Patent Publication Number: US-2020282135-A1

Title: Delivery of fluid from a syringe

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 62/814,989, filed Mar. 7, 2019, which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     The present invention generally relates to delivery of fluid from a syringe, and more particularly to a pump set, syringe stand, syringe assembly, flow control apparatus and associated methods to deliver fluid from the syringe. 
     SUMMARY 
     Administering medicine or nutrition to a patient who cannot intake the medicine or nutrition orally can be effected by utilizing peristaltic flow control systems. Typically in such systems, fluid is delivered to the patient by a pump set including a flexible elastomeric tubing loaded on a flow control apparatus, such as a peristaltic pump, which delivers fluid to the patient at a controlled rate of delivery. The peristaltic pump usually has a housing that includes a rotor operatively engaged to a motor through a gearbox. The rotor drives fluid through the flexible tubing of the pump set by the peristaltic action effected by reversible compression created by impingement, e.g., pinching, by one or more rollers on the rotor. Rotation of the rotor progressively compresses the elastomeric tubing that drives the fluid at a controlled rate. The pump set may have a valve mechanism for permitting or preventing fluid flow communication through the pump set. The flow control system may also have a controller that operatively regulates the one or more motors which effectively controls fluid flow. 
     Peristaltic pumps operate by delivering fluid in small charges called “aliquots”. The rotor engages elastomeric tubing of the pump set, pinching off a portion of the elastomeric tubing and pushing fluid forward of the pinch point, e.g., closer to the patient than to the source of fluid toward the patient. Typically, the volume of fluid to be administered to the patient is controlled in the pump by counting the number of aliquots, each being of substantially the same volume, and stopping when the number reaches an amount corresponding to the total desired volume of fluid to be delivered. Peristaltic pumps are sanitary and generally accurate and therefore very useful in the administration of medication and therapeutic fluids to the patient. 
     In one aspect, a method of delivering fluid from a syringe to a subject using a pumping device of a flow control apparatus generally comprises locating the flow control apparatus on a horizontal support surface. Providing the syringe with a volume of fluid including a total amount of preferred nutrient and an amount of non-preferred nutrient liquid. Mounting the syringe relative to the flow control apparatus whereby the syringe is oriented in a generally vertical orientation such that an outlet of the syringe faces upward. Initiating operation of the pumping device to draw the fluid from the syringe for a duration of time. Delivering at least a portion of the volume of fluid from the syringe to the subject such that at least 40% of the total amount of preferred nutrient in the fluid is delivered from the syringe within a first third of the duration of time the pumping device is operated to draw the fluid from the syringe. 
     In another aspect, a syringe stand for supporting a syringe including a barrel having an outlet and a plunger received in an end of the barrel opposite the outlet generally comprises a base for supporting the syringe stand on a horizontal support surface. A holder secures the syringe to the syringe stand. The holder is attachable to the base and selectively positionable relative to the base to orient the syringe in at least two different positions. 
     In yet another aspect, a flow control apparatus for use with a pump set to deliver fluid from a feeding source through the pump set to a subject generally comprises a pumping device capable of acting on the pump set to produce a fluid flow within the pump set during a feeding cycle. A controller is in communication with the pumping device for controlling operation of the pumping device in a feeding configuration for producing flow of a fluid in the pump set. The controller includes a processor and a memory. The controller is adapted to store in the memory a selected flow rate and a desired fluid volume of the fluid. The controller is configured to execute in the processor a feed time compensator to adjust a feed time for operating the pumping device for delivering the fluid through the pump set during the feeding cycle to account for a detected deviation in actual flow rate from the feeding source from the selected flow rate. 
     In still another aspect, a support for a flow control apparatus including a pumping system for engaging a pump set mounted on the apparatus generally comprises a base for receiving at least a portion of the flow control apparatus. The base is configured to support the flow control apparatus on a horizontal support surface whereby the flow control apparatus is oriented in a generally horizontal orientation. At least one adjustable leg on the base is configured to change an angular orientation of the base with respect to a horizontal axis when the base is supported on the horizontal support surface thereby changing an angular orientation of the flow control apparatus when the flow control apparatus is received in the base. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a feeding system including an enteral feeding pump, a pump support, a feeding set assembly and a syringe; 
         FIG. 2  is an fragmentary, perspective view of the feeding system including the enteral feeding pump, and part of the feeding set assembly; 
         FIG. 3  is the perspective view of  FIG. 2 , but with portions of the cassette removed; 
         FIG. 4  is a front perspective view of the enteral feeding pump; 
         FIG. 4A  is a rear perspective view of the enteral feeding pump; 
         FIG. 5  is a perspective of the cassette; 
         FIG. 6  is a perspective of a fitting of the cassette; 
         FIG. 7  is a front perspective view of a pump support and syringe of the feeding set assembly; 
         FIG. 8  is a rear perspective view of the pump support and syringe; 
         FIG. 9  is a perspective of a syringe connector of the feeding set assembly; 
         FIG. 10  is another perspective of the syringe connector; 
         FIG. 11  is a section of the syringe connector; 
         FIG. 12  is a front perspective view of the pump support; 
         FIG. 13  is a front perspective view of a base of the pump support; 
         FIG. 14  is a front perspective view of a syringe holder of the pump support; 
         FIG. 15  is a front view of the pump support with the syringe holder in a horizontal orientation; 
         FIG. 16  is a front view of the pump support with the syringe holder in a vertical orientation; 
         FIG. 17  is the front view of  FIG. 16  with the syringe loaded in the syringe holder and schematically showing breast milk in the syringe; 
         FIG. 18  is a front view of the syringe stand with the syringe holder in an angled orientation; 
         FIG. 19  is a block diagram showing components of the enteral feeding pump that may be utilize to implement one or more aspects disclosed herein; 
         FIG. 20  is a graph showing a percentage of fat delivered at a given time over a delivery cycle of breast milk for various syringe orientations; 
         FIG. 21  is a graph showing a percentage of total accumulated fat delivered over time for a delivery cycle of breast milk for various syringe orientations; 
         FIG. 22  is a front perspective of another embodiment of a pump support; 
         FIG. 23  is a rear perspective of the pump support of  FIG. 22 ; 
         FIG. 24  is an exploded view of the pump support of  FIG. 22 ; and 
         FIG. 25  is a front view of the pump support with a leg of the pump support pivoted to engage a support surface to orient the pump support in an angled orientation. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION 
     One or more aspects of the present invention pertain to peristaltic pumps such as rotary peristaltic pumps and particularly to a feeding set assembly mountable on a rotary peristaltic pump for providing a fluid delivery apparatus that accurately detects and controls the amount of fluid delivered to a patient (e.g., infant) and maximizes nutrient delivery to the patient. Any one or more advantageous features or structures that provide or facilitate any one or more of such features may be implemented in a peristaltic pump employed in various commercial and industrial applications. Thus, although the detailed discussion is directed to an enteral feeding pump with a and feeding set assembly including a cassette, any one or more features of the invention may be embodied or implemented in other peristaltic pumps. For example, although the exemplarily discussed pump is a rotary peristaltic enteral feeding pump, the present invention has application to other types of peristaltic pumps (not shown), including medical infusion pumps. Additionally, one or more of the various features and aspects of the invention may be implemented in peristaltic pumps that use mechanisms other than rollers without departing from the scope of the present invention such as linear peristaltic pumps. Moreover, feeding set assemblies (not shown) that do not include cassettes may also be used within the scope of the present invention. 
     Referring now to the drawings, and in particular  FIGS. 1-6 , an exemplary enteral feeding pump (broadly, “flow control apparatus”) constructed according to any one or more of the principles of the present invention is generally indicated at  1 . The feeding pump may comprise a housing generally indicated at  3  that is constructed so as to mount a cassette, generally indicated at  5 , of a feeding set assembly (broadly, a “pump set”), generally indicated at  7 . The feeding set assembly  7  may include a syringe assembly  12  connected to the cassette  5  via tubing  77 . The cassette  5  of the feeding set assembly  7  is releasably attachable to the housing  3 . In the illustrated embodiment, a cassette shell  9  of the cassette is removably received in a cassette recess  6  ( FIG. 4 ) in the housing  3 . It will be appreciated that “housing” as used herein may include many forms of supporting structures (not shown), including without limitation multi-part structures and structures that do not enclose or house the working components of the pump  1 . The pump  1  may also have a display screen  10  on the housing  3  capable of displaying information about the status and operation of the pump. Moreover, various aspects and features of the present invention can be implemented without the recess  6 . One or more buttons  11  which can be proximate the display screen  10  can be provided for use in controlling and obtaining information from the pump  1 , and one or more light emitting diodes  13  can provide status information for the pump. 
