Patent Publication Number: US-2003229309-A1

Title: Inner lumen anti-free flow device

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a device for preventing fluid free flow in a fluid administration system, and more particularly to an anti-free flow valve device disposed within a lumen of a tube assembly. More specifically, the present invention relates to an anti-free flow valve device that prevents fluid free flow when the tube assembly is in a relaxed condition, while permitting fluid flow when the tube assembly is in a stretched condition.  
       [0003] 2. Prior Art  
       [0004] Administering fluid, such as medication, saline and nutritional formula, to a patient is generally well known in the art. Typically, fluid is supplied to a patient by a tube assembly of a fluid administration system which provides a fluid pathway between a fluid source and the patient. The fluid is supplied to the patient through the tube assembly by either an enteral connection which accesses a visceral organ (gastrointestinal feeding) of a patient or through a parenteral connection which accesses a non-visceral organ (intravenous feeding).  
       [0005] Fluid flow rate through the tube assembly may be manually controlled by a mechanical clip which is designed to progressively occlude the tube assembly and selectively impede fluid flow induced by gravity. One such mechanical clip which operates to occlude a portion of the tube assembly is a conventional roller clamp that has a hollow body with opposed openings and a pair of angled slots formed opposite of one another transverse to the openings. The clip further includes a wheel having an axle which is coupled to the body through the slots. A portion of the tube assembly is then inserted through both the openings of the roller clamp and the wheel axially advanced along the slots to pinch a portion of the tube assembly against the body which progressively occludes the tube assembly. Although the mechanical clip operates to provide a cost-efficient method for controlling fluid flow rate, the clip must be manually actuated by the user. Further, the wheel of the mechanical clip can be inadvertently bumped or jostled out of position resulting in an inappropriate flow rate.  
       [0006] In order to better enhance fluid flow rate control in a fluid administration system, calibrated pumps have been utilized. One such calibrated pump is a peristaltic pump connected in-line along a portion of the tube assembly between the fluid source and the patient. The peristaltic pump advances the fluid through the tube assembly by progressively occluding successive portions of the tube assembly and urging each occluded portion forward by rotating the rotor of the pump. When a peristaltic pump is utilized to control the fluid flow rate, mechanical clips are typically not employed or are disengaged to prevent the clip from interfering with the operation of the pump.  
       [0007] Although peristaltic pumps have substantially advanced the art, further improvements are required. For example, once the tube assembly is disengaged from the rotor of the pump, fluid flow through the tube assembly becomes unrestrained as fluid is drawn through the tube assembly by the force of gravity. This situation is known as fluid free flow and may present an undesirable, or even life-threatening situation, if left undetected because of the risk of overfeeding or overmedicating a patient.  
       [0008] In order to overcome the above-noted drawbacks to fluid administration systems utilizing pumps, several devices have been suggested which operate to automatically occlude a portion of the tube assembly and prevent fluid free flow when the tube assembly becomes disengaged from the rotor of the pump while also permitting uninhibited fluid flow when the tube assembly is properly engaged to the pump. For instance, a variety of automatic occluders have been suggested to improve the art such as those disclosed in U.S. Pat. No. 4,689,043 to Bisha entitled “IV Tube Activator” which describes a clamp for use with a peristaltic pump. The clamp includes a V-shaped channel which is spring biased into a closed position where the narrow portion of the V-shaped channel is sized to substantially crimp, or occlude, a portion of the tube assembly and prevent fluid free flow therethrough. The clamp is placed in an open position by a handle which overlays the pump and depresses the springs such that the tube assembly is positioned within the wider portion of the V-shaped channel to permit unrestricted fluid flow through the tube assembly when the pump is operating. When the handle is released, the V-shaped portion will automatically slide into the closed position and prevent fluid free flow by occluding a portion of the tube assembly.  
       [0009] Another automatic occluder is disclosed in U.S. Pat. No. 5,704,582 to Winterer, et al. entitled “Pinched Clipped Occluder for Infusion Sets” which describes a clip that is positioned between a housing and a cover of a pump. The clip has a plunger biased by a spring against the lumen of the tube assembly so that the lumen becomes occluded by the plunger. Fluid flow through the tube assembly may only be established when the plunger is biased away from the lumen of the tube assembly which occurs when the cover is properly coupled with the housing. However, once the cover becomes disengaged from the housing, the plunger is automatically biased into the closed position by the spring to prevent fluid free flow.  
