Vascular access

Abstract

A device may include a hollow needle, a dilator mounted coaxially on the needle, and a sheath mounted coaxially on the dilator. The dilator may be slideably displaceable relative to the sheath.

1 . A device comprising:
 a hollow needle defining a side hole and having:
 a bore so sized as to receive a guidewire; and 
 a sharpened distal tip distal to the side hole; 
   a dilator coaxially mounted on the needle thereby defining a first space between the dilator and needle, the first space communicating with the hollow needle bore through the side hole so that a fluid, if any, exiting the side hole may flow to the first space; and   a sheath coaxially mounted on the dilator;   wherein:
 at least one of the dilator and sheath is clear, semi-opaque, or translucent, so that fluid, if any, inside the device, may be visualized through the dilator and/or sheath to confirm proper placement of the needle in a cavity containing the fluid; 
 the dilator is slideably displaceable relative to the sheath; and 
 the dilator includes a proximal portion and a distal portion, the distal portion having a larger cross-sectional area than the proximal portion. 
   
   
   
       2 . The device of  claim 1 , wherein the dilator further comprises a transition region between the proximal portion and the distal portion, and wherein the transition region defines a dilator side hole. 
   
   
       3 . The device of  claim 2 , wherein the transition region has a constant cross-section. 
   
   
       4 . The device of  claim 1 , wherein the dilator is formed as a single piece. 
   
   
       5 . The device of  claim 1 , wherein the distal portion of the dilator is solid, and the proximal portion defines a dilator side hole. 
   
   
       6 . The device of  claim 1 , wherein the proximal portion of the dilator comprises a shaft, the distal portion of the dilator is affixed to the shaft, and the distal portion of the dilator defines the first space. 
   
   
       7 . The device of  claim 6 , wherein the first space cross-sectional area is no smaller than about 25% of the needle bore cross-sectional area. 
   
   
       8 . (canceled) 
   
   
       9 . A device comprising:
 a hollow needle defining a side hole and having:
 a bore so sized as to receive a guidewire; and 
 a sharpened distal tip distal to the side hole; 
   a needle hub attached to a proximal end of the needle and defining a lumen sized and positioned to receive a guidewire;   a dilator coaxially mounted on the needle thereby defining a first space between the dilator and needle, the first space communicating with the hollow needle bore through the side hole so that a fluid, if any, exiting the side hole may flow to the first space; and   a sheath coaxially mounted on the dilator;   wherein:
 at least one of the dilator and sheath is clear, semi-opaque, or translucent, so that fluid, if any, inside the device, may be visualized through the dilator and/or sheath to confirm proper placement of the needle in a cavity containing the fluid; 
 the dilator is slideably displaceable relative to the sheath; and 
 wherein the needle hub is transitionable between a first state in which the lumen is so patent as to allow the guidewire to slide freely through the needle hub and a second state in which the lumen is so obstructed as to clamp the guidewire in the needle hub. 
   
   
   
       10 . The device of  claim 9 , wherein the needle hub further comprises a sealing member configured to seal on a guidewire, if any, positioned in the lumen. 
   
   
       11 . The device of  claim 9 , further comprising a dilator hub attached to a proximal end of the dilator, the dilator hub being slideably displaceable over the needle and releasably attachable to the needle hub by complementary mating elements of the dilator hub and the needle hub. 
   
   
       12 . The device of  claim 9 , wherein the needle hub comprises two finger grips separated from one another in a rest condition, wherein at least one finger grip is so coupled to the needle hub mating element as to cause the needle hub mating element to move when the at least one finger grip is moved in at least one direction. 
   
   
       13 . The device of  claim 9 , wherein the needle hub lumen tapers distally. 
   