     The display screen  10  may be part of a front panel (generally indicated at  19 ) of the housing  3  and may be removably attached to the housing. The enteral feeding pump may further include a pumping unit indicated generally at  23  ( FIGS. 3 and 4 ) comprising a pump motor  27  ( FIG. 19 ) connected to a rotor shaft (not shown). A battery (not shown) may be received in the housing  3  for powering the pump motor. A power source other than or in addition to the battery could be used to energize the pump including one or more prime motors which drive the pumping unit through the rotor shaft. 
     The pumping unit  23  has a rotor (generally indicated at  37 ) which can be coupled to the rotor shaft. The rotor  37  may include an inner disk  39 , an outer disk  41 , and four rollers  43  (only three of which are shown) mounted between the inner and outer disks for rotation relative to the disks about their longitudinal axes. The rollers  43  engage a tube  45  ( FIG. 3 ) of the feeding set assembly  7  that forms part of the cassette  5  to deliver fluid through the feeding set assembly  7  to a subject when the cassette  5  is attached to the housing  3 . For example nutritional liquid (e.g., breast milk and/or fortifier) may be delivered to an infant using the pump  1 , cassette  5 , and feeding set assembly  7 . Other fluids may also be delivered using the pump  1  without departing from the scope of the disclosure. In the illustrated embodiments, the fluid in the syringe  14  is drawn from the syringe by a vacuum pressure applied by the pumping unit  23 . However, certain aspects of the present invention have equal application if the fluid from the syringe  14  is delivered from the syringe in other ways, such as by driving the plunger into the barrel of the syringe. 
     Referring to  FIGS. 5 and 6 , the cassette shell  9  comprises a cassette body  51  having a front  53 , a back  55 , a top  57 , and a bottom  59 . Side walls  61  and top wall  63  may extend from the back  55  of the cassette body  51  forming a back cavity configured for receiving a fitting  65 . The tube  45  may be releasably attached to the fitting  65 . The fitting  65  may have tabs  88  that allow the fitting  65  to be secured or snapped into the cassette. In some cases, the fitting can be removably secured to the cassette. 
     Referring to  FIG. 6 , the fitting  65  comprises a base  67 , an inlet port  69 , and an outlet port  71 . The inlet port  69  may include a first attachment portion  73  for insertion into an inlet end of the tube  45 , and a pair of second attachment portions  75 A,  75 B for receiving inlet tubing  77  ( FIG. 3 ). The outlet port  71  may include a first attachment portion  79  for engagement or attachment to, such as by insertion into an outlet end of the tube  45 , and a second attachment portion  81  for attachment to such as by receiving outlet tubing  83 . Second attachment portion  75 A may be placed in fluid communication with a feeding source (e.g., syringe  14 ), and second attachment portion  75 B may be placed in fluid communication with a flushing source (e.g., flushing fluid bag) via the inlet tubing  77 . Alternatively, second attachment portion  75 B could be attached to the feeding source and second attachment portion  75 A could be attached to the flushing source. Alternatively, the fitting  65  may be formed integrally with the cassette body  51 , or omitted. Additionally, second attachment  75 B could be open to air so that once the feeding of nutritional liquid (e.g., breast milk) through second attachment portion  75 A is complete, second attachment portion  75 B could be used to clear the line of breast milk by pulling air through the line. This prevents breast milk form being left in the tubing and wasted. It will be understood that second attachment portions  75 A and  75 B could be switched whereby breast milk is fed through second attachment portion  75 B, and the flushing action is performed through second attachment portion  75 A without departing from the scope of the disclosure. 
     The inlet tubing  77 , tube  45 , fitting  65 , and outlet tubing  83  are considered part of the feeding set assembly  7 . The cassette  5  is considered to be part of the feeding set assembly  7  for purposes of this description. The syringe  14  may also be considered part of the feeding set assembly  7 . However, feeding set assemblies including more of fewer components than described herein are within the scope of the present invention. 
     In a preferred embodiment, the cassette shell  9  is made from a polymeric material such as polycarbonate. Referring to  FIGS. 3 and 4 , an insert  105  may be received in the cassette recess  6  in the housing  3  to aid in securing the cassette shell  9  and tube  45  in the cassette recess. The insert  105  may be positioned in the recess  6  such that the insert  105  is received in the back cavity of the cassette shell  9  when the cassette is attached to the housing  3 . The insert  105  may comprise a pair of opposing first projections  107  disposed at an inlet side of the insert for receiving the inlet portion of the tube  45 , and a pair of opposing second projections  109  disposed at an outlet side of the insert for receiving the outlet portion of the tube. Indicia  112  may be disposed on at least one of the second projections  109  indicating the direction of fluid flow in the tube  45 . In the illustrated embodiment, the indicia  112  is in the form of an arrow. 
     Referring to  FIGS. 1 and 7-11 , a pump support is generally indicated at  16 . The pump support  16  comprises a base  60  for supporting the pump support on a horizontal support surface such as a tabletop, and a syringe holder  62  attached to the base for securing the syringe  14  to the base. The syringe  14  and syringe holder  62  comprise the syringe assembly  12 . The pump support  16  supports the syringe  14  relative to the pump  1  when the pump is mounted on the pump support. More particularly, and as will be explained in greater detail below, the pump support  16  is configured to orient the syringe in multiple angular orientations. Alternatively, the pump support  16  may be configured as a syringe stand such that the holder receives and supports the syringe  14  but does not also mount and/or support the pump  1 . 
     The syringe  14  may be a conventional syringe including a barrel  18 , which may be graduated, and a plunger  20  slidably received in the barrel. In the illustrated embodiment, the syringe  14  includes a female tip  24  including an external thread  26  and defining an outlet  28  and tip passage in communication with an interior of the barrel  18 . The female tip  24  is centered about a longitudinal axis LA of the syringe  14 . The syringe  14  may be of other configurations without departing from the scope of the present disclosure. For example, the syringe may have an eccentric tip such that the female tip is positioned off-center of the longitudinal axis of the syringe. Still other syringe configurations are envisioned within the scope of the disclosure. 
     Referring to  FIGS. 1 and 9-11 , syringe connector  30  attaches the syringe  14  to the inlet tubing  77  to fluidly connect the syringe to the inlet tubing. The syringe connector  30  comprises a one-piece, integrally formed, molded connector body, generally indicated  34 . The connector body  34  includes a syringe-connecting portion  38  adapted to removably connect to the female tip  24  of the syringe  14 , a tube-connecting portion  40  that receives an end of the inlet tubing  77  to fluidly connect an output of the syringe with the second attachment portion  75 A of the inlet port  69  of the cassette  5 , and a valve portion  41  receiving a valve or plug  47  and configured to purge the syringe after delivery of the feeding fluid. The syringe-connecting portion  38  includes a male component  42  configured to form a liquid-tight seal with the female tip  24  of the syringe  14  when inserted into the tip passage. An outer skirt  44  of the syringe-connecting portion  38  surrounds the male component  42  and includes an internal thread  46  configured to threadably mate with the external thread  26  of the female tip  24 . 
     The syringe connector  30  defines air and enteral fluid passages  50 ,  52 , respectively. The enteral fluid passage  52  fluidly connects the interior of the barrel  20  with the inlet tubing  77 . The air passage  50  is configured to fluidly connect the inlet tubing  77  with atmosphere to purge the inlet tubing of fluid, as explained in more detail below. The enteral fluid passage  52  has a first portion  52   a  extending generally along an axis A 1  of the connector body  34 , through the male component  42  of the syringe-connecting portion  38 . A second portion  52   b  of the enteral fluid passage  52  leading to the inlet tubing  77  extends through the tube-connecting portion  40  generally orthogonal to the first portion  52   a  and the axis A 1  of the connector body. The air passage  50  has a first portion  50   a  extending generally along the axis A 1  of the connector body  34 , through the valve portion  41 . A second portion  50   b  of the air passage  50  leading to the inlet tubing  77  extends through the tube-connecting portion  40  generally orthogonal to the first portion  50   a  and the axis A 1  of the connector body. The second portion  50   b  of the air passage  50  is coincident with the second portion  52   b  of the enteral fluid passage  52  such that they occupy the same passage through the connector  30 . 
