Patent Publication Number: US-10327997-B2

Title: Enteral feeding extension set connector

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 13/896,403, filed on May 17, 2013, which is a continuation of U.S. application Ser. No. 12/977,677, filed on Dec. 23, 2010, now U.S. Pat. No. 8,449,528, which claims priority to U.S. Provisional Application No. 61/369,432, filed on Jul. 30, 2010, all of which are incorporated herein in their entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to improved connectors that convey fluids from a supply tube to an indwelling tube or catheter. More particularly, it relates to an enteral feeding connector which joins a feeding extension set to an enteral feeding tube. 
     BACKGROUND OF THE INVENTION 
     Numerous situations exist in which a body cavity needs to be catheterized to achieve a desired medical goal. One relatively common situation is to provide nutritional solutions or medicines directly into the stomach or intestines. A stoma is formed in the stomach or intestinal wall and a catheter is placed through the stoma. This surgical opening and/or the procedure to create the opening is common referred to as “gastrostomy”. Feeding solutions can be injected through the catheter to provide nutrients directly to the stomach or intestines (known as enteral feeding). A variety of different catheters intended for enteral feeding have been developed over the years, including some having a “low profile” relative to the portion of the catheter which sits on a patient&#39;s skin, as well as those having the more traditional or non-low profile configuration. These percutaneous transconduit catheters (sometimes referred to as “percutaneous transconduit tubes”) are frequently referred to as “gastrostomy catheters”, “percutaneous gastrostomy catheters”, “PEG catheters” or “enteral feeding catheters”. U.S. Pat. No. 6,019,746 for a “Low Profile Balloon Feeding Device” issued to Picha et al. on Feb. 1, 2000, provides an example of one device. 
     The enteral feeding catheter serves as the pathway through the stoma for transconduit of feeding solution into the stomach or intestine. During feeding, the enteral feeding catheter must be connected to separate feeding tube that is associated with a pump that generates pressure to drive feeding solution from a reservoir through the feeding tube and into and through the enteral feeding catheter into the stomach or intestine. Feeding may take several hours and may occur at night while a patient is sleeping. Maintaining a robust and leak proof connection between the feeding tube and the enteral feeding catheter is important. It is also very desirable that the connection withstand twisting and pulling forces generated by movement of a patient. 
     However, a problem universal to low profile and non-low profile enteral feeding catheters is the difficulty in connecting and disconnecting the locking adapter of the feeding tube to and from the enteral feeding catheter base or head. Many prior art enteral feeding catheters, such as the one shown, for example, in cross-section in  FIG. 1 , have a low profile base B and a catheter C which extends through the base and a distance from the base. A distal end of the catheter of such a device/assembly often includes a balloon which may be expanded to hold the catheter in a position in a body lumen, such as a stomach lumen. Such an enteral feeding device/assembly also often has a plug “P” attached to the low profile or non-low profile device by a tether “T.” 
     Connecting a feeding tube to conventional enteral feeding catheters requires removing the plug P from the base to allow access to the feeding passage opening. Conventional enteral feeding catheters are designed with a base or “head” having a locking cap member fitting in the feeding passage opening. The locking cap member is configured to receive a conventional locking adapter connected to the end of a feeding tube. Generally speaking, these locking cap members have a keyway, a groove, a stop member and incorporate a slot to provide a design that is similar to the female portion of a bayonet fitting. A locking adapter has a dispensing projection and a key portion attached to that projection that fit into the locking adapter. The locking adapter is pushed into the locking cap member and twisted in place until it locks. Exemplary illustrations of these conventional features may be found in the above referenced U.S. Pat. No. 6,019,746. 
     Connecting, changing and/or disconnecting a feeding tube having a conventional locking adapter to/from a conventional enteral feeding catheter can be a surprisingly difficult exercise. If the patient is overweight, his or her size can limit visibility of the enteral feeding catheter base from the patient so that the patient has to maneuver the locking adapter in or out of the enteral feeding catheter base by touch or feel rather than by sight. If the patient has impaired motor skills, fitting a lock adapter in the locking cap member presents challenges during the positioning, pushing and twisting steps. If the patient is young, it is often necessary or desirable to change the assembly while the patient is sleeping. The turning on of a light during the night can wake the patient. Yet, without being sure that the new tube is correctly connected, there is a risk of the leaking of gastric contents onto a patient&#39;s skin surface, clothing, and the like. There is also a similar risk of the leaking of the feeding solution. Further, when the connector sits tightly within the base, it may be difficult to remove, thereby requiring extensive pulling, movement of the connector and base and even unwanted displacement of the base, all of which can cause leakage or irritate a sensitive stoma site. 
     Some conventional locking adapters are configured to allow partial twisting or rotation after the adapter has been locked in place. That is, after the locking adapter is twisted in the locked cap member so the key portion travels past a “detent”, the locking adapter can rotate between a position where the key portion contacts a stop and a position where the key portion contacts a detent. Unfortunately, the limited range of motion allows the conventional locking adapter to transmit twisting force to the enteral feeding catheter. This transfer of force may cause the catheter to twist or pull which can cause leakage or irritate a sensitive stoma site. If sufficient twisting force is inadvertently encountered, the key portion of the locking adapter may be forced past the detent as it would be when a patient or care give is disconnecting the locking adapter. After the key portion is forced past the detent, it can readily align with the slot/keyway thereby allowing the connector to inadvertently become completely disconnected. These conventional connectors have evident drawbacks that remain unresolved. 