       [0010] Although both of the aforementioned automatic occluders have advanced the art, both devices are mechanically complex and prone to mechanical failure. In addition, the mechanical complexity of these devices also results in occluders which are expensive to manufacture. Accordingly, there is a need in the art for a valve device disposed within a lumen of a tube assembly that is capable of preventing fluid free flow when the tube assembly is disengaged from the pump, while also being mechanically uncomplicated, reliable and low cost to manufacture.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0011] In brief summary, the present invention overcomes and substantially alleviates the deficiencies present in the art by providing a valve device for a fluid administration system which is adapted to prevent fluid free flow when the tube assembly is in a relaxed condition, while permitting fluid flow when the tube assembly is engaged to the pump.  
       [0012] Preferably, the pump of the fluid administration system used with the present invention includes a rotor for advancing fluid through the tube assembly and a pair of recesses formed adjacent the rotor for retaining portions of the tube assembly to the housing of the pump during operation of the system. The tube assembly is an elongated tube with a lumen formed therethrough which provides a fluid pathway having three interconnected tube segments each including respective distal and proximal ends. The distal end of the first tube segment is attached to the fluid source, while the proximal end thereof is connected to the distal end of the second tube segment by a drip chamber having an abutment surface. The proximal end of the second tube segment is interconnected to the distal end of the third tube segment by a coupling having an external flange. Finally, the proximal end of the third tube segment is connected to an enteral or parental connection on the patient.  
       [0013] The tube assembly is engaged to the pump by engaging the second tube segment around the rotor with the abutment surface and external flange engaged within the respective recesses of the pump. Preferably, the length of the second tube segment permits the abutment surface and the external flange of the tube assembly to be properly captured by the first and second recesses, respectively, and place the second tube segment in a stretched condition around the rotor of the pump.  
       [0014] Preferably, the valve device comprises a body disposed in a flexible tube portion that forms a part of the valve device and is interposed between and in communication with the second tube segment and the coupling. The preferred embodiment of the body includes a sealing member formed at the distal end thereof with a plurality of legs which extend in a tapered fashion from the plunger portion and collectively terminate at an annular flange or retention member that defines an opening at the proximal end of the body. An aperture is formed between each of the legs and communicates with the opening through an inner chamber space formed between the legs of the body. The tube portion is made of a flexible elastomeric material which securely houses the body inside a channel defined by the valve tube portion having proximal and distal ends. The proximal end of the channel defines a groove and the distal end forms a valve seat or outlet. The groove is formed around the wall of the channel and is sized and shaped to securely retain the retention member of the valve body within the channel. The valve seat functions as part of a sealing arrangement which is adapted to provide a fluid tight engagement with the sealing member of the body when the valve device is placed in the closed position. When the valve device is in the closed position, the head of the sealing member is securely seated against the valve seat and prevents fluid flow therethrough.  
       [0015] In an alternative embodiment of the body, the legs of the body extend from the sealing member in a straight fashion rather than being tapered as disclosed in the preferred embodiment. In yet another alternative embodiment, the body includes a tapered elongated shaft which extends from the sealing member and terminates at a proximal portion having opposing dual channels formed therethrough which communicate with the either side of the elongated shaft. The proximal portions of both embodiments are also configured to retain the body within the groove formed around the valve tube portion.  
       [0016] In operation, the valve device of the present invention prevents fluid free flow whenever the tube assembly is disengaged from the pump while also permitting fluid flow when the tube assembly is engaged around the rotor of the pump or manually actuated by the user. The body is inserted within the channel of the tube portion during manufacturing of the valve device. To utilize the valve device of the present invention with the fluid administration set, the user first connects one end of the tube assembly with a fluid source and allows fluid to travel through the tube assembly until it reaches the point where the valve device is disposed. The user then primes the tube assembly to evacuate air from all the remaining portions of the tube assembly. Preferably, the tube assembly may be manually primed by pulling, stretching, or bending the portion of the tube assembly adjacent the tube portion which pulls the body away from the coupling and unseats the sealing member from the valve seat. This operation allows fluid to flow and forces air out the remaining portions of the tube assembly until all the air is evacuated from the tube assembly. Once the fluid administration system has been primed, the proximal end of the third segment may be attached to either an enternal or parenternal connection made with the patient.  
