Abstract:
A syringe barrel including a tubular, barrel body operable to receive a syringe plunger at a proximal end thereof and a syringe needle at a distal end and sidewalls of said syringe body being flexible and elliptical in cross-section and opposing compression of said syringe barrel at opposite ends a major axis of said syringe barrel cross-section serving to operably flex the elliptical cross-section of said syringe body into a more circular cross-sectional configuration and increasing the volume of said syringe barrel body and concomitantly serving to create a relative vacuum within said syringe body as compared with the configuration of said syringe tubular, barrel body prior to application of said compression.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0001]    The present invention relates to a syringe device for safely and facilely administering a fluid injectant into a patient. More particular, the invention relates to certain improvements for single-use syringes for injecting liquids or gels with selective aspirating capabilities. The syringe device can be economically molded from a single material and can be similar in appearance to a common syringe and easily adaptable to the current administering techniques. The syringe, when injecting, can be disposed in a natural hand-held position to minimize movement insuring the same sampling and injection site. 
         [0002]    The use of conventional syringes for patient injections is known. A syringe device typically comprises: a rigid, circular cylindrical barrel defining a fluid retaining chamber with an open proximal end and a distal wall having a central frustum having a fluid passageway communicating the barrel with an attached distally extending cannula. A plunger extends proximally from of the barrel and with a distal stopper in a fluid-tight engagement within the barrel. 
         [0003]    When it is necessary to know needle placement relative to a patient&#39;s vascular system, aspiration is necessary. To aspirate, the volume of the syringe barrel is expanded to create a vacuum and ultimately draw bodily fluid into the neck of the syringe to determine if a blood vessel has been penetrated. This may be done actively or passively. 
         [0004]    Active aspiration is typically performed by manually retracting a syringe plunger from within the syringe barrel after inserting a sharp cannula into the patient to obtain an observable body fluid sample in the neck of the syringe barrel. This can be a two handed awkward process. Another active aspirating method is to retract the plunger seal&#39;s leading face by withdrawing an attached central shaft within the plunger to create a vacuum within the syringe barrel chamber to aspirate body fluids into the barrel to detect the possible presence of blood in the sample. Another process utilizes a hand apparatus enclosing the syringe which mechanically retracts or extends the plunger to aspirate or inject. 
         [0005]    Other types of syringe bodies offer passive aspiration. In one example, a plunger is momentarily depressed into the syringe barrel expanding a pliable, sealing member prior to placing the needle stick. After the needle is inserted into a patient the plunger is released allowing the sealing member to retract and reestablish an initial configuration. This creates a vacuum to draw up bodily fluids into barrel neck for checking needle placement. A major drawback with this process is the awkwardness of depressing the plunger and maintaining the expanded sealing member prior to and during the needle stick. Another passive version uses a momentary syringe barrel, sidewall compression prior to inserting the needle into the patient. When released, the barrel volume returns to initial shape drawing in bodily fluid. This also has a degree of awkwardness associated with maintaining a consistent barrel compression during the needle stick. Both examples can expel a random amount of injectant prior to needle placement making dosages uncertain. 
         [0006]    This invention relates to transitioning syringe barrel and plunger configurations after needle placement. A circular barrel cross-section provides the largest internal volume for a given barrel circumference or perimeter. Any distortion of a non-circular or non-regular polygonal cross-section to achieve a circular or regular polygonal cross-section will increase the section&#39;s area and ultimately its respective volume for a given barrel length. The barrel volume referred to is the actual fluid volume established by the plunger seal position within the barrel. This distortion may result in circular, elliptical, or linear sidewalls or a combination configuration. This sidewall flexibility is achieved either with wall thickness, thickness variations, a compliment of living hinges, or a combination thereof. The overall shape of the syringe body may be cylindrical or conical for an elliptical cross-section, or planar for a regular polygonal cross-section. 
         [0007]    A distortion of a molded configuration may be achieved through folding, stretching, and/or squeezing the syringe barrel. There is a pressure differential between a gripping pressure required to place a needle into a patient and the pressure required to aspirate fluid from the patient. This prevents inadvertent aspiration prior to the needle stick possibly drawing air into the syringe. 