     The popularity of low profile enteral feeding catheter heads or bases has also resulted in a low-profile conversion kit that provides a base or head component that is clamped onto a percutaneous transconduit catheter (i.e., only the tube) inserted through the abdominal wall using conventional endoscopic procedures or with a replacement percutaneous transconduit catheter (i.e., only the tube) that is inserted through a patient&#39;s stomach. Such a low-profile conversion kit is described in U.S. Pat. No. 5,549,657. According to that patent, base or head component has an anti-reflux valve assembly and a two-part clamp. After the base or head component is clamped on the end a percutaneous transconduit catheter, it functions as the base or head for the percutaneous transconduit catheter. The anti-reflux valve assembly includes a circular seat. A recess located beneath the seat is configured to receive opposed lips of a snap-fit feeding tube connector that snaps onto the circular seat. An example of such a low-profile conversion kit is commercially available as the Gaurderer Genie™ PEG System Kit available from Bard Nordic (Helsingborg, Sweden), a subsidiary of C.R. Bard Inc. 
     When a patient is ready to be fed, a snap-type feeding tube connector is snap fitted onto the anti-reflux valve assembly by pressing the snap-type feeding tube connector against the anti-reflux valve assembly to urge the lips of the feeding tube connector over the circular seat and into the recess located beneath the circular seat. When feeding is complete, the snap-type feeding tube connector is removed by prying or pulling on a set of opposed ears. Attachment and detachment of the feeding tube connector is facilitated by a set of opposed slots that enhances axial and radial distortion and flexure of snap-type connector when a force is applied to one or both of the opposed ears. 
     Connecting, changing and/or disconnecting a snap-type feeding tube connector to/from such a low-profile enteral feeding catheter head or base may also be a surprisingly difficult exercise at least for the same reasons as conventional locking adapter. Moreover, the application of force to press the snap-type feeding tube connector onto the head and also to pry it off the head transfers forces directly to the enteral feeding catheter which may create discomfort and cause irritation to the sensitive stoma site. The low-profile of the head and its relatively small size (e.g., typically between about 13 mm and 25 mm in diameter) also create difficulty in that opposed ears of the snap-type feeding tube connector can extend over the ends of the head and lie adjacent or even against the skin of the patient to make it difficult to grasp or pinch the ears between the fingers. 
     Accordingly, there is a need for a connector for coupling a medical fluid supply tube to the head of a catheter device having a circular hub. For example, there is a need for an enteral feeding extension set connector which permits a user or health care provider a way to easily connect and disconnect an extension set to the base of an enteral feeding tube. Such a system would permit a user or health care provider to easily and reliably disconnect the previous, used, feeding connector and connect a new feeding connector, desirably without needing to see the base. 
     SUMMARY OF THE INVENTION 
     In response to the difficulties and problems discussed herein, the present invention provides a connector for coupling a medical fluid supply tube (e.g., a feeding extension set) to a base of a catheter device (e.g., an enteral feeding tube or enteral feeding catheter device) when the base is equipped with a circular hub having a radius, a top surface, a side surface, and a circumferential recess defined in the side surface. The connector is composed of a resilient assembly that may optionally include a cover or head. A plurality of release tabs or buttons (e.g., two or more release tabs or buttons) extends from the resilient assembly. The connector may also include a conduit defining a fluid pathway for transferring feeding solution from the feed extension tube to the lumen of the catheter device. 
     Generally speaking, each release tab or button has a first portion including a finger contact zone and a second portion including a catch. The catch is configured to releasably engage the circumferential recess defined in the side surface of the circular hub. The connector is coupled to the circular hub by positioning the connector on the circular hub and depressing the connector until the catches engage the circumferential recess defined in the side surface of the circular hub. The connector is decoupled from the hub by applying force (e.g., pressing) the release buttons to reversibly displace the respective catches radially to disengage from the circumferential recess. The release buttons may be resiliently biased by the resilient assembly. The resilient assembly contains at least one resilient member that may include cantilevered springs, compression springs, extension springs, resilient foams or the like and combinations thereof. In such configuration, the connector is decoupled from the hub by applying force (e.g., pressing) the release buttons to reversibly displace the resilient element (e.g., cantilever springs) thereby moving the respective catches radially to disengage from the circumferential recess. 
     The connector is rotatably coupled to the circular base on the base of the enteral feeding catheter device. That is, when coupled to the base of the enteral feeding catheter device, the connector may rotate completely about the circular hub in either direction of rotation without inadvertently decoupling from the enteral feeding catheter device or causing the enteral feeding catheter device to twist. Desirably, the connector will provide relatively little resistance to rotation so it may move readily in response to twisting or other forces to avoid kinking the feeding tube or transferring force to the catheter device. 
     In an aspect of the invention, the extension set connector may include a central support having an upper surface. The upper surface of the central support may form a distal portion of the connector. Cantilevered springs may extend radially outward from the central support, each spring having a least a one arm, each arm having a first end, a central section, and a second end that is joined to the central support. The cantilevered springs may be compound cantilevered springs. It is contemplated that the cantilevered springs may be bridged together and connected by a cross-member to form the resilient assembly without the need for a central support. Alternatively, it is contemplated that the cantilevered springs and the head or cover of the connector such that the head or cover and the cantilevered springs are unitary. 
