Compact needle shielding device

A catheter and introducer needle assembly with needle shield that is connected to the needle hub by a pleated tether. The tether defines a plurality of holes therein to allow the introducer needle to extend through the tether. The tether prevents unwanted proximal movement of the needle with respect to the needle shield once the needle has been withdrawn into the needle shield.

BACKGROUND OF THE INVENTION
 The subject invention relates to a catheter and introducer needle assembly
 that includes a needle shield that will safely shield the sharp distal tip
 of the introducer needle after the needle has been used to insert the
 catheter into a patient.
 Catheters, particularly intravenous (IV) catheters, are used for infusing
 fluid, such as normal saline solution, various medicaments and total
 parenteral nutrition, into a patient or withdrawing blood from a patient.
 Peripheral IV catheters tend to be relatively short, and are on the order
 of about one and one-half inches in length. The most common type of IV
 catheter is an over the needle peripheral IV catheter. As its name
 implies, an over the needle catheter is mounted over an introducer needle
 having a sharp distal tip. The catheter and the introducer needle are
 assembled so that the distal tip of the introducer needle extends beyond
 the distal tip of the catheter with the bevel of the needle facing up away
 from the patient's skin.
 The catheter and introducer needle assembly is inserted at a shallow angle
 through the patient's skin into a peripheral blood vessel. These are
 smaller blood vessels that are not connected directly to the heart but are
 the branches of the central blood vessels that are directly connected to
 the heart. In order to verify proper placement of the assembly in the
 blood vessel, the clinician confirms that there is flashback of blood in
 the needle and in a flashback chamber located at the proximal end of the
 needle. The flashback chamber is typically formed as part of the needle
 hub. Once proper placement is confirmed, the clinician applies pressure to
 the blood vessel by pressing down on the patient's skin over the distal
 tip of the introducer needle and the catheter. This finger pressure
 occludes further blood flow through the introducer needle. The clinician
 withdraws the introducer needle, leaving the catheter in place, and
 attaches a fluid-handling device to the catheter hub.
 Clinicians typically use a specific technique when inserting over the
 needle catheters into a patient. This technique varies depending on
 whether a ported over the needle catheter or a straight over the needle
 catheter is used. A ported catheter includes a radially extending side
 port integral with the catheter hub. In a ported catheter, the
 fluid-handling device is connected to the side port. Such ported catheters
 are typically used in Europe. A straight catheter does not include a side
 port so that the fluid-handling device is connected to the proximal end of
 the catheter hub. Such straight catheters are typically used in the United
 States.
 Once the introducer needle is withdrawn from the catheter, it is a "blood
 contaminated sharp" and must be properly handled. In recent years, there
 has been great concern over the contamination of clinicians with a
 patient's blood and a recognition that "blood contaminated sharps" must be
 immediately disposed. This concern has arisen because of the advent of
 currently incurable and fatal diseases, such as Acquired Immunosuppressive
 Deficiency Syndrome ("AIDS") and hepatitis, which can be transmitted by
 the exchange of body fluids from an infected person to another person.
 Thus, contact with the body fluid of an AIDS or hepatitis infected person
 must be avoided to prevent the transmission of such diseases to a healthy
 person. As noted above, if an introducer needle has been used to place a
 catheter in the vein of an AIDS or hepatitis infected person, the
 introducer needle is a vehicle for the transmission of the disease.
 Although clinicians are aware of the need to properly handle "blood
 contaminated sharps", unfortunately in certain medical environments, such
 as emergency situations or as a result of inattention or neglect,
 needlesticks with contaminated introducer needles still occur.
 As a result of the problem of accidental needlesticks by "blood
 contaminated sharps", various needle shields have been developed.
 Generally, such needle shields work for their intended purpose but could
 be improved. For example, some needle shields are bulky, difficult to use
 or require special features or techniques to be operative or are
 ergonomically uncomfortable for the clinician to use. In addition, some
 needle shields cannot be used with both ported and straight catheters or
 would require a significant change in technique by the clinician in order
 to be used in both ported and straight catheters. Furthermore, certain
 needle shields prevent access through the introducer needle to the blood
 vessel during venipuncture.
