Abstract:
An administration set flow condition monitor ( 30 ) includes a body member ( 32 ) configured to communicate with a fluid conduit ( 12 ) of the administration set ( 10 ). A flow monitoring mechanism ( 40 ) is carried by the body member ( 32 ) for indicating flow in the fluid conduit ( 12 ) of the administration set ( 10 ). An enunciator ( 56, 58 ) is associated with the flow monitoring mechanism ( 40 ) to indicate flow condition in the fluid conduit ( 12 ) of the administration set ( 10 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority from Australian Provisional Patent Application No. 2009903559 dated 30 Jul. 2009, the contents of which are incorporated herein by reference in their entirety. 
       FIELD 
       [0002]    This disclosure relates, generally, to an administration set and, more particularly, to an administration set flow condition monitor and to an administration set including a flow condition monitor. 
       BACKGROUND 
       [0003]    In gravity-type administration sets, a drip chamber is provided immediately below the fluid reservoir to allow a nurse quickly and visually to check that the intravenous fluid is indeed flowing. It also enables the nurse visually to set the flow rate by adjusting a flow controller such as a roller clamp. The nurse sets the flow rate by counting the number of drops (which generally have a known volume) over a set period of time. Further, the drip chamber traps air and inhibits entry of air into the venous system. 
         [0004]    In sets where pressure is imparted to the fluid, such as in an ambulatory system. there is usually no need for a drip chamber. Air is expelled through an air externalisation filter. The absence of a drip chamber means that there is no way of instantly determining that there is fluid flow. 
       SUMMARY 
       [0005]    In a first aspect there is provided an administration set flow condition monitor which includes 
         [0006]    a body member configured to communicate with a fluid conduit of the administration set; 
         [0007]    a flow monitoring mechanism carried by the body member for indicating flow in the fluid conduit of the administration set; and 
         [0008]    an enunciator associated with the flow monitoring mechanism to indicate flow condition in the fluid conduit of the administration set. 
         [0009]    The body member may include an attachment formation for attachment to the fluid conduit of the administration set. In an embodiment, the body member may be mountable about the conduit. In another embodiment, the body member may be mountable in line in the fluid conduit. In still another embodiment, the body member may be formed integrally with the fluid conduit as a one piece unit. 
         [0010]    The body member may include a flow control device arranged within the body member, the flow monitoring mechanism being responsive to flow through the flow control device for indicating flow in the fluid conduit of the set. 
         [0011]    The flow monitoring mechanism may be selected from the group consisting of mechanical devices, thermal devices, electronic devices, aural devices (including ultrasonic devices), and combinations of the foregoing. Further, the mechanical devices may include pressure measuring devices and visual, movement indicating devices. 
         [0012]    The flow monitoring mechanism may be configured to indicate flow rate through the conduit of the administration set. The flow rate may be a current, or instantaneous flow rate, it may be an average flow rate or it may indicate that flow is within a range such as, for example, 0-5 ml/hr, 5-20 ml/hr, or the like. 
         [0013]    The enunciator is at least one of a visual unit, an audible unit and a combination of the foregoing. Further, the enunciator may include a discernible unit which is discernible remotely from the location of the administration set. At least the discernible unit may emit both an audible and a visual alarm signal. The signal may be transmitted via wire, radio frequency such as Bluetooth, infrared, or other means. 
         [0014]    In a second aspect there is provided an administration set which includes a flow condition monitor, as described above. 
         [0015]    Preferably the administration set has no drip chamber. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]    Embodiments are now described by way of example with reference to the accompanying drawings in which:— 
           [0017]      FIG. 1  shows a front view of an embodiment of an administration set including an embodiment of a flow condition monitor; 
           [0018]      FIG. 2  shows a schematic, sectional side view of the embodiment of the flow condition monitor used in the administration set of  FIG. 1 ; 
           [0019]      FIG. 3  shows a side view of the flow condition monitor of  FIG. 2 ; 
           [0020]      FIG. 4  shows a schematic, sectional side view of another embodiment of a flow condition monitor; 
           [0021]      FIG. 5  shows a schematic, sectional side view of a further embodiment of a flow condition monitor; and 
           [0022]      FIG. 6  shows a schematic, sectional side view of still another embodiment of a flow condition monitor. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0023]    Referring initially to  FIG. 1  of the drawings, reference numeral  10  generally designates an embodiment of an administration set. The administration set  10  includes tubing  12  depending from a spike  14 . The spike  14  is, in use, received in a reservoir of fluid (not shown), such as a flexible bag, to be dispensed intravenously. The spike  14  is closed off by an end cap  16 . An air externalisation filter  18  is arranged in the tubing  12 , downstream of the spike  14 . An optional slide clamp  20  is provided on the tubing  12  to block flow of fluid in the tubing  12 . 