     The release buttons (also referred to as release tabs) are joined with the respective first ends of the cantilevered springs. The relationship between the cantilever springs and the release buttons may be characterized as a cantilevered structure in that the release button has one portion that is supported by the cantilevered spring and another portion that projects outwardly away from the resilient assembly. Each release button has a first portion with an exterior, outer or outward facing surface that forms or includes a finger contact zone. In addition, each release button has a second portion with an interior, inner or inward facing surface that forms or includes a catch on the inner surface. The catch is configured to releasably engage the circumferential recess defined in the side surface of the circular hub. Desirably, each catch may have a top surface configured to releasably engage the circumferential recess and a bottom surface and desirably the bottom surface is beveled. 
     The release button may desirably include a transition or delineation between the first portion and second portion. The second portion of the release button may also form a proximal portion of the connector; that is, the portion of the connector that is closest to the base when the connector is coupled to the base. The second portion of the release button may further include a boss adjacent the catch. Desirably, the boss slightly displaces the resilient assembly (e.g., the cantilevered springs of the resilient assembly) when the connector is coupled to the base. This displacement provides a tension or load the cantilevered springs that is transferred to the catches to hold the connector more securely to the circular hub. 
     The cantilever springs may be a pair of cantilever springs in opposed relationship and the release buttons may be a pair of release buttons. The pair of release buttons will also be in generally opposed relationship. 
     A conduit may define a fluid pathway through the connector and can be configured to supply a feeding solution to a lumen of the enteral feeding catheter device. The fluid pathway may be located between the pair of opposed cantilevered springs and the pair of release buttons. The fluid pathway may define a 90-degree bend such that the fluid pathway is generally perpendicular to the lumen of the enteral feeding catheter device. Alternatively, the fluid pathway may be configured to have the same orientation as the lumen of the enteral feeding catheter device. Such a configuration is desirable for delivering a bolus of feeding solution. The conduit may be in the form of a nozzle that is configured to engage an orifice defined in the hub to supply a feeding solution to a lumen of an enteral feeding catheter device. Alternatively, the conduit may be configured to engage a nozzle protruding from the surface of the hub to supply a feeding solution to the lumen of an enteral feeding catheter device. 
     The connector may further include motion limiters to limit the pitch of the connector. These motion limiters may be configured to contact an upper surface of the hub or an upper surface of the base of the enteral feeding catheter device. For example, the motion limiters may constitute a portion of the cantilever springs. The connector may also include a head joined to the central support. The head may form a distal portion of the connector. The head may also form a proximal portion of the connector. The motion limiters may be formed by a portion of the head and/or a proximal portion of the connector. 
     The present invention also encompasses an enteral feeding assembly. The enteral feeding assembly is composed of: (i) an enteral feeding catheter device having a base and including at least one catheter or tube with a lumen positioned through the base, the base having at least one circular hub having a radius, a top surface, a side surface and a circumferential recess defined in the side surface; and (ii) an extension set connector as generally described above for rotatably coupling a feeding extension set to a base of an enteral feeding catheter device wherein the connector allows for fluid communication between the feeding extension set and at least one lumen of the enteral feeding tube device. 
     The present invention further encompasses a feeding extension set. The feeding extension set includes a feeding extension tube and a connector in fluid communication with the enteral feeding extension tube, the connector configured for use with an enteral feeding catheter device having a circular hub. The connector has a plurality of release buttons incorporating catches. The connector is configured to rotatably couple to a circular hub by positioning the connector on a hub and pressing down on (e.g., depressing) the connector until the catches engage a circumferential recess defined in a side surface of a circular hub and the connector is further configured to decouple from a hub by squeezing or pinching the release buttons to move the respective catches radially to disengage from a circumferential recess. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a prior art enteral feeding assembly, showing a base and attached catheter, and a plug used to close an opening which provides access to the catheter, the plug coupled to the base by a tether. 
         FIG. 2  is a perspective view illustrating an exemplary connector for coupling a feeding extension set to an enteral feeding catheter device having a circular hub. 
         FIG. 3A  is perspective view illustrating a detail of a portion of an exemplary extension set connector. 
         FIG. 3B  is a perspective view illustrating a detail of a portion of an exemplary extension set connector which highlights the release buttons. 
         FIGS. 3C to 3E  are top view illustrations of variations of the resilient assembly. 
         FIGS. 3F and 3G  are side cross-sectional view illustrations of variations of the circular hub. 
         FIG. 3H  is a side view illustration of a variation of the resilient assembly. 
         FIG. 3I  is a top view illustration of a variation of the resilient assembly. 
         FIG. 4A  is an exploded perspective view illustrating an exemplary enteral feeding catheter device equipped with a base having a circular hub and the extension set connector. 
         FIG. 4B  is a perspective view illustrating the components shown in  FIG. 4A  as they would appear when a connector is coupled to the circular hub on the base of the enteral feeding catheter device. 
         FIG. 5  is a perspective view illustrating a detail an exemplary extension set connector including a conduit. 
         FIG. 6  is a cross-sectional view illustrating a detail an exemplary extension set connector including a conduit. 
         FIGS. 7A to 7D  are side views illustrating a portion of an exemplary connector and a circular hub on the base of an enteral feeding catheter device in various stages of the process of coupling. 