 SUMMARY OF THE INVENTION
 It is therefore an object of this invention to provide a needle shield that
 is compact.
 It is another object of this invention to provide a needle shield that is
 simple and easy to use.
 It is still another object of this invention to provide a needle shield
 that requires no special features or technique to be operative.
 It is yet another object of this invention to provide a needle shield that
 is ergonomically comfortable for the clinician to use.
 It is a further object of this invention to provide a needle shield that
 can be used with both ported and straight catheters so that the clinician
 does not need to change her insertion technique.
 It is yet a further object of this invention to provide a needle shield
 that will allow access through the introducer needle to the blood vessel
 during venipuncture.
 The catheter and introducer needle assembly with the needle shield and
 tether of this invention includes a catheter having a distal end and a
 proximal end connected to the distal end of a catheter hub. The introducer
 needle has a sharp distal tip and a proximal end connected to the distal
 end of a needle hub. A flashback chamber is defined in the needle hub. A
 vented plug may be located in the open proximal end of the flashback
 chamber to allow air to escape from the flashback chamber when blood
 enters the flashback chamber from the introducer needle. When the vented
 plug is removed during venipuncture, the clinician can gain access to the
 blood vessel through the introducer needle. The catheter is coaxially
 disposed over the introducer needle so the sharp distal tip of the
 introducer needle is distal of the distal end of the catheter.
 The needle shield is located substantially between the catheter and the
 needle hub and defines a longitudinally extending passage through which
 the introducer needle extends. The needle shield may include some barrier
 or other mechanism that prevents the sharp distal tip of the needle from
 being moved distally with respect to the needle shield after the sharp
 distal tip of the needle has been withdrawn into the needle shield. This
 prevents the sharp distal tip of the needle from being reexposed once it
 has been withdrawn into the needle shield.
 The needle shield is connected to the needle hub by a tether that prevents
 the needle shield from being moved distally past the sharp distal tip of
 the needle. The tether ensures that the needle shield cannot be moved
 distally past the sharp distal tip of the needle once has been proximally
 withdrawn into the needle shield. The combination of the barrier or other
 mechanism associated with the needle shield and the tether prevents distal
 movement of the needle with respect to the needle shield. This ensures
 that the sharp distal tip of the needle remains trapped in the needle
 shield after the needle has been withdrawn proximally into the needle
 shield after use.
 The tether is folded over itself to form a plurality of pleats like an
 accordion. Each pleat or fold defines a central opening therein to allow
 the needle to extend through each pleat or fold no matter whether the
 tether is completely extended or completely folded with the needle shield
 adjacent to the needle hub. Because the tether can be folded into a small
 space so it is located between the needle shield and the needle hub, the
 overall device is compact. This makes the overall device easier to control
 by the clinician. In addition, the pleated configuration of the tether
 allows the clinician to better control the action of the needle shield.

DETAILED DESCRIPION OF THE INVENTION
 As used herein, the term "proximal" refers to a location on the catheter
 and introducer needle assembly with the needle shield and tether of this
 invention that is closest to the clinician using the device and farthest
 from the patient in connection with whom the device is used when the
 device is used in its normal operation. Conversely, the term "distal"
 refers to a location on the catheter and introducer needle assembly with
 the needle shield and tether of this invention that is farthest from the
 clinician using the device and closest to the patient in connection with
 whom the device is used when the device is used in its normal operation.
 The catheter and introducer needle assembly of this invention is identified
 generally by the numeral 10. It includes a catheter assembly 20 and an
 introducer needle assembly 30 that includes a needle shield 40 and a
 tether 44.
