Abstract:
A catheter and introducer needle assembly having a needle attached to a needle hub, and a enlarged area disposed thereon, and a tubular catheter wherein the introducer needle being coaxially received within the catheter. The device has a hollow catheter hub attached to the catheter and in fluid communication therewith. The catheter hub has an interior having a raised annular rib disposed thereon. The assembly includes a needle tip protector disposed within the catheter hub and including at least one unrestrained radially extending lip disposed distal to the annular rib so as to retain the protector within the hub. The distal end of the protector does not abut against the hub interior. The protector has a proximal opening at the proximal end having an unrestrained size greater than the size of the needle diameter and smaller than the enlarged area such that when the needle is removed from the catheter the protector remains attached to the needle.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates, in general, to intravenous (IV) catheters and, more particularly, to a safety IV catheter with a needle tip protector that will automatically cover the needle tip upon needle withdrawal.  
         BACKGROUND OF THE INVENTION  
         [0002]    I.V. catheters are used primarily to administer fluids directly into a patient&#39;s vascular system. The catheter is inserted into a patient&#39;s vein by a clinician using a handheld placement device that includes a needle with a sharp distal end. The needle is positioned in the interior hollow portion of the catheter with its sharp distal tip extended slightly beyond the distal edge of the catheter. The proximal end of the needle is connected to a needle hub which is held by the clinician during the insertion procedure.  
           [0003]    During the insertion procedure, the clinician inserts the needle and catheter together into the patient&#39;s vein. After insertion of the needle point into the vein, the catheter is forwarded into the vein of the patient by the clinician pushing the catheter with their finger. The clinician then withdraws just the needle by grasping the hub attached to the proximal end of the needle while at the same time applying pressure to the patient&#39;s skin at the insertion site, thus holding the catheter fixed in place. The clinician then typically tapes the proximal end of the now inserted catheter to the patient&#39;s skin and connects the proximal end of the catheter, containing a Luer connector catheter hub, to the source of the fluid to be administered into the patient&#39;s vein.  
           [0004]    It is the period of time just as the needle is withdrawn from the catheter that poses great risk to the clinician. The clinician is at risk of an accidental needle stick from the sharp needle which has just been contaminated with a patients blood. This leaves the clinician vulnerable to the transmission of dangerous blood-borne pathogens, including hepatitis and AIDS. The risk of a contaminated needle stick is not isolated just to clinicians. Careless disposal of used needles can put other health care workers at risk as well. Even others outside the health care profession, for example those involved in the clean-up and final disposal of medical waste, are at risk of an accidental needle stick from a carelessly discarded needle.  
           [0005]    A number of “safety” IV catheters have been developed to address the issue of accidental needle stick. For example, in U.S. Pat. No. Re. 34,416 to Lemieux, a safety catheter is disclosed which includes an element which covers the needle tip upon removal of the needle from the catheter. The safety element includes a split flange at its proximal end which is expanded by the needle as the needle is inserted into an undersized hole at the center of this flange. The safety element is thus held secure within the catheter hub by inserting the needle through the undersized hole which forces the outside perimeter of the split flange against the inside wall of the catheter hub.  
           [0006]    One of the drawbacks to this design is the amount of friction force exerted against the needle by the split flange. A tight fit of the flange against the catheter wall causes great friction against the needle making it difficult to be withdrawn from the catheter by the clinician. A loose fit leaves the flange prone to releasing prematurely from the catheter as the needle is withdrawn, creating the potential that the needle tip will be left exposed.  
           [0007]    In U.S. Pat. No. 6,117,108 to Woehr et al, a safety IV catheter is described including a resilient needle guard which protects the needle tip upon removal of the needle from the catheter hub. The needle guard includes an arm that includes an opening through which a needle passes causing radial movement of the arm. This radial movement forces the arm into a groove or behind a rib located on the inside of the catheter hub, capturing the needle guard in the catheter hub. A potential issue with this design develops when the needle guard is not properly seated into the catheter hub. If the distal end of the needle guard arm is not in alignment with the groove in the catheter hub, excessive forces are placed on the needle causing a high drag force as the clinician removes the needle. And, since the needle guard arm is not properly seated in the groove, it may prematurely release from the catheter hub upon the removal of the needle leaving the needle tip exposed.  
           [0008]    The prior art safety catheters all exhibit one or more drawbacks that have thus far limited their usefulness and full acceptance by health-care workers. What is needed therefore is a safety IV catheter that functions reliably, is easy and inexpensive to manufacture, and easy to use.  