     The valve  47  is received in the valve portion  41  of the syringe connector  30  and seals the air passage  50  from atmosphere. With the valve  47  received in the valve portion  41 , normal operation of the pump  1  may be engaged whereby the rotation of the rotor  37  creates a vacuum in the barrel  20  of the syringe  14  for drawing fluid from the syringe. However, once all the fluid has been delivered from the syringe  14 , there may still be some fluid left in the inlet tubing  77  that has not been pumped to the subject. In order to deliver this portion of the fluid, the valve  47  can be opened thereby communicating the air passage  50  with atmosphere. Atmospheric air is then allowed to flow into the air passage  50  and into the inlet tubing  77  forcing the fluid in the tubing through the line and to the subject. This ensures that all the enteral fluid in the syringe  14  is delivered to the subject. The valve  47  can then be closed for subsequent feedings. In one embodiment, the valve  47  comprises a 1-way check valve such as a duckbill valve that allows air into the connector  30  once a pressure difference between the interior of the connector and atmosphere reaches at least 8 psi. In one example, the valve  47  may open when the pressure difference reaches between about 8 and about 10 psi. In one embodiment, the rotor  37  is rotated to a position where the tube  45  is not occluded to allow the air to force the fluid past the rotor and to the subject. The body  34  of the syringe connector  30  may be broadly considered a valve housing including a valve  47  for purging the inlet tubing  77  of fluid. 
     Referring to  FIGS. 12 and 13 , the pump support  16  comprises base  60  for supporting the pump support on a horizontal support surface such as a tabletop, and syringe holder  62  for securing the syringe  14  to the pump support. The holder  62  is attachable to the base  60  and selectively positionable relative to the base to orient the syringe  14  in a plurality of different positions on the pump support  16 . For example, the pump support  16  is configured to orient the syringe  14  is a first configuration ( FIG. 15 ) whereby the syringe is oriented in a generally horizontal orientation, and a second orientation ( FIG. 16 ) whereby the syringe is oriented in a generally vertical orientation. The pump support  16  may also be configurable to orient the syringe  14  in a third configuration ( FIG. 18 ) whereby the syringe  14  is oriented at an angle between the horizontal and vertical orientations. The pump support  16  may still also be configurable to orient the syringe in additional orientations between the horizontal and vertical orientations. 
     The base  60  has a flat bottom surface  64  for resting the base on a horizontal support surface. Thus, the base  60  itself is not configured to change its angular position with respect to a horizontal axis when resting on a horizontal support surface. A back wall  66  extends upward from the bottom surface  64  and mounts the pump  1  to the base  60 . A pair of side walls  68  extend laterally from the back wall  66  opposing opposite sides of the pump  1  when the pump is mounted to the base  60 . The back wall  66  and side walls  68  together define a receiving space  70  for the pump  1 . A mount  101  may be disposed on the back wall  66 . In the illustrated embodiment, the mount  101  has a rounded triangular or arched shape and includes a mounting flange  103  that diverges on opposite sides of the mount. The mounting flange  103  of the mount  101  may be configured to slidingly engage a groove  136  ( FIG. 4A ) formed in a back surface of the pump  1  to mount the pump to the base  60 . A post  111  may be disposed on the back wall  66  within the perimeter of the mount  101  and may have a receptacle for receiving a retainer (not shown) for locking the pump  1  to the base  60 . A cutout  120  in the back wall  66  forms a handle on the base  60  for carrying the pump support  16 . The back wall  66  attaches to the holder  62  to locate the holder relative to the base  60 . In the illustrated embodiment, multiple holes  117  are formed in the back wall  66  and are configured to receive fasteners  74  for attaching the holder  62  to the base  60 . It will be understood that other means for attaching the holder  62  to the base  60  may be utilized without departing from the scope of the disclosure. 
     A pass-thru connector  76  is formed on and extends through the back wall  66  in the cutout  120 . The pas-thru connector  76  includes a plug  78  that extends forwardly on the connector  76  and into the receive space  70 . A port  80  is formed in a reward side of the connector  76  and extends at least partially through the connector. The port  80  is in electrical communication with the plug  78  such that power and data can be transferred from the port to the plug and thus through the connector  76 . The plug  78  is configured to connect to a port  82  on the back of the pump  1  ( FIG. 4A ). The port  80  on the base  60  is configured to receive a plug of a power cord (now shown) such that power from the power cord is transferred to both the pump support  16  and the pump  1  when the plug  78  of the pump support is received in the port  82  on the pump  1 . In the illustrated embodiment, the pass-thru connector  76  is formed integrally with the base. However, the pass-thru connector  76  could be formed separately from the base  60  and suitably attached to the base. Additionally, a USB or other suitable connector (not shown) may be provided on the base  60 . The USB connector is configured to transfer data to the pump support  16  and pump  1 . For example, software updates may be communicated to the pump support  16  and pump  1  through the USB connector. In one embodiment, the USB connector is formed as part of the pass-thru connector  76 . 
     Referring to  FIGS. 12 and 14 , the syringe holder  62  includes a floor  86 , a rear wall  88  extending from the floor, and opposing side walls  90  extending laterally from the rear wall and away from the floor. The floor  86 , rear wall  88 , and side walls  90  together define a receiving space  92  for at least a portion of the syringe  14 . A first pair of flanges  94  extend from respective side walls  90  of the holder  62  near a top of the holder. Each side wall  90  has a recessed portion  99  above the flange  94  forming a second pair of flanges  96  longitudinally spaced from the first pair of flanges  94 . A portion of the barrel  18  of the syringe  14  is received between the first pair of flanges  94  and between the second pair of flanges  96 . The flanges  94 ,  96  prevent lateral movement of the barrel  18  in the holder  62  along an axis parallel to the rear wall  88 . A pair of rails  98  extend between the floor  86  and the first pair of flanges  94 . A U-shaped plate  100  is fixedly disposed at a top end of the rails  98 , and a U-shaped slide  102  is disposed around a bottom end of the rails and configured to move or slide along the rails. A gap  104  is formed between the first pairs of flanges  94  and the U-shaped plate  100 . The gap  104  is configured to receive a flange  58  of the barrel  18  of the syringe  14  ( FIG. 7 ). The length of the gap  104  is slightly larger than a thickness of the flange  58 . Thus, the flange  58  is held fixed between the flanges  94  and the plate  100  thereby fixing the barrel  18  against longitudinal movement within the holder  62 . Further, when the syringe  14  is received in the holder  62 , a flange  44  of the plunger  20  is held between a lever  121  and the slide  102 . For example, the lever  121  is actutable to rotate the lever to the left as shown in  FIG. 14  to slide the lever down the rail  98  to provide clearance for the plunger flange  44 . The U shape of the slide  102  and plate  100  are sized and shaped to receive a rod of the plunger  20  therein. The lever  121  can then be rotated back to the right to slide the lever up the rail  98  to secure the plunger flange  44  to the slide  102 . As will be explained in greater detail below, fluid being drawn from the barrel  18  of the syringe  14  causes the plunger  20  to move away from the floor  86 . The movement of the plunger  20  is guided by the slides  102  on the rails  98  so that the plunger moves along a substantially linear axis. Alternatively, the syringe holder could be configured to fix the longitudinal position of the plunger  20  and allow the barrel  18  to move relative to the plunger when fluid is drawn from the barrel. 