   
       14 . A device comprising:
 a hollow needle defining a side hole and having:
 a bore so sized as to receive a guidewire; and 
 a sharpened distal tip distal to the side hole; 
   a guidewire having a distal end and being so preloaded that the guidewire distal end terminates proximal to the needle side hole and does not obstruct the needle side hole;   a dilator coaxially mounted on the needle thereby defining a first space between the dilator and needle, the first space communicating with the hollow needle bore through the side hole so that a fluid, if any, exiting the side hole may flow to the first space; and   a sheath coaxially mounted on the dilator;   wherein:
 at least one of the dilator and sheath is clear, semi-opaque, or translucent, so that fluid, if any, inside the device, may be visualized through the dilator and/or sheath to confirm proper placement of the needle in a cavity containing the fluid; and 
 the dilator is slideably displaceable relative to the sheath. 
   
   
   
       15 . The device of  claim 14 , further comprising:
 a wedging member removably so pressing against the guidewire as to immobilize the guidewire with respect to the needle.   
   
   
       16 . The device of  claim 14 , wherein
 the sheath has a distal tip with a parabolic curve.   
   
   
       17 . The device of  claim 14 , wherein:
 the dilator has a distal tip with a parabolic curve.   
   
   
       18 . A device comprising:
 a hollow needle defining a side hole and having:
 a bore so sized as to receive a guidewire; and 
 a sharpened distal tip distal to the side hole; 
   a pressure gauge in fluid communication with the needle side hole;   a dilator coaxially mounted on the needle thereby defining a first space between the dilator and needle, the first space communicating with the hollow needle bore through the side hole so that a fluid, if any, exiting the side hole may flow to the first space; and   a sheath coaxially mounted on the dilator;   wherein:
 at least one of the dilator and sheath is clear, semi-opaque, or translucent, so that fluid, if any, inside the device, may be visualized through the dilator and/or sheath to confirm proper placement of the needle in a cavity containing the fluid; and 
 the dilator is slideably displaceable relative to the sheath. 
   
   
   
       19 . The device of  claim 14 , wherein
 the guidewire includes a movement-impeding member.   
   
   
       20 . The device of  claim 19 , wherein the movement-impeding member comprises a handle or a stopper. 
   
   
       21 . The kit device of  claim 19 , wherein the movement-impeding member comprises a covering over at least a portion of the guidewire. 
   
   
       22 . A method comprising:
 providing a device comprising:
 a hollow needle defining a side hole and having:
 a bore so sized as to receive a guidewire; and 
 a sharpened distal tip distal to the side hole; 
 
 a guidewire having a distal end and being so preloaded that the guidewire distal end terminates proximal to the needle side hole and does not obstruct the needle side hole; 
 a dilator coaxially mounted on the needle thereby defining a first space between the dilator and needle, the first space communicating with the hollow needle bore through the side hole so that a fluid, if any, exiting the side hole may flow to the first space; and 
 a sheath coaxially mounted on the dilator; 
 wherein:
 at least one of the dilator and sheath is clear, semi-opaque, or translucent, so that fluid, if any, inside the device, may be visualized through the dilator and/or sheath to confirm proper placement of the needle in a cavity containing the fluid: and 
 the dilator is slideably displaceable relative to the sheath; 
 
   introducing the distal tip of the hollow needle into a cavity;   advancing the guidewire through the distal tip of the needle into the cavity;   advancing the dilator and sheath together over the needle into the cavity; and   removing the needle and the dilator, thereby leaving the sheath in place to provide access to the cavity.   
   
   
       23 . The method of  claim 22 , further comprising immobilizing the guidewire relative to the needle before advancing the dilator and sheath. 
   
   
       24 . The method of  claim 22 , wherein the cavity is a vein, and the method further comprises aspirating blood through the device to confirm that access has been obtained to the vein. 
   
   
       25 . The method of  claim 22 , wherein the cavity is an artery, and the method further comprises observing blood color or pulsatile flow of blood in the device to confirm that access has been obtained to the artery. 
   
   
       26 . The method of  claim 22 , further comprising removing the guidewire together with the needle and the dilator. 
   
   
       27 . (canceled)