       [0017] To regulate and urge fluid through the tube assembly, the tube assembly is engaged around the rotor of the pump. To properly engage the tube assembly, the abutment surface of the drip chamber is inserted within the first recess of the pump, while the second tube segment is stretched by the user around the rotor. The external flange of the tube assembly is then inserted into the second recess in order to retain the second tube segment in a stretched condition around the rotor. In the stretched condition, a tensile force is applied along the second tube segment which also stretches the tube portion and places the valve device in an open position. In the open position, the body is pulled away from the valve seat which unseats the sealing member from the valve seat and permits fluid flow through the valve device. However, if the tube assembly becomes disengaged from the pump, either intentionally or unintentionally, the tensile force applied along the second tube segment and the tube portion is released which places the valve device in the closed position. In the closed position the sealing member of the body is driven back against the valve seat in fluid tight-engagement as the second tube segment and the tube portion move from the stretched condition to the relaxed condition and fluid free flow is prevented through the valve device. Because the retention member of the valve body is always retained within the groove of the tube portion, the body is placed in the open position whenever the second tube segment and the valve tube portion are in the stretched condition. Conversely, the body is always placed in the closed position whenever the second tube segment and the tube portion are returned to the relaxed condition.  
       [0018] Accordingly, the primary object of the present invention is to provide a valve device which prevents fluid free flow in a fluid administration system.  
       [0019] A further object of the present invention is to provide a valve device adapted for use with a pump assembly in a fluid administration system.  
       [0020] Another object of the present invention is to provide a valve device which prevents fluid free flow while being mechanically simple in order to reduce the opportunity of mechanical failure.  
       [0021] Another further object of the present invention is to provide a valve device of the above character that forms a part of the tube assembly.  
       [0022] These and other objects of the present invention are realized in the preferred embodiment, described by way of example and not by way of limitation, which provides for a valve device for use in a fluid administration system to prevent fluid free flow within the tube assembly whenever the tube assembly is disengaged from the pump.  
       [0023] Additional objects, advantages and novel features of the invention will be set forth in the description which follows, and will become apparent to those skilled in the art upon examination of the following more detailed description and drawings in which like elements of the invention are similarly numbered throughout.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0024]FIG. 1 is a partial front view of the tube assembly engaged with the pump according to the present invention;  
     [0025]FIG. 2 is a perspective view of the fluid administration system comprising a fluid source, tube assembly and valve device according to the present invention;  
     [0026]FIG. 3 is a partial cross-sectional view of the valve device shown in the closed position according to the present invention;  
     [0027]FIG. 4 is a partial cross-section view of the valve device shown in the open position according to the present invention;  
     [0028]FIG. 5 is a side view of the preferred embodiment of the valve body according to the present invention;  
     [0029]FIG. 6 is an end view of the preferred embodiment of the valve body according to the present invention;  
     [0030]FIG. 7 is a perspective view of the preferred embodiment of the valve body according to the present invention;  
     [0031]FIG. 8 is a side view of an alternative embodiment of the valve body according to the present invention;  
     [0032]FIG. 9 is a perspective view of the alternative embodiment of the valve body according to the present invention;  
     [0033]FIG. 10 is an end view of the alternative embodiment of the valve body according to the present invention;  
     [0034]FIG. 11 is a side view of another alternative embodiment of the valve body according to the present invention;  
     [0035]FIG. 12 is a perspective view of the alternative embodiment of the valve body shown in FIG. 11 according to the present invention; and  
     [0036]FIG. 13 is an end view of the alternative embodiment of the valve body shown in FIG. 11 according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0037] Referring to the drawings, the preferred embodiment of the valve device of the present invention is illustrated and generally indicated as  16  in FIG. 1. The valve device  16  is used in a fluid administration system  10  having a tube assembly  12  and a pump  14  with device  16  disposed within tube assembly  12  for preventing fluid free flow when assembly  12  is disengaged from the pump. For ease of reference, proximal shall refer to the end of valve device  16  or tube assembly  12  closest to the fluid source  46  while distal shall refer to the end of valve device  16  or tube assembly  12  farthest from fluid source  46  as illustrated in FIG. 2.  
