Abstract:
A catheter and needle system includes a solid piercing needle, a catheter, and a needle tip enclosure, as well as a method of utilization. The solid needle reduces the possibility of transmitting infectious agents to a user otherwise resulting from accidental needle punctures. The system has two configurations, a first for inserting the assembly into a patient, and a second for withdrawing and disposing of the piercing needle. The catheter has means for receiving, delivering and viewing fluids at the insertion site. The needle and enclosure operate cooperatively to enable medical procedures to be conducted without hinderance, and to automatically cleanse and enclose the piercing portion of the needle upon withdrawal. The system also provides for the safe withdrawal of the needle without the need to disturb the catheter once it is inserted.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    Not applicable.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    Numerous medical procedures involve the insertion of intravenous devices into patients with varying medical conditions. Among these medical conditions are a number of diseases that also present a risk of infection to the medical practitioner providing care. The insertion of intravenous devices generally requires the use of a sharp implement, which conventionally has been a hollow bore needle, for piercing the skin to allow insertion of a hollow catheter. The distal end of the catheter must be inserted into, but not through, a blood vessel. Normally, proper placement of the catheter is confirmed by visual observation of a “flash-back” of blood that passes through the hollow needle into a stationary flash chamber located at the proximal end of the catheter assembly, where it is visualized. Once the catheter has been inserted to the proper position within the blood vessel, the sharp implement needs to be withdrawn and properly discarded. The acts of withdrawal and disposal pose the greatest threat to the health of the practitioner, since the implement remains sharp enough to pierce skin and is potentially carrying an infectious agent. With the prior art designs, the hollow needle and flash chamber contain a rather large amount of potentially infectious blood, with the result that inadvertent skin puncture of the practitioner can lead to significant transference of infectious agent from the patient to the practioner.  
           [0004]    A system for providing protection from the risk of infection during withdrawal and disposal of a piercing instrument must accommodate various operational constraints. A primary constraint is to minimize interference with the execution of the medical procedure prior to withdrawal and disposal. Accordingly, the system should minimize or eliminate additional steps and preferably should not significantly alter the steps performed without the system. Medical care often occurs in stressful and hurried situations and hence, ease of use is a second constraint. Preferably, the system should not compel the practitioner to carry out any but the most minimal actions to accomplish safe withdrawal and disposal. Additional constraints include cost and ease of construction, compatibility with existing equipment, and adaptability of use across variations in patients and insertion locations.  
           [0005]    A very desirable benefit of such systems would be reduction in the risk of accidental infection. Risk of infection can be reduced by, inter alia, automatic operation, encapsulation of the piercing implement, and a reduction in the fluid and tissue volume associated with piercing instrument removal — since greater volume potentially increases the amount of the infectious agent present. Risk can also be reduced by quick operation. If the system is effective simultaneously with, or at least immediately subsequent to withdrawal, exposure of the piercing instrument is minimized, as is the risk of accidental infection.  
           [0006]    Numerous approaches to providing a safer withdrawal and disposal system have been employed, though two general categories of systems predominate. One category of system deploys a secondary sheath between a needle and a catheter to envelope the needle upon withdrawal from the piercing site, prior to complete withdrawal of the secondary sheath and needle from the catheter. This category of system is relatively sizable and complex, yet still poses a risk of reemergence of the needle. Preventing reemergence may necessitate even more apparatus. Withdrawal is also generally associated with emission of a significant amount of body fluid with this category of system, among other adverse consequences. The second category of system involves affixing a point guard about the tip of the piercing instrument after withdrawal. This approach often requires substantial complexity and substantial additional actions to implement. What&#39;s more, with this second category of system, better execution of one desirable benefit, such as secure encapsulation of a piercing instrument, is often exchanged for a poorer execution of another desirable benefit, such as automatic operation.  
           [0007]    As mentioned above, most prior approaches utilize a hollow needle (in fluid communication with a stationary flash chamber having a relatively large volume) for piercing. Hollow needle and flash chamber assemblies, however, present a risk of exposure to the body fluids they contain when the needle is withdrawn. In fact, research reveals that the risk of infection from a hollow needle is many times greater than that from a solid needle. This difference probably arises from the large reservoir of blood within the hollow needle and flash chamber assembly, that then becomes the source of inoculation when inadvertent needle stick injuries occur. Solid needles, on the other hand, have no such reservoir for inoculation. Moreover, when using a hollow needle with a catheter the user may receive an incorrect “flashback” signal. The “flashback” signal is the entry, or “flashing” , of blood into a viewing chamber (called the flashback chamber) in the interior of the catheter and needle system. The flash occurs when a blood vessel is entered and blood can flow into the catheter interior. Hollow needles allow blood to flow into the catheter interior even if only the needle, but not the catheter, has entered the blood vessel. Hence, the user must guess to what degree it is necessary to further insert the needle and catheter, after observing the flashback, to ensure that the catheter is correctly inserted. A system providing greater certainty of correct catheter insertion is preferable.  
         SUMMARY OF THE INVENTION  
         [0008]    The objectives of the present invention include:  
           [0009]    The provision of an improved piercing system which entails a minimum of hindrance to the optimum execution of a medical procedure.  
           [0010]    The provision of an improved piercing system that requires minimum additional actions following the execution of a medical procedure such as the insertion of a catheter.  
           [0011]    The provision of an improved piercing system that requires minimal alterations of the actions involved in the execution of a medical procedure such as the insertion of a catheter.  
           [0012]    The provision of an improved piercing system with ease of use sufficient to curtail any additional demands on the medical practitioner&#39;s attention.  
           [0013]    The provision of an improved piercing system that requires minimal additional actions by the medical practitioner to realize the improvement in safety.  
           [0014]    The provision of an improved system and method for catheter insertion using a solid needle to reduce the possibility of infection transference.  
           [0015]    The provision of an improved piercing system that is relatively inexpensive.  
           [0016]    The provision of an improved piercing system of simplified construction.  
           [0017]    The provision of an improved piercing system compatible with existing medical equipment.  
           [0018]    The provision of an improved piercing system adaptable for use across variations in patients and piercing locations.  
           [0019]    The provision of an improved piercing system that reduces the risk of accidental infection.  
           [0020]    The provision of an improved piercing system that operates automatically.  
           [0021]    The provision of an improved piercing system that completely encloses the penetrating elements of the piercing instrument.  
           [0022]    The provision of an improved piercing system that reduces the amount of fluids and tissue which accompany withdrawal of the piercing instrument.  
           [0023]    The provision of an improved piercing system that occurs sufficiently fast to be in effect simultaneously with or at least immediately after withdrawal of the piercing instrument.  
           [0024]    The provision of an improved piercing system, comprised of a catheter and needle, that gives visual confirmation only when the catheter is correctly inserted, and not when just the needle is correctly inserted. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS FIG.  1 A is a longitudinal partial cross-section top plan view of a first embodiment of the present invention in a first configuration.  
       [0025]    [0025]FIG. 1B is a longitudinal cross-section top plan view of a catheter portion of the first embodiment of the present invention depicted in FIG. 1A.  
         [0026]    [0026]FIG. 2 is a longitudinal partial cross-section top plan view of two parts of the first embodiment of the present invention in a second configuration.  
         [0027]    [0027]FIG. 3 is a longitudinal cross-sectional elevation of the first embodiment of the present invention, in the configuration of FIG. 1A.  
         [0028]    [0028]FIG. 3A is a cross-section view along line  3 A- 3 A in FIG. 3 of a needle element of the first embodiment of the present invention.  
         [0029]    [0029]FIG. 4 is a longitudinal cross-sectional elevation of the first embodiment of the present invention, in the second configuration shown in FIG. 2.  
         [0030]    [0030]FIG. 5 is a longitudinal cross-sectional elevation similar to a portion of FIG. 3, illustrating a second embodiment of the present invention.  
         [0031]    [0031]FIG. 5A is a cross-sectional view along line  5 A- 5 A of portions of catheter and needle elements of the second embodiment of the present invention.  
         [0032]    [0032]FIG. 6 is a view along the longitudinal axis  12  in the direction  12 P of FIG. 1A, of a catheter and needle tip of a third embodiment of the present invention. Similar reference characters indicate similar parts throughout the several views of the drawings. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0033]    In FIGS. 1A, 1B &amp;  2 - 4  a first embodiment of a catheter and needle assembly  10  of the present invention is shown in two configurations. A first configuration for insertion of the catheter and needle assembly is depicted in FIGS. 1A &amp; 3. Two components of the catheter and needle assembly, in a second configuration for safe withdrawal and disposal following insertion, is depicted in FIGS. 2 &amp; 4.  
