Abstract:
A valve for a tubing kit used provides a resilient element naturally moving to a closed state to reduce opportunity for inadvertent leakage of medicine and to reduce effort required by healthcare personnel to seal the fluid line. In one embodiment the resilient element is a spring serving to compress the walls of IV tube in the closure and in a second embodiment the resilient element is an elastomeric member that is deformed to provide an opening to allow passage of fluid through the fluid line.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    -- 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to medical pumps for the delivery of medicines to patients and in particular to an anti-free-flow valve integrated to a tubing kit and limiting accidental release of medicine prior to the tubing kit being installed in the medical pump or as it is being removed from the pump. 
         [0003]    Medical pumps, such as syringe pumps or peristaltic infusion pumps, are known for computer-controlled delivery of medication or contrast agents (henceforth drugs) to patients over a period of time. Typically, the drug is provided in a syringe or a flexible bag that may be connected to a fluid line attached to a needle for insertion into the patient. 
         [0004]    When a nurse or other health care professional ministering to the patient receives the drug, for example, in a flexible bag, the fluid line must be attached, typically by inserting a fluid line spike attached to one end of the flexible tubing into the bag. During a priming process, fluid from the bag is allowed to flow through the fluid line to purge bubbles from the fluid line and then the fluid line is installed in the pump typically by threading the fluid line through compressive fingers of a peristaltic pump. During the first steps of priming the fluid line, it is important that any clamps on the fluid line be open. After a purging of air from the line, the clamps are closed to prevent leakage until the fluid line is loaded into the pump. Immediately before loading of the fluid line into the pump, however, the clamps that were closed must be opened again so that the pump may operate without obstruction. When the fluid line is taken out of the pump at any point, it is important to ensure the line is closed and there is no uncontrolled fluid freely flowing to patient body. However, the caregiver may forget to close clamp manually. In some situations, such mistake has serious consequences. A valve that automatically closes when the fluid line is released from the pump can avoid such undesired situations and could save lives in critical scenarios. 
         [0005]    U.S. Pat. No. 8,469,933 entitled “Pump Activated Pinch Valve”, assigned to the assignee of the present invention and hereby incorporated by reference, discloses a valve for a fluid line that may be closed about the fluid line after priming of the fluid line and bag to prevent fluid leakage and then installed in the pump in a closed state. When the door of the medical pump is closed, the clamp automatically opens. In this way preparation of the fluid line and installing it to the pump is greatly simplified with reduced risk of leakage while also preventing unintended blockage of the flow of medicine. The clamp provides a single piece plastic element having a natural resilience tending to move it to an open position. The clamp element is compressed against this resilience to close the fluid line and held in that close position by a catch. The catch is automatically released by an element on the pump door once the clamp element is installed on the pump and the door is closed. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides valve that may be automatically released by a medical pump after it is installed in the pump. In contrast to the valve described above, however, a resilient element in the valve closes the fluid line in a relaxed rather than a compressed state. Because the valve is normally closed in the relaxed state, inadvertent leakage is less likely and the force required to close the fluid line reduced. The valve design provides a more compact form factor compatible with a wide variety of medical pumps. 
         [0007]    In one embodiment, the invention provides a fluid line kit having a length of flexible tubing terminating at opposed first and second ends and a valve mechanically retained on the IV tubing between the first and second ends. The valve includes a housing positioned between a first and second portion of the IV tubing and a fluid blocking element positioned within the housing and resiliently biased to block fluid flow in a relaxed state and to permit fluid flow in a compressed state. The valve is configured to permit a feature from a medical pump to compress the fluid blocking element from the relaxed state to the compressed state when the fluid line kit is installed in the medical pump. 
         [0008]    It is thus a feature of at least one embodiment of the invention to provide a simple valve for a fluid line kit that is normally in a closed position. It is another feature of at least one embodiment of the invention to provide a valve whose natural resilience aids in closure, reducing the forces required to close the valve by the user. 
         [0009]    The housing may provide a first tube extending along an axis in an axial telescopic sliding relationship with a second tube, the first and second tubes having passageways extending transversely through opposed walls of the tubes perpendicular to the axis and further including a spring biasing the first and second tube apart along the axis. The opening in the second tube may provide the fluid blocking element operating, when the fluid line is threaded through the passageways of the first and second tubes, to compress the fluid line to prevent flow therethrough in the relaxed state when the passageways through the first and second tubes are displaced from alignment and to release the fluid line in the relaxed state when the passageways through the first and second tubes are aligned. 
