Abstract:
A catheter and introducer needle assembly having a needle with a proximal and distal end attached to a needle hub and a bent area therebetween. The device further includes a tubular catheter having proximal and distal ends in which the introducer needle can be coaxially received within the catheter. The device has a hollow catheter hub having a distal end attached to the proximal end of the catheter and is in fluid communication therewith. The assembly includes a needle tip protector having a proximal end and a distal end disposed within the catheter hub. The distal end of the protector covers the needle tip when the needle is removed from the catheter. The protector has a proximal opening at its proximal end wherein the bent area is angled away from the proximal opening such that when the needle is removed from the catheter the protector remains attached to the needle.

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  
     In accordance with the present invention there is provided a catheter introducer assembly. The catheter introducer assembly comprises a needle assembly having a needle attached to a needle hub and a distal end extending therefrom. The needle includes a bent area disposed between its proximal and distal ends. The catheter introducer assembly further includes a catheter assembly having a tubular catheter with a proximal end attached to a catheter hub. The needle is coaxially received within the catheter. The catheter introducer assembly further includes a needle tip protector disposed within the catheter hub. The needle tip protector is slidably disposed onto the needle, whereby when the needle is proximally removed from the catheter the protector remains attached to 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 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; 
         FIG. 5  is a section view of the catheter assembly and needle assembly taken along line  5 — 5  of  FIG. 1 ; 
         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; 
         FIG. 7  is a section view of the catheter hub with needle tip protector installed taken along line  7 — 7  of  FIG. 5 ; 
         FIG. 8  is a perspective view of the needle tip protector shown as installed in the catheter hub with the needle inserted therethrough; 
         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; 
         FIG. 10  is a perspective view of an alternate embodiment of the needle tip protector of the present invention. 
     
    
    
     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 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. 
     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 bend  44  is located at the distal end of needle  38  proximal to bevel  42  and is curve in needle  38 . Needle bend  44  can be created by bending method such as “rotary draw bending.” Rotary draw bending is a process well known in the metal bending art and involves using a clamp die and a bend die, which are molded to match the nominal diameter of needle  38 , to rotate needle  38  against a pressure die. A mandrel is inserted into needle  38  during the procedure to minimize the stretching that occurs along the outer radius of needle  38 , while a wiper die reduces wrinkling along the inner radius of needle  38 . Bend  44  is formed at an angle away from 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 angle of bend  44  is 45 to 90 degrees away from second flange hole  72 . 
     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 , 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. 5–7 ) 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 0.005–0.009 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 slidably 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. 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 . 
     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 . 
     Referring now to  FIGS. 5–9 , needle tip protector  26  is assembled to needle  38  as follows; 
     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 first flange hole  70  and then through second flange hole  72  in needle tip protector  26 , moving from proximal to distal; 
     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 ); 
     Needle bend  44  is added to the distal end of needle  38  just proximal to bevel  42 . Bend  44  is angled away from second flange hole  72  locally (see  FIG. 9 ) thus preventing the complete removal of needle tip protector  26  from the distal end of needle  38 . 
     Now needle assembly  24 , including needle tip protector  26 , is assembled into catheter assembly  22  as follows; 
     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 ; 
     As needle assembly  24  continues to move distally, needle tip protector  26  enters the opening in the proximal end of catheter hub  30 ; 
     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 ; 
     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 . 
     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 ). 
     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 . 
     Now, in actual clinical use, the IV catheter assembly  20  of the present invention functions as follows; 
     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 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 bend  44  on the distal end of needle  38  comes into contact with second flange hole  72 . Just before bend  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 . After stop flange  102  and first lip  98  move normal to and across the center axis of needle  38 , first beam  96  and second beam  100  prevent axial movement of needle  38  preventing needle  38  from being twisted enabling bend  44  to be manipulated through second flange hole  72 ; 
     Since bend  44  is angled away from second flange hole  72  and first beam  96  and second beam  100  prevent axial movement of needle  38  securing bend  44  from being manipulated through 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 ; 
     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. 
       FIG. 10  shows an alternate embodiment of the present invention. In this embodiment, needle  138 , similar to needle  38 , includes sleeve  199 . Sleeve  199  can be slidably or fixedly attached on needle  138  proximal to bend  144  such that sleeve  199  is biased against second flange hole  172  when needle  138  is removed from catheter assembly  22 . Sleeve  199  helps prevent needle tip protector  126  from being completely removed from needle  138  by ensuring that bend  144  can not be manipulated through second flange hole  172 . 
     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.