Abstract:
A vascular access system comprises a needle having a distal tip and a proximal fitting section and a dilator having a solid distal section connected to a solid proximal section and an annular recess therebetween, the dilator having a passageway so that the dilator is coaxially positioned around the needle. The needle has at least one opening positioned proximal to its distal tip so that, when the distal end of the needle enters a blood vessel, blood enters the annular recess to show the operator that access has been achieved. Optionally, a sheath having a distal tip, a proximal fitting section, and a lumen sufficient to coaxially fit over the dilator.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is based upon U.S. provisional patent application Ser. No. 60/343,814, filed Dec. 26, 2001. 

   FIELD OF THE INVENTION 
   This invention is directed to vascular access. More particularly, this invention is directed to a vascular access device that is easier, safer, and faster to use than prior such devices. 
   BACKGROUND OF THE INVENTION 
   A preferred non-surgical method for inserting a catheter or vascular sheath into a blood vessel involves the use of the Seldinger technique, which includes an access needle that is inserted into a patient&#39;s blood vessel. A guidewire is inserted through the needle and into the vessel. The needle is removed, and a dilator and sheath combination are then inserted over the guidewire. The dilator and sheath combination is then inserted a short distance through the tissue into the vessel, after which the dilator is removed and discarded. 
   The catheter is then inserted through the sheath into the vessel to a desired location. A number of vascular access devices are known. See, for example, U.S. Pat. Nos. 4,581,019, 4,629,450, 4,772,264, 4,978,334, 5,158,544, 5,424,410, 5,312,355, 5,512,052, 5,728,132, 5,885,217, 5,919,160, 6,120,494, 6,179,823, and 6,210,366, each of which is incorporated herein by reference, wherein various devices for vascular access are described. However, none of these devices has the ease and safety of use that physicians would prefer, and there is thus a need for an easier-to-use and safer vascular access device, especially one that would clearly indicate when a blood vessel has been punctured. 
   OBJECTS OF THE INVENTION 
   It is an object of the invention to provide vascular access. 
   It is also an object of the invention to provide easier, safer, and faster vascular access. 
   It is additionally an object of the invention to provide a vascular access device that eliminates the possibility of inadvertent guidewire misplacement into the vascular system during the vascular access procedure. 
   It is a further object of the invention to provide a method of introducing catheters or other medical devices in an easier, safer, and faster procedure, where the appearance of a patient&#39;s blood in the vascular access device indicates to the practitioner that the needle has accessed the desired vessel. 
   These and other objects of the invention will become more apparent in the discussion below. 
   SUMMARY OF THE INVENTION 
   According to the invention, a dilator or a sheath and dilator are mounted on a needle, which needle has a lateral opening proximal to the needle distal tip. Prior to insertion, the needle is positioned so that the distal end of the needle is distal to the distal end of the dilator. After insertion of the needle into a blood vessel, the needle opening permits blood to flow into an annular space in the dilator or between the needle and the dilator to indicate that the distal end of the needle has punctured the blood vessel. Additionally or alternatively, blood flows into an annular space formed by the sheath to indicate that the blood vessel has been punctured. In addition, blood may flow to an optional side port to provide further indication access has been achieved. 
   Once vascular access is achieved, that is, once the distal tip of the needle punctures a blood vessel and blood flows through a lateral opening in the needle to one of the annular spaces described above and as appropriate, into a side port, a guidewire is threaded through the needle, and then the entire apparatus, including the needle, the dilator, and a sheath, can be advanced over the guidewire into the blood vessel. At a desired time the sheath, needle, and dilator can be advanced over the guidewire. When the sheath is in position, the inner dilator, needle and guidewire can be removed together. Thus, the guidewire protects the needle tip, and the needle, with the guidewire in it, can then be bent for added safety, to prevent removal of the guidewire and consequential exposure of the needle tip. Alternatively, the guidewire can be left in place for catheter placement. 
   In one embodiment of the invention, the dilator has a distal member that can be advanced distally or the distal tip of the needle can be retracted so that the distal tip of the dilator distal member extends distally over the distal tip of the needle. The dilator distal member then protects the blood vessel wall as the needle, dilator or needle, dilator, sheath are advanced or withdrawn from a blood vessel, preferably over a guidewire. In addition, when the needle, dilator or needle, dilator, sheath are pulled out, the healthcare worker is protected. 
   In another embodiment of the invention, there is a coaxial dilator system, with an inner dilator and an outer dilator. The inner dilator can be advanced independently distally to the distal tip of the needle. The inner dilator then covers the needle tip, the inner dilator distal member then protects the blood vessel wall as the needle, dilator or the needle, dilator, sheath are advanced or withdrawn from a blood vessel, preferably over a guidewire. In addition, when the needle or needle, dilator, and/or sheath are pulled out, the worker is protected. 