     A door or gate  106  is pivotably attached between one of the first pair of flanges  94  and one of the second pair of flanges  96  and moveable between an open position to allow the syringe  14  to be received in the receiving space  92 , and a closed position for retaining the syringe in the receiving space. A sensor  108  ( FIG. 14 ) may be provided on the holder  62  to detect the position of the door  106  once it is moved the closed position. Based on the position of the door  106 , a determination of the size of the syringe  14  can be made. For instance, a controller  72  ( FIG. 19 ) in the pump  1  may initiate a prompt requiring confirmation by a user in response to the door  106  being located at a predetermined position indicating the size of the syringe  14  as a preprogrammed size stored within a memory  93 . Alternatively, the controller  72  may automatically determine the size of the syringe  14  based on the position of the door  106 . A connection arm  110  extends from one of the side walls  90  and is configured to attach the holder  62  to the base  60 . In particular, the connection arm  110  includes multiple holes  113  corresponding to the holes  117  in the back wall  66  of the base  60  so the fasteners  74  can be received through the holes to attach the holder  62  to the base. 
     Referring to  FIGS. 1 and 14 , a position sensor  115  may be attached to the rear wall  88  to detect movement of the plunger  20 . In the illustrated embodiment, the position sensor  115  comprises a linear resistive potentiometer. A contact  114  of the potentiometer  115  is disposed on a movable portion of the holder  62 , such as the slide  102 , so that movement of the slide causes the contact to move along the potentiometer  115 . Because the barrel  18  is held fixed in the holder  62 , as fluid is withdrawn from the barrel, the plunger  20  will move into the barrel. The flange  44  of the plunger  20  engages the slide  102  as the plunger moves into the barrel  18  causing the slide to move along the rails  98 . Therefore, in this embodiment, movement of the contact  114  represents the movement of the plunger  20  relative to the barrel  18  and holder  62  caused by the feeding fluid being drawn out of the syringe  14 . Stated another way, the movement of the contact  114  corresponds to the distance which the plunger  20  has advanced into the barrel  18 . Since the cross-sectional area of the internal cavity of the barrel  18  is known from the detection of the syringe size, the potentiometer  115  can be calibrated so that the movement of the contact  114  indicates the volume of fluid expelled from the syringe  14 . In particular, by knowing the inner diameter of the barrel  18  of the syringe  14 , in combination with the distance the slide  102 /plunger  20  has moved, the volume of fluid delivered from the syringe  14  can be determined. The potentiometer  115  may be electrically connected to the controller  72  for receiving position signals from the potentiometer  115  indicating the movement of the slide  102 . The controller  72  may be located in the pump  1  or may be located remote from the pump  1  and in communication with the pump  1 . For example, the controller  72  may be located in the pump support  16 . In the embodiment where the plunger  20  is held fixed and the barrel  18  moves relative to the plunger, the movement of the contact represents the movement of the barrel  18 . 
     Other position sensors are also envisioned without departing from the scope of the disclosure. For example, a linear magneto resistive potentiometer (not shown) may be used. In this embodiment, a magnetic contact can be attached to the slide  102 , or alternatively attached to a structure attached to the plunger  20 , to gauge the movement of the slide/plunger. The magnetic contact being attached to the plunger would require syringes that have the magnetic contact to be used with the pumping system. Still further, an inductive position sensor (not shown) could be used. In still another embodiment, a camera (not shown) could be used to monitor the movement of the plunger  20 . In this embodiment, the movement of any point on the syringe  14  (e.g., plunger  20 ) can be tracked using image analysis software in communication with the camera. The size of the syringe  14  can also be automatically detected using the camera and image software. In still another embodiment, a foil sensor or nonmagnetic sensor may be employed. In further embodiments, fluid delivery amounts could be determined by weight detection. The examples of position sensing devices is not exhaustive of those which fall within the scope of the present invention. 
     The exemplary feeding set assembly  7  may be used for enteral feeding of neonates to achieve metered fluid delivery using the enteral feeding pump  1 . In such a method, the enteral liquid is drawn into the syringe  14  by pulling back on the plunger  20 . The amount of enteral liquid may be measured using graduation markings on the barrel  18  of the syringe  14 . After filling the syringe  14  with the proper amount of enteral liquid, the syringe connector  30  can be attached to the syringe tip  24 , such as by threading the syringe-connecting portion  38  onto the tip. The tube-connecting portion  40  can also be connected to the inlet tubing  77 . Prior to attaching the cassette  5  to the pump housing  3 , the inlet tubing  77  can be connected to the outlet port  69 , and the outlet tubing  83  may be attached to the outlet port  71  of the cassette  5 . 
     To attach the cassette  5  to the pump housing  3 , one or more pins or raised projections  119  ( FIG. 5 ) at the bottom  59  of the cassette body  51  of the cassette shell  9  may be inserted in slots  124  ( FIGS. 3 and 4 ) at the bottom of the recess  6  in the housing  3 . The engagement between the raised projections  119  and slots  124  generally locates the cassette shell  9  on the housing  3 . The cassette body  51  can then be rotated up until ledges  123  on a tab  125  at the top  57  of the cassette body are captured by a catch  127  at the top of the recess  6  ( FIGS. 2 and 4 ). To detach the cassette  5  from the pump housing  3 , the tab  125  can be depressed to disengage the ledges  123  from the catch  127 . Once the cassette  5  is attached to the pump housing  3 , the tube  45  is positioned for engagement by the rollers  43  of the pump  1 . 
     The pump support  16  is configurable to place the syringe holder  62  in a plurality of different angular orientations while the pump  1  and base  60  of the pump support are supported in a horizontal orientation on a support surface S in order to place the syringe  14  received in the syringe holder in a corresponding angular orientation. Orienting the syringe  14  in a particular orientation may be advantageous for delivering a preferred nutrient within a volume of fluid in the syringe earlier in a feeding cycle. In one embodiment, the syringe  14  is selectively positionable in a horizontal orientation ( FIG. 15 ) whereby the longitudinal axis LA of the syringe is oriented generally parallel to a horizontal axis when the syringe is received in the holder  62 . This is done by attaching the connection arm  110  of the holder  62  to the back wall  66  of the base  60  in a first attachment position aligning the holes  113  in the connection arm with the holes  117  in the back wall in a first alignment orientation. In one embodiment, the syringe  14  is selectively positonable in a vertical orientation ( FIG. 16 ) whereby the longitudinal axis LA of the syringe is oriented generally parallel to a vertical axis such that the tip  24  of the syringe is facing upward when the syringe is received in the holder  62  ( FIG. 17 ). This is done by attaching the connection arm  110  of the holder  62  to the back wall  66  of the base  60  in a second attachment position, different from the first attachment position, aligning the holes  113  in the connection arm with the holes  117  in the back wall in a second alignment orientation. If the nutritional liquid held in the syringe  14  is breast milk M for example, by orienting the tip  24  of the syringe upward, natural separation of the contents of the breast milk M will cause any fat F within the milk M to rise to the top of the mixture, thereby locating the fat F closest to the outlet  28  of the syringe  14  relative to the non-fat liquid portion of the breast milk. Therefore, the fat F, which is the most important part of the milk M for the infant, will be delivered to the infant first. This will not occur when the syringe  14  is arranged so that the barrel  18  is oriented horizontally. In this orientation, the fat F of the breast milk M tends to accumulate at the top of the barrel  18 , away from the tip  24  so that in a horizontal orientation the watery content of the milk M is delivered first. Often neonates can tolerate only very small quantities of milk at a given feeding. Thus, it is important that the neonate receives as much fat as possible and as soon as possible in a feeding. It is envisioned that preferred nutrients other than fat may be preferentially delivered with the syringe  14  positioned in the tip up vertical angular orientation. For example, vitamins and/or minerals within a nutritional liquid may be preferentially delivered in this angular orientation. 
     The pump support  16  is also configured to orient the syringe  14  in other angular orientations. In one embodiment, the syringe  14  is selectively positonable in an angled orientation ( FIG. 18 ) whereby the longitudinal axis LA of the syringe is disposed at an angle to the vertical and horizontal axes such that the tip  24  of the syringe is facing upward at an angle when the syringe is received in the holder  62 . This is done by attaching the connection arm  110  of the holder  62  to the back wall  66  of the base  60  in a third attachment position, different from the first and second attachment positions, aligning the holes  113  in the connection arm with the holes  117  in the back wall in a third alignment orientation. Orienting the syringe  14  in this manner also allows for the natural separation of the contents of breast milk in the syringe. In the illustrated embodiment, the syringe is oriented at about a 40 degree angle with respect to the horizontal axis. However, the syringe  14  could be positioned at other angles without departing from the scope of the disclosure. In one embodiment, the syringe  14  can be oriented at an angle between about 20 and about 60 degrees with respect to the horizontal axis. In one embodiment, the syringe  14  can be oriented at an angle between about 20 and about 40 degrees with respect to the horizontal axis. 