         SUMMARY OF THE INVENTION  
         [0009]    In accordance with the present invention there is provided a catheter and introducer needle assembly including a needle having a diameter, proximal end, attached to a needle hub, a distal end, and a enlarged area disposed therebetween. The assembly further includes a tubular catheter having proximal and distal ends, the introducer needle being coaxially received within the catheter, and a hollow catheter hub having a distal end attached to the proximal end of the catheter and in fluid communication with the catheter. The catheter hub includes an interior having a raised annular rib disposed thereon. The assembly also includes a needle tip protector having a proximal end and a distal end disposed within the catheter hub. The proximal end including at least one unrestrained radially extending lip disposed distal to the annular rib so as to retain the protector within the hub, wherein the distal end of the protector does not abut against the hub interior. The protector having a proximal opening at the proximal end having an unrestrained size greater than the size of the needle diameter and smaller than the enlarged area such that when the needle is removed from the catheter the protector remains attached to the needle.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which:  
         [0011]    [0011]FIG. 1 is a perspective view of the catheter and needle assembly of the present invention;  
         [0012]    [0012]FIG. 2 is an exploded perspective view of the catheter assembly and needle assembly including the needle tip protector of the present invention;  
         [0013]    [0013]FIG. 3 is a perspective view of the needle tip protector of the present invention;  
         [0014]    [0014]FIG. 4 is an elevation view of FIG. 3 taken along line  4 - 4  illustrating the hole positions in the rear flanges of the needle tip protector as manufactured;  
         [0015]    [0015]FIG. 5 is a section view of the catheter assembly and needle assembly taken along line  5 - 5  of FIG. 1;  
         [0016]    [0016]FIG. 6 is an enlarged partial section view of FIG. 5 illustrating the relative position of the needle tip protector tab and catheter hub rib;  
         [0017]    [0017]FIG. 7 is a section view of the catheter hub with needle tip protector installed taken along line  7 - 7  of FIG. 5;  
         [0018]    [0018]FIG. 8 is a perspective view of the needle tip protector shown as installed in the catheter hub with the needle inserted there through, catheter hub not shown for clarity;  
         [0019]    [0019]FIG. 9 is a perspective view of the needle tip protector shown as removed from the catheter hub and illustrating the needle tip covered by the protector;  
         [0020]    [0020]FIG. 10 is a perspective view of an alternate embodiment of the needle tip protector of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    As used herein, the term “proximal” refers to a location on the catheter and needle assembly with needle tip protector closest to the clinician using the device and thus furthest from the patient on which the device is used. Conversely, the term “distal” refers to a location farthest from the clinician and closest to the patient.  
         [0022]    As illustrated in FIGS. 1 and 2, IV catheter assembly  20  comprises catheter assembly  22  and needle assembly  24 . Needle assembly  24  further includes needle tip protector  26 . Catheter assembly  22  includes catheter  28  which is a tubular structure having a proximal end  31  and distal end  29 . Proximal end  31  of catheter  28  is fixedly attached to catheter hub  30 . Catheters are well known in the medical art and one of many suitable materials, most of which are flexible thermoplastics, may be selected for use in catheter  28 . Such materials may include, for example, polyurethane or fluorinated ethylene propylene. Catheter hub  30  is a generally tubular structure having an internal cavity in fluid communication with the internal lumen of catheter  28 . Catheter hub  30  may be made from a suitable, rigid medical grade thermoplastic such as, for example, polypropylene or polycarbonate. For illustration purposes catheter hub  30  is shown translucent, though in actual use it may be translucent or opaque. At the proximal end of catheter hub  30  is integrally attached Luer fitting  32 , commonly known in the medical art. Luer fitting  32  provides for secure, leakproof attachment of tubing, syringes, or any of many other medical devices used to infuse or withdraw fluids through the catheter assembly. As is more clearly illustrated in FIGS. 5 and 6, rib  34  is a raised annular ring integral to and extending from internal sidewall  36  of catheter hub  30 . Rib  34  is located approximately mid way between the proximal end and distal end of sidewall  36 . Rib  34  plays an important role in securing needle tip protector  26  in catheter hub  30 , as will be described in more detail later.  
         [0023]    Referring again to FIGS. 1 and 2, needle assembly  24  comprises needle  38 , which is a tubular structure with a proximal end  39  and distal end  41 , needle hub  40 , and needle tip protector  26 . Needle tip protector  26  is assembled slidably on needle  38 . Needle  38  is preferably made of stainless steel. Proximal end  39  of needle  38  is fixedly attached to needle hub  40 . A bevel  42  is located at the most distal end of needle  38  creating a sharp piercing tip. Needle crimp  44  is located at the distal end of needle  38  proximal to bevel  42  and is larger in diameter than the nominal diameter of needle  38 . Needle crimp  44  is created by “coining” an area on the outside diameter of needle  38  resulting in two opposed bumps located approximately 180 degrees across the center axis of needle  38 . Coining is a process well known in the metal forming art and involves using a hardened tool to strike a softer object to deform or displace a portion of the softer object. In the present case a portion of the exterior surface of the softer metal needle  38  is displaced by a harder metal tool so as to raise bumps on the exterior surface of needle  38 . The resulting crimp  44  is larger in dimension than the nominal diameter of needle  38 . Crimp  44  is larger in dimension than the diameter of second flange hole  72  in needle tip protector  26  and is important in preventing the complete removal of needle tip protector  26  from needle  38 , as will be described in more detail later. In the preferred embodiment the dimension across crimp  44  is 0.0001-0.004 inches larger than second flange hole  72 , dependant upon needle “gauge” size.  