         [0008]    In one embodiment, the syringe body sidewall is elliptical in cross-section. The wall thickness may be constant or could vary from the opposing, circular, structural portions capping the major axis to the opposing, gradually thinning, yieldable elliptical ones capping the minor axis. The gradual thinning sidewalls produce a more predictable barrel volume increase by encouraging the elliptical section center to move outward initially. The technique is to squeeze the barrel&#39;s circular sections after the needle stick to transition its elliptical cross-section towards a circular cross-section increasing the section&#39;s respective area and the barrel&#39;s overall volume for a given plunger-seal position. 
         [0009]    Another embodiment uses planar sidewalls forming a parallelogram with uneven diagonals. These sidewalls may have a uniform structural thickness with living hinges at their junctures; together, when depressed, allow the shape to transition towards a square increasing the body&#39;s volume. This thickness needs to be sufficient for gripping and needle placement without body deformation, but yieldable when the living hinges capping the longest diagonal are depressed when aspiration is desired. 
         [0010]    The frustum of the barrel&#39;s distal wall may have a stepped interior volume to provide a smaller volume, viewing window permitting a smaller, concentrated fluid sampling. This window may be visible behind a partial luer-lock coupler if one is present. 
         [0011]    This invention provides a syringe which may be selectively aspirated single-handedly, without altering one&#39;s grip, after the needle is inserted into a patient during an injection. 
         [0012]    The difficulties and limitations suggested in the preceding and desired features are not intended to be exhaustive but rather are among many which may tend to reduce the effectiveness and user satisfaction with previously known syringes. Other noteworthy problems and limitations may also exist; however, those presented above should be sufficient to demonstrate that syringes appearing in the past will admit to worthwhile improvement. 
       BRIEF SUMMARY 
       [0013]    One preferred embodiment of the invention which is intended to address concerns and accomplish at least some of the foregoing objects comprises a syringe capable of being selectively molded from a single material. This embodiment resembles a typical syringe in appearance, except with an elliptical instead of a circular cross-sectional body. This unique body is sufficiently rigid for gripping, yet flexible enough to be reshaped allowing a user to selectively aspirate for determining proper needle placement without changing hand positioning before completing an injection. A typical grip would be to hold the syringe with one&#39;s thumb and middle finger on the pads capping the major axis of the distal wall or the actual syringe body in the region of the plunger seal, and depress the plunger with the index finger. Alternatively the syringe barrel may be grasped between the index and middle finger with an operator&#39;s thumb on the syringe plunger. To aspirate, one simply squeezes the elliptical body about the major axis transforming it towards a circular configuration after placing the needle. An aspirated, fluid sample is visible in a reduced diameter, neck portion at the barrel&#39;s distal end. This chamber&#39;s length with reduced volume requires less fluid for determining the aspirated fluids origin. The injection is completed by then depressing the plunger and properly disposing the spent syringe. 
         [0014]    Stowing the syringe prior to disposal may be accomplished with any of the current techniques, such as recapping, flip enclosures for shielding the needle tip, retracting needles, and others. Any needle attachment means may be used, such as insertion with adhesive or a luer lock coupler arrangement. The sealing member of the plunger may be formed entirely of the same material as the body using a modified partial O-ring or inverted cup-shaped configuration; or from an elastomeric material, such as rubber or silicone, with resilient, sealing engagement bands. The latter is secured to the plunger shaft with a complementing groove to the periphery bead of the plunger base. The plunger may have webs or similar structure to center itself within the chamber of the body and an elliptical base which maintains the body&#39;s elliptical nature in the sealing region. On the body, there are graduated indicia to determine the volume in relation to the plunger seal&#39;s position within syringe body. 
     
    
     
       DRAWINGS 
         [0015]    Other objects and advantages of the present invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings wherein: 
           [0016]      FIG. 1  is an axonometric view of a syringe in accordance with one embodiment of the invention. 