     In one embodiment, the pump support  16  can be attached to a vertical support such as an IV pole to orient the syringe  14  in a second vertical orientation whereby the longitudinal axis LA of the syringe is generally parallel to the vertical axis such that the tip  24  of the syringe is facing downward. For example, the pump support  16  can be configured in any of the angular orientations of  FIGS. 15, 16, and 18  and mounted on the IV pole via a mount  129  on the back of the pump support. The pump support  16  can then be manipulated (e.g., rotated or turned) to orient the syringe  14  such that it extends vertically with the tip  24  pointing down. Orienting the syringe  14  in this manner facilitates delivery of fortifier in the syringe  14  to an infant. This is because the nutrients in the fortifier will sink to the bottom of the barrel  20  of the syringe  14 . Thus, if the tip  24  of the syringe  14  is located at the bottom of the syringe  14 , the nutrients from the fortifier will be delivered first. Additionally, with the pump support  16  configured in any of the angular orientations of  FIGS. 15, 16, and 18  and mounted on a vertical support, the pump support can be manipulated to orient the syringe  14  in any desired angular orientation. 
     In one embodiment, the pump support  16  is configured such that the orientation of the syringe holder  62  cannot be changed while the pump  1  is received on the pump support. Thus, the syringe holder  62  must remain in a selected orientation once operation of the pump  1  has begun. Therefore, changing the orientation of the syringe holder  62  requires removal of the pump  1  from the pump support  16  and a tool to detach the syringe holder  62  from the base  60  to reposition the syringe holder as desired. In one embodiment, the pump support  16  must be returned to a hospital biotech department or to the manufacturer to change the position of the syringe holder  62 . 
     Referring to  FIGS. 20 and 21 , it has been found that orienting the tip  24  of the syringe upward when delivering breast milk to an infant provides a significant increase in the delivery of fat within the initial stages of delivery. In a comparison study, center-tip syringes filled with breast milk were oriented at different angular positions during feeding cycles and the amount and time of fat delivery was monitored throughout the delivery process. In particular, the study monitored breast milk deliver in syringes held at a horizontal angular orientation, at a 25 degree angle to horizontal with the syringe tip facing upward, at a 45 degree angle to horizontal with the syringe tip facing upward, at a vertical orientation where the syringe is positioned at a 90 degree angle to horizontal with the syringe tip facing upward, and a vertical orientation where the syringe is positioned at a 90 degree angle to horizontal with the syringe tip facing downward. Generally speaking, the syringes that were oriented such that the tips of the syringes were facing upward delivered a larger percentage of the fat portion of the breast milk earlier in the delivery cycle. Conversely, the syringes oriented with their tips facing downward delivered the lowest percentage of the fat portion of the breast milk in the earlier stages of the delivery cycle. 
     The feeding cycle for each syringe orientation lasted for 60 minutes. Of the five syringe orientations, the vertical orientation with the syringe tip facing upward was the most effective at delivering the fat content of the breast milk within the early stages of the feeding cycle. Referring to  FIG. 21 , within the first 20 minutes of the feeding cycle, over 40% of the total amount of fat in the breast milk was delivered. In one embodiment, over 44% of the total amount of fat was delivered within the first 20 minutes. Moreover, within a portion of that time, each quantity of breast milk being delivered included over 10% fat ( FIG. 20 ). In one embodiment, for at least 5 minutes within the first 20 minutes of delivery each quantity of breast milk being delivered included over 10% fat. None of the other orientations were able to reproduce these fat delivering capabilities within the first 20 minutes of the delivery cycle. 
     Referring to  FIG. 21 , within the first 30 minutes of the feeding cycle, over 60% of the total amount of fat in the breast milk was delivered. In one embodiment, over 63% of the total amount of fat was delivered within the first 30 minutes. Moreover, within a portion of that time, each quantity of breast milk being delivered included over 10% fat ( FIG. 20 ). In one embodiment, for at least 10 minutes within the first 30 minutes of delivery each quantity of breast milk being delivered included over 10% fat. None of the other orientations were able to reproduce these fat delivering capabilities within the first 30 minutes of the delivery cycle. 
     Referring to  FIG. 21 , within the first 40 minutes of the feeding cycle, over 65% of the total amount of fat in the breast milk was delivered. In one embodiment, over 70% of the total amount of fat was delivered within the first 40 minutes. In one embodiment, over 71% of the total amount of fat was delivered within the first 40 minutes. Within the first 50 minutes of the feeding cycle, over 80% of the total amount of fat in the breast milk was delivered. In one embodiment, over 84% of the total amount of fat was delivered within the first 50 minutes. Finally, by the completion of the feeding cycle, over 90% of the total amount of fat was delivered. In one embodiment, over 94% of the total amount of fat was delivered by the end of the feeding cycle. 
     With the syringe  14  loaded in the holder  62  of the pump support  16  and attached to the tubing  77 , the pump  1  is configured for delivering the feeding solution in the syringe to a subject. Operation of the pump  1  causes the rollers  43  to engage the tube  45  in the cassette shell  9  to pump the feeding solution from the syringe  14  to the subject. Engagement of the tube  45  by a roller  43  causes the rollers  43  to occlude the tube  45 . If the pump support  16  is configured such that the syringe is oriented in the vertical orientation with the tip  24  facing upward, gravity does not assist in drawing feeding fluid out of the syringe. Additionally, there is no direct actuation of the plunger  20  that forces fluid upward out of the barrel  18 . Thus, as the rotor  37  rotates to occlude the tube  45  with the rollers  34 , air, not liquid, is first drawn out of the inlet tubing  77  and barrel  18  of the syringe  14  which increases the vacuum pressure within the syringe. After a sufficient number of rotor rotations, a vacuum is created in the inlet tubing  77  and syringe  14 . Continued rotation of the rotor  37  will draw feeding fluid from the barrel  18  into the inlet tubing  77  through the inlet port  69  and tubing  45  of the cassette shell  9  to be pumped by the pump  1  into the outlet tubing  83  to the subject. However, rotation of the rotor  37  does not produce a continuous uniform flow of feeding fluid through the feeding set  7  as may be the case in traditional pumping arrangements where the outlet of the syringe is oriented such that gravity aids in expelling the feeding fluid downward out of the syringe. To the contrary, fluid is drawn from the syringe  14  in segments or increments which are irregular in volume and discontinuous in time. For example, during a first period of rotor rotation no fluid is drawn from the syringe  14 . In this period, the plunger  20  remains stationary with respect to the barrel  18 . Eventually, rotation of the rotor  37  causing the vacuum in the fluid line will draw a first volume of fluid from the syringe  14  to be pumped to the subject. The plunger  20  lurches farther into the barrel  18  as the first incremental volume is delivered, but then stops again as vacuum pressure drops. The operation of the pump motor to drive rotation of the rotor may be temporarily stopped after a movement of the plunger  20  of a sufficient amount (for example, and without limitation, movement associated with at least about 0.1 ml of liquid being delivered). Once the movement is detected, there is a delay before the stopped position of the plunger is read, to allow the motion to stop. Temporarily stopping the rotation of the rotor  37  halts the increase of vacuum pressure in the feeding line to help prevent the formation of air bubbles. Rotation is restarted after rotor rotation has been stopped for a period of time, as will be described more fully hereinafter. Continued rotation of the rotor  37 , however, will not cause a constant flow of fluid out of syringe  14 . Rather, a second period of time will elapse while the rotor  37  is being rotated where no fluid is drawn from the syringe  14 . Eventually, this further rotation of the rotor  37  will cause the plunger  20  to lurch forward again into the barrel  18  and a second incremental volume of fluid to be drawn from the syringe  14 . This process continues for the entire feeding cycle. The volume of fluid drawn from the syringe  14  in each segment may vary as well as the periods of time between the fluid draws. Thus, in order to deliver the prescribed amount of nutrient liquid to the subject, a feed time calculation is made which takes into consideration the nonlinear fluid delivery produced by the pump  1 . 