         FIG. 8  is a side view illustrating a feature of an example connector highlighting a portion of an exemplary cantilevered spring. 
         FIGS. 9A and 9B  are side views illustrating a portion of an exemplary connector and a circular hub on the base of an enteral feeding catheter device in various stages of the process of decoupling. 
         FIG. 10  is a side view illustrating a feature of an example connector highlighting a portion of an exemplary cantilevered spring. 
         FIG. 11  is a cross-sectional view illustrating a portion of an exemplary connector having a cover or head contacting a circular hub. 
         FIG. 12  is a side view illustrating a portion of an exemplary connector and a circular hub on a base of an enteral feeding catheter device. 
         FIG. 13  a partial exploded perspective view illustrating an extension set connector in which both a proximal end and a distal end of a conduit a defining a fluid pathway is axially aligned with the lumen of an enteral feeding catheter device. 
         FIG. 14  is a side perspective view showing the extension set connector of  FIG. 13  engaged with the base of an enteral feeding catheter device. 
         FIG. 15  is a bottom view of an exemplary connector in which the cantilever springs are integrated with or joined to the head or cover. 
         FIG. 16  is a top perspective view showing the exemplary connector of  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to one or more embodiments, examples of which are illustrated in the drawings. It should be understood that features illustrated or described as part of one embodiment may be used with another embodiment to yield still a further embodiment. It is intended that the claims include these and other modifications and variations as coming within the scope and spirit of the disclosure. 
     Turning now to the drawings, it will be understood that an example of the prior art is illustrated in  FIG. 1  and has been described above.  FIG. 2  of the drawings is a perspective view illustrating an exemplary connector for coupling a medical fluid supply tube (e.g., feeding extension set) to a base of a catheter device (e.g., an enteral feeding catheter device) having a circular hub. As used herein, the term “fluid” encompasses liquids, gases and combinations thereof. An example of a liquid includes nutritional liquids that may be supplied to a patient through a feeding tube. An example of a gas may be a gas vented from the stomach or intestine of a patient. The connector  10  (referred to hereinafter as an “extension set connector”) has a resilient assembly  11  that may optionally include a cover or head  12 . The connector  10  also includes a plurality of release buttons  14  (e.g., two or more release buttons which may also referred to as tabs, projections, tongues, etc.) extending from the resilient assembly  11 . The connector may also include a conduit  16  defining a fluid pathway for transferring feeding solution from the feed extension tube  18  to the lumen of an enteral feeding catheter device  20 . 
     The extension set connector  10  is shown in position above an enteral feeding catheter device  20  that is equipped with a base  22  having a circular hub  24 . The circular hub has a radius “R”, a top surface  26 , a side surface  28 , and a circumferential recess  30  defined in the side surface  28 . In other words, the circular hub  24  has a generally horizontal top surface  26  that extends over a generally vertical side surface  28  forming rim, collar, rib or flange structure that defines a circumferential recess  30  which is sized to engage the catches  56  of the connector  10 . The radius “R” is the distance from the center of the hub  24  to the outermost edge “E” of the portion of the top surface  26  forming the rim, collar, rib or flange structure that defines the recess  30 . The circular hub  24  also includes an orifice “O” at the center of the hub. A valve “V” is desirably used to seal the orifice “O” when the connector  10  is not engaged with the circular hub  24 . 
     Generally speaking, each release button has a first portion including a finger contact zone and a second portion including a catch, described in more detail below. The catch is configured to releasably engage the circumferential recess  30  defined in the side surface  28  of the circular hub  24 . The connector  10  is coupled to the circular hub  24  by positioning the connector  10  on the circular hub  24  and depressing the connector until the catches engage the circumferential recess defined in the side surface of the circular hub. Of course, the connector  10  may be coupled to the circular hub  24  by squeezing or pinching the release buttons  14  between the fingers so the catches  56  clear the outermost edge “E” of the top surface forming the rim, collar, rib or flange structure  30 , seating the connector  10  on the circular hub  24  and releasing the squeezing or pinching force on the release buttons so the catches  56  engage the circumferential recess  30 . The connector is decoupled from the hub by pressing (e.g., squeezing or pinching) the release buttons to reversibly displace the respective catches radially (e.g., radially outward) to disengage from the circumferential recess. Desirably, the connector is rotatably coupled to the circular base on the base of the enteral feeding catheter device. That is, the connector may rotate completely about the circular hub in either direction of rotation without disconnecting from the enteral feeding catheter device or causing the enteral feeding catheter device to twist. It is desirable for the connector to be rotatably coupled such that it can rotate freely around the circular hub with relatively little resistance. 
     The release buttons may be resiliently biased by the resilient assembly  11 . The resilient assembly contains at least one resilient member that may include cantilevered springs, compression springs, resilient foams or the like and combinations thereof. If the resilient assembly  11  includes cantilevered springs, each cantilevered spring has at least one arm. Each arm has a first end, a central section, and a second end that is joined to a central support. In such configuration, the connector is decoupled from the hub by depressing the release buttons to reversibly displace the resilient element (e.g., cantilever springs) thereby moving the respective catches radially (e.g., radially outward) to disengage from the circumferential recess. 
