Abstract:
An intravenous catheter introducer assembly having a safety feature to prevent accidental needle sticks. The introducer assembly includes a needle assembly having a groove disposed on its outer surface. The introducer includes a protector made of a hollow member having an open distal end and a inwardly disposed resilient flange disposed thereon. The protector is coaxially slidably disposed around the needle with the flange abutting the outer surface of the needle and adapted to engage the groove when a catheter assembly is removed from the needle assembly.

Description:
FIELD OF THE INVENTION 
     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 
     An intravenous (IV) catheter is an instrument that is used to introduce certain fluids such as saline solution directly into the bloodstream of a patient. Typically, a needle or other stylet is first introduced through the cannula portion of the catheter and into the skin of the patient at the desired location such as the back of the patient&#39;s hand or a vessel on the inside of the arm. Once insertion is complete, the needle is removed from the cannula portion of the catheter. After removing the needle, a fluid handling device such as a syringe is attached to the luer fitting located at the proximal end of the catheter hub. Fluid then flows directly from the fluid handling device through the catheter into the bloodstream of the patient. 
     When the needle is removed from the cannula, the health care worker must place the exposed needle tip at a nearby location while simultaneously addressing the task required to accomplish the needle removal. It is at this juncture that the exposed needle tip creates a danger of an accidental needle stick occurring which leaves the health care worker vulnerable to the transmission of various, dangerous blood-borne pathogens such as human immune virus (HIV) and hepatitis. 
     The risk of a contaminated needle stick is not just isolated to the health care worker inserting the intravenous catheter. 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. 
     The danger to health care workers and others outside the health care profession from accidental needle sticks has yielded the development of catheters with safety mechanisms in which the occurrence of such accidental needle sticks is prevented. An example of a catheter having a safety mechanism is disclosed in U.S. Pat. No. Re. 34,416 issued to Lemieux. A safety catheter is described which includes an element that 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. 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 lose 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. 
     Another example of a catheter having a safety mechanism is disclosed in U.S. Pat. No. 6,117,108 issued 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 axial movement of the arm. This axial 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. 
     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 
     An intravenous catheter introducer assembly having a safety feature to prevent accidental needle sticks. The introducer assembly includes a needle assembly having an elongated hollow tubular needle with a proximal end attached to a catheter hub and a distal end extending therefrom. The needle has a groove disposed on its outer surface. The introducer includes a protector made of a hollow member having an open distal end and a inwardly disposed resilient flange disposed thereon. The protector is coaxially slidably disposed around the needle with the flange abutting the outer surface of the needle. The introducer also includes a catheter assembly having an elongated hollow tubular catheter with a proximal end attached to a catheter hub and a distal end extending therefrom. The catheter is coaxially disposed about the needle. The catheter hub has a retainer for keeping the protector within the catheter hub until the catheter assembly and needle assembly are separated wherein the flange engages the groove and secures the protector to the needle such that the open distal end of the protector is distal to the distal end of the needle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
     FIG. 1 is a perspective view of the catheter and needle assembly of the present invention. 
     FIG. 2 is an exploded perspective view of the catheter assembly and needle assembly including the needle tip protector of the present invention 
     FIG. 3 is a perspective view of the needle tip protector of the present invention; 
     FIG. 4 is a view of FIG. 3 taken along line  4 — 4  illustrating the tab of the present invention. 
     FIG. 5 is a section view of the catheter assembly and needle assembly taken along line  5 — 5  of FIG.  1 . 
     FIG. 6 is a perspective view of the needle tip protector with the needle inserted therethrough shown prior to locking the protector over the needle tip. 
     FIG. 7 is a perspective view of the needle tip protector shown as locked onto the needle after removal from the catheter hub and illustrating the needle tip covered by the protector. 
     FIG. 8 is a perspective view of an alternate embodiment of the needle tip protector. 
     FIG. 9 is a side view of another alternate embodiment of the needle tip protector shown as removed from the catheter hub and illustrating the needle tip covered by the protector. 
     FIG. 10 is a cross-sectional view taken along line  10 — 10  of FIG. 9 showing the clip which locks the needle tip protector over the needle tip. 
     FIG. 11 is a perspective view of another alternate embodiment of the needle tip protector shown with the needle inserted therethrough. 
     FIG. 12 is a side view of another alternate embodiment of a non-circular needle tip protector which illustrates the needle tip covered by the protector. 