     The pump  1  can be programmed or otherwise controlled for operation in a desired manner. For instance, the pump  1  can begin operation to provide feeding fluid from the syringe  14  to the subject. A user such as a caregiver may select (for example) the amount of fluid to be delivered, the flow rate of the fluid, and the frequency of fluid delivery. The pump  1  may have a controller  72  ( FIG. 19 ) including a processor such as a microprocessor  89  that allows it to accept programming and/or to include pre-programmed operational routines, e.g., algorithm, that can be initiated by the user. The controller  72  may also be connected to the pump motor  27  for controlling its operation to actuate the rotor  37 . 
     The amount of feeding fluid that is delivered to the subject is typically controlled by the number of rotations of the rotor  37  (in a counterclockwise direction as viewed in  FIG. 3 ). In the exemplarily illustrated embodiment, the rotor  37  includes three rollers  43  so that each one-third of a rotation delivers one aliquot of fluid to the subject. As each roller  43  first engages the tubing  45 , it pinches off the tubing thereby closing off an amount of fluid forward (i.e., toward the subject) from the fluid coming from the feeding source. The roller  43  continues in the counterclockwise rotation which pushes the pinched-off volume of fluid forward of the roller, e.g., the aliquot, toward the subject. Finally, the leading roller  43  releases engagement with the tubing  45  at about the same time the trailing roller engages the tubing for pinching it off for delivering the next aliquot of fluid. Thus, when the microprocessor  89  receives a command to deliver a selected fluid flow rate, it would typically calculate the number of rotations within a given period of time that will deliver a number of aliquots producing the desired flow rate. The selected flow rate may be a rate that is input or selected by the doctor, nurse or other caregiver, or may be a default feeding rate pre-programmed into the pump  1 . 
     However, as described above, the pump  1  does not produce a constant flow of fluid when the rotor  37  is operated and the syringe  14  is oriented in a vertical orientation with the tip  24  facing upward. Rather, nutrient liquid is drawn from the syringe  14  in multiple segments or increments which are nearly always non-uniform in volume and time. Accordingly, the controller  72  may comprise a timer  91  and a memory area  93  including a feed time compensator  85  which adjusts the feeding time if the segments of fluid being drawn from the syringe deviate from the programmed flow rate after a period of time has elapsed during the feeding cycle. In the illustrated embodiment, the feed time compensator  85  may include feed time compensation instructions  95  and feed time compensation functions  97 . The feed time compensation instructions  95  are machine readable instructions on any suitable medium, broadly identified as the memory area  93 . These instructions can be executed by the microprocessor  89 . The timer  91  may be initiated in a suitable manner when a feeding cycle (broadly, “operation cycle”) is initiated or performed for delivering feeding fluid from the syringe  14  to the subject. The feed time compensator  85  may use this information along with additional parameters of the feeding cycle to compensate for the potentially non-uniform volume of feeding fluid that is delivered during the feeding cycle. 
     The feed time compensator  85  can operate to adjust the duration of time for delivering the feeding fluid through the feeding set  7  to account for the deviation in feeding fluid volume drawn for the syringe  14  and delivered to the subject during the time the pump  1  operates in the feeding phase. This adjustment factor may be dependent on a selected or preprogrammed flow rate for the feeding fluid, a volume of feeding fluid delivered to the subject, and the amount of time the pump  1  has been operating in the feeding cycle. More specifically, the controller  72  may employ the following function to determine an adjusted or compensated feed time: 
         X =( Y+Y   1 )/( Z+Z   a ) 
     X is the selected flow rate for the feeding fluid during the feeding cycle. Y is a volume of the feeding fluid drawn from the syringe  14  and considered in all previous compensation calculations in the feeding cycle. Y 1  is a volume of feeding fluid drawn from the syringe  14  since the previous compensation calculation. Z is the total time elapsed since the onset of the feeding cycle to the beginning of the feed compensation operation. Z n  is an adjusted or compensated feeding cycle time that is added to the total feeding cycle time. The function can be stored in the controller  72  so that when one or more of the factors are input into the pump  1  by the caregiver (or included in a preprogrammed feed setting), the microprocessor  79  can calculate the feeding time adjustment Z n  according to the equation Z n =(Y+Y 1 −XZ)/X. The feed time compensator  85  provides computer-executable instructions  86  for use in calculating Z n =(Y+Y 1 −XZ)/X. In one embodiment, the feed time calculation is performed after each segment or increment of fluid is drawn from the syringe  14  while rotation of the rotor  37  is stopped. The feed compensation functions  97  will then cause the pump  1  to pause in operation by an amount of time Z n  to bring the actual fluid flow rate close to the selected fluid flow rate. 
     In practice, there may be several very small movements of the plunger  20  with respect to the barrel  18  before a significant volume of fluid is delivered in a larger movement. In one embodiment, these smaller movements are ignored. In other words, the feed time compensator  85  may not initiate the feed time compensation calculation until a threshold volume of feeding fluid has been drawn from the syringe  14 . For instance, the feed time compensation calculation may not be run until movement associated with at least about 0.05 mL of fluid has been detected. The threshold for onset of the feed time compensation calculation may be other than described, for example and without limitation the threshold may be 1 ml, 2 ml or more within the scope of the present invention. 
     Further, by using the “lurch” fluid delivery approach, a system is produced in which only the minimum amount of vacuum needed to move the syringe is created. By using the smallest vacuum possible, the formation of air bubbles in the liquid is greatly reduced and in some cases eliminated. Having air bubbles suspended in the liquid creates gross measurement accuracy errors and is therefore undesirable. 
     Additionally or alternatively, the feed time compensator  85  may compare the Y+Y 1  value (volume of the feeding fluid previously drawn from the syringe  14  plus the most current increment) to the desired total volume of feeding fluid to be delivered to the subject. If Y is within a predetermined range of the desired total volume then the feeding cycle will be stopped. For instance, if Y is within 0.1 mL of the desired total volume then the feeding cycle will be stopped. Other ranges (e.g., 0.05 ml, 0.15 ml, 0.2 ml, 0.25 ml, 0.3 ml, etc.) may be used without departing from the scope of the disclosure. 
     In embodiments where a camera is used to detect the position of the plunger  20  of the syringe  14  relative to the stand  16  and barrel  18 , the camera may pick any reference point on the plunger and determine the length of movement by monitoring the changing position of the selected reference point. As stated previously herein, the camera may also be used to detect the type (e.g., brand or size) of syringe so that the appropriate cross sectional area (or diameter) of the internal volume is known to calibrate the linear movement with the delivered fluid volume. However, in cases where the internal diameter of a particular syringe barrel is not known, calibration of the controller  72  can be undertaken by a comparison of the linear movement of the plunger  20  with respect to the barrel  18  and stand  16  with the actual volume of fluid delivered. For example, in a calibration mode of the pump  1 , a syringe  14  filled with a liquid may be installed on the stand  16  and connected to the pump. The pump  1  can be initiated to cause liquid to be delivered from the syringe  14 . The user is asked to enter the amount and the controller  72  keeps track of the position of the plunger  20  in the barrel  18  for the measured amount. This operation is repeated according to instructions appearing on the pump display to generate several data points of plunger position and volume delivered. These points can be used in a line fitting calculation to calibrate the controller  72  for operation with the particular syringe. The information can be saved in the controller  72  so that it can be used whenever a syringe  14  of the particular type calibrated is used. 
     Alternatively, the controller  72  of the pump  1  can be programmed to instruct a user to perform a series of syringe operations to advance the plunger  20  in the barrel  18  and the microprocessor  89  can record the movement of the syringe to calibrate the movement with the volume of liquid dispensed. For example, the controller  72  could instruct the user to move the plunger  20  in the barrel  18  of the syringe  14  to the 0 mL mark and then verify that the action was taken. The microprocessor  89  would then record the measurement. This process can be repeated again at the center of the syringe where instructions can be given to move the syringe to another volume marker (e.g. 30 mL). The microprocessor  89  will then record the distance the syringe (i.e., barrel  18 ) moved. Finally, instructions can be provided to move the plunger  20  in the syringe  14  to another volume marker, such as at or near the end of the barrel  18 . The microprocessor  89  will again record the distance the syringe moved. Using these three data points, a straight line curve calibration for the syringe can be produced. 