     Referring now to  FIG. 3A  of the drawings, there is shown in perspective view an illustration detailing of a portion of an exemplary connector. More particularly,  FIG. 3A  illustrates a portion of an exemplary resilient assembly  11  for resiliently biasing the release buttons. The resilient assembly  11  desirably includes a central support  32  having an upper surface  34 . The upper surface  34  of the central support  32  may form a distal portion of the connector. That is, the upper surface may form the portion of the connector that is farthest from the enteral feeding catheter device  20 . The portion of the resilient assembly  11  also includes cantilevered springs  36  extending radially outward from the central support  32 , each cantilevered spring  36  may have at least one arm  38 . Each arm  38  has a first end  40 , a central section  42 , and a second end  44  that is joined to the central support  32 . The cantilevered springs  38  may be compound cantilevered springs. Release buttons  14  are engaged with the resilient assembly  11  by being joined with the respective first end  40  of a cantilevered spring  36 . The relationship between the cantilever spring and the release button may be characterized as a cantilevered structure in that the release button has one portion that is supported by the cantilevered spring and another portion that projects outwardly away from the resilient assembly. While  FIG. 3A  illustrates the cantilever springs as two pairs of cantilever springs in opposed relationship and the release buttons as a pair of release buttons that are also configured in opposed relationship, it is contemplated that other configurations may be used. For example, three cantilevered springs (or more) and three release buttons (or more) may be used and can be configured to be operated by three fingers (e.g., thumb, index finger and middle finger) or various combinations of more fingers. 
     Referring now to  FIG. 3B  of the drawings, there is shown in perspective view an illustration which highlights a detail of a portion of the resilient assembly  11  and the release buttons  14 . Each release button  14  has a first portion  46  with an exterior, outer or outward facing surface  48  that forms or includes a finger contact zone  50 . In addition, each release button has a second portion  52  with an interior, inner or inward facing surface  54  that forms or includes a catch  56  on the inner surface  54 . The catch  56  is configured to releasably engage the circumferential recess  30  defined in the side surface  28  of the circular hub  24 . Desirably, each catch  56  may have a top surface  58 . The top surface  58  is configured to releasably engage an underside (not shown) of the generally horizontal top surface  26  that extends over the generally vertical side surface  28  forming rim, collar, rib or flange structure that defines the circumferential recess. Each catch may also have a bottom surface  60 . Desirably, a portion of the bottom surface  60  may have a bevel  62 . The bevel  62  can be adjusted to provide an angle sufficient to allow for easier attachment when the connector  10  is pressed downward against the circular hub  24  to avoid applying a level of force that creates discomfort and causes irritation to the sensitive stoma site. 
     The release button  14  may desirably include an optional transition or delineation  64  between the first portion  46  and the second portion  52 . This transition  64  helps define the finger contact zone  50 . The finger contact zone  50  is illustrated in  FIG. 3B  as generally smooth. The finger contact zone  50  may have topography to help the users identify the finger contact zone  50  through visual and/or tactile indicia such as, for example, bands, bumps, ridges, raised dots, random rough texture, contracting color or the like. Alternatively and/or additionally, the cover or head  12  of the extension set connector  10  may include indicia “I” as illustrated in  FIGS. 4A, 4B  as well as  FIGS. 13 and 14 . These indicia “I” may be used to provide a tactile or visual cue to a user about the location of the release buttons and/or the direction to press squeeze or pinch the release buttons. 
     In an aspect of the invention, the second portion  52  of the release button may form a proximal portion of the connector  10  (i.e., the portion of the connector (excluding any projecting nozzle or conduit) that is oriented toward and generally positioned closest to the exterior surface of base  22  of the enteral feeding catheter device  20 ). For example, the bottom face  66  of the second portion  52  of the release button  14  may form the proximal portions of connector  10 . As another example, the bottom face  66  of the second portion of the release button  14  and the bottom surface  60  of the catch  56  may form proximal portions of the connector  10 . In another aspect of the invention, the second portion  52  of the release button  14  may further include a boss  68  adjacent the catch  56 . The purpose of the boss  68  is to slightly displace the resilient assembly (e.g., the cantilevered springs of the resilient assembly) when the connector is coupled to the base. This displacement provides a tension or load to the cantilevered spring  36  that is transferred to the catches  56  to secure the connector  10  to the circular hub so it does not wobble or rattle, yet is able to rotate in response to a relatively low level of force. 