           [0017]      FIG. 2  is a longitudinal cross-section, side view of  FIG. 1 ; 
           [0018]      FIG. 3  is an additional longitudinal cross-section, top view of  FIG. 1 ; 
           [0019]      FIG. 4  is a cross-section of the syringe&#39;s elliptical body; 
           [0020]      FIG. 5  is an enlarged view of a plunger&#39;s sealing member; 
           [0021]      FIG. 6  is an enlarged view of the body&#39;s distal end; 
           [0022]      FIG. 7  is another embodiment with a greater axes length differential; 
           [0023]      FIG. 8  is a longitudinal cross-section, side view of  FIG. 7 ; 
           [0024]      FIG. 9  is a longitudinal cross-section, top view of  FIG. 7 ; 
           [0025]      FIG. 10  is a cross-section of the syringe barrel of  FIG. 7 ; 
           [0026]      FIG. 11  is a side cross-section of  FIG. 7  with an alternative plunger sealing member; 
           [0027]      FIG. 12  is a cross-section of the distal region of the syringe in  FIG. 7 ; 
           [0028]      FIG. 13  is a side cross-section of  FIG. 7  revealing an aspirated state; 
           [0029]      FIG. 14  is a top cross-section of  FIG. 7  complimenting  FIG. 13 ; 
           [0030]      FIG. 15  is a cross-section of the syringe body prior to aspiration; 
           [0031]      FIG. 16  is a cross-section of the syringe body during aspiration; 
           [0032]      FIG. 17  is an additional embodiment utilizing a conical body; 
           [0033]      FIG. 18  is a side cross-section of  FIG. 14 ; 
           [0034]      FIG. 19  is a top cross-section of  FIG. 14 ; 
           [0035]      FIG. 20  is an enlarged cross-section of syringe body; 
           [0036]      FIG. 21  is an enlarged view of  FIG. 18  in the region of the plunge seal; 
           [0037]      FIG. 22  is an alternative kite shaped embodiment; 
           [0038]      FIG. 23  is a longitudinal cross-section, side view of  FIG. 22 ; 
           [0039]      FIG. 24  is an additional longitudinal cross-section, top view of  FIG. 22 ; 
           [0040]      FIG. 25  is an enlarged cross-section of the syringe body; 
           [0041]      FIG. 26  is an alternative blended embodiment; 
           [0042]      FIG. 27  is a longitudinal side cross-section; 
           [0043]      FIG. 28  is a longitudinal side cross-section; 
           [0044]      FIG. 29  is a cross-section of the elliptic cylindrical body; and 
           [0045]      FIG. 30  is a cross-section of the circular cylindrical body. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    Referring now particularly to the drawings, wherein like reference characters refer to like parts, and initially to  FIG. 1 , there will be seen an axonometric view of a syringe  10  in accordance with one preferred embodiment of the invention. The syringe  10  in  FIG. 1  comprises a distally truncated, elliptic cylindrical barrel or body  11  and an axially sliding, sealing plunger  15 . The barrel  11  has a uniform wall thickness  14  which provides a distinct difference between the gripping pressure needed to perform the needle stick and the compressive pressure needed for aspiration. This prevents an inadvertent aspiration prior to the needle stick. The distal end wall  12  has a frustum  16  possessing a stepped passageway  17  to provide fluid communication between a fluid chamber  18  of the barrel  11  and a needle. A retention ring  19  integrally surrounds the frustum  16  to selectively retain the needle cap with mating detent. At an open, proximal end  13  of barrel  11 , a peripheral, gripping flange  24  maintains the elliptical nature of the barrel  11  and assists the holding of the syringe  10  during filling and administering an injection. The plunger  15  consists of a ribbed shaft  25  with distal and proximal ends,  26  and  27  respectively. A distal end  26  provides a slidable, cup seal  28  which is in fluid tight engagement with the sidewall  29  of fluid chamber  18 . A  15 &#39;s proximal end  27  of plunger  15  has a pressure pad  28  for finger placement to comfortably depress the plunger  15 . 
         [0047]      FIGS. 2 and 3  reveal side and top cross-sections of  FIG. 1 , respectively. Due to the elliptical nature of the barrel body  11 , the profile  37  of the body in  FIG. 2  is wider than the profile  38  in  FIG. 3 . 
         [0048]      FIG. 4  is a cross-section of barrel body  11  revealing the elliptical sidewall  29  configuration of uniform thickness  14 . 