     FIG. 13 is a cross-sectional view taken along line  13 — 13  of FIG. 12 of the non-circular needle and needle tip protector. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
     As illustrated in FIGS. 1 and 2, IV catheter assembly  20  comprises catheter assembly  22  and needle assembly  24 . Needle assembly  24  further includes 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, leak proof attachment of tubing, syringes, or any of many other medical devices used to infuse or withdraw fluids through catheter assembly  22 . As shown in FIGS. 1,  2 , and  5 , retainer  60 , which is located approximately mid way between the proximal end and distal end of sidewall  36  and fixedly attached thereto as at shoulder  34 , includes aperture  62  which is an opening therethrough. Retainer  60  is generally a doughnut shaped washer made of a material such as, for example, silicone or any other flexible material known to those skilled in the art. As will be described in more detail later, retainer  60  plays an important role in securing protector  26  in catheter hub  30 . 
     Referring again to FIGS. 1 and 2, needle assembly  24  comprises needle  38 , which is a tubular structure with proximal end  39  and distal end  41 , needle hub  40 , and protector  26 . Protector  26  is assembled slidably on needle  38 . Needle  38  which is preferably made of stainless steel has a lumen therethrough created by its inner diameter. Proximal end  39  of needle  38  is fixedly attached to needle hub  40 . Bevel  42  which is located at distal end  41  of needle  38  creates a sharp piercing tip. Needle groove  44 , which includes proximal wall  43  and distal wall  45 , is located at distal end  41  of needle  38  proximal to bevel  42  and is smaller in diameter than the nominal outer diameter of needle  38 . Needle groove  44  can be created by any number of means known to those skilled in the art. One such method is by machine grinding around the outside diameter of needle  38  resulting in an annular channel between its nominal outer diameter and inner diameter. Machine grinding is a process well known in the metal forming art. The resulting groove  44  is smaller in dimension than the nominal outer diameter of needle  38  but greater in dimension that the lumen in needle  38  and is important in preventing the complete removal of protector  26  from needle  38 , as will be described in more detail later. In the preferred embodiment, the dimension across groove  44  is 0.002-0.003 inches smaller than the dimension of the nominal outer diameter of needle  38 , dependent upon needle “gauge” size. 
     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. 
     Referring now to FIGS. 3 and 4, protector  26  has a proximal end  49  and a distal end  50  and is preferably a hollow tubular structure with cavity  72  therethrough formed from a single piece of thin, resilient material such as, for example, stainless steel or a polymer. Located distal to proximal end  49  of protector  26  is resilient flange  70 . Flange  70  includes a proximal wall and a distal wall. The longitudinal width of flange  70 , the distance between the proximal wall and the distal wall, is less than the longitudinal width of needle groove  44  and is important in preventing the complete removal of protector  26  from needle  38 , as will be described in more detail later. As shown in FIG. 4, resilient flange  70  is biased into cavity  72  of protector  26  resulting in dimension “a” which, when the flange  70  is in its relaxed unrestrained condition, is less than the nominal outer diameter of needle  38 , permitting for a very close but slidable fit of protector  26  over needle  38 . 
     Referring now to FIGS. 5-7, it can understood how protector  26  is assembled to needle  38 . 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. The distal end of needle  38  is inserted through proximal end  49  of protector  26  and then advanced through cavity  72 , moving from proximal to distal. Flange  70  is flexed, as a result of its resilient property, so that needle  38  will pass through cavity  72  of protector  26 . Needle groove  44  is located at the distal end of needle  38  just proximal to bevel  42 . Groove  44  decreases the diameter of needle  38  locally to a dimension smaller than the nominal outer diameter of needle  38 . When needle  38  is retracted, flange  70  locks into groove  44  preventing the complete removal of protector  26  from the distal end of needle  38 . 
     As shown in FIG. 1, needle assembly  24 , including protector  26 , is assembled into catheter assembly  22 . Distal end  41  of needle  38  extends distally from distal end  29  of catheter  28 . Protector  26  is held distal to retainer  60  inside the cavity in catheter hub  30  by aperture  62 , which has a diameter smaller in dimension than the outer diameter of protector  26 . Protector  26  is also located proximal to catheter  28 , which has an inner diameter smaller than the outer diameter of protector  26  preventing any further distal movement. Needle assembly  22  is secured onto luer fitting  32  of catheter hub  30 . 