 Catheter assembly 20 includes a catheter 21 that has a proximal end and a
 distal end. A catheter hub 24 is affixed to the proximal end of catheter
 21. Suitable materials for catheter 21 include, but are not limited to,
 thermoplastic resins such as polytetrafluoroethylene (PTFE), fluorinated
 ethylene propylene copolymer (FEP), polyurethane and the like. Preferably,
 catheter 21 is formed from a thermoplastic hydrophilic polyurethane that
 softens with exposure to physiological conditions present in the patient's
 body. Suitable materials for catheter hub 24 include, but are not limited
 to, thermoplastic polymeric resins such as polycarbonate, polystyrene,
 polypropylene and the like.
 Catheter hub 24 may include a radially outwardly extending side port 25,
 which is useful for connecting a fluid handling device to catheter 21 for
 infusing fluids into the patient's blood vessel. See FIG. 1. Preferably,
 side port 25 extends upwardly away from the patient when catheter 21 is
 inserted into the patient. In addition, a pair of wings 26 may be attached
 to or integrally formed with catheter hub 24. Wings 26 are useful to
 stabilized catheter 21 in the patient and provide a surface that
 facilitates taping of catheter assembly 20 to the patient to fix catheter
 21 properly in the patient's vasculature.
 Although, the majority of the description of catheter and introducer needle
 assembly 10 of this invention is directed to a catheter having a side
 port, it is to be understood that this invention can also be used with a
 straight catheter. See for example, FIG. 9.
 A cover 27 may be used to cover catheter 21 and the introducer needle 31
 prior to use. Preferably cover 27 is formed from a hard polymeric material
 such as thermoplastic polymeric resins, which include polycarbonate,
 polystyrene, polypropylene and the like. Of course other materials may
 also be used for cover 27.
 Introducer needle assembly 30 includes introducer needle 31 having a sharp
 distal tip defined by a bevel. The proximal end of introducer needle 31 is
 connected to a needle hub 34. Introducer needle 31 is preferably formed
 from stainless steel. Needle hub 34 can include an integrated flashback
 chamber having an open proximal end. Needle hub 34 is preferably formed
 from the same types of materials that are used to form catheter hub 24.
 Preferably, the open proximal end of needle hub 34 is closed to fluid flow
 by a vented plug 35 which allows air but not fluid to flow therethrough.
 This facilitates blood flow into the flashback chamber but prevents blood
 from leaking out.
 Vented plug 35 may be removably connected to the open proximal end of
 needle hub 34. This allows a clinician to gain access to the patient's
 blood vessel during venipuncture. In this way, a syringe could be attached
 to the open proximal end of needle hub 34 for aspiration during insertion
 of catheter and introducer needle assembly 10.
 Needle hub 34 may also include a radially extending tab 36, which may be
 grasped in combination with side port 25 to facilitate insertion of
 assembly 10 into the patient. Tab 36 may also be useful for withdrawing
 introducer needle 31 from catheter 21 after catheter 21 has been properly
 located in the patient's vasculature.
 In addition, needle hub 34 may include a pair of longitudinally extending
 fingers 39. These fingers 39 frictionally engage needle shield 40. In this
 way, needle hub 34 is held in place adjacent to catheter hub 24 so that
 the sharp distal tip of introducer needle 31 extends distally of the
 distal end of catheter 21. The proximally directed force needed to
 overcome the frictional engagement between fingers 39 and needle shield 40
 is less than the proximally directed force needed to overcome the
 removable connection between needle shield 40 and catheter hub 24.
 As noted above, introducer needle assembly 30 also includes needle shield
 40. Like catheter hub 24 and needle hub 34, suitable materials for needle
 shield 40 include, but are not limited to, thermoplastic polymeric resins
 such as polycarbonate, polystyrene, polypropylene and the like. Needle
 shield 40 includes main body portion 41, which defines a longitudinally
 extending passage 42 therethrough. Longitudinally extending passage 42
 allows introducer needle 31 to extend longitudinally through main body
 portion 41. The diameter of longitudinally extending passage 42 is
 slightly larger than the diameter of the main portion of introducer needle
 31. This allows the main portion of introducer needle 31 to easily pass
 through longitudinally extending passage 42.