     Thus it may be seen that the various objects and features are achieved by the various embodiments disclosed herein. The pump controller  72  has the feed time compensator  85  that allows the microprocessor  89  to adjust the duration of time for operating the rotor  37  to deliver the feeding fluid through the feeding set  7  to account for the deviation in volume drawn for the syringe  14  and delivered to the subject during the time the pump  1  operates in the feeding phase. Therefore, the subject can receive more accurate volume amounts of feeding fluid for a given feeding cycle. 
     Referring to  FIGS. 22-25 , a pump support of another embodiment is generally indicated at  116 . The pump support  116  is configured to receive the pump  1  and support the pump on a horizontal support surface S such as a tabletop. The holder  116  comprises a base  122  defining a pocket  124  for receiving the pump  1  therein. The base  122  includes a rear wall  126 , a bottom wall  128  projecting forwardly from the rear wall, and a pair of side walls  130  projecting upwardly from the bottom wall and forwardly from the rear wall at opposite sides of the rear wall. A mount  132  may be disposed on the rear wall  126 . In the illustrated embodiment, the mount  132  has a rounded triangular or arched shape and includes a mounting flange  134  that diverges on opposite sides of the mount generally from a top of the base toward the bottom wall  128 . The mounting flange  134  of the mount  132  may be configured to slidingly engage the groove  136  ( FIG. 4A ) formed in a back surface of the pump  1  to mount the pump to the support  116 . A post  138  may be disposed on the rear wall  126  within the perimeter of the mount  132  and may have a receptacle for receiving a retainer (not shown) for locking the pump  1  to the base  122 . 
     Legs  142  are pivotably attached to respective attachment arms  144  disposed at a bottom of the base  122 . Each attachment arm  144  extends from a respective opposite side of the base  122  generally between the bottom wall  128  and a respective side wall  130 . Each attachment arm  144  includes an extension portion  146  and a pivot portion  148  at an end of the extension portion. The legs  142  pivot about the pivot portion  148  of the attachment arm  144 . Each leg  142  includes a planar top surface  150 , a planar bottom surface  152 , and an edge surface  154  connecting the top and bottom surfaces. The legs  142  may pivot upward until they engage a corresponding side wall  130 , and downward until they engage the extension portion  146  of the attachment arm  144  to which they are attached. In one embodiment, each leg  142  is configured to pivot over a range of about 180 degrees. However, other pivot ranges are envisioned. 
     When the support  116  is supported on a horizontal support surface S, each leg  142  is independently pivotable and configured to pivot about an axis defined by the pivot portion  148 . As such, the legs  142  are configured to pivot toward the support surface for engagement with the support surface, and away from the support surface to disengage at least a portion of the legs from the support surface. For example, one of the legs  142  may be pivoted to engage the bottom surface  152  and/or edge surface  154  of the leg with the support surface S (e.g., as shown in  FIG. 25 ) to lift or tilt one side of the support  116 , and pump  1  on the support, above the other side to change the angular orientation of the pump. For a pump  1  with a syringe mounted thereon in a horizontal orientation this can cause the tip of the syringe to tilt upward or downward depending on the direction in which the tip faces and the leg that is pivoted to engage the support surface. In the instance where the tip of the syringe is tilted upward, this will provide a similar function to the pump support  16  where the syringe will be oriented at an angle to the horizontal and vertical axes. As discussed above, this orientation has benefits when breast milk is being delivered from the syringe. The legs  142  are configured to angle the support  116  at an angle between about 1 and about 40 degrees with respect to a horizontal axis when the holder is seated on a horizontal support surface. The legs  142  may also be operated to orient a syringe mounted on the pump  1  in other orientations without departing from the scope of the disclosure. The pump support  116  is also configured for attachment to a clamp device (not shown) for attaching the pump support to a support such as an IV pole. 
     Embodiments may be described in the general context of computer-executable instructions, such as program modules, executed by one or more computers or other devices. The computer-executable instructions may be organized into one or more computer-executable components or modules including, but not limited to, routines, programs, objects, components, and data structures that perform particular tasks or implement particular abstract data types. Aspects may be implemented with any number and organization of such components or modules. For example, various features or aspects are not limited to the specific computer-executable instructions or the specific components or modules illustrated in the figures and described herein. Other embodiments may include different computer-executable instructions or components having more or less functionality than illustrated and described herein. 
     Further, the order of execution or performance of the operations in any of the embodiments illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of one or more aspects. 
     In operation, microprocessor  89  of the controller  72  executes computer-executable instructions such as those illustrated in the figures to implement one or more aspects disclosed herein. Any of the various aspects may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices. 
     When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. 
     As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
     Other Aspects of the Disclosure 
     A1. A pump set for use with a flow control apparatus having a pumping system including a rotor for rotation about a pump axis and at least one roller mounted on the rotor for engaging the pump set, the pump set comprising: 
     tubing configured for engagement by the pumping system of the flow control apparatus to pump feeding fluid through the tubing; and 
     a syringe assembly connected to the tubing, the syringe assembly comprising a syringe and a stand configured to support the syringe in a generally vertical orientation, the syringe as supported by the stand being oriented such that an outlet of the syringe in fluid communication with the tubing faces generally upward when the syringe is supported on the stand. 
     A2. The pump set as set forth in A1, wherein the stand is configured to hold the plunger in a fixed position relative to the stand. 
     A3. The pump set as set forth in A2, wherein the stand comprises a base and a guide wall projecting upwardly from the base, the base being formed to capture an end of the plunger. 
     A4. The pump set as set forth in A3, wherein the stand further comprises a gripper mounted for movement along the guide wall, the gripper being configured to hold the barrel of the syringe about the base of the stand. 
     A5. The pump set as set forth in A2 or A3 wherein the base is constructed to rest on a supporting surface with the guide wall extending upwardly from the supporting surface and the syringe extending upwardly from the base. 
     B1. A syringe assembly for use with a flow control apparatus, the syringe assembly comprising: 
     a syringe for holding a volume of feeding fluid, the syringe comprising a barrel for holding the volume of feeding fluid and a plunger movable in the barrel to draw fluid into and force fluid out of the barrel; 
     a stand comprising a support configured to support the syringe in a feeding position; and 
     a position sensor attached to the stand and configured to detect movement of the syringe barrel with respect to the stand that is indicative of the feeding fluid being delivered out of the barrel. 
     B2. A syringe assembly as set forth in B1, wherein the position sensor comprises one of a potentiometer, a camera, a magnetic foil sensor, and a non-magnetic induction sensor. 
     B3. A syringe assembly as set forth in B1 or B2 wherein the stand comprises a gripper configured to connect to the barrel of the syringe, the gripper being movable with respect to the stand. 
     B4. A syringe assembly as set forth in B3, wherein the gripper is connected to the position sensor. 
     B5. A syringe assembly as set forth in B1, wherein the position sensor comprises a camera, the syringe assembly further comprising a controller configured to detect the type of syringe installed on the stand. 
     C1. A flow control apparatus for use with a pump set to deliver fluid from a feeding source through the pump set to a subject, the flow control apparatus comprising: 
     a pumping device capable of acting on the pump set to produce a fluid flow within the pump set during a feeding cycle; and 
     a controller in communication with the pumping device for controlling operation of the pumping device in a feeding configuration for producing flow of a fluid in the pump set, the controller including a processor and a memory, the controller being adapted to store in the memory a selected flow rate and a desired fluid volume of the fluid, the controller configured to execute in the processor a feed time compensator to adjust a feed time for operating the pumping device for delivering the fluid through the pump set during the feeding cycle to account for a detected deviation in actual flow rate from the feeding source from the selected flow rate. 
     C2. The flow control apparatus as set forth in C1, wherein the controller pauses operation of the pumping device to compensate for the detected deviation of the actual flow rate from the selected flow rate. 
     C3. The flow control apparatus as set forth in C1 or C2 wherein the controller compares a total actual delivered volume of fluid with the desired volume of the fluid and ends the feeding cycle if the difference is within a predetermined threshold. 