         [0049]      FIG. 5  is an enlarged view showing a sealing engagement of cup seal  30  with the sidewall  29 . This fluid tight engagement is accomplished a hollowed, elastomeric cup-seal  30  with two sidewall  29  engaging bands  32 , spaced apart to ensure axial travel the cup seal  30 . The seal  30  is affixed to the plunger  15  about a beaded edge  36  on a distal base  35  of plunger  15  by a proximal peripheral groove  33 . A hollowed interior  31  of the cup seal  30  permits a distal surface  34  to partially collapse when aspirating close to it, but resiliently reshapes to expel the injectant. The distal base  35  maintains the elliptical configuration of the barrel body  11  at the seal even when aspirating distortion is induced. 
         [0050]      FIG. 6  is an enlarged view showing the frustum  16  in greater detail. Within the frustum  16 , the stepped passageway  17  has a flared distal opening  20  to accommodate adhesive to affix a needle in socket  21 . The fluid passageway narrows forming a needle stop  22  before flaring again to form the viewing conical chamber  23  which allows the viewing of a smaller, concentrated sampling of the aspirated, fluid specimen prior to it entering the fluid chamber  18 . 
         [0051]      FIG. 7  is an axonometric view of another embodiment of a selectively aspirating syringe. Syringe  40  shares many similar features and their functionalities with syringe  10 , such as a similar distally truncated, elliptic, cylindrical body  41  with gripping flange  44  and an axially sliding, ribbed plunger  52  with a distal seal  56  and a proximal finger pad  59 . Two opposing, finger detents  67  and  68  on the distal end of aspirating rib sections  65  and  66 , respectively, establish finger placement for holding the syringe. More distinguishing features of syringe  40  are revealed in detail in  FIGS. 10-12 . 
         [0052]      FIGS. 8 and 9  display side and top sections, respectively, of  FIG. 7 . The profile  63  of body  41  in  FIG. 8  is broader compared to the profile of body  41  in  FIG. 9  due to its elliptical nature.  FIG. 8  also displays finger detents  67  and  68  on the aspirating ribs  65  and  66 . As explained earlier, these detents indicate proper finger placement for grasping the syringe body  41  to avoid inadvertent aspiration. 
         [0053]      FIG. 10  is cross-section of an elliptical syringe barrel body  41 . This illustrates a thickness variation of the sidewall  60  which promotes a predictable transition from an elliptical to a round configuration when the elliptical wall section  61  capping the major axis is depressed. This depression of wall section  61  causes a reduced radius in wall section  62  which caps the minor axis of the ellipse and transitions the elliptical body towards a circular shape which increases the section area and chamber volume. 
         [0054]      FIG. 11  is an enlarged partial section of  FIG. 8  which shows an integral plunger seal  56 . The seal  56  of the plunger is a pair of O-rings  58  integrally molded onto a distal base  57  of the plunger, which when placed within the elliptical body  41  forms a fluid-tight engagement with sidewall  60  and maintains an axial travel seal. These O-rings  58  also assist in maintaining the elliptical nature of body  41  when a portion of the sidewall is depressed for aspiration. The surface contour of distal base  57  replicates the interior of distal end wall  42 . This sealing means may have other forms: such as an applied O-ring instead of being integrally molded, or an outward, distal extension of the distal surface forming an inverted cup to serve as a wiper, or other slideable, sealing structure. 
         [0055]      FIG. 12  is an enlarged view of distal wall features. The distal wall  42  has an extended, central frustum  45  and two opposing stanchions  48  which support a partial, luer thread  49  for needle attachment. The continuous pitch of the two partial sections of luer thread  49  draws a luer coupler of a needle sealingly onto frustum  45 . The distal wall  42  surrounding the frustum varies in thickness for structural and yielding considerations. The thickened pads  50  support the luer thread stanchions  48  and provide gripping integrity for the needle stick, whereas the thinner panels  51  yield to assist in selective aspiration. The thinner yielding panels  51  distort during aspiration, but return to an initial configuration when the aspirating depression ceases and the actual injection occurs. Within the frustum  45 , the passageway  46  expands proximally to form a viewing chamber  47 . This permits viewing a smaller sampling of concentrated, aspirated fluid. The frustum hub  45  is of sufficient length to permit the viewing chamber  47  to be visible behind the luer coupler. 