         [0010]    It is thus a feature of at least one embodiment of the invention to provide a simple valve that may work external to the IV tubing to avoid the need for contact between the valve elements and the fluid in the IV tubing. 
         [0011]    The first and second tubes may provide interengaging lock elements holding the valve in the compressed state when the lock elements are engaged and releasing the valve to the relaxed state when the lock elements are released. 
         [0012]    It is thus a feature of at least one embodiment of the invention to allow the fluid line to be easily commissioned and to reduce cold flow of the fluid line during storage of the tubing kit by providing an interlock holding the valve in the compressed state. 
         [0013]    The interengaging lock elements may be disengaged by relative rotation of the first and second tubes along the axis. 
         [0014]    It is thus a feature of at least one embodiment of the invention to allow simple release of the valve by rotation of the elements without the need for a tool or the like. 
         [0015]    The lock element may include a radially extending pin on one of the first and second tubes and an axial slot on another of the first and second tubes providing a catch location releasable by relative rotation of the first and second tubes. 
         [0016]    It is thus a feature of at least one embodiment of the invention to provide a simple interlock system that may be readily fabricated when these parts are constructed according to injection molding techniques. 
         [0017]    A passageway in at least one of the first and second tubes may be substantially larger than the fluid line to allow axial rotation of the first and second tubes with respect to each other. 
         [0018]    It is thus a feature of at least one embodiment of the invention to prevent the fluid line from blocking rotational adjustment of the valve. 
         [0019]    The spring element may be a helical compression spring contained within at least one of the first and second tubes. 
         [0020]    It is thus a feature of at least one embodiment of the invention to permit the use of a metallic spring element resistant to cold flow and memory under long periods of compression. 
         [0021]    In a second embodiment, the housing may provide a tubular sleeve having an internal chamber communicating with the IV tubing extending axially from connections on opposite sides of the tubular sleeve so that the internal chamber is positioned along the flow path between the IV tubing on opposite sides of the tubular sleeve. 
         [0022]    It is thus a feature of at least one embodiment of the invention to provide an in-line valve that need not deform the fluid line of the tubing meeting any constraints requiring high forces or specially compliant IV line material or problems related to permit deformation of the fluid line. 
         [0023]    The tubular sleeve may hold a resilient elastomer element in a relaxed state filling at least a portion of the tubular sleeve to block fluid flow between the connections and in a compressed state allowing fluid flow between the connections. 
         [0024]    It is thus a feature of at least one embodiment of the invention to produce a valve using a resilient element that can be tailored to the desired forces and properties needed. 
         [0025]    The elastomeric element may include a slot through the elastomer element that is closed when the elastomer element is in a relaxed state and open when the elastomer element is in a compressed state. 
         [0026]    It is thus a feature of at least one embodiment of the invention to provide an extremely simple valve element in which the valve and resilient elements are integrated. 
         [0027]    The valve may alternatively include a plunger for compressing the elastomer element away from the connectors in a compressed state so that fluid flow may pass around the plunger and the elastomer element is displaced away from the fluid flow. 
         [0028]    It is thus a feature of at least one embodiment of the invention to provide a simple valve element providing a sweeping action of the valve element tending to clear debris from the valve channel for more robust closure. 
         [0029]    The plunger may include a seal displaced from the plunger to prevent outflow from the tubular sleeve when fluid flow passes around the plunger. 
         [0030]    It is thus a feature of at least one embodiment of the invention to ensure leak-proof operation when the valve is in the open state. 
         [0031]    The valve may include a compressor removably attaching to the housing to hold the elastomer element in the compressed state when the compressor is attached to the housing. 
         [0032]    It is thus a feature of at least one embodiment of the invention to permit ready priming of the fluid line in which the valve is ideally held in an open state. 