     C4. The flow control apparatus as set forth in any one of C1-C3 wherein the feed time compensator calculates the compensated feed time based on the equation: X=(Y+Y 1 )/(Z+Z n ) where X is the selected flow rate for the fluid, Y is a volume of the fluid already delivered from the feeding source during the feeding cycle, Y 1  is a volume of feeding fluid delivered from the feeding source since the most recent prior compensation calculation, Z is a total time elapsed in the feeding cycle, and Z n  is a feed time adjustment. 
     C5. The flow control apparatus as set forth in any one of C1-C4, wherein the controller is programmed to execute the feed time compensator only after a threshold volume of fluid has been delivered from the feeding source. 
     D1. A method of delivering fluid from a syringe having a barrel and a plunger received in the barrel using a pumping device of a flow control apparatus that acts on a pump set attached to the flow control apparatus to produce fluid flow through the pump set, the method comprising: 
     inputting into a controller of the pumping device at least one of a selected flow rate and a total volume of fluid to be delivered from the syringe during a cycle of operation; 
     initiating operation of the pumping device using the controller to draw fluid from the syringe; 
     detecting relative movement between the plunger and the syringe and sending a signal representative of the detected relative movement to the controller; 
     calculating using computer executable instructions in the controller a compensated feed time for operating the pumping device to deliver the fluid through the pump set during the cycle of operation to compensate for any deviation in the rate at which fluid is actually delivered from the syringe and the selected flow rate; and 
     operating the flow control apparatus to deliver the fluid through the pump set at the compensated feed time. 
     D2. The method as set forth in D1, wherein the controller delays onset of operation of the pumping device by the calculated compensated feed time. 
     D3. The method as set forth in D1 or D2 wherein the controller halts operation of the pumping device upon detection of relative movement between the plunger and the syringe. 
     D4. The method as set forth in D3, wherein the controller halts operation of the pumping device upon detection of relative movement between the plunger and the syringe that exceeds a predetermined threshold movement. 
     D5. The method as set forth in any one of D1-D4, wherein the compensated feed time is calculated when the pumping device is not operating to pump fluid through the pump set. 
     E1. A method of delivering breast milk to an infant, the method comprising: 
     retrieving breast milk stored in a syringe having a barrel and a plunger received in the barrel; 
     attaching the syringe to a stand so that a longitudinal axis of the syringe is generally vertical with an outlet of the syringe being located at a top; and 
     delivering breast milk from the syringe while in the stand to the infant. 
     E2. The method as set forth in E1, wherein delivering the breast milk comprises drawing breast milk from the syringe by applying a vacuum pressure to the outlet of the syringe. 
     E3. The method as set forth in A1 or E2 wherein delivering the breast milk includes moving the barrel of the syringe with respect to the stand and plunger. 
     F1. A method of calibrating a flow control apparatus used to deliver fluid from a syringe to a subject, the method comprising: 
     causing an instruction to appear on a display of the flow control apparatus to initiate a calibration routine stored by the flow control apparatus; 
     saving an initial position of a plunger of the syringe relative to a barrel of the syringe; 
     delivering a first amount of the fluid from the syringe; 
     prompting entry into the flow control apparatus of the first amount of fluid delivered; 
     saving a second position of the plunger; 
     operating the flow control apparatus to deliver a second amount of fluid; 
     prompting entry into the flow control apparatus of the second amount of fluid delivered; 
     saving a third position of the plunger; 
     determining within the flow control apparatus a displacement/amount relationship between displacement of the plunger relative to the barrel of the syringe and amount of fluid delivered; 
     storing the displacement/amount relationship in a memory of the flow control apparatus; and 
     storing a syringe identifier for the syringe whereby the flow control apparatus is able to recall the displacement/amount relationship for use of the syringe in a later delivery of fluid. 
     G1. A method of calibrating a flow control apparatus used to deliver fluid from a syringe to a subject, the method comprising: 
     causing an instruction to appear on a display of the flow control apparatus to initiate a calibration routine stored by the flow control apparatus; 
     saving in the flow control apparatus an initial position of a plunger of the syringe relative to a barrel of the syringe; 
     causing an instruction to appear to move the plunger relative to the barrel to a second position at a first known volume marker; 
     recording in the flow control apparatus movement of the plunger relative to the barrel from the initial position to the second position; 
     causing an instruction to appear to move the plunger relative to the barrel to a third position at a second known volume marker; 
     recording in the flow control apparatus movement of the plunger relative to the barrel from the second position to the third position; 
     determining within the flow control apparatus a displacement/volume relationship between displacement of the plunger relative to the barrel of the syringe and volume of fluid delivered; and 
     storing the displacement/volume relationship in a memory of the flow control apparatus. 
     G2. The method of G1 further comprising storing a syringe identifier for the syringe whereby the flow control apparatus is able to recall the displacement/volume relationship for use of the syringe in a later delivery of fluid. 
     H1. A method of delivering fluid from a syringe having a barrel and a plunger received in the barrel using a pumping device of a flow control apparatus that acts on a pump set attached to the flow control apparatus to produce fluid flow through the pump set, the method comprising: 
     inputting into a controller of the pumping device at least one of a selected flow rate and a total volume of fluid to be delivered from the syringe during a cycle of operation; 
     initiating operation of the pumping device using the controller to draw fluid from the syringe; 
     detecting relative movement between the plunger and the syringe and sending a signal representative of the detected relative movement to the controller; 
     halting operation of the pumping device to limit the vacuum pressure in the syringe; and 
     re-starting the pumping device. 
     I1. A flow control apparatus for use with a pump set to deliver fluid from a feeding source through the pump set to a subject, the flow control apparatus comprising: 
     a pumping device capable of acting on the pump set to produce a fluid flow within the pump set during a feeding cycle; and 
     a controller in communication with the pumping device for controlling operation of the pumping device in a feeding configuration for producing flow of a fluid in the pump set, the controller including a processor and a memory, the controller being adapted to store in the memory a selected flow rate and a desired fluid volume of the fluid, the controller configured to operate the pumping device to limit vacuum pressure delivered on the feeding source. 
     J1. A flow control apparatus for use with a pump set to deliver fluid from a feeding source through the pump set to a subject, the flow control apparatus comprising: 
     a pumping device capable of acting on the pump set to produce a fluid flow within the pump set during a feeding cycle; and 
     a controller in communication with the pumping device for controlling operation of the pumping device in a feeding configuration for producing flow of a fluid in the pump set, the controller, the controller being configured upon detection of delivery of a predetermined amount of feeding solution from the feeding source to stop the operation of the pumping device. 
     J2. The flow control apparatus as set forth in J1 wherein the feeding source is a syringe including a barrel and a plunger received in the barrel, wherein the controller stops the pumping device when a predetermined movement of the plunger is detected. 
     K1. An enteral feeding system for delivering fluid to a subject comprising: 
     a feeding set assembly including a cassette and tubing mounted to the cassette; 
     a syringe assembly including a syringe connected to the tubing and a stand configured to support the syringe, the stand including a base for supporting the stand on a horizontal support surface, and a holder for securing the syringe to the stand, the holder being attachable to the base and selectively positionable relative to the base to orient the syringe in at least two different positions; and 
     a flow control apparatus including a pumping device capable of acting on the tubing to draw fluid from the syringe to produce a fluid flow within the feeding set. 
     L1. A feeding set assembly for use with a flow control apparatus comprising: 
     a cassette configured for releasable attachment to the flow control apparatus, the cassette including an inlet port; 
     tubing connected to the inlet port; and 
     a valve assembly connected to the tubing, the valve assembly including a valve housing and a valve actuatable between a closed position preventing ambient air from entering the tubing and an open position permitting ambient air to enter the tubing to purge the tubing of fluid in the tubing. 
     M1. A method of delivering fortifier from a syringe to a subject using a pumping device of a flow control apparatus, the method comprising: 
     providing the syringe with a volume of fortifier including a total amount of preferred nutrient and an amount of non-preferred nutrient liquid; 
     mounting the syringe relative to the flow control apparatus; 
     orienting the syringe in a generally vertical orientation such that an outlet of the syringe faces downward; 
     initiating operation of the pumping device to draw the fortifier from the syringe; and 
     delivering at least a portion of the volume of fortifier from the syringe to the subject such that the preferred nutrient in the fortifier is preferentially delivered from the syringe.