       FIGS. 3C through 3I  are illustrations of alternate variations of the resilient assembly and release buttons as well as variations of the circular hub  24 . In one example shown by top view illustration in  FIG. 3C , the resilient assembly  11  may include cantilevered springs arranged so they are oriented generally parallel with the top surface  26  of the circular hub  24 .  FIG. 3D  is a top view illustration of the resilient assembly  11  joined with the head or cover  12 . As can be seen, the release buttons  14  extend radially outward so that squeezing or pinching the release buttons between two fingers displaces the catches  56  radially outward and removing the pinching or squeezing force allows the catches  56  to move radially inward.  FIG. 3E  is a top view illustration of the resilient assembly  11  with cantilevered springs arranged so they are oriented generally parallel with the top surface  26  of the circular hub  24  and in which the release buttons  14  and catches are configured so that pinching or squeezing the release buttons  14  between two fingers flexes the cantilevered springs so the catches  56  are displaced radially inward and removing the pinching or squeezing force allows the catches to move radially outward. Such a configuration illustrated in  FIG. 3E  is useful for an alternative version of a circular hub as illustrated in cross-sectional view in  FIG. 3F . As can be seen, the hub  24  is in the form of a ring or circular band  100  projecting from the base  22  of the enteral feeding device. The band  100  has top surface  102  and a side  28 . The projection or overlap of the top surface  102  over the side defines a recess  30 . The top surface  102  may project over the side in a radially inward direction to define a recess as shown in  FIG. 3F  or it may project in a radially outward direction to define a recess as shown in  FIG. 3G   
     According to an aspect of the invention, the release buttons may be joined to arms or elements that are inflexible or relatively rigid unlike the cantilevered springs. Referring now to  FIG. 3H and 3I , it is contemplated that the release buttons  14  may be joined to inflexible arms  200  that are attached to the central support  32  or directly to the head or cover  12  utilizing a pivot connector  206 , a living hinge or the like. A spring or resilient material such as foam can be used to provide the radial force to urge the release buttons  14  and their respective catches  56  in the desired direction. For example, one end of an extension spring  204  (or resilient foam or the like) may be joined to the central support  32  or to the head or cover  12  and the other end may be joined to a portion of the arm  200  or to the release button  14  itself so that the extension spring  204  provides a radially directed force that resiliently biases the second portion the release buttons (including the catches) in a radial direction—in this example in the radially inward direction (i.e., toward the center of the resilient assembly  11 ). Alternatively and/or additionally, it is contemplated that one end of a compression spring  202  (or resilient foam or the like) may be joined to the central support  32  or to the head or cover  12  and the other end may be joined to a portion of the arm  200  or to the release button  14  itself so that the compression spring  202  provides a radially directed force that resiliently biases the second portion the release buttons (including the catches) in radial direction—in this example in the radially outward direction (i.e., away from the center of the resilient assembly  11 ).  FIG. 3I  is a top view illustration showing an exemplary arm  200  arranged so it is oriented generally parallel with the top surface  26  of the circular hub  24 . One end of a compression spring  202  is joined to the central support  32  (or to the head or cover  12 ) and the other end of the compression spring is joined a portion of the arm  200  or to the release button  14 . As can be seen in the illustration, the release button  14  and catch  56  are configured so that pinching or squeezing a pair of the release buttons mounted on arms in this manner between two fingers would displace the arms  200  and release buttons so the catches are displaced radially inward and removing the pinching or squeezing force allows the catches to move radially outward. 
       FIG. 4A  is an exploded perspective view showing the relationship between the enteral feeding catheter device  20  equipped with a base  22  having a circular hub  24  and the extension set connector  10  including a resilient assembly  11  with an optional cover or head  12 . As can be seen in this configuration, the head or cover  12  may be formed separately from the resilient assembly  11 . In other configurations, the resilient assembly  11  may be one in which the cantilever springs, central support, and the head or cover are integrated or formed as a unitary component. The conduit  16  provides a passage for transferring feeding solution from the feed extension tube  18  through the connector  10  and into the base  22  of the enteral feeding device  20 .  FIG. 4B  is perspective view of the components shown in  FIG. 4A  as they would appear when the connector  10  is coupled to the circular hub  24  on the base  22  of the enteral feeding catheter device  20 . 
     Referring now to  FIGS. 5 and 6 ,  FIG. 5  shows a perspective view of a connector  10  including a conduit  16  defining a fluid pathway  70  through the connector and  FIG. 6  shows a cross-sectional view of a connector  10  including a conduit  16  defining a fluid pathway  70  through the connector. The conduit  16  is configured to supply a feeding solution to a lumen of the enteral feeding catheter device. In some embodiments, the conduit  16  defining the fluid pathway  70  may be located in a space “S” defined by the central support  32  between the pair of opposed cantilevered springs and the pair of release buttons as generally illustrated in  FIGS. 3 and 4 . A proximal end  72  of the conduit  16  defining the fluid pathway may be axially aligned with the lumen of the enteral feeding catheter device and then may have a 90 degree bend such that the distal end  74  of the conduit extends in a generally perpendicular manner to proximal end. This configuration is useful for most feeding applications. Alternatively, the proximal end  72  of the conduit  16  defining the fluid pathway may be axially aligned with the lumen of the enteral feeding catheter device and then may continue such that the distal end  74  of the conduit extends continues in an axially aligned manner to proximal end as illustrated in exploded perspective view in  FIG. 13 . Such a configuration is desirable for delivery of a bolus of feeding solution.  FIG. 14  is a side perspective view showing the extension set connector  10  of  FIG. 13  coupled with the base  22  of an enteral feeding catheter device  20 . 
     The conduit  16  may be in the form of a nozzle as generally illustrated in  FIGS. 2, 5 and 6  that is configured to extend past the proximal end of the connector to engage an orifice “O” defined in the hub  24  to supply a feeding solution to a lumen of an enteral feeding catheter device. Alternatively, the conduit  16  may be configured to engage a nozzle (not shown) protruding from the surface of the hub to supply a feeding solution. 
