, the housing 80, disc member 108, plunger member 110 and cap member 122 are sized relative to each other such that the camming surfaces 120, 128 are in direct contact with each other and the opposed ends of the disc member 108 are abutted against the interior surface 88 and head portion 114, respectively, when the cap member 122 is attached to the flange portion 132. As further seen in FIG. 6, when the camming surfaces 120, 128 are abutted against each other, the distal rim of the inner flange portion 124 is abutted against the inner surface of the head portion 114 of the plunger member 110. To aid in the rotation of the cap member 122, formed on the outer surface of the outer flange portion 126 are a plurality of gripping ribs 134. 
     Importantly, due to the manner in which the plunger member 110 and cap member 122, and in particular the camming surfaces 120, 128 thereof, are cooperatively engaged to each other, the rotational movement of the cap member 122 facilitates the axial movement of the plunger member 110 relative thereto. As such, the rotation of the cap member in a first, clockwise direction facilitates the axial movement of the plunger member 110 toward the flow path 96, 96a, and the resultant compression of the disc member 108 which, as previously explained, is abutted against and captured between the interior surface 88 and head portion 114. Conversely, the rotation of the cap member 122 in a second, counter-clockwise direction facilitates the movement of the plunger member 110 away from the flow path 96, 96a, thus facilitating the resilient return of the disc member 108 to an uncompressed condition. The receipt of the anti-rotation dog 116 into the slot 118 prevents the plunger member 110 from rotating concurrently with the cap member 122. 
     In the flow control valve 78, the compression of the disc member 108 resulting from the rotation of the cap member 122 facilitates the resilient deformation of the disc member 108 into the flow path 96, 96a. When the disc member 108 is in its normal, uncompressed condition, fluid flows through the flow control valve 78 from the inlet passage 90 to the outlet passage 92 via the channel defined by the apertures 94, flow path 96, 96a, and disc member 108. When the disc member 108 is uncompressed, the sizing of the flow path 96, 96a facilitates a flow rate through the flow control valve 78 of approximately 250 ml per hour. This flow rate can be incrementally decreased to complete shut-off by the gradual compression of the disc member 108 via the rotation of the cap member 122. In this respect, the greater the compressive force applied to the disc member 108, the greater the degree of resilient deformation thereof into the flow path 96, 96a. As will be recognized, the rate of flow through the flow control valve 78 is decreased in proportion to the level of deformation of the disc member 108 into the flow path 96, 96a. Shut-off of the flow control valve 78 is accomplished by deforming the disc member 108 into the flow path 96, 96a such that the same is completely obstructed thereby. 
     Having thus described the structure and method of operation of the flow control valve 78, the manner of integrating the same into the infusion device 10 will be discussed with particular reference to FIGS. 1-3, 9 and 10. 
     As previously explained, the infusion device 10 of the present invention is used in conjunction with the standard, off-the-shelf partial fill bag 72. Initially, the flow control valve 78 is fluidly connected to the bag 72 by advancing the inlet portion 82 thereof through the second outlet port 76 in the previously described manner. Thereafter, a tubular fluid line 136 is typically connected to the outlet portion 84 of the flow control valve 78. As will be recognized, when the flow control valve 78 is attached to the bag 72, the same is in the fully closed position to prevent any flow of the contents of the bag 72 therethrough. 
     The bag 72 and flow control valve 78 are then positioned within the housing 12 subsequent to the movement of the lid member 64 to its open position. In particular, the filled bag 72 is placed into the medicament chamber 70, with the flow control valve 78 being oriented in alignment with the cavity 60 formed within the actuator plate 52. When the bag 72 is positioned within the medicament chamber 70, the flow control valve 78 is maintained in alignment with the cavity 60 by the receipt of the retention tab 106 extending from the Luer connector 102 into a complementary channel 138 disposed within the bottom wall 16 of the housing 12. As best seen in FIGS. 2 and 3, the channel 138 is formed and extends about a first notch 140 which is also disposed within the bottom wall 16 and is sized to accommodate the Luer connector 102. 