         [0033]    These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1  is a simplified perspective view of an infusion pump and medicine bag, the latter of which may be attached to an tubing kit by means of a bag spike on one end of a fluid line leading to a luer lock, the fluid line having an intervening valve that may be automatically operated by the infusion pump; 
           [0035]      FIG. 2  is a fragmentary perspective view of the valve of  FIG. 1  as positioned on the fluid line in a first embodiment; 
           [0036]      FIG. 3  is an exploded perspective view of the valve of  FIG. 2 ; 
           [0037]      FIGS. 4 a -4 c    are cross-sectional views along line  4 - 4  of  FIG. 2  showing respectively: the valve in a first compressed state allowing free flow of liquid through the fluid line during IV line priming, the valve in a relaxed state blocking fluid flow through the fluid line, and the valve in a second compressed state allowing fluid flow through the fluid line when activated by the pump; 
           [0038]      FIG. 5  is a perspective view of a second embodiment of the invention employing a T-tube with a received slotted resilient element; 
           [0039]      FIGS. 6 a  and 6 b    are cross-sectional views along lines  6 - 6  of  FIG. 5  showing respectively the resilient element in a relaxed state blocking flow through the fluid line and in a compressed state allowing flow through the fluid line, the latter figure also showing a cap element holding the resilient element in a compressed state during IV line priming; 
           [0040]      FIG. 7  is a perspective view similar to that of  FIG. 5  of a third embodiment having a resilient element and a tandem plunger fitting within a T-tube; 
           [0041]      FIGS. 8 a  and 8 b    are cross-sectional views along lines  8 - 8  showing respectively: the resilient element in a relaxed state blocking flow through the fluid line and the resilient element in the compressed state allowing flow through the fluid line, the latter figure also showing a cap element holding the resilient element in a compressed state during IV line priming; and 
           [0042]      FIG. 9  is a figure similar to that of  FIG. 8 a    showing a modification of the valve using a door affixed activating pin. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0043]    Referring now to  FIG. 1 , a medical pump assembly  10 , for example, may include an infusion pump  12  having a housing  14  incorporating a pump compartment  16  providing a channel  18  through which a fluid line  20  may be threaded. The pump compartment  16  may expose pump elements  22  that may compress the fluid line  20  to provide peristaltic pumping action as is generally understood in the art. In addition, the pump compartment  16  may provide for a valve retention socket  24  as will be discussed in detail below. The pump compartment  16  may be covered by a hinged pump door  26  having a valve operating compressor  29  aligned with the socket  24  to activate a valve in the socket  24  when the door  26  is closed and latched. 
         [0044]    The fluid line  20  may be part of a fluid line kit  28  providing the fluid line  20  an IV bag spike  30  that may be used to connect to an IV bag  32  as is generally understood in the art. An opposite end of the fluid line  20  may have a Luer lock  33 , for example, to connect with a hypodermic needle  35  or the like. Other features may be found on the fluid line including an injection port  34  for joining the fluid line  20  with other lines or providing for the admission of other fluids into the fluid line, and a standard IV line roller clamp or slide clamp  36 . Per the present invention, the fluid line  20  will provide valve  38  of the present invention either fixed to the fluid line  20  along its length or slidable on the fluid line  20  but constrained by the spike  30  and luer lock  33  against removal from the fluid line  20 . 
         [0045]    Referring now to  FIGS. 2 and 3 , in a first embodiment, the valve  38  may have an outer tube  40  defining a generally cylindrical cavity closed at the bottom end extending along an axis  42 . A second inner tube  44  has an outer diameter to be received within the cavity of the outer tube  40  in telescopic fashion to slide therein. A helical compression spring  46  fits between the bottom of outer tube  40  and the bottom of inner tube  44  to bias them apart along axis  42 . 
         [0046]    Each of the outer tube  40  and inner tube  44  has transverse holes  48  and  50 , respectively, extending perpendicularly to axis  42  through opposite sidewalls of each outer tube  40  and inner tube  44 . When the holes  48  and  50  are aligned by movement of these inner tubes  44  and compression of spring  46 , the fluid line  20  may be threaded through the assembly as shown in  FIG. 2  to pass both through aligned openings  48  and  50 . Generally hole  48  will be sized to be close to the diameter of the fluid line  20  whereas hole  50  will be larger to permit axial rotation of the inner tube  44  when hole  50  receives the fluid line  20 . 