     [0038] Pump  14  is preferably a rotary peristaltic pump as shown in FIG. 1, although one skilled in the art can best appreciate that a variety of other pumps, such as linear peristaltic pumps, may be utilized with valve device  16  without departing from the novel aspects of the present invention. Specifically, pump  14  includes a housing  47  having a rotor  48  and a control panel  49  located adjacent rotor  48  which permits a user to monitor and adjust the rotation rate of rotor  48  for controlling fluid flow rate by pump  14 . Housing  47  further includes a first recess  50  and a second recess  52  formed above rotor  48  for engaging and retaining a portion of tube assembly  12  in a stretched condition as will be discussed in greater detail below.  
     [0039] Referring to FIG. 2, tube assembly  12  comprises a first tube segment  54 , second tube segment  56  and third tube segment  58  which are in communication with one another through a lumen  39  with each tube segment  54 ,  56  and  58  having a respective proximal end  60 ,  64  and  68  and a respective distal end  62 ,  66  and  70 . Proximal end  60  of first tube segment  54  is connected to fluid source  46  for providing fluid to a patient, while distal end  62  thereof is connected to an abutment surface  42  of a drip chamber  40 . Drip chamber  40  is a metering system which interconnects distal end  62  with the proximal end  64  of second tube segment  56 . As further shown, distal end  66  of second tube segment  56  is connected to a coupling  44  having an external flange  45  which interconnects distal end  66  with the proximal end  68  of third tube segment  58 . Finally, distal end  70  of third tube segment  58  communicates with either an enteral or parenteral connection made with a patient for delivery of fluid through tube assembly  12 .  
     [0040] As illustrated back in FIG. 1, abutment surface  42  and external flange  45  of tube assembly  12  are sized and shaped to be retained within a first recess  50  and a second recess  52 , respectively, formed along the housing  47  of pump  14  The length of second tube segment  56  permits abutment surface  42  and external flange  45  to be properly captured within first recess  50  and second recess  52 , respectively, while placing second tube segment  56  in a stretched condition as it is engaged around rotor  48 . Accordingly, the amount of tensile force applied along second tube segment  56  as it is stretched around rotor  48  may be varied by altering the length of tube segment  56 .  
     [0041] Referring to FIGS. 3 and 4, the preferred embodiment of valve device  16  comprises a flexible valve tube portion  18  and solid valve-body  20 . Valve tube portion  18  forms a part of tube assembly  12  and is located proximate the distal end  66  of second tube segment  56  at its connection with coupling  44  (FIG. 2). A channel  22  is defined through the interior of valve tube portion  18  having a proximal section  24  and an opposing distal section  26  in communication with lumen  39 . As further shown, a groove  23  is formed adjacent proximal section  24  of channel  22  and serves as a means for securely retaining valve body  20  within valve tube portion  18 . The distal end  26  of channel  22  defines a valve seat  25  which forms an opening adapted to engage and seal against valve body  20  when valve device  16  is placed in the open position as shall be discussed in greater detail below. Preferably, valve tube portion  18  is constructed from an elastomeric material, such as silicone, although any suitable medical grade material that exhibits sufficient resilience and stretching characteristics when subjected to a tensile force is felt to fall within the spirit of the present invention.  
     [0042] Referring to FIGS.  5 - 7 , the preferred embodiment of valve body  20  is illustrated. Valve body  20  comprises a sealing member  28  which acts as a sealing member for preventing fluid flow communication through valve device  16 . Sealing member  28  has a generally dome-shaped configuration which is adapted to seat in a fluid tight engagement against valve seat  25  (FIG. 3) when valve device  16  is placed in the closed position. Valve body  20  includes a plurality of legs  30  which extend proximally from sealing member  28  in a tapered fashion and terminate along an annular-shaped retention member  34  formed at the proximal end  31  of valve body  20 . Valve body  20  further includes a plurality of apertures  32  formed between each set of respective legs  30 . As shown specifically in FIGS. 6 and 7, retention member  34  defines an annular-shaped opening  36  which communicates with apertures  32  through an inner chamber  38  defined between legs  30 . The apertures  32 , chamber  38  and opening  36  collectively provide a fluid pathway through valve body  20  when valve device  16  is placed in the open position and fluid free flow is permitted through valve tube portion  18 .  