 An annular lip 43 is located along the distal portion of longitudinally
 extending passage 42. Preferably, lip 43 is integrally formed with needle
 shield and contacts the main portion of introducer needle 31. In this way,
 lip 43 acts as a fluid seal along the main portion of introducer needle
 31. During venipuncture, blood flow between introducer needle 31 and
 needle shield 40 is minimized to minimize blood leakage from the device.
 A transverse barrier 49 located in needle shield 40 to act as a barrier to
 reexposure of the sharp distal tip of introducer needle 31 after it has
 been withdrawn into main body portion 41. Transverse barrier is preferably
 formed from a resilient metal, such as stainless steel, with two lips 49a
 in the configuration of a duckbill. Prior to use, lips 49a extend toward
 the proximal end of introducer needle 31 and generally parallel to main
 body portion of introducer needle 31. See FIG. 7. After proper placement
 of catheter 21 into a patient's blood vessel, lips 49a ride along the main
 portion of introducer needle 31 when introducer needle 31 is being
 withdrawn from catheter 21. Once the sharp distal tip of introducer needle
 31 is withdrawn to a position proximal of lips 49a, the resilient nature
 of lips 49a causes them to return to a position that is transverse to
 introducer needle 31. The configuration of lips 49a as shown in FIG. 8
 prevents reexposure of the sharp distal tip that could occur if introducer
 needle 31 were thereafter moved distally with respect to needle shield 40.
 See FIG. 8.
 Other types of transverse barriers could also be used. For example, a
 transverse barrier having a single arm could be used in place of the pair
 of lips 49a forming a duckbill.
 Main body portion 41 also includes a plurality of longitudinally extending
 fingers 47. Fingers 47 engage catheter hub 24 to hold introducer needle
 assembly 30 together with catheter assembly 20. Thus, as needle hub 34 is
 moved proximally with respect to catheter hub 24, needle shield 40 remains
 adjacent to catheter hub 24. As described in more detail below, tether 44
 has a length that maintains the sharp distal tip of introducer needle 31
 in main body portion 41 of needle shield when tether 44 is fully extended.
 Thus, once the sharp distal tip of introducer needle 31 is moved into main
 body portion 41 of needle shield 40, any additional proximally directed
 movement applied to needle hub 24 will overcome the friction force between
 fingers 47 and catheter hub 24. In this way, needle shield 40 can be
 removed from catheter hub 24. If desired, main body portion 41 may be
 configured so that the exterior surface of the distal portion of main body
 portion 41 frictionally engages the interior surface of catheter hub 24 to
 help hold needle shield 40 with catheter hub 24.
 Fingers 47 may also include radially inwardly directed projections 48.
 Projections 48 are sized to mechanically engage catheter hub 24 by a snap
 fit. If projections 48 are used, the force needed to remove main body
 portion 41 from catheter hub 24 may be more precisely controlled than if
 only fingers 47 or a friction fit are used. Once the proper proximally
 directed force is applied to main body portion, projections 48 override
 catheter hub 24 and main body portion 41 can be removed from catheter hub
 24. Again, tether 44 maintains main body portion 41 in the proper location
 so that the sharp distal tip of introducer needle 31 is safely located
 within main body portion 41 of needle shield 40.
 Tether 44 has a length that is comparable to the exposed length of
 introducer needle 31. This length maintains the sharp distal tip of
 introducer needle 31 in main body portion 41 of needle shield when tether
 44 is fully extended. Tether 44 is folded over itself to form a plurality
 of pleats 44a like an accordion. Each pleat 44a defines a central opening
 45 therein to allow introducer needle 31 to extend through each pleat 44a
 whether tether 44 is completely extended, see FIG. 4, or completely folded
 with main body portion 41 of needle shield 40 adjacent to needle hub 34,
 see FIG. 3. By forming tether 44 in this way, a compact design is achieved
 for catheter and introducer needle assembly 10.
 Tether 44 can be made of any relatively stiff yet flexible material.