         [0047]    A sidewall of inner tube  44  may have a radially extending pin  52  received within a corresponding axially extending slot  54  in an outer wall of outer tube  40 . As inner tube  44  moves axially within outer tube  40 , pin  52  may move axially along slot  54 . Slot  54  may have a catch ledge  56  extending circumferentially outward from one of its axial walls. This catch ledge  56  may capture the pin  52  against upward axial movement under the biasing force of the spring  46  as shown generally in  FIG. 4 a   . When the pin  52  is so captured, the inner tube  44  will be held fully retracted in outer tube  40 , compressing helical compression spring  46  so that inner tube  44  extends out from outer tube  40  by a priming distance  60 . At this priming distance  60 , holes  50  and  48  are non-overlapping but not perfectly centered, with hole  48  being displaced toward the top edge of hole  50  as depicted. Nevertheless, the fluid line  20  (depicted to the side for clarity) inserted through the holes  50  and  48  will be uncompressed allowing free flow of liquid. This mode may be used during priming of the fluid line. 
         [0048]    Referring now to  FIG. 4 c   , a slight downward compression of inner tube  44  with respect to outer tube  40  will cause pin  52  to rotate leftward guided by an inwardly sloping wall beneath the catch ledge  56  pushing the pin  52  beyond the ledge  56  so that it may move upward in the slot  54  (as shown in  FIG. 4 c   ) allowing relaxation of the compression spring  46  and inner tube  44  to move upward as indicated by arrow  62  to an extension distance  64 . At this extension distance  64 , hole  50  will partially occlude hole  48  causing IV line  20  to be compressed into a closed state not allowing liquid to flow through the fluid line  20 . The force of the spring  46  is sufficient to provide for this compression of the fluid line  20 . It should be noted that the spring  46  operates to perform the compression thus relieving the user of the need to provide a force on inner tube  44  sufficient for this compression process as is necessary in the prior art. 
         [0049]    Referring now to  FIGS. 1 and 4   c , the outer tube  40  may fit within a socket  24  in the pump compartment  16  when the fluid line  20  is installed in the pump  12  so that when the valve  38  is inserted into the pump  12  and the door  26  is closed, a compressor  29  on the door  26  compresses inner tube  44  downward to extend by an operating distance  70  from outer tube  40 . At the operating distance  70 , holes  48  and  50  are aligned (concentric) releasing IV line  20  to allow free fluid flow. Note that this operating distance  70  is generally less than distance  60  so that there is no danger of pin  52  being captured by ledge  56  when the inner tube  44  is at the compression distance. 
         [0050]    Generally the inner tube  44  and outer tube  40  may be constructed from injection molded thermoplastic and the helical spring  46  from a stainless steel. 
         [0051]    Referring now to  FIG. 5 , in an alternative embodiment, the valve  38  may provide for a T-tube  74  including a tubular sleeve  76  defining an internal chamber open at a front end  78  and integrally molded (for example, from thermoplastic) to two intersecting, axially opposed connector tubes  80   a  and  80   b  so that the internal chamber of the tubular sleeve  76  communicates with and is positioned along the flow path from tube  80   a  to tube  80   b  extending on opposite sides of the tubular sleeve  76 . The tube  80   a  and  80   b  may receive and retain ends of the fluid line  20  so as to be placed in series with the fluid line  20  by means of barbs, press fit, adhesive, or a welding process. 
         [0052]    The opening of the tubular sleeve  76  at the front end  78  is substantially cylindrical to receive and be sealed by a cylindrical clastomeric plug  82  inserted into the tubular sleeve. The elastomeric plug  82  may, for example, be a silicone material. The elastomeric plug  82  has a diametric slot  84  extending along the axis of the elastomeric plug  82 . The diametric slot  84  is positioned near the middle of the elastomeric plug  82  to align with the path between the connector tubes  80   a  and  80   b . Elastomeric plug  82  is sized to abut a rear, closed end of the chamber of the tubular sleeve  76  when the diametric slot  84  is aligned with the connector tubes  80 . 
         [0053]    Referring now also to  FIG. 6 a   , in a relaxed (relatively uncompressed) state, the diametric slot  84  is held closed by the natural resilience of the elastomeric plug  82  preventing flow through the connector tubes  80   a  and  80   b  or into or out of the chamber of the tubular sleeve  76 . In some embodiments a flat interface between the elastomeric plug  82  and the openings of the connector tubes  80   a  and  80   b  in the tubular sleeve  76  may be provided for improved sealing in this state. 