         [0056]      FIGS. 13 and 14  show an aspirating compression of another syringe embodiment  70  with similar body features  71  to syringe embodiment  40 , and plunger  72  and distal wall  73  features similar to syringe embodiment  10 .  FIG. 13  is a side sectional view of syringe  70  showing fingers  74 . Along curved walls  80  and  81  capping the major axis are points  84  of compression. The walls  82  and  83  capping the minor axis expand outwardly transitioning circularly during aspiration. 
         [0057]      FIGS. 15 and 16  are cross sections of body  71  at the points of compression  84 .  FIG. 15  is prior to aspiration and  FIG. 16  is at full aspiration. The varying wall thickness predictably transitions the body  71  uniformly from elliptical to circular. This shape transitioning creates a greater cross-sectional area from  85  to  86  resulting in a larger chamber volume which aspirates a sufficient specimen for viewing in the frustum window  87  to determine needle placement. 
         [0058]      FIG. 17  is an axonometric view of another syringe embodiment  90  with a body  91  being a combination of two differing shapes: an elliptic cylinder  93  joined to a truncated, elliptic cone  94 . This structural configuration permits selective aspiration to occur along the entire length of the body  91  regardless of where the points of compression are made. This is useful when finger placement is removed from the distal wall due to accessibility of the injection site, for example, dental syringes. 
         [0059]    The barrel body  91  consists of two central body portions,  93  and  94 , a closed distal end  99 , and an open proximal end  100 . The juncture  101  of these two portions,  93  and  94 , is smooth and continuous to assist an elliptical body  91  in circular transitioning. The proximal body portion  93  is an elliptical cylinder to provide the sliding seal  106  of plunger  92  with a common axial, cylindrical surface for a fluid tight engagement during travel. The distal portion  94  is an elliptic cone used to influence the entire sidewall portions  95  and  96 , and  97  and  98  capping the major and minor axes, respectively, to hinge inwardly and outwardly, respectively, pivoting about their common distal end  99 , when selective, aspirating compression occurs. The wall thickness thins from regions  95  and  96  to regions  97  and  98 , respectively, to also assist transitioning. To assist in the uniform, hinged compressions of sidewalls  95  and  96 , there are opposing, continuous ribs  102  and  103  with finger placement detents  104  and  105 . As compression pressure is applied to finger detents  104  and  105 , ribs  102  and  103  move inwardly transitioning body  91  into a circular section posture. The distal wall  99  and proximal opening  100  are similar in structure to embodiment  10 . Wall  99  supports frustum  107  with stepped passageway  108  and cap retention ring  109 . A peripheral, gripping flange  111  is formed about opening  100 . The plunger  92  is structurally similar to previous versions with a ribbed shaft  109 , finger pad  110 , and an attachment means  115  to the elastomeric seal  106 . 
         [0060]      FIGS. 18 and 19  are side and top sections of  FIG. 17 . These views illustrate the configuration of seal  106  and its relationship within the body  91 . The seal  106  has two components which are shown in  FIG. 21 . 
         [0061]      FIG. 20  represents a cross-section of the elliptical conical body  91 . This view reveals thinning of the sidewalls from the major axis capping sections  95  and  96  to the minor axis capping sections  97  and  98 . The ribs  102  and  103  sit atop the major axis. 
         [0062]      FIG. 21  is an enlarged portion of the side section of body  91  showing a seal configuration  106  and fluid tight relationship with body  91 . Like the body  91 , its proximal portion  112  is an elliptical cylinder and the distal portion  113  is a truncated elliptic cone. Cylindrical portion  112  has two spaced, integrally molded O-rings  114  for the fluid seal and to ensure axial travel within body  91 . The hollow, elliptic cone  113  will partially collapse when aspirating compression is applied to finger detents  104  and  105  forcing ribs  102  and  103  inward. 