     Now, it will be described how in actual clinical use, the IV catheter assembly  20  of the present invention functions. The distal end of needle  38  which extends just past the distal end of catheter  28  is inserted into the patient&#39;s vein. The clinician observes blood in the flash chamber in needle hub  40 . The clinician grasps needle hub  40 , and catheter assembly  22  alone is moved distally into the vein. The clinician applies slight pressure to the insertion site to hold catheter assembly  22  secure. The clinician grasps needle hub  40  and begins withdrawal of needle assembly  24  from catheter assembly  22 . During this process, protector  26  remains secure inside catheter hub  30  until groove  44  on needle  38  comes into contact with flange  70 . Prior to groove  44  encountering flange  70 , retainer  60  blocks any further proximal movement of protector  26 . During withdrawal, needle  38  is retracted proximally into catheter  28  and catheter hub  30 . When groove  44  of needle  38  comes into contact with flange  70  of protector  26 , the distance between proximal wall  71  and distal wall  73  of flange  70  which is less than the distance between proximal wall  43  and distal wall  45  of groove  44  causes flange  70  which is biased into cavity  72  to engage into groove  44  thus locking protector  26  on needle  38 . After flange  70  locks into groove  44 , continued proximal movement of needle  38  carries protector  26  proximal as well, forcing proximal end  49  of protector  26  against retainer  60 . When enough force is applied by protector  26 , aperture  62  dilates due to the resilient property of retainer  60 , permitting continued movement proximal, past retainer  60 . Needle assembly  24  is now removed entirely from catheter assembly  22 , with the needle tip covered by protector  26  of the present invention. 
     A first alternate embodiment of the present invention is shown in FIG.  8 . In this embodiment, protector  126 , similar to protector  26 , is generally hollow tubular structure formed from a single piece of thin, resilient material such as, for example, stainless steel or a polymer. This embodiment has a plurality of flanges  170 . Flanges  170  are located distal to proximal end  149  of protector  126 . Flanges  170  create proximal walls  171  and distal walls  173  and are biased into cavity  172  of protector  126 . 
     A second alternate embodiment of the present invention is shown in FIG.  9 . In this embodiment, protector  226 , similar to protector  26 , includes clip  270 . Clip  270 , which functions to replace flange  70  in the preferred embodiment, is slidably assembled to protector  226 . Clip  270  is preferably made of a resilient material such as, for example, stainless steel, or any other suitable material known to those skilled in the art. As shown in FIG. 10, clip  270  is generally a U-shaped wireform secured to protector  226  by bridges  264  and  266 . 
     FIG. 11 shows a third alternate embodiment where protector  326  is a hollow tubular structure preferably formed from a single piece of thin, resilient material such as for example, stainless steel or a polymer. In this embodiment, protector  326  has a flat formed on one side along its entire length. Located distal to proximal end  349  of protector  326  is flange  370 , similar to flange  70 . Needle notch  344 , which functions to replace needle groove  44 , is an indentation in needle  338 . In this embodiment, the depth from surface  347  of needle notch  344  to the outer surface of needle  338  is 0.002-0.003 inches, dependent upon needle “gauge” size. However, the depth from surface  347  of needle notch  344  to the outer surface of needle  338  could be larger than 0.003 inches possibly exposing the lumen of needle  338 . Needle notch  344  locks with flange  370  preventing the complete removal of protector  326  from distal end  341  of needle  338 . To ensure the alignment of flange  370  with notch  344 , needle  338  also has a flat along its entire length which takes the shape of protector  326  to prevent any axial movement of needle  338  in protector  326 . Needle notch  344  could be a single indentation in needle  338  or multiple indentations possibly spaced 180° apart. Similarly, protector  326  could contain a single flange or multiple flanges possibly spaced 180° apart. 
     FIGS. 12 and 13 shows a fourth alternate embodiment of the present invention. In this embodiment, protector  426  is a hollow non-circular tubular structure preferably formed from a single piece of thin, resilient material such as, for example, stainless steel or a polymer. Located distal to proximal end  449  of protector  426  is flange  470 , similar to flange  370 . Needle notch  444 , similar to notch  344 , functions to replace needle groove  44 . Needle notch  444  is an indentation in needle  438  which locks with flange  470  preventing the complete removal of protector  426  from distal end  441  of needle  438 . In this embodiment, the depth from surface  447  of needle notch  444  to the outer surface of needle  438  is 0.002-0.003 inches, dependent upon needle “gauge” size. However, the depth from surface  447  of needle notch  444  to the outer surface of needle  438  could be larger than 0.003 inches possibly exposing the lumen of needle  438 . To ensure the alignment of flange  470  with notch  444 , needle  438  is also non-circular taking the shape of protector  426  to prevent any axial movement of needle  438  in protector  426 . Needle notch  444  could be a single indentation in needle  438  or multiple indentations possibly spaced 180° apart. Similarly, protector  426  could contain a single flange or multiple flanges possibly spaced 180° apart. 
     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.