 However, polyethylene terephthalate (PET) is the preferred material. One
 benefit of using PET is that it is relatively stiff so that when it is
 folded into a pleated or an accordion-like configuration, it provides a
 slight biasing force to help maintain tether 44 in the completely extended
 position. This in turn aids in maintaining needle shield 40 in position
 over the sharp distal tip of introducer needle 31.
 Tether 44 can be connected to needle hub 34 and needle shield 40 by any
 standard means, such as by an adhesive or by heat-sealing. Preferably,
 tether 44 is connected to needle hub 34 and needle shield 4o through
 mechanical engagement as well as by an adhesive. For example, a slot 37
 may be formed along a distal portion of needle hub 34 where one end of
 tether 44 can be placed. Slot 37 thus provides an edge along which a
 proximal pleat 44b of tether 44 can mechanically engage needle hub 34 to
 prevent tether 44 from being removed from needle hub 34 during use.
 Similarly, a distal pleat 44c can be looped around main body portion 41 of
 needle shield 40 to prevent tether 44 from being removed from main body
 portion 41 during use. Although it is preferred to have tether 44
 connected to needle hub 34 and needle shield 40 as described above, it is
 to be understood that other well known methods for joining two pieces
 together may be used.
 The combination of the material for tether 44, the pleated configuration of
 tether 44, and the specific connection of distal pleat 44c to main body
 portion 41 causes the longitudinal axis of main body portion 41 may be
 used to form an oblique angle with respect to introducer needle 31 when
 tether 44 is fully extended. This helps to ensure that the sharp distal
 tip of introducer needle 31 remains trapped inside needle shield 40 if
 introducer needle 31 were to subsequently be moved distally with respect
 to main body portion 41 and prevents the sharp distal tip of introducer
 needle 31 from being reexposed after use.
 In order to place catheter 21 into a patient's blood vessel, the clinician
 substantially longitudinally aligns introducer needle 31 and catheter 21
 with the target blood vessel. The bevel defining the sharp distal tip of
 introducer needle 31 should be facing substantially away from the skin
 surface during venipuncture. The clinician inserts introducer needle 31
 and catheter 21 at a shallow angle, preferably less than about 35 degrees,
 into the skin so that the sharp distal tip of introducer needle 31 enters
 the target blood vessel. The clinician then preferably observes a blood
 flashback in the flashback chamber.
 After confirming placement of introducer needle 31 and catheter 21 in the
 target blood vessel, the clinician advances catheter 21 distally axially
 along introducer needle 31 into position in the blood vessel. After proper
 placement of catheter 21 is achieved, the clinician places a finger from
 her other hand on the patient's skin over the blood vessel distal of
 distal end of catheter 21 and the sharp distal tip of introducer needle
 31. By placing her finger on the patient's skin and applying sufficient
 pressure on the skin, the clinician thereby minimizes blood flow through
 catheter 21. The clinician then withdraws introducer needle 31 from
 catheter 21 by pulling needle hub 34 in a proximal direction. Once sharp
 distal tip of introducer needle 31 is located within main body portion 41
 of needle shield 40, continued proximal movement of needle hub 34 will
 result in a force sufficient to overcome the force holding fingers 47 to
 catheter hub 24 so that main body portion 41 can be removed from catheter
 hub 24. Thereafter, the clinician may attach any desired fluid-handling
 device to side port 25, if a ported catheter is used, or to catheter hub
 24, if a straight catheter is used, and commence the planned treatment.
 Main body portion 41 of needle shield 40 with the sharp distal tip of
 introducer needle 31 shielded therein may then be disposed of according to
 the facility's disposal protocol.
 Thus, it is seen that a catheter and introducer needle assembly with a
 needle shield and tether is provided that is compact, simple and easy to
 use, that requires no special features or technique to be operative, that
 is ergonomically comfortable for the clinician to use, that can be used
 with both ported and straight catheters without any change in technique by
 the clinician, and that allows access through the introducer needle to the
 blood vessel during venipuncture.