       FIGS. 7A to 7D  of the drawings are a series of illustrations showing a side view of a portion of an exemplary connector  10  composed of the resilient assembly  11  and the release buttons  14  as they interact with the circular hub  24  in various stages of the process of coupling or connection.  FIG. 7A  illustrates the connector  10  is positioned directly over the circular hub  24 .  FIG. 7B  illustrates the connector initially contacting the circular hub  24  as it is depressed onto the circular hub.  FIG. 7C  illustrates the arms  38  of the cantilevered springs  36  providing a resilient bias to the release buttons  14  such that the release buttons  14  readily deflect (illustrated by arrows “D”) as the downward pressure or force (illustrated by arrow “F”) is applied to the connector allowing the catches  56  to slide past the edge of the circular hub.  FIG. 7D  illustrates the catches  56  engaged in the circumferential recess  30  defined in the side surface  28  of the hub  24  to couple the connector to the circular hub  24  on the base of an enteral feeding catheter device. The top surface  58  is configured to releasably engage an underside (not shown) of the generally horizontal top surface  26  that extends over the generally vertical side surface  28  forming rim, collar, rib or flange structure that defines the circumferential recess. 
     The downward force needed to accomplish the coupling is generally less than about 10 Newtons and is desirably between about 0.1 Newtons and 8 Newtons. Such a low level of force is very important because the downward force is transferred directly to the enteral feeding catheter device which resides in the sensitive stoma site. This configuration avoids much higher levels of forces required to snap a snap-type connector into place. For example the downward force needed to snap a snap-type connector into place is generally much greater. This is very important because the present invention avoids irritating the sensitive stoma site and the low level of force used to engage the connector helps patients that are mobility impaired, sight impaired, or who otherwise have difficulty seeing or reaching the feeding device (e.g., obese patients, patients with poor motor skills, etc.). 
     The cantilevered springs and release buttons also provide a positive tactile signal when the catches  56  slide into the circumferential recess  30  defined in the side surface  28  of the hub. The cantilevered springs provide increasing resistance as the release buttons deflect while the connector is depressed onto the hub. The resistance immediately dissipates when the catches enter the recess to provide a tactile signal. This action also produces an audible signal that may be characterized as a “snap” or “click” to alert the user that the catches are engaged in the recess. These tactile and audible signals are very important for users and care providers to know that a proper and secure connection is made. 
       FIG. 8  is a side view illustrating the general locations for determining the length “L” of the arm  38  of a cantilevered spring  36  by measuring the distance between the locations of the connections at each end of the arm(s)  38  of the spring  36 . The location of the connection between the arm  38  and the release button  14  is shown by a broken line “J”. Similarly, the location of the connection between the arm  38  and the central support  32  is shown by a broken line “K” in  FIG. 8 . While it is contemplated that various geometries, tapers or connection configurations may be used in the construction of the arm and/or between the arm and the release button and/or the central support, the length measurement is intended to be straightforward and determined as the distance between the two connections. If differences exist between the lengths of the upper and lower surfaces of the arm  38 , an average of the two lengths may be used. If a compound cantilevered spring is used, the length measurement is determined by measuring the distance between the two connections. While it is contemplated that configurations may be used that result in varying lengths for opposed cantilevered springs, it is thought to be desirable for the length of each opposed cantilevered spring to be equal otherwise an imbalance in performance or force would occur. In situations where a cantilevered spring  26  has multiple arms  38  as illustrated in  FIGS. 3 and 4  and differences exist between the lengths of these arms, an average of the two lengths may be used 
     Each arm  38  of a cantilevered spring  36  may have a length “L” measured from its connection with the release button  14  to its connection with the central support that is from about 0.75 to about 1.25 times the length of the radius of the circular hub. For example, each arm  38  of a cantilevered spring  36  may have a length measured from its connection with the release button  14  to it connection with the central support  32  that is from about 0.85 to about 1.15 times the length of the radius of the circular hub. As another example, each arm may have a length that is from about 0.9 to about 1.10 times the length of the radius of the circular hub. While the inventors should not be held to any specific theory of operation, the specified ratio between the length of each arm  38  and the radius “R” of the circular hub  24  is thought to provide a length sufficient for the arm(s) of the cantilevered spring (when made of suitable plastic or other material including, but not limited to, nylon, polycarbonate, polyurethane, or the like) to deflect enough to allow coupling and decoupling of the connector at the predetermined levels of force and without causing premature fatigue of the materials in the spring. Generally speaking, the radius of the circular hub may range from about 0.75 inch to about 0.12 inch (˜19 mm to 3 mm). For example, the radius of the circular hub may range from about 0.66 inch to about 0.25 inch (˜17 mm to 6 mm). As another example, the radius of the circular hub may be from about 0.5 inch to about 0.33 inch (˜13 mm to ˜8 mm). 
     According to the invention, the connector  10  is decoupled from the circular hub  24  by depressing the release buttons  14  to reversibly displace the respective catches  56  radially outward to disengage from the circumferential recess  30 . When the release buttons  14  are resiliently biased by cantilevered springs  36 , the arms  38  of the cantilevered springs are reversibly displaced when a force is applied to their respective release buttons  14  at the finger contact zone  50  as generally illustrated in  FIGS. 9A and 9B . By squeezing or pinching the release buttons  14  between two fingers, a force “F” is directed radially inward toward the central support. The force is translated into a torque or rotational force that deflects “D” the arms  38  and moves “M” the respective catches  56  radially outward away from the central support  32  to disengage the circumferential recess  30  defined in the side surface  28  of the circular hub  24 . For example, each arm  38  of the cantilever spring  36  desirably is reversibly displaced by a force of between about 2 and about 14 Newtons applied to its respective release button. As another example, each arm of the cantilever spring desirably is reversibly displaced by a force of between about 4 and about 12 Newtons applied to its respective release button at the finger contact zone radially inward (e.g., toward the central support or the center of the connector). As another example, each arm of the cantilever spring desirably is reversibly displaced by a force of between about 6 and about 8 Newtons applied to its respective release button at the finger contact zone radially inward (e.g., toward the central support or the center of the connector). 