         [0024]    An end of the tubing  12 , opposite the end having the spike  14 , includes a locking member in the form of a Luer lock  22  with a cap  24  being provided to close off the lock  22 . 
         [0025]    An embodiment of a flow condition monitor, generally by the reference numeral  30 , is mounted in line in the tubing  12  and communicates with an interior of the tubing  12  to monitor flow of fluid in the tubing  12 . In other embodiments, the flow condition monitor could be mounted about the tubing  12  or could be formed integrally with the tubing  12 . 
         [0026]    An embodiment of the flow condition monitor  30  is illustrated in greater detail in  FIGS. 2 and 3  of the drawings. The flow condition monitor  30  includes a body member, or housing,  32  attachable to the tubing so that an interior  34  of the housing  32  communicates with the interior of the tubing  12  of the administration set  10 . 
         [0027]    The flow condition monitor  30  includes a flow monitoring mechanism  40  arranged within the interior  34  of the housing  32 . In this embodiment, the flow monitoring mechanism  42  includes a resiliently flexible membrane  42  arranged within the interior  34  of the housing  32  to extend from a first, upstream end  32 . 1  of the housing  32  to a second, downstream end  32 . 2  of the housing  32 . The membrane  42  is of a resiliently flexible material such as an elastomeric material. The membrane  42  is arranged on opposed sides of a flow control device in the form of an orifice plate  44  arranged substantially centrally within the interior  34  of the housing  32 . 
         [0028]    The membrane  42  cooperates with a sensing arrangement  46  arranged within the interior  34  of the housing on opposite sides of the orifice plate  44 . In this embodiment, the sensing arrangement  46  comprises an anchor  48  defining a pivot point  50 . A pair of spaced feet  52  bear against the membrane  42 , one foot  52  being arranged on each side of the anchor  48 . The feet  52  are arranged at opposed ends of a beam  54  pivotally mounted to the anchor  48  via the pivot point  50 . 
         [0029]    The flow condition monitor  30  comprises a local enunciator in the form of a pair of flags  56  and  58 . The flag  56  is associated with the upstream foot  52  and the flag  58  is associated with the downstream foot  52 . The flags  56 ,  58  are mounted to the feet at the hinged connection of each foot  52  to its associated end of the beam  54 . Further, the flags  56  and  58  are differently coloured so that a user can readily discern the condition of flow in the tubing  12 . For this purpose, the housing  32  includes a window  60  through which at least one of the flags  56  or  58  is visible as shown in  FIG. 3  of the drawings. 
         [0030]    In use, when fluid is flowing through the tubing  12  and, as a result, through the interior  34  of the housing  32 , a higher pressure is generated at an upstream end of the orifice plate  44  then at a downstream end. As a result, the upstream end of the membrane  42  bulges outwardly urging the flag  56  into the window  60  of the housing  32 , as shown in  FIG. 3  of the drawings while the downstream end of the membrane  42  is substantially unstressed. Should a blockage occur, a higher pressure will build up downstream of the orifice plate  44 . This causes the downstream portion of the membrane  42  to bulge outwardly. The upstream end of the membrane  42  is substantially unstressed and the flag  58  is urged into the window  60 . 
         [0031]    Further, when fluid flow stops, for example, as a result of the fluid reservoir of the set  10  being empty, the pressure across the orifice plate  44  equalises so that at least a portion of each flag  56 ,  58  is visible through the window  60 . In this way, the condition of fluid flow in the administration set  10  can be determined by a quick visual inspection. 
         [0032]    It will be appreciated that the sensing arrangement  46  is localised so that medical staff can only determine whether or not there is fluid flow in the set  10  by being present in the vicinity of the set  10 . However, it would be desirable if a user could also determine, remotely, if the administration set  10  is operating normally and that there is normal fluid flow in the set  10 . For this purpose, at least one pair of normally open contacts  62  is arranged within the interior of the housing  32 , the contacts being associated with the flag  58 . When there is a blockage in the tubing  12  resulting in a higher pressure downstream of the orifice plate  44  and the flag  58  is displaced into the window  60 , the contacts  62  close. A signal  64  ( FIG. 1 ) is generated and is sent to a remote enunciator  66 . The enunciator  66  generates a discernible alarm. As illustrated, the enunciator  66  includes a speaker  68  to output an audible alarm as well as a visual indicator such as a lamp  70  to output a visual alarm. In this way, for example at a nurses station, the medical staff can take action when a blockage occurs. 
         [0033]    If desired, a further set of contacts (not shown) can be included in the housing  32  so that, when fluid flow ends, and the sensing arrangement  46  adopts its quiescent state where both flags  56  and  58  are at least partially visible in the window  60 , a further signal is generated resulting in the generation of a further alarm at the enunciator  66 , the further alarm possibly having different characteristics such as a different cadence or frequency of sound and/or a different colour of light. 
         [0034]    The enunciator  66  communicates with the sensing arrangement  46  in any of a number of ways such as by being wired to the sensing arrangement  46 , wirelessly, a short range radio technology such as Bluetooth, or the like. 
         [0035]    While the above embodiment has been described with reference to the flow monitoring mechanism being in the form of a membrane  42  arranged within the housing  32 , it will be appreciated that, instead, the flow monitoring mechanism could be a balloon-type arrangement. Instead, the flow monitoring mechanism could constitute one wall of the housing  32  with the sensing arrangement  46  being arranged externally of the housing  32 . 
         [0036]    It is also possible to use the flow condition monitor  30  to determine the flow rate of fluid in the tubing  12 . This is effected by knowing the elastic properties of the membrane  42  and the characteristics of the orifice plate  44 . A position sensing arrangement (not shown) which is responsive to the position of the upstream foot  52 , is connected to the sensing arrangement  46  so that, as the upstream foot  52  is displaced, flow rate can be inferred. The flow rate is sent via an appropriate signal to the enunciator  66  to be displayed on a display  72  for medical staff. 
         [0037]    In  FIG. 4  of the drawings, a further embodiment of the flow condition monitor  30  is illustrated. The monitor  30  of this embodiment is a temperature sensitive device and includes a heater  74  incorporating a temperature sensor, for heating an upstream portion of fluid flowing in the tubing  12  of the set  10 . The flow condition monitor  30  further includes a temperature sensor  76  for monitoring the downstream temperature of the fluid flowing in the tubing  12 . Under normal flow conditions, the downstream temperature, as measured by the sensor  76 , will be lower than the upstream temperature of the fluid. The difference in temperature is an indication of the flow rate. If there is a blockage, the temperature equalises and a control unit  78  of the monitor  30  generates an appropriate alarm to enable action to be taken. 
         [0038]    In  FIG. 5  of the drawings, the fluid condition monitor  30  is a mechanical device. More particularly, the monitor  30  comprises a propeller  80  arranged downstream of the orifice plate  44  in the tubing  12 . The propeller  80  provides a ready, visual indication of flow through the orifice plate  44 . Preferably, the propeller  80  is a low friction, lightweight device to accommodate low flow rates in the tubing  12 . 
         [0039]    In  FIG. 6  of the drawings, the flow condition monitor  30  comprises a plurality of balls  82  arranged in the housing  32 , downstream of the orifice plate  44 . In the administration set  10 , laminar flow occurs in a part  84  of the tubing  12  upstream of the orifice plate  44 . As the fluid passes through the orifice plate, the flow changes to turbulent flow in the interior  34  of the housing  32 . Once the fluid passes through the housing  32  into a downstream part  86  of the tubing  12 , the flow reverts to laminar flow. The presence of turbulent flow in the interior  34  of the housing  32  agitates the balls  82  contained within the interior  34  of the housing  32  providing a ready, visual indication of the flow of fluid in the tubing  12 . It will be appreciated that, should a blockage occur or the fluid receptacle empty, the balls  82  will adopt a rest condition in the interior  34  of the housing  32 . 
         [0040]    It is therefore an advantage of the disclosed embodiments that a flow condition monitor  30  is provided which provides a ready indication to medical staff of flow in an administration set  10 . In certain embodiments, low cost flow condition monitors  30  are provided which would find use in poorer areas or less developed areas of the world. By early alarm or warning to medical staff, remedial action can be taken when blockage occurs. It will be appreciated that this is of increased importance in the case of arterial infusion where early warning of cessation of flow is required. 
         [0041]    It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the scope of the disclosure as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.