         [0024]    Needle hub  40  is generally a tubular structure having an internal cavity in fluid communication with the lumen in needle  38 . It is preferably made of a translucent or transparent generally rigid thermoplastic material such as, for example, polycarbonate. At the most proximal end of the internal cavity in needle hub  40  is fixedly attached porous plug  46 . A flashback chamber  48  is created in the cavity distal to porous plug  46 . Porous plug  46  contains a plurality of microscopic openings which are large enough to permit the passage of air and other gasses but small enough to prevent the passage of blood. Flashback chamber  48  fills with blood upon successful entry of the needle tip into the targeted vein, providing the clinician visual conformation of the correct placement of the needle.  
         [0025]    Referring now to all figures, needle tip protector  26  has a proximal end  49  and distal end  50  and is preferably a unitary structure formed from a single piece of thin, resilient material, preferably stainless steel. First flange  66  and second flange  68  are generally square and are integrally connected at right angles to first outer wall  74  and second outer wall  76 , respectively. First outer wall  74  is connected at a right angle to first tab flange  78 . First tab flange  78  and second tab flange  80  are each formed at angles slightly greater than 90 degrees to second outer wall  76  so that the resulting dimension c is slightly larger than inside diameter d (see FIGS.  6 - 7 ) across rib  34  in catheter hub  30 . In the preferred embodiment angles a and b are each approximately 94.25 degrees. In the preferred embodiment dimension c is approximately 0.001-0.009 inches larger than dimension d. First flange hole  70  is located in the center of first flange  66  and is over-sized to slidably receive needle  38 . Second flange hole  72  and skirt  82  are located in the center of second flange  68 . Skirt  82  is integral to second flange hole  72  and is formed by extruding material from second flange hole  72  in a direction distal to second flange  68 . This permits for a very close but slidable fit over the nominal diameter of needle  38 . Skirt  82  also functions to help maintain alignment of needle  38  to the center axis of needle tip protector  26 . As would be understood by one skilled in the art, flange hole  72  would be appropriately sized to the particular needle “gauge” size to which it is designed to receive.  
         [0026]    First tab  86  and second tab  88  are connected at right angles to first tab flange  78  and second tab flange  80 , respectively, and protrude outward away from the center axis of needle tip protector  26 . First tab edge  90 , located on the outer portion of first tab  86 , and second tab edge  92 , located on the outer portion of second tab  88 , are each arcuate to approximately match the curve of sidewall  36  in catheter hub  30 .  
         [0027]    Referring again to FIG. 3, first beam  96  extends distally from first outer wall  74  and is angled toward and extends past the center axis of needle tip protector  26 . At the distal end of first beam  96  is integrally formed curved first lip  98  which extends across and through the center axis of needle tip protector  26 . Second beam  100  extends distally from second outer wall  76  and is angled toward and extends past the center axis of needle tip protector  26 . At the distal end of second beam  100  is stop flange  102  which extends across and normal to the center axis of needle tip protector  26 . At the end of stop flange  102  opposite its connection to second beam  100  is integrally formed curved second lip  104 .  
         [0028]    Referring now to all figures, needle tip protector  26  is assembled to needle  38  as follows;  
         [0029]    The proximal end of needle  38  is fixedly attached to the distal end of needle hub  40 , which contains porous plug  46  fixedly attached to its proximal end;  
         [0030]    The distal end of needle  38  is inserted through first flange hole  70  and then through second flange hole  72  in needle tip protector  26 , moving from proximal to distal;  
         [0031]    First beam  96  and second beam  100  are flexed, as a result of their resilient properties, normal to the center axis of needle tip protector  26  so that needle  38  will pass between first lip  98  and second lip  104  (see FIG. 8);  
         [0032]    Needle crimp  44  is added to the distal end of needle  38  just proximal to bevel  42 . Crimp  44  increases the diameter of needle  38  locally to a dimension larger than the inside diameter of second flange hole  72  (see FIG. 9) thus preventing the complete removal of needle tip protector  26  from the distal end of needle  38 .  