     Once the opposite end of the fluid line 136 has been placed into fluid communication with a desired anatomical passage, the flow control valve 78 is set to a desired flow rate, with the lid member 64 then being moved to its closed position. Thereafter, the latch member 26 of the base plate 24 is disengaged from the housing 12, thus resulting in the movement of the base plate 24 toward its second position, and the movement of the actuator plate 52 toward its outer position. Importantly, as the actuator plate 52 moves toward its outer position, the bag 72 is compressed between the neoprene pad member 62 and the lid member 64 due to the gradually decreasing volume of the medicament chamber 70. 
     Since the negator spring 42 is preferably a sixteen (16) pound spring, with the camming members 32, 54 of the base and actuator plates 24, 52 providing a four to one cam action, approximately sixty-four (64) pounds of pressure is applied to the bag 72 by the actuator plate 52 as the same moves toward its outer position. Such application of pressure to the bag 72 facilitates the drainage of its contents through the flow control valve 78 which, as previously indicated, is preferably set to a desired flow rate. The complete drainage of the bag 72 as the actuator plate 52 moves toward its outer position is aided by the slightly sloped configuration of the front surface 58 thereof. 
     As seen in FIGS. 9 and 10, as the actuator plate 52 moves toward its outer position, the flow control valve 78 is received into the cavity 60. Though not shown, the cavity 60 of the actuator plate 52 may also be fully or partially filled with neoprene material, with the flow control valve 78 being partially embedded within such material as the actuator plate 52 moves toward its outer position. If the cavity 60 is filled with such material, the pressure applied to the flow control valve 78 thereby will only be in the range of approximately five (5) pounds per square inch. 
     As the base plate 24 moves toward its second position, the graduation markings 50 applied thereto will progressively advance from the bottom wall 16 of the housing 12 via the slot 30 formed therein. Advantageously, the graduation markings 50, as they protrude from the housing 12, correspond to and reflect the gradually decreasing fluid level within the bag 72. Thus, simple observation of the graduation markings 50 provides a fast indication of the remaining fluid level within the bag 72. An indication of the fluid level of the bag 72 may also be obtained through the observation thereof through the transparent lid member 64. 
     The infusion device 10 of the present invention need not include the flow control valve 78 previously described. In this respect, the partial fill bag 72 may include a tubular fluid line or other infusion device which is fluidly connected to the first outlet port 74. Such alternative fluid line or infusion device is extended through and accommodated by a second notch 142 which is disposed in the bottom wall 16 of the housing 12 in side-by-side relation to the first notch 140. Thus, the infusion device 10 finds utility in relation to infusion therapy applications with or without the flow control valve 78. When the flow control valve 78 or a similar metering device is not utilized, the steady application of pressure to the bag 72 by the actuator plate 52 as the same moves toward its outer position facilitates a tightly controlled and accurate rate of flow from the bag 72. 
     The infusion device 10 of the present invention presents numerous advantages over the previously described prior art mechanical and electromechanical infusion devices. In this respect, the infusion device 10 is adapted to accommodate the standard, off-the-shelf partial fill bags 72, and does not require any transfer of the therapeutic fluid within the bag 72. The lack of any need for this additional transfer step substantially reduces the risks of inadvertent fluid contamination. Additionally, the pressure applied to the bag 72 by the actuator plate 52 is constant throughout the movement of the actuator plate 52 to its outer position. Thus, unlike prior art spring biased infusion devices wherein the pressure applied by the biasing spring gradually decreases as the fluid level decreases, the rate of fluid flow from the bag 72 is constant with or without the flow control valve 78 coupled thereto. Moreover, the infusion device 10 does not include any electrical components, and despite providing an extremely accurate rate of fluid flow, does not require any programming or specialized training for its operation. 
     Additional modifications and improvements of the present invention may also be apparent to those skilled in the art. Thus, the particular combination of parts described and illustrated herein is intended to represent only certain embodiments of the present invention, and is not intended to serve as limitations of alternative devices within the spirit and scope of the invention.