         [0054]    Referring now to  FIGS. 1 and 6   b , the compressor  29  on the door  26  may be a pin that can be received through the open front end  78  of the tubular sleeve  76  to compress the elastomeric plug  82  along its axis against the closed end of the tubular sleeve  76  causing a deformation of the material of the elastomeric plug  82  such as opens the slot  84  to allow flow between the connector tubes  80   a  and  80   b . The elastomeric plug  82  under such compression tightly seals against the inner surface of the tubular sleeve  76  near the front end  78  to prevent any leakage out of the valve  38  during this time. Removal of the compressor  29  causes the slot  84  to close again as shown in  FIG. 6   a.    
         [0055]    The valve  38  may be shipped with an activation cap  86  attached over the front end  78  and held to the tubular sleeve  76  by snap detent elements  88 . This activation cap  86  may include a pin portion  90  extending into the tubular sleeve  76  operating in a manner similar to the compressor  29  shown in  FIG. 6 b    to hold the slot  84  open during initial priming of the fluid line  20 . This activation cap  86  is then removed, sealing the fluid line against leakage until it is placed in the pump  12  and the door closed. Although not shown in this figure, the activation cap  86  may be tethered to the tubular sleeve  76 , for example, by a molded interconnecting element. 
         [0056]    Referring now to  FIGS. 7, 8   a  and  8   b , in an alternative embodiment the T-tube  74  may receive a shorter elastomeric plug  82 , without a slot, that in a relaxed state blocks the passage of fluid between connector tubes  80   a  and  80   b , as described before, but which may be compressed by a tandem piston assembly  100  to push it away from the connector tubes  80   a  and  80   b  to allow flow between the connector tubes  80   a  and  80   b  through the fluid line  20 . 
         [0057]    The tandem piston assembly  100  provides a first plunger element  102  abutting an end of the elastomeric plug  82  nearest to the front end  78  that may perform the compression operation moving the elastomeric plug  82  away from the openings of the connector tubes  80 . A short spacer shaft  104  connects the plunger element  102  to a seal disk  106  displaced along the axis of the tubular sleeve  76  toward the front end  78  and having a circumferential seal such as an O-ring  108  fitting tightly against a cylindrical inner surface of the tubular sleeve  76  to prevent fluid flow out of the tubular sleeve  76  past the seal disk  106 . When the elastomeric plug  82  is compressed away from the openings of the connector tubes  80 , fluid may flow around the spacer shaft  104  but is blocked from exiting the open front end  78  by the seal disk  106 . 
         [0058]    A short extender shaft  110  may connect to the seal disk  106  and pass out of the open front end  78  of the tubular sleeve  76  when the elastomeric plug  82  is in the relaxed state to engage with a compression compressor  29  on the door as discussed before causing the plunger element  102  to compress the elastomeric plug  82 . An activation cap  86  may fit on and be held by means of detent elements  88  over the open front end  78  to press inward on the extender shaft  110  holding the valve  38  in the open state during IV line commission as has been discussed above. After priming, this activation cap  86  may be folded out of the way as attached to the tubular sleeve  76  by a molded tether element  89 . Alternatively, the activation cap  86  may be untethered and discarded after use. 
         [0059]    Each of the elements of the tubular sleeve  76 , the connector tubes  80 , and the tandem piston assembly  100  and the tether element  89  may be constructed of injection molded thermoplastic material. 
         [0060]    Referring now to  FIG. 9 , in an alternative embodiment, the extender shaft  100  may be removed from the embodiment of  FIG. 8  in favor of an activation pin  112  extending inward from the door  26  serving the same purpose as the extender shaft  102  push plunger elements  102  and seal disk  106  inward when the door  28  is closed and flow through the line  20  is desired. In this case, cap  86  may, like cap  86  of  FIG. 6 , include a pin portion  92  allow priming of the line  20  before the valve  38  is inserted in the pump  12 . 
         [0061]    Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
         [0062]    When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
         [0063]    It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications are hereby incorporated herein by reference in their entireties.