     In an aspect of the invention, the upper surface  34  of the central support  32  may be located above the transition  64  between the first portion  46  and second portion  52  of the release button  14 . In such a configuration, the arm  38  of a cantilevered spring  36  may define an angle “θ” of between about 35 degrees and about 50 degrees with respect to an axis “A” normal to the central support as generally illustrated in  FIG. 10 . For example, each arm of a cantilevered spring may define an angle of between about 40 degrees to about 45 degrees with respect to an axis normal to the central support. While the inventors should not be held to any specific theory of operation, the specified angle θ between the arm  38  of the cantilevered spring and the axis “A” normal to the central support is thought to allow sufficient deflection of the arm(s) of the cantilevered spring (when made of suitable plastic or other material including, but not limited to, nylon, polycarbonate, polyurethane or the like) to allow coupling and decoupling of the connector at the predetermined levels of force and without causing premature fatigue of the materials used in the spring. 
     Referring now to  FIG. 11 , the connector  10  may further include motion limiters  80  to limit the pitch of the connector. More particularly,  FIG. 11  is a cross-sectional view of a portion of an exemplary connector  10  having a cover or head  12  contacting a circular hub  24 . A defined fluid pathway  70  may pass through conduit  16  of the connector  10 . The motion limiters  80  may be integrated with or joined to part of the cover or head  12  and configured to contact an upper surface of the hub  24  or an upper surface of the base  22  of the enteral feeding catheter device. Alternatively and/or additionally, the motion limiters  80  may constitute a portion of the cantilever springs  36  or catches  56  as generally illustrated in  FIG. 12 . For example, the arms  38  of the cantilevered springs may be configured to contact a portion of the circular hub  24  to function as motion limiters  80 . As yet another example, the bottom face  66  of the second portion  52  of the release button  14  may form a proximal portion of connector  10  (i.e., the portion of the connector that is oriented toward and generally positioned closest to the base  22  of the enteral feeding catheter device  20 ) and function as a motion limiter  80 . 
     As noted above, the connector may include a cover or head  12 . The head  12  may have a clamshell or bowl shape to cover the cantilevered springs  36  and central support  32 . The head  12  may be joined to the central support  32  or may be formed as a unitary element with the central support. The head  12  may form a distal portion of the connector i.e., the portion of the connector that is oriented or positioned furthest away from the base  22  of the enteral feeding catheter device  20 ). 
     According to an aspect of the invention, the cantilever springs  36  may be configured so they are integrated with the head  12  of the connector  10  such that the integrated cantilever springs are able to resiliently bias the release buttons. Referring now to  FIG. 15 , there is shown a bottom view of an exemplary connector  10  in which the cantilever springs  36  are integrated with or joined to the head or cover  12 . That is, the central support  32  illustrated in  FIG. 3A  may be unitary with the cover  12  such that the arms  38  of the cantilevered springs  36  extend radially outward from a central portion of the cover  12 .  FIG. 16  is a top perspective view showing the exemplary connector of  FIG. 15 . 
     According to the invention, the connector  10  is “rotatably coupled” to the circular hub  24 . That is, the connector freely rotates completely about the circular hub when coupled to the base of the enteral feeding catheter device. The connector is configured to freely rotate completely around the hub without passing through a position or location where the connector encounters a feature such as a keyway, a groove, a slot or the like which would allow the connector to be inadvertently disengaged and/or without encountering a feature such as a stop, detent or the like that would inhibit or prevent rotation completely around the hub thereby causing the enteral feeding catheter device to twist. Desirably, the connector is configured to rotate completely around the hub multiple times while providing little or no resistance so that the enteral feeding catheter device does not twist or turn. 
     The present invention also encompasses an enteral feeding assembly. The enteral feeding assembly is composed of: (i) an enteral feeding catheter device having a base and including a catheter with a lumen positioned through the base, the base having a circular hub having a radius, a top surface, a side surface and a circumferential recess defined in the side surface; and (ii) an extension set connector for rotatably coupling a feeding tube to a base of an enteral feeding catheter device. The extension set connector is the connector as generally described above. 
     The present invention further encompasses a feeding extension set. The feeding extension set includes a feeding extension tube and a connector for use with an enteral feeding catheter device having a circular hub. The connector has a plurality of resiliently biased release buttons incorporating catches. The connector is configured to rotatably couple to the circular hub by positioning the connector on the hub and depressing the connector until the catches engage a circumferential recess defined in a side surface of the circular hub and the connector is further configured to decouple from the hub by depressing the release buttons to move the respective catches radially outward to disengage from the circumferential recess. The release buttons may be resiliently biased the resilient assembly. The resilient assembly includes at least one resilient element which may be compression springs, extension springs, resilient foams or the like and combinations thereof. If the resilient assembly includes cantilevered springs, each cantilevered spring has at least one arm. Each arm has a first end, a central section, and a second end that is joined to a central support. 
     While the present invention has been described in connection with certain preferred embodiments it is to be understood that the subject matter encompassed by way of the present invention is not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims.