Patent Publication Number: US-2003229316-A1

Title: Medical device

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates generally to needle shield assemblies for blood collection/intravenous infusion devices. More particularly, the present invention relates to a needle shield assembly having a needle shield that may be activated by a single-handed operation in order to avoid accidental needle sticks.  
       DESCRIPTION OF THE PRIOR ART  
       [0002] A conventional IV infusion or blood collection assembly includes an elongated small gauge plastic flexible tubing material having a disposable needle and a body or hub for holding the needle on one end. Usually, the hub is adhered to one end of the flexible tube by a friction fit. The hub includes wings extending on either side for the phlebotomist or user to grasp and position the hub for inserting the needle into a patient. Such assemblies may be used for infusing medication into a patient or for collecting blood from a patient. Generally, at the end of the flexible tube opposite the needle, is a female connection for connecting supplies of fluid to be infused or for connecting apparatus for collecting blood, as required.  
       [0003] After the needle of the assembly has been withdrawn from a patient, protection of the used needle tip becomes important. Accidental sticks with a used needle can transmit bloodborne disease such as hepatitis, AIDS and other similar diseases. As a result, there is a present need for methods and devices to enclose the used disposable needle by providing some sort of covering for the used needle tip after it has been withdrawn from the patient.  
       [0004] Many needle guards are known including placing a separate needle cap over the needle after use, positioning a sliding shield distally over the used needle, or hiding the withdrawn needle within a hollow needle bearing holder. Many current needle guards employ a two handed technique. Such a two handed technique is awkward to use and may still pose a risk of accidental needle stick.  
       [0005] In addition to safety shielding devices for needles which require two-handed operation, the art has also seen the use of needle shield devices which are automatic and do not require one-handed or two-handed activation. However, many of these shields can be activated unintentionally, thus rendering the unused instrument unsuitable for its intended purpose.  
       [0006] There exists a need for a simple, straight-forward, reliable, easily fabricated needle assembly which is self-contained, capable of single-handed activation, and can be used with blood collection and intravenous delivery devices.  
       SUMMARY OF THE INVENTION  
       [0007] The present invention provides a safety shield which can be activated using a one-handed technique for use with blood collection devices.  
       [0008] A safety shield assembly for an intravenous apparatus is provided including a needle, a needle hub, a forward shield, a guide element and a locking member. The needle hub is in fluid communication with a proximal end of the needle and includes a pair of flexible wings. The shield includes a distal blunting end having a distal aperture and a proximal needle passageway. The shield is moveable from a retracted position, in which the needle tip is exposed through the distal aperture, to an extended position, in which the needle tip is withdrawn from the aperture and is covered by the blunting end. The guide element is arranged on the hub for slidably accommodating the shield for movement from the retracted position to the extended position. The locking member locks the forward shield with respect to the guide element in the extended position, upon slidable movement of the shield into the extended position.  
       [0009] A safety shield assembly for an intravenous apparatus is provided including a needle, a needle hub, a forward shield, and a guide element. The needle hub is in fluid communication with a proximal end of the needle and includes a pair of flexible wings. The forward shield includes a distal blunting end, a proximal finger contact surface, an arched barrier arm interposed between the blunting end and the finger contact surface, and a wedge-shaped locking projection having a wider proximal end than a distal end. The shield is moveable from a retracted position, in which the needle tip is exposed through the distal aperture, to an extended position, in which the needle tip is withdrawn from the aperture and is covered by the blunting end. The guide element is arranged on the hub for slidably accommodating the forward shield for movement from the retracted position to the extended position. The guide element includes a guide groove having a pair of inwardly directed projections, whereby the inwardly directed projections engage the locking projection to prevent retrograde movement when the forward shield is in the extended position. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010]FIG. 1 is a perspective top view of a conventional blood infusion set, without a needle shield assembly;  
     [0011]FIG. 2 is a top view of the assembly of FIG. 1;  
     [0012]FIG. 3 is a side view of a safety shield assembly according to the present invention with the shield in a retracted position and attached to a blood collection or intravenous tube;  
     [0013]FIG. 4 is a side view of the needle assembly of FIG. 3 with the shield in an extended position;  
     [0014]FIG. 5 is a side view of a safety shield assembly according to the present invention showing the shield in an extended position with the needle tip out of alignment with the aperture of the blunting end of the forward shield;  
     [0015]FIG. 6 is a top plan view of a barrier arm according to the present invention;  
     [0016]FIG. 7 is a side view of a safety shield assembly according to the invention including a retaining projection and color segments;  
     [0017]FIG. 8 is a side view of a safety shield assembly according to the present invention with the shield in the retracted position and including a spring member and releasable latch for assisting forward movement of the forward blunting member;  
     [0018]FIG. 9 is a side view of a safety shield assembly according to the present invention with the shield in the extended position and having a spring member and releasable latch for assisting forward movement of the forward blunting member;  
     [0019]FIG. 10 is a front view of a cross section of a guide element according to an embodiment of the invention, along lines X-X of FIG. 4;  
     [0020]FIG. 11 is a perspective plan view of a needle cap according to the invention; and  
     [0021]FIG. 12 is a cross-sectional view of the needle cap of FIG. 11 along lines XI-XI of FIG. 11. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0022] While this invention is satisfied by embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. The scope of the invention will be measured by the appended claims and their equivalents.  
     [0023] Referring to the drawings in which like characters refer to like parts throughout the several views, FIGS. 1 and 2 show a conventional IV infusion set  910 , including a needle  912  embedded in a needle hub  914  toward the proximal end of the needle  912 . Flexible tubing  932  extends from the proximal end of the hub  914  which is conventional tubing for allowing the user to connect to supplies of infusion liquids or collection tubes for blood collection. The IV infusion set generally includes flexible wings  930  attached to and projected outwardly from the hub  914 . The flexible wings  930  are usually integral with the hub  914 .  
     [0024] The safety shield assembly of the present invention includes a safety shield in cooperative engagement with a guide member. The shield slides over the needle to protect the needle tip. Features of the invention include one or more retaining members to keep the shield in place in a retracted position and to keep the needle tip available for use. A locking member is provided to keep the shield in place over the needle tip in an extended position after the needle has become contaminated. These and other features of the invention are described in detail below.  
     [0025] Referring now to FIGS. 3 and 4, a safety shield assembly  10  according to the present invention, is shown. The safety needle assembly includes a needle  12  having a proximal end, a distal end, with a lumen therethrough, and a sharp distal tip  16 . A needle hub  14  is arranged at the proximal end of the needle  12  and has an interior cavity in fluid communication with the lumen. The needle hub  14  has a distal end, a proximal end and a main body therebetween. A pair of flexible wings  30  are positioned on the main body of the hub  14  for guiding the needle  12  during venipuncture.  
     [0026] In this configuration, a guide element  24  is a separate part connected to the needle hub  14 . In this case, the guide element  24  is connected toward a distal end of the hub  14 . The guide element  24  includes a guide groove (not shown) and is generally axially oriented about the needle and dimensioned to accept a forward shield  26 . The guide element  24  may be attached to the hub  14  through the use of any suitable joining technique such as adhesives, ultrasonic welding and the like. For low volume production, attaching the guide element to an existing hub  14 , is desirable from a cost standpoint. It is within the purview of the present invention to include an integrally molded one-piece hub  14  and guide element. For high volume production it may be desirable that the needle hub  14  and guide element  24  be of one-piece integrally molded thermoplastic.  
     [0027] Referring again to FIGS. 3 and 4, the forward shield  26  includes an elongate barrier arm  40  having a blunting end  18  for protecting the needle tip  16  arranged toward the distal end of the arm  40 . The blunting end  18  has a distal aperture  20  and a proximal needle passageway  22  for accommodating the needle  12 . The barrier arm  40  is positioned within the guide groove  34  (not shown). The needle  12  is positioned within the proximal needle passageway  22  of the blunting end  18 .  
     [0028] As can be seen in FIG. 10, which is a partial cross-sectional view of lines X-X of FIG. 4, the guide groove  34  is sized to accommodate a portion of the barrier arm  40  of the shield  26 . The barrier arm  40  of the forward shield  26  is thus slidably connected to the guide element  24  via the guide groove  34 . The barrier arm  40  includes a rib  42  which fits into the guide groove  34 . The forward shield  26  is movable from at least a retracted position as illustrated in FIG. 3, wherein the needle tip  16  passes completely through the blunting end  18  and is exposed through the aperture  20 , to an extended position, in which the needle tip  16  is withdrawn from the aperture  20  and resides inside the blunting end  18 , as illustrated in FIG. 4.  
     [0029] Preferably, the barrier arm  40  and blunting end  18  of the forward shield  26  are integrally molded of the same material. However, the barrier arm  40  and the blunting end  18  can be separately formed and joined together by any suitable means such as adhesive, ultrasonic welding and frictional or snap-fit type engagement. The barrier arm  40  and blunting end  18  can also be separately formed and connected by a separate element such as a metal clip (not shown).  
     [0030] A proximal end of the forward shield  26  includes a finger contact surface  28  to allow the single-handed movement of the barrier arm  40  from the retracted position of FIG. 3 to the extended position of FIG. 4. In this preferred embodiment, finger contact surface  28  is provided on the proximal end of the elongate barrier arm  40 . Application of a digital pressure to the finger contact surface  28  moves the forward shield  26  into the extended position. The forward shield  26  slides along the guide groove  34  after the needle  12  has been used. Thus, a one handed method can be used to place the forward shield  26  in the extended position and shield the needle tip  16  so as to prevent injury. This position for the finger contact surface is preferred because it is the farthest position from the sharp needle tip  16 .  
     [0031] The barrier arm  40  can be single-handedly advanced from the retracted position to the extended position by holding the hub  14  in one hand and pushing on finger contact surface  28  with the thumb or the index finger of the holding hand. Dorsal placement of the guide element  24  and the forward shield  26  with respect to the needle  12  and hub  14  allows for the wings  30  to be used unimpeded during placement of the needle in the patient. The ability to allow single-handed operation is significant since it allows the person administering the injection to use the other hand for other purposes such as applying pressure to a vein to prevent bleeding.  
     [0032] Referring now to FIGS. 6 and 10, showing a top view of the guide element  24  and a front cross-sectional view of the forward shield  26 , respectively, a further aspect of the invention is shown. In this aspect, a further retaining member is provided for retaining the shield  24  in the retracted position. The further retaining member includes a recess  84  in the barrier arm  40  for accepting a retaining projection  66  on the guide element  24  when the barrier arm  40  is in the retracted position. In this position, the barrier arm  40  does not have to be tightly contained within the guide groove  34 . Accordingly, the plastic components are not stressed during the long period of time between manufacture and use.  
     [0033] Upon applying force to the barrier arm  40  to move it distally, retaining projection  66  rides up a ramped portion  86  of retaining recess  84  to immediately increase the force necessary to move the barrier arm  40  in a distal direction. This design helps to retain the barrier arm  40  in the retracted position. The shapes of retaining projection  66  and the ramped portion  86  may be configured so that there is an audible click when retaining projection  66  leaves retaining recess  84 , further communicating to the healthcare worker that the barrier arm  40  is in motion toward the second extended position.  
     [0034] Referring now to FIG. 7, a first retaining member for releasably retaining the barrier arm  40  in the first retracted position is shown. This function can be accomplished by dimensioning the barrier arm  40  and the groove  34  in the guide element  24  to have a frictional fit. In this preferred aspect, the barrier arm  40  is arched. Specifically, a distal end and a proximal end of the barrier arm  40  define longitudinal axes A 1  and A 2 , respectively. A 1  and A 2  are at an obtuse angle “α” with respect to each other. The retaining arm  34  defines a substantially rectilinear opening for accommodating a straight member. The non-straight or arched configuration of the barrier arm  40 , when it enters a groove  34  sized for a straight barrier arm, provides a frictional relationship which keeps the barrier arm  40  from moving distally under less than the desired force.  
     [0035] Additionally, the present invention includes a locking member for preventing retrograde movement of the barrier arm  40  from the extended position. The locking member is activated by movement of the barrier arm  40  into the extended position.  
     [0036] Referring now to FIG. 5, in one aspect of the invention, a locking member is shown. The locking member locks the barrier arm  40  in the extended position. The locking member is essentially the same as the aforementioned first retaining member. The locking member includes the distal end of the barrier arm  40  defining a distal longitudinal axis B 1  and the proximal end of the barrier arm defining a proximal longitudinal axis B 2 . The barrier arm  40  is arched so that the distal longitudinal axis and the proximal longitudinal axis are at obtuse angle “β” with respect to each other, when the barrier arm is in the second extended position. Due to the arched configuration of the barrier arm  40 , the distal end of the needle is out of alignment or “off center” with the distal aperture  20  when the forward shield  26  is in the extended position. An attempt to move the barrier arm  40  from the second extended position will cause the sharpened distal tip  16  of the needle to embed itself into an interior wall of the blunting end  18  of the forward shield  26  to help prevent re-exposing the needle tip  16 . This is an important feature of the present invention because the locking member is essentially part of the forward shield  26 . As a result, additional parts and structures such as latches, ledges, triggers and the like, which add to cost and complexity and can adversely affect reliability, are avoided.  
     [0037] Referring now to FIGS. 5 and 10, a further locking member of the invention is shown. In this embodiment, the needle shield assembly includes additional structure features to further resist retrograde motion of the barrier arm  40  from the extended position to the retracted position. In this embodiment, the guide groove  34  and the barrier arm  40  include a combination of projections and recesses which allow the barrier arm  40  to slide along the guide groove  34 , in a distal direction, by application of digital pressure on finger contact surface  28 . However, the projections and recesses are configured such that returning the barrier arm  40  to the retracted position is not possible using forces normally associated with operating the invention.  
     [0038] In FIG. 10, a partial front cross-sectional view of line X-X of FIG. 4 is shown. The guide element  24  includes sidewalls  48  and  50  having generally opposed inwardly directed projections  52  and  54 , respectively. The projections  52  and  54 , include indents  53  and  55 , configured to interact with a raised locking projection  56  on barrier arm  40  as shown in FIG. 5. The raised locking projection  56  is wedge-shaped and is wider at its proximal end than at its distal end.  
     [0039] When force is applied to the barrier arm  40  to move the guide element  24  from the first retracted position to the second extended position, then distal motion of the barrier arm  40  will cause raised locking projection  56  to contact indents  53  and  55  on projections  52  and  54  of the guide element  24 . Additional force will be required to force the raised locking projection  56  through the indents in the projections  52  and  54 . This action expands the space between the sidewalls  48  and  50  of the shield  26  to accommodate the locking projections  56 . Once this occurs, the projections  52  and  54  will return to their original position and an edge  58  on projection  52 , and an edge  60  on projection  54  will form a locking relationship with respect to back wall  62  of raised locking projection  56  to prevent retrograde movement. This aspect of the invention can optionally be used with the previously described locking member to help prevent retrograde movement of the barrier arm  40  from the second extended position. There is no particular limitation on placement of the recesses and projections. For example, the recesses and projections may be placed on the top of the guide element and barrier arm, respectively.  
     [0040] In a further aspect of the invention, the projections  52  and  54  on the guide element and raised locking projection  56  on the barrier arm  40  are configured so that when the barrier arm  40  is moved distally into the second extended position, the projections  52  and  54  will snap past the end of raised locking projection  56 , making an audible sound to provide an audible indication that the barrier arm  40  is moved into the second extended position. It is preferred that two projections be provided on the guide element, however, only one projection will work and is within the purview of the present invention.  
     [0041] In a further aspect of the invention, the assembly is provided with color segments to visually verify when the barrier arm  40  is in the second extended position. Referring now to FIGS. 5 and 7, a color segment  64  on barrier arm  40  and a color segment  80  on the guide element  24  are shown. When the barrier arm  40  is in the retracted position, as shown in FIG. 7, then the color segment  64  on barrier arm  40  is in non-alignment with the color segment  80  on the guide element  24 . When the barrier arm  40  is in the extended position, the color segment  64  is in alignment with the color segment  80  of the guide element  24 . Alignment of the color segments  64  and  80  forms a continuous transverse color bond. This indicates the assembly  10  is fully in the extended position, and therefore safer for disposal. In one embodiment, the guide element  24  includes two generally opposed color segments on the guide element  24 . Any color, including black and white, can be used to form the color segments. However, green is preferred, because it is generally accepted to indicate safety.  
     [0042] The needle shield assembly of the invention provides an easy to use shield which can be operated manually using a one handed technique. The user is protected from inadvertent needle sticks by pushing the shield distally until the blunting end covers the needle tip. However, it is also useful to have the shield move automatically over the needle tip upon release of the shield from the hub. To this end, a further aspect of the invention is provided including a spring activated assist mechanism for distally moving the barrier arm  40  into the second extended position.  
     [0043] Referring now to FIGS. 8 and 9, a spring  88  is arranged between the guide element  24  and a proximal edge  90  of the blunting end  18 . The spring  88  wraps around the needle  12  and is held in place by a pivoting latch  92 . The pivoting latch  92  includes a pivot arm  98 , a pivot lever  100  and a pivot point  94  therebetween. The pivoting latch  92  is anchored onto the barrier arm  40  at pivot point  94 . In a closed position, pivot arm  98  is arranged in an opening or channel  96  on the barrier arm  40  so as to hold the spring  88  in a biased state.  
     [0044] The pivoting latch  92  is activated by putting downward pressure on the pivot lever  100  so as to elevate the pivot arm  98  from the opening  96  and release the spring  88 . Once released, the spring  88  exerts a compression force against the proximal end  90  of the blunting end  18 . The compression force thereby assists in moving the forward shield  26  into the second extended position. In this embodiment, the user does not have to manually push the shield  24  distally. Rather, activation of the pivot lever is all that is required to safely guard the needle.  
     [0045] Referring now to FIGS. 10, 11 and  12 , a needle cap is shown. A further aspect of the present invention includes a needle cap  69  having a side wall  70  which defines a cavity therebetween for receiving the needle  12 . A proximal end of the needle cap  70  includes an opening configured to releasably engage a portion of the guide element. The cap serves to hold the needle shield in a needle protecting position while the barrier arm  40  is in the first retracted position. The needle cap  70  is configured so that when the barrier arm  40  is in the second extended position, the needle cap  70  cannot be connected to the needle assembly.  
     [0046] Needle cap  70  is removably connected to the guide element  24  through action of projections  72  and  74  at the proximal end of the needle cap  70  which interact with complimentary recesses  76  and  78  on the guide element  24 . The needle cap  70  is configured to accept the barrier arm  40  so that there can be a substantially complete shielding of the needle. Accordingly, the needle cap  70  can effectively protect the needle from damage and inadvertent contact from the time of manufacture until the time of use, at which point the cap  70  is appropriately discarded. After the forward shield  26  is moved to the second extended position, the needle cap  70  can no longer be used with the safety shield assembly  10  of the present invention.  
     [0047] An alternate aspect of the invention includes a barrier arm  40  having a proximal end and a distal end. The barrier arm  40  includes a blunting end  18  having a distal end, a proximal end, and a needle passageway  22  therethrough. This alternate needle assembly functions in substantially the same manner as the needle assembly taught in FIGS.  3 - 11  except that the needle passageway  22  is generally continuous throughout the length of the forward shield. When the forward shield  26  is moved to the second extended position, the sharpened tip  16  of the needle  12  will be pressing firmly against the sidewalls of the needle passageway  22  so that any attempt to move the barrier arm  40  from the second extended position to the first retracted position will cause the needle to embed itself in the sidewall of needle passageway  22  to inhibit proximal movement of the barrier arm.  
     [0048] Another alternative aspect of the safety shield assembly includes the hub  14  and the guide element  24  being integrally formed of one-piece construction, preferably of thermoplastic material, most preferable a clear transparent thermoplastic material.  
     [0049] The needle assembly of the present invention is suitable for use with a wide variety of medical devices, including blood collection devices. The invention is illustrated in FIGS.  3 - 8  as being used with blood collection and/or fluid delivery tubing  32 .  
     [0050] Various other modifications to the foregoing disclosed embodiments will now be evident to those skilled in the art. Thus, the particularly described preferred embodiments are intended to be illustrative and not limited thereto. The true scope of the invention is set forth in the following claims.