         [0033]    Now needle assembly  24 , including needle tip protector  26 , is assembled into catheter assembly  22  as follows;  
         [0034]    The distal end of needle  38  is positioned into the proximal end of catheter hub  30  and needle assembly  24  is moved distally causing needle  38  to enter catheter  28 ;  
         [0035]    As needle assembly  24  continues to move distally, needle tip protector  26  enters the opening in the proximal end of catheter hub  30 ,  
         [0036]    Continued distal movement of needle assembly  24  causes the distal edge of needle hub  40  to push first tab  86  and second tab  88  on needle tip protector  26  into contact with rib  34  located on hub sidewall  36 ;  
         [0037]    Continued distal movement forces first tab  86  and second tab  88 , due to the resilient properties of needle tip protector  26 , past rib  34  and in contact with sidewall  36 , just distal to rib  34 .  
         [0038]    Needle tip protector  26  is thus held distal to rib  34  inside the cavity in catheter hub  30  by the flexural forces of first tab  86  and second tab  88  since dimension c on needle tip protector  26  is larger than dimension d across rib  34  inside catheter hub  30 . (see FIG. 6).  
         [0039]    As is best illustrated in FIG. 7, the movement of first tab  86  and second tab  88  as needle tip protector  26  is finally seated distal to rib  34  causes flexure in second outer wall  76  and first tab flange  78  resulting in the approximate alignment of first flange hole  70  and second flange hole  72 .  
         [0040]    Now, in actual clinical use, the IV catheter assembly  20  of the present invention functions as follows;  
         [0041]    The distal end of needle  38  which extends just past the distal end of catheter  28  is inserted into the patient&#39;s vein;  
         [0042]    The clinician observes blood in the flash chamber in needle hub  40 ;  
         [0043]    The clinician grasps needle hub  40 , and catheter assembly  22  alone is moved distally into the vein;  
         [0044]    The clinician applies slight pressure to the insertion site to hold catheter assembly  22  secure;  
         [0045]    The clinician grasps the needle hub and begins withdrawal of needle assembly  24  from catheter assembly  22 . During this process, needle tip protector  26  remains secure inside catheter hub  30  until raised crimp  44  on the distal end of needle  38  comes into contact with second flange hole  72 . Just before raised crimp  44  encounters second flange hole  72 , the biasing forces of first beam  96  and second beam  100  cause stop flange  102  and first lip  98  to move normal to and across the center axis of needle  38 , blocking any further distal movement of needle  38  relative to needle tip protector  26 ;  
         [0046]    Since crimp  44  is larger than second flange hole  72 , continued proximal movement of needle  38  carries needle tip protector  26  proximal as well, forcing first tab  86  and second tab  88  on needle tip protector  26  against rib  34 . First tab  86  and second tab  88  are forced to flex normal to and toward the center axis of needle tip protector  26 , permitting continued movement proximal, past rib  34 ;  
         [0047]    Needle assembly  24  is now removed entirely from catheter assembly  22 , with the needle tip covered by needle tip protector  26  of the present invention.  
         [0048]    [0048]FIG. 10 shows an alternate embodiment of the present invention. In this embodiment, needle tip protector  126 , is preferably a unitary structure formed from a single piece of thin, resilient material such as, for example, stainless steel, similar to needle tip protector  26 . Needle tip protector  126  includes first flange  166  and second flange  168 . First flange  166  and second flange  168  are generally arcuate and are integrally connected to first outer wall  174  and second outer wall  176 , respectively. Extending distally from first outer wall  174  of needle tip protector  126  is first beam  196 . First beam  196 , which has an arcuate outer edge, is angled toward and extends past the center axis of needle tip protector  126 . First beam  196  further includes first rib  314  coined therein to add stiffness.  
         [0049]    At the distal end of first beam  196  is integrally formed curved first lip  198  which extends across and through the center axis of needle tip protector  126 . Extending distally from second outer wall  176  of needle tip protector  126  is second beam  200 . Second beam  200 , which has an arcuate outer edge, is angled toward and extends past the center axis of needle tip protector  126 . Second beam  200  further includes second rib  316  (not visible) coined therein to add stiffness. The distal end of second beam  200  is connected to the proximal end of wing base  306 . Wing base  306  extends across and parallel to the center axis of needle tip protector  126 . Wing base  306  further comprises first wing side  308  and second wing side  310 . Integrally attached to first wing side  308  of wing base  306  at approximately a 90° angle is wing  312 . Wing  312 , which extends parallel to the center axis of needle tip protector  126 , prevents any further radial movement of needle  138  by retaining it within needle tip protector  126 . Connected to the distal end of wing base  306  is the proximal end of stop flange  302 . Stop flange  302  extends across needle  138  and is angled toward the center axis of needle tip protector  126 . At the distal end of stop flange  302  opposite its connection to wing base  306  is integrally formed curved second lip  304 . Second lip  304  is curved toward proximal end  149  of needle tip protector  126  to prevent any further distal movement of needle  138 .  
         [0050]    While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims. In addition, it should be understood that every structure described above has a function and such structure can be referred to as a means for performing that function.