         [0063]      FIGS. 22 and 25  are an axonometric view and a cross-sectional view, respectively, of polygonal syringe embodiment  120 . A distinguishing feature is its “n-gon” cross-sectional shape, where “n” represents the number of sides. In this instance, body  121  is a modified kite shaped polygon. The polygon&#39;s vertices are replaced with living hinges  128 ,  129 , and  130 . These hinge sections are of sufficient interior, tangential radii to permit a fluid tight engagement of the plunger seal  134  and the interior sidewall&#39;s surfaces of body  121 . The body panels  133 ,  134 ,  135 , and  136  and living hinges  128 ,  129 ,  130 , and  131  are of sufficient thickness to maintain the body&#39;s configuration and thinness to be yieldable allowing deformation for aspiration This thickness may be uniform throughout or have subtle variations expressed in the outer surface only, leaving a continuous inner surface  124  for a fluid tight arrangement with plunger seal  138 . 
         [0064]    Aspiration is performed by compressing body  121  about living hinge  128  and panel  137 , shortening major diagonal and lengthening minor diagonal. As the two short sides of the kite shape become linear the cross sectional area increases. The kite body  121  transitions about living hinges  131  and  132  of base  137 . Arcuate base  137  is of sufficient thickness to support frustum  126  in distal wall  123  minimizing movement. In this embodiment, body panels  133 ,  134 ,  135 , and  136  are planar, but could be slightly arcuate. The frustum  126  of the distal wall  123  is no longer central but moved towards base panel  137  to allow the temporary flattening of central panel  125  during aspiration. The thickness of panel  125  reestablishes its shape once aspiration is complete. This movement of frustum  126  permits a partial luer thread coupler to be attached below panel  137  for single axis molding. 
         [0065]    In this embodiment the frustum  126  on the distal wall  123  and the plunger configuration  122  and seal attachment means  142  directly references syringe  10 . However, a complete or partial luer coupler feature or any needle attachment means along with any fluid tight seal arrangement could replace one or both. 
         [0066]      FIGS. 23 and 24  are side and top sectional views of syringe  120 , respectively. They reveal the fluid tight arrangement of the plunger  122 &#39;s seal  138  with the inner wall surface  124  of body  121 . Seal  138  has two, spaced rings  139  and  140  which sealingly engage sidewall  124  and promote axial travel of the plunger  122 . The distal seal wall  142  has the identical configuration as distal wall  123  including central portion  125  to totally evacuate body  121  when plunger  122  is depressed. 
         [0067]      FIG. 26  displays an axonometric view of another embodiment  150  utilizing an efficient, circular cylindrical body  155  blending into an elliptical cylinder  154  distally for an aspiration region. This embodiment  150  uses several of the above, previously described features, including plunger  153  and distal wall features  152 . The finger placement platforms  165  and  166  are similar in function to detents  67  and  68  in  FIGS. 7 and 8  for syringe  40 . In this embodiment a circular cylinder  155  is the predominant body configuration with a small, distal, elliptic cylindrical region  154  for aspiration. This provides a maximum volume for the syringe dimensions  150  with an elective aspiration option. 
         [0068]      FIGS. 27 and 28  are longitudinal, side and top cross-sections of syringe  150 , respectively. The plunger sealing and axial traveling means of seal  156  is identical to  FIG. 10 . However, the distal configuration  157  mimics the body distal interior  158  of body  151  to provide total evacuation of the syringe barrel when injecting a mendicant. The profiles  159  and  160  of the predominant body regions are the same in both views; however, the elliptical aspirating region is wider in  FIG. 26  compared to profile  162  in  FIG. 27 . This reflects the predominantly circular nature of the body  155  with an elliptical nature of aspirating region  154 . 
         [0069]      FIGS. 29 and 30  are cross-sectional views of the body  151  in circular cylindrical and elliptic cylindrical regions  155  and  154 , respectively. It reveals the uniform, structural wall thickness  163  of the circular region and the varied, yieldable thickness  164  of the elliptical region. 
         [0070]    A transition of the syringe body increasing its cross-sectional area and the syringe barrel volume for selective aspiration. The various, above described features can be interchangeable within the various embodiments and utilizing the various embodiments of the subject invention an aspiration and injection procedure can be facilely performed with one hand.