   In another embodiment of the invention the needle can be rotated relative to the dilator or the dilator and sheath, so that the needle tip, which is inserted into a blood vessel with the needle distal tip bevel up, can be rotated 180° so that the needle distal tip bevel is down. When the needle distal tip is in this position, it is less likely that movement of the needle distal tip will cause injury to the blood vessel. The proximate portion of the needle member may have color coding, words, or other indicia to indicate the relative position of the needle tip level. Also, the needle member proximal portion may have a notch, pivot, indent, or other mechanism to indicate relative position and/or to hold the needle member in position relative to the dilator or the dilator and sheath. 
   The vascular access device of the invention has several uses, including access to every vessel when a vascular sheath is needed as in stent placement, Percutaneous Transluminal Coronary Angioplasty (PTCA), etc. or when a peel-away sheath is needed, for example, for inserting PICC lines, pacemaker leads, etc. In addition, the invention would be useful for access to dialysis grafts and fistulas, which are superficial structures and where access is sometimes needed quickly, especially during a de-clotting procedure. Another use would be for placement of central lines (subdlavian or internal jugular). Instead of use of a large (18 G) needle (current technique), followed by advancement of a dilator over a guidewire and exchanging it for a triple lumen catheter or vascular sheath, according to the invention a large needle or a small needle can be used to gain vascular access with a vascular sheath through which a triple lumen or any other catheter can be safely placed. 
   The present invention has several advantages, the first of which is its efficiency. Instead of the current multi-step access method with an exchange of guidewires and sheaths, this invention reduces the number of steps and simplifies access. Another advantage is safety. After a vessel is accessed, the guidewire can be left in to protect the needle tip. The needle, dilator and guidewire can be removed together after the sheath is in place. If no additional access is needed in the same procedure, the needle can be bent for added safety. This is contrary to the current technique where the unprotected bloody needle is removed from the guidewire after vascular access is gained. Alternatively, the guidewire can be left in place to provide further access through the sheath and the dilator distal member protects the distal tip of the needle and ultimately the user. Another advantage is the reduction of infection. By minimizing the number of guidewires and sheaths necessary to obtain vascular access, the opportunities for inadvertent contamination are decreased. A further advantage is that under non-hospital or field conditions, use of the invention will decrease the possibility of infection due to a non-sterile environment. A yet further advantage is the added stiffness of the system. The added stiffness provided by the needle is enabling advancement of the system without multiple dilatations and reduced trauma to the patient. 
   An even further advantage relates to the bleeding from the needle, the dilator, and around the wires that occurs during guidewire exchanges with current techniques. Such bleeding increases the spread of blood over the surgical field and the operator&#39;s gloves, thereby, increasing the chance of infection in case an inadvertent needle stick happens. The device of the invention will decrease this risk of infection because the blood will flow into the sheath rather than into the surgical field as in the current technique. 
   Another and further advantage of one embodiment of the invention, is that there is no need for over-the-wire exchanges. The device can be configured to eliminate the possibility of inadvertent guidewire misplacement into the vascular system during the access procedure. In the current technique, with exchange of the needle for a dilator and then for the sheath, it is a known complication that the operator fails to grasp the guidewire during those exchanges and the guidewire is inadvertently advanced with the dilator or catheter into the patient&#39;s vascular system. The guidewire then has to be removed either surgically or snared percutaneously. 
   Lastly, the present invention will be cost-effective. The system of the invention will eliminate the need for an additional guidewire and coaxial dilator to be used in gaining vascular access. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1 and 2  are each a schematic representation of one embodiment of the invention; 
       FIGS. 3 and 4  are each a schematic representation of another embodiment of the invention; 
       FIG. 5  is a partly cross-sectional view of a further embodiment of the invention; 
       FIG. 5   a  is a cross-section along line  5   a — 5   a;    
       FIG. 6  is a partly cross-sectional view of another aspect of the invention; 
       FIG. 7  is a partly cross-sectional view of a further aspect of the invention; 
       FIG. 8  is a partly cross-sectional view of an embodiment of the invention where the distal portion of the dilator extends distally; 
       FIGS. 9   a  to  9   c  are schematic representations of use of the embodiment of the invention shown in  FIG. 8 ; 
       FIGS. 10   a  and  10   b  are schematic representations of an embodiment of the invention with a coaxial dilator system; 
       FIG. 11  is a schematic cross-sectional view of the proximal portion of the system of  FIGS. 10   a  and  10   b.    
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The invention can perhaps be better appreciated from the drawings. In  FIGS. 1 and 2  a needle section  102  comprises a needle  104  and a proximal portion  106  with a twist lock member  108 , and a dilator section  112  comprises a dilator  114  and a hub  116 . In a preferred embodiment of the invention, needle  104  has one or more openings  120 . Dilator  114  is preferably clear, semi-opaque, or translucent so that when blood flows into needle  104  and then through an opening  120  either (1) into an annular space  122  between needle  104  and dilator  114  or (2) into or through spaces (not shown) in dilator  114 , the physician can see the blood. This will indicate to the physician that the distal end  124  of needle  104  has punctured a blood vessel (not shown). 
   As can be seen in  FIG. 2 , dilator hub  116  releasably engages needle proximal section  106 . Here, dilator hub  116  comprises a conical recess  117  that receives a conical member  119  forming a part of needle proximal section  106 . Needle proximal section  106  comprises an annular portion  121  having threading  123  that engages reciprocal threading  125  on hub  116 . Other arrangements of threading, detents, or other snap- or force-fit configurations that achieve the same purpose of releasably engaging the proximal portions of the needle and dilator sections are also within the scope of the invention. 
   Hub  116  may optionally have a porous vent  128 . Needle proximal portion  106  may optionally have a porous vent plug  130  that fits a channel  132  in fluid communication with lumen  134  of needle  104 , recess  117 , and needle proximal portion  106  having lumen  136 . 
   Needle proximal portion  106  may have color coding, words, or other indicia, such as a pivot or notch, to indicate to the operator the position of the bevel of distal tip  124  relative to dilator  114 . Also, there may be a mechanical fit between dilator  114  and needle  104  so that the operator would sense by feel or sound when the needle has been rotated to change the position of the needle tip bevel. 
   In the embodiment of the invention shown in  FIGS. 3 and 4 , a needle section  142  comprises a needle  144  and a proximal portion  146  with a twist lock member  148 , a dilator section  150  comprises a dilator  152  and a hub  154 , and a sheath section  160  comprises a sheath  162  and a proximal portion  164 . In a preferred embodiment of the invention, needle  144  has one or more openings  149 . Dilator  152  and sheath  162  are preferably clear, semi-opaque, or translucent so that when blood flows into needle  144  and then through opening  149  (1) into an annular space  170  between needle  144  and dilator  152 , (2) into or through spaces (not shown) in dilator  152 , or (3) through an opening  172  into an annular space  174  between dilator  152  and sheath  162 , the physician can see the blood. As above, this will indicate to the physician that the distal end  176  of needle  144  has punctured a blood vessel (not shown). Preferably sheath proximal portion  164  has a port  178  so that blood can be aspired through a syringe (not shown). The sheath may contain a hemostatic valve (not shown) in the distal end  164  to prevent blood flow out the distal end of the sheath. 
   Proximal sections  108  and  116  and  146  and  154 , respectively, may optionally have leur connecting members. For example, section  108  may have a male luer lock  129 , and section  116  may have a female luer connector  131 . Sections  146  and  154  may have comparable members, respectively. 
   As shown in  FIG. 4  sections  142 ,  150 , and  160  can be inserted into one another. Proximal sections  146 ,  154 ,  164  can twist or snuggly fit together, such as with a luer connector, threading, a pressure or snap fit, a detent/groove arrangement, or a combination thereof. The structure shown in  FIG. 2  is especially applicable here. 
   In another embodiment of the invention as shown in a partial cross-section in  FIG. 5 , needle  180  has an opening or side hole  182 . Dilator  184 , which is arranged coaxially to needle  180 , has a substantially hollow distal section  186  and a substantially solid proximal section  188 , which sections  186  and  188  are connected by rigid or substantially rigid longitudinal members  190 , to form an interrupted or discontinuous structure. The space between sections  186  and  188  not occupied by members  190  constitutes an annular or substantially annular space  194 , into which blood can flow from opening  182 . Sheath  196  is transparent or translucent, so that the blood in space  194  can be observed by the physician. 
   Preferably dilator  184  has one or more small openings, pores, or porous material  200 , for example, in sheath  196 , to allow air or gas to leave annular space  194  as blood enters. The openings themselves, or the openings in the porous material, are small enough that air will escape but blood will be retained. Suitable porous materials include a porous polymer such as self-sealing, white porous HDPE of pore size 2.5 microns. 