     [0043] In operation, the user of the present invention first connects the proximal end  60  of first tube segment  54  to fluid source  46  so that fluid flows by the force of gravity through lumen  39  and forces air downstream until the fluid reaches the point were valve device  16  is disposed within valve tube portion  18 . With tube assembly  12  in its free state and disengaged from pump  14 , valve device  16  is in the closed position and prevents fluid free flow through third tube segment  58 . In the closed position illustrated in FIG. 3, second tube segment  56  is in a relaxed condition such that sealing member  28  of valve body  20  is securely seated against valve seat  25  of valve tube portion  18  in fluid tight engagement thereto. The user may then prime tube assembly  12  in order to evacuate remaining air from the tube assembly  12  by manually applying a tensile force along a portion of second tube segment  56  proximate valve tube portion  18 . As shown in FIG. 4, applying a tensile force causes valve tube portion  18  to stretch such that valve body  20  is carried in the proximal direction relative to coupling  44  due to the flange  34  of valve body  20  being engaged and retained within groove  23 . The act of stretching valve tube portion  18  causes sealing member  28  of valve body  20  to unseat from valve seat  25  and allow fluid free flow through valve device  16  which evacuates the remaining air from tube assembly  12 .  
     [0044] To regulate and urge fluid flow after priming, tube assembly  12  is engaged to pump  14 . Specifically, abutment surface  42  of drip chamber  40  is first positioned within first recess  50  by the user and second tube segment  56  is engaged around a portion of rotor  48 . External flange  45  of tube assembly  12  is then inserted into second recess  52  such that a tensile force is applied along second tube segment  56  and places valve device  16  in the open position shown in FIG. 4. As the tensile force is applied along second tube segment  56 , tube segment  56  becomes stretched and taut which carries valve device  16  away relative to coupling  44  and unseats sealing member  28  from valve seat  25 , thereby permitting fluid flow through and around valve body  20  and into third tube segment  58 . However, if tube assembly  12  becomes disengaged from pump  14  the tensile force applied along second tube segment  56  is released. Once the tensile force-is released, valve device  16  is returned to the closed position shown in FIG. 3 as plunger portion  28  is driven back into fluid tight engagement against valve seat  25  and fluid free flow is prevented through tube assembly  12 .  
     [0045] Referring to FIGS.  8 - 10 , an alternate embodiment of valve body  20  is shown. Valve body  120  is generally similar to the preferred embodiment in that body  120  comprises a sealing member  128  having a similar shaped dome configuration adapted to seat against valve seat  25  of valve tube portion  18 . However, unlike the preferred embodiment, legs  130  of the alternative embodiment extend in a substantially straight fashion from sealing member  128  rather than being tapered as in the preferred embodiment. As shown specifically in FIG. 9, legs  130  terminate along the inner surface of an annular-shaped retention member  134  formed at the proximal end  31  of valve body  120  with a plurality of apertures  132  formed between each respective leg  130 . As further illustrated in FIG. 10, flange  134  defines a generally circular opening  136  which communicates with apertures  132  through an inner chamber  138  defined between legs  130  that collectively define a fluid pathway through valve body  20  when valve device  120  is placed in the open position.  
     [0046] Referring to FIGS.  11 - 13 , another alternative embodiment of valve body  20  is shown. Valve body  220  of the alternative embodiment comprises a sealing member  228  having a similar shaped dome configuration as the other two embodiments. However, valve body  220  includes an elongated tapered shaft  230  which extends from sealing member  228  and terminates at retention member  232  formed at the proximal end  31  thereof. Retention member  232  of the alternative embodiment has a generally circular-shaped configuration adapted for retention inside groove  23  of valve tube portion  18  with opposing first and second channels  234 ,  236  defined on either side of member  230 . As further shown, first and second channels  234 ,  236  provide fluid pathways through valve body  220  when valve device  16  is placed in the open position.  
     [0047] It should be understood from the foregoing that, while particular embodiments of the invention have been illustrated and described, various modifications can be made thereto without departing from the spirit and scope of the present invention. Therefore, it is not intended that the invention be limited by the specification; instead, the scope of the present invention is intended to be limited only by the appended claims.