         [0034]    Referring now to FIG. 1A, a first embodiment of a needle tip enclosing catheter and needle assembly  10  in the first configuration is depicted in partial cross-section. The catheter and needle assembly has a longitudinal axis  12 , with a proximal direction  12 P and a distal direction  12 D. Directions referred to hereafter as transverse are perpendicular to the longitudinal axis  12 . It should be understood that in the FIGS. the catheter and needle assemblies are depicted in straight linear configurations for purposes of clarity only. Depending upon the application, the catheter and needle assembly may have both flexible and inflexible portions. Accordingly, axis  12 , though depicted as a straight line, may also be curvilinear in correspondence to the actual disposition of assembly  10  when in use. In a case of curvilinear disposition, directions  12 P and  12 D indicate relative directions along the longitudinal extent of the catheter and needle assembly. The direction  12 P is along axis  12  pointing towards the proximal end of the assembly, and the direction  12 D is along axis  12  pointing towards the distal end of the assembly.  
         [0035]    [0035]FIG. 1B is a cross-section view of a catheter  20  employed in the first embodiment. Catheter  20  has a proximal base  22  with a plurality of flanges  24  that flare transversely. Base  22  adjoins a transitional section  26  which connects to a conduit  28 . Conduit  28  terminates in a distal tip  30 . An opening  32  is formed in distal tip  30 .  
         [0036]    Returning to FIG. 1A, catheter  20  is shown in relation to the other parts of the assembly  10  when in the first configuration for insertion into a blood vessel (not shown). An aperture  34  proximate tip  30  is in fluid communication with an interior passageway  36  — seen in FIG. 1B —of catheter  20 . A catheter hub  38  securely mates with a needle tip enclosure  50  at a distal enclosure adaptor  52 . Enclosure  50  has an enclosure housing  54 , which includes a plurality of intermediate side tabs  56 . A proximal portion  58  of enclosure housing  54  has a proximal orifice  60  formed therein. Proximal orifice  60  is in fluid communication with a cavity  62 . Cavity  62  runs longitudinally through enclosure housing  54  to a distal orifice  64 .  
         [0037]    Referring now to FIG. 2, a cross-section view of needle tip enclosure  50  is depicted in the second configuration, following successful insertion of catheter  20  into a blood vessel (not shown). Within the cavity  62  is a blocking member  66 , seen end-on. When in the second configuration, the position of blocking member  66  obstructs movement through the cavity  62 .  
         [0038]    In FIG. 4, blocking member  66 , forced by a spring  67  (or by any other conventional device or material), crosses cavity  62  and contacts an interior wall  68  of the enclosure housing  54 . Housing  54  has first and second sides  70  and  72 . In a proximal portion of side  72  is a vent  74  from the cavity  62 .  
         [0039]    Referring again to FIG. 2, a solid piercing needle  80  and enclosure  50  are depicted in the second configuration. The solid needle  80  has a distal tip  82  and a shaft  84  (shown to be semi-elliptical in cross-section—FIG. 3A), and is attached to a proximal control elemental  86 . In FIG. 3, needle tip  82  is seen to have a proximal face  88  at the boundary between the tip  82  and the shaft  84 .  
         [0040]    In operation, assembly  10  is initially in the first configuration (shown in FIGS. 1A and 3) for inserting catheter  20  by piercing the skin with solid needle tip  82 . In the first configuration, enclosure adaptor  52  is fully engaged in hub  38 , needle  80  is at its farthest distal position in catheter  20  and needle enclosure  50 , and needle tip  82  emerges from the distal opening  32  in readiness for piercing the skin of the patient. During insertion, needle control element  86  is flush against the enclosure  50  with needle shaft  84  passing throughout the enclosure cavity  62  and the catheter interior passageway  36 . Within cavity  62 , needle shaft  84  confines the blocking member  66  to a first position that is not obstructing cavity  62  as depicted in FIG. 3. Also in the first configuration, the proximal face  88  of needle tip  82  is disposed distally past aperture  34 , to allow passage of bodily fluids through aperture  34  and into an open space  90  within interior passageway  36 . The space  90  is the fraction of interior passageway  36  and cavity  62  not occupied by needle shaft  84 . Vent  74  is closed by a well-known air permissible plug  91  that allows air to escape from housing  54  but prevents the escape of blood or other body fluids. At least a portion of housing  54  is preferably transparent to form a movable flashback chamber (space  90  and vent  74 ) which is visible to the user. When aperture  34  enters the blood vessel, blood flows along space  90  into housing  54  where it is visible to the user through the transparent portion (not depicted) of housing  54 . In contrast to prior approaches, the flow of blood along space  90  does not occur immediately upon insertion of the needle  80  into a blood vessel. The prior approaches use hollow needles that allow blood flow through the hollow needle and into the catheter and into a hollow flash chamber in the proximal portion of the apparatus. These approaches allow the blood flow into the catheter and flash chamber even if the needle is inserted in the blood vessel, but the catheter is not. Hence, there is a degree of uncertainty as to whether the catheter is correctly inserted with the prior approaches. The solid needle  80 , catheter  20 , and aperture  34  of the present invention cooperate to allow blood flow into space  90  only once the catheter  20  is correctly inserted such that aperture  34  of catheter  20  has entered a blood vessel. This “flashback” of blood indicates proper placement of catheter  20 . Inspection of the flash chamber allows the medical practitioner inserting the catheter and needle assembly  10  to visually determine if the assembly is correctly inserted, i.e., the catheter tip containing aperture  34  has entered the blood vessel.  
         [0041]    After insertion of catheter  20 , removal and disposal of needle  80  will follow. Once the catheter and needle assembly  10  is inserted into a blood vessel, needle enclosure  50  is moved distally along direction  12 D (FIG. 1A) while simultaneously needle  80  is withdrawn proximally along direction  12 P until needle tip  82  is completely within enclosure  50 . This movement of enclosure or housing  50  distally relative to the proximal movement of needle  80  automatically disposes catheter  20  within the blood vessel. The transition to the second configuration is complete when needle tip  82  is locked within enclosure  50  by blocking member  66  crossing cavity  62 . Needle  80  and enclosure  50  are usually then separated from catheter  20 , which is left inserted in the blood vessel. Also the construction and operation of enclosure  50 , as it moves proximally along direction  12 P from configuration  1  (shown in FIGS. 1A and 3) to configuration  2  (shown in FIGS. 2 and 4), in cooperation with the construction of needle  80 , automatically effects a cleansing and encapsulation of needle  80 .  
         [0042]    Beginning from the first configuration (FIG. 1A, 3), withdrawal is initiated by movement of needle  80  in the proximal direction  12 P relative to catheter  20  and enclosure  50 . Proximal orifice  60  is constructed to fit closely to, while still allowing relatively unimpeded travel of, shaft  84 . This close fit provides at least two functional benefits. The first benefit is the prevention of escape of needle tip  82  from enclosure  50  in the direction  12 P, since the needle tip cross-section is too great to pass through proximal orifice  60 . The second benefit, as a result of the close fit of proximal orifice  60  to shaft  84 , is a wiping off of body fluids and tissue from shaft  84  as it passes through proximal orifice  60 . This wiping reduces the medical practitioner&#39;s exposure to infectious agents along shaft  84  by limiting the emission of fluids and tissues that accompanies the withdrawal of needle  80 . Once the needle tip  82  has left catheter  20 , needle tip  82  enters cavity  62 . As enclosure  50  moves distally and needle  80  simultaneously moves proximally, fluids in space  90  pass around tip  82  and remain within catheter  20  or exit into vent  74 , as a result of the relatively loose fit between the body of catheter  20  and needle  80 . Vent cap  91  prevents egress of fluids outside enclosure  50 . This movement of fluids out of space  90  during the transition from configuration  1  to configuration  2  minimizes the total fluid held within enclosure  50  at the completion of catheter insertion. This in turn minimizes the volume of potential contaminants to which the practitioner is exposed.  
         [0043]    Upon sufficient movement of the needle proximally into cavity  62 , needle tip  82  passes blocking member  66 , thereby releasing blocking member  66 . Upon release, member  66  is moved by spring  67  (or other suitable flexible material or structure) to the position shown in FIG. 4 in which it blocks cavity  62 , thereby trapping tip  82  in enclosure  50 . Alternatively, the housing interior wall  68  may have a recess (not depicted) that the blocking member  66  fits into for a more secure closure of cavity  62 . The presence of member  66  blocking cavity  62  is a barrier to the reemergence of needle tip  82 . When positioned across cavity  62 , blocking member  66  also tends to prevent passage of fluids and tissues from cavity  62  and vent  74  through distal orifice  64 . Also during transition from configuration  1  to configuration  2  the total volume of blood contained within the flash chamber of enclosure  50  has been minimized and positioned distally away from the practitioner, thereby potentially decreasing the likelihood of exposure. The operation of enclosure  50  is automatic upon removal of the needle  80  and requires minimal additional or altered actions by the medical practitioner. The movement of catheter  20  into the blood vessel following catheter tip placement occurs automatically during proximal movement of enclosure  50  along needle  80 . Once entirely removed, needle tip  82  is contained within enclosure  50 , and needle  80  and enclosure  50  can be discarded without exposing the practitioner to contaminated needle tip  82 .  
         [0044]    Viewed in cross-section along line  3 A- 3 A in FIG. 3, FIG. 3A shows how the spatial relationships of catheter  20  and needle shaft  84  provide the space  90 . In alternate embodiments (not depicted), shaft  84  may occupy a lesser amount of the cross-sectional area of catheter  20 . In these embodiments, the space  90  will be a greater fraction of the cross-sectional area of catheter  20 , and space  90  may also extend around the sides or below needle shaft  84 .  
         [0045]    The transverse cross-section of catheter  20  and needle  80 , as well as the form of the needle tip  82 , can differ both in size and shape in various embodiments. Particular medical applications will preferentially utilize specific configurations, including both symmetrical and asymmetrical structures. The movable transparent flash chambers can also differ in size, shape and topography in various embodiments of the present invention when advantageous.  
         [0046]    Referring now to FIGS. 5, a second embodiment of the present invention is partially depicted in cross-section. Significant modifications from the prior embodiment include: the form of a needle tip  82 A, the relation of tip  82 A to a shaft  84 A, and the form of a proximal face  88 A. The disposition of needle shaft  84 A within space  90  is also altered, in part, due to the modified relation of tip  82 A to shaft  84 A. Needle shaft  84 A having the option, as depicted, of a relatively lesser cross-sectional area than needle shaft  84  also contributes to its altered disposition within space  90 . FIG. SA shows both the transverse cross-section of needle shaft  84 A within the space  90 , and the proximal portion  88 A of needle tip  82 A. The axial position of needle shaft  84 A is approximately centered in relation to the distal tip  82 A. The embodiment depicted in FIGS. 5 &amp; 5A is well suited for providing an alternative option in medical circumstances, such as pediatric care, where a catheter with a lesser width  92  is desirable.  
         [0047]    Referring now to FIG. 6, a third embodiment of the present invention is depicted in an increased scale relative to FIG. 5. FIG. 6 shows an alternative needle tip  82 B which is differentiated from needle tip  82 A of FIGS. 5 &amp; 5A by the presence of a needle groove  94 . Needle groove  94  extends longitudinally through the tip  82 B and may also extend along a portion of the length of a shaft  84 B, partially seen through a gap  96  formed by the sides of groove  94  and a catheter  20 B. Catheter  20 B is identical to the catheter  20  of the previous embodiments except for a lack of aperture  34 . Groove  94  is of sufficient depth to allow the flow of bodily fluids through gap  96  between the boundaries of groove  94  and catheter  20 B, into the open space  90 . As depicted, the radius of shaft  84 B is greater than is the radius of tip  82 B at the bottom of groove  94 . Alternatively, the bottom of groove  94  may reach to a lesser depth (not depicted), such that the radius of tip  82 B at the bottom of groove  94  is not less than the radius of the shaft  84 B. An additional alternative embodiment (not depicted) would continue groove  94  along part or all of shaft  84 B to further increase the space  90  available for blood flow. A distal point  98  of needle tip  82 B is seen to be off-centered, relative to the longitudinal axis  12 . The distal point  98  may also be arranged to one side or the other of groove  94  (not depicted) or centered (not depicted) relative to the longitudinal axis  12 . These variations in the disposition of distal point  98  may also be optionally employed with any of the other embodiments of the present invention.  
         [0048]    A variety of physical mechanisms can serve as the blocking member  66 . Although only one example is depicted herein for illustrative purposes, numerous variations in the construction of the blocking member  66 , variations in the means of biasing towards a blocking position, as well as variations in the means of effecting a blocking action upon needle withdrawal are within the scope of the present invention. The various applicable mechanisms are well known to those of skill in the art, and do not compromise elements essential to the present invention.  
         [0049]    In view of the above, it will be seen that the various objects and features of the invention are achieved and other advantageous results obtained. The examples contained herein are merely illustrative and are not intended in a limiting sense.