   The distal end  202  of a guidewire  204  is preferably preloaded, that is, positioned within a lumen  206  of needle  180 . In this way blood will flow into needle  180  and out through opening  182 , and not proximally out lumen  206 . Once the physician sees the blood in annular space  194 , guidewire  204  can be advanced distally through lumen  206  into a blood vessel (not shown). Another view of the relationship between needle  180 , dilator longitudinal members  190 , and sheath  196  can be seen in the cross-sectional view shown in  FIG. 5   a.    
   Separate designs for a dilator member according to the invention are shown in more detail in  FIGS. 6 and 7 . In  FIG. 6 , a dilator  210  shown has conical elements. A distal dilation section  212  comprises a double cone design with a passageway  214  extending from the tip of one conical element  216  to the tip of another conical element  218 . At least two stabilizing longitudinal members  220  extend from distal section  212  to a proximal section  222 , which preferably comprises a single conical element  224  with a passageway  226  and a proximal twist or locking section  228 . 
   The embodiment of the invention shown in  FIG. 7  comprises a dilator-needle combination where the dilator device described in  FIG. 6  also comprises a needle  232  that extends through passageway  214  to and through passageway  226 . Needle  232  has a proximal section  234  that comprises a twist or locking arrangement. 
   In the partial representation of an embodiment of the invention shown in  FIG. 8 , a dilator  240  is arranged circumferentially around a needle  242 . Dilator  240  has a distal portion  244  that extends distally toward the distal tip  246  of needle  242 . Alternatively, the inner, elongated dilator is coaxially located within the larger outer dilator. The inner elongated member can be advanced over the needle to protect the tip. As depicted in  FIGS. 9   a  to  9   c,  a needle  252  is positioned in a puncture opening  254  in a blood vessel  256 . A guidewire  258  extends distally from needle  252  into a lumen  260  of blood vessel  256 . A dilator  262  positioned circumferentially around needle  252  has a distal portion  264 . As shown in  FIG. 9   b,  dilator distal portion  264  can be advanced over needle  252  so that the distal tip  268  of dilator distal portion  264  extends distally of the distal tip  270  of needle  252 . Then, when, as shown in  FIG. 9   c,  needle  252  and dilator  262  are advanced distally over guidewire  258 , needle distal tip  270  is protected by dilator distal portion  264 . 
   The embodiment of the invention shown in  FIGS. 10   a  and  10   b  comprises a coaxial dilator system comprising inner dilator  276  and outer dilator  278 . Dilators  276  and  278  are arranged around needle  280 , and the distal end  282  of inner dilator  276  is initially slightly distal of the distal end  284  of outer dilator  278 . The proximal end (not shown) of inner dilator  276  is advanced distally to cause inner dilation distal end  282  to cover the distal end  288  of needle  280 . Preferably dilators  276  and  278  interact or are held so that they retain their relative positions with regard to each other and needle  280  as the needle, dilator or needle, dilator, sheath combination is advanced into or withdrawn from a blood vessel (not shown), optimally over a guidewire (not shown). 
   The coaxial dilator system shown in  FIGS. 10   a  and  10   b  requires an activation system that causes one dilator to move in relation to the other dilator. It is preferred that the inner dilator would be advanced distally to cover the distal end of the needle while the outer dilator remains constant, or in place. Preferably the dilator system would be configured so that the outer dilator would remain relatively, substantially in place while the inner dilator is pushed, pulled, or slid in the distal direction. In the embodiment shown in  FIG. 11 , a proximal needle section  290  is circumferentially surrounded by a proximal inner dilator section  292  and an outer dilator section  294 . Tapered needle hub  296  has at least one annular projection or ring  298  that is received in an annular groove  302  in the tapered outer dilator proximal hub  304 . Inner dilator hub  306  has threading  308  that engages reciprocal threading  310  on needle  290  or on a separate needle member attached to needle  290  or needle hub  296 . Inner dilator hub  304  has a projection or wing  312  that moves within, and is guided by, a slot  316  that prevents rotation of inner dilator  292  with respect to outer dilator  294 . It is within the scope of the invention that other mechanical arrangements known or discernible to those skilled in the art would be acceptable, so long as they permitted advancement of the distal portion of the inner dilator over the distal portion of the needle without rotation of the inner dilator relative to the outer dilator. 
   The invention herein is comprised of conventional, physiologically acceptable materials. For example, the needle consists of a rigid polymer or a metal such as stainless steel, nitinol, or the like. The other elements will typically consist of suitable polymeric materials, such as polyethylene, polypropylene, fluoropolymers and copolymers such as perfluoro (ethylene-propylene) copolymer, polyurethane polymers or co-polymers. 
   The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims.