阅读说明：本技术 带有可封闭的针的导管针组件 (Catheter needle assembly with closeable needle ) 是由 雅各布·亨策尔 詹姆斯·黑尔 于 2020-03-19 设计创作，主要内容包括：一种针导管插入装置,包括导管-扩张器组件,针穿过该导管-扩张器组件,其中扩张器和针可相对于彼此移动,使得针导管插入装置可以从针的尖端被暴露的就绪位置移动到扩张器围包住针的屏护位置。针导管插入装置被定位到屏护位置可以通过将扩张器手动致动到针的毂内的锁定构型来实现。(A needle catheterization device includes a catheter-dilator assembly through which a needle passes, wherein a dilator and the needle are movable relative to each other such that the needle catheterization device may be moved from a ready position in which a tip of the needle is exposed to a shielded position in which the dilator surrounds the needle. Positioning of the needle catheter insertion device to the shielding position can be achieved by manually actuating the dilator to a locked configuration within the hub of the needle.)

1. A catheter assembly, comprising:

a dilator comprising a dilator tube extending from a dilator hub, the dilator hub comprising a locking feature and an actuator tab;

a needle comprising a needle cannula having a sharp tip and a needle hub positioned at a proximal end of the needle cannula, the needle cannula having a needle lumen extending therethrough and in fluid communication with a flash chamber in the needle hub, wherein in a ready position, the needle is positioned within the dilator and the sharp tip extends distally of the dilator tube; and

a catheter including a catheter tube extending from a catheter hub, the catheter positioned over the dilator; and is

Wherein displacement of the dilator hub relative to the needle hub until the locking feature engages a portion of the needle hub positions the dilator in a locked configuration in which the distal end of the dilator tube extends beyond the sharp end.

2. The catheter assembly of claim 1, wherein the needle hub further comprises a body member coupled to the needle hub, wherein the body member is positioned adjacent the dilator hub such that distal movement of the body member distally moves the dilator hub, wherein relative movement of the dilator hub with respect to the body member positions the locking feature within a recess in the body member resulting in locking of the body member with the dilator hub.

3. The catheter assembly as defined in claim 2, wherein the dilator hub is positioned outside of the needle hub and within a channel of the body member such that, prior to locking, the dilator hub is slidable within the channel of the body member.

4. The catheter assembly as defined in claim 3, wherein the channel of the body member includes at least one rail member, and wherein the dilator hub includes at least one slot, wherein the at least one slot receives the at least one rail member, thereby preventing rotation of the dilator hub relative to the body member.

5. The catheter assembly as defined in claim 4, wherein a portion of the at least one rail member is coupled to the needle hub through the at least one slot.

6. The catheter assembly as defined in claim 2, wherein the actuator tab extends radially beyond the body member, wherein the actuator tab allows the dilator hub to move distally relative to the body member until the body member locks with the dilator hub.

7. The catheter assembly of claim 1, wherein the locking feature engages a portion of the flash chamber to assume a locked configuration.

8. The catheter assembly of claim 1, wherein the needle hub is configured to slide around the flash chamber.

9. The catheter assembly of claim 1, further comprising a plug positioned in the flash chamber, wherein the plug allows gas to pass therethrough while preventing liquid from passing therethrough.

10. A method of accessing a blood vessel, the method comprising:

providing a catheter assembly comprising a needle having a needle cannula with a sharp tip and a needle hub positioned at a proximal end of the needle cannula, the needle cannula having a needle lumen extending therethrough and in fluid communication with a flash chamber in the needle hub, a dilator comprising the catheter assembly further comprising a dilator tube extending from a dilator hub, the dilator hub comprising a locking feature and an actuator tab, wherein the dilator tube is positioned proximal to the sharp tip of the needle cannula, the catheter assembly further comprising a catheter having a catheter tube extending from a catheter hub, the catheter being positioned external to the dilator, wherein in a ready position the sharp tip extends distal to the dilator tube, the catheter assembly further comprising a catheter having a catheter tube extending from a catheter hub, the catheter is positioned over the dilator;

advancing a catheter assembly into tissue such that the sharp tip of the cannula enters a blood vessel;

observing blood from a blood vessel in the flash chamber;

advancing the dilator distally toward the needle such that the dilator tube extends distally beyond the sharp tip to a locked position upon observing the presence of blood in the flash chamber and without moving the sharp tip of the cannula from the blood vessel; and

advancing the locked dilator and needle as needed to allow the distal tip of the catheter to enter a vein,

stabilizing the locked needle and dilator assembly and then advancing the catheter distally into the vein or artery to a desired length; and is

Withdrawing the needle and the dilator from the blood vessel and tissue such that the catheter provides an access path into the blood vessel.

11. The method of claim 10, wherein the needle hub further comprises a body member coupled to the needle hub, wherein advancing the dilator distally to the locked position comprises advancing the actuator tab relative to the body member such that the locking feature of the dilator hub engages a recess in the body member to result in the locked position.

12. The catheter assembly as defined in claim 10, wherein the dilator hub is positioned outside of the needle hub and within a channel of the body member such that the dilator hub is slidable within the channel of the body member prior to the locked position.

Background

Over-the-needle catheters typically include a cannula having a sharp tip that extends through the lumen of a catheter tube, with the sharp tip protruding from the distal end of the tube. The medical provider advances the sharp tip of the cannula through the skin and into the blood vessel. As the cannula (also referred to as a needle) is advanced further, the distal end of the catheter is advanced into the blood vessel. Once the catheter tube is in the blood vessel, the caregiver withdraws the needle while leaving the catheter tube in the blood vessel, and the hub of the catheter is exposed for access to the blood vessel and as a connection for delivering or withdrawing medical fluid from the blood vessel.

After removing the needle cannula from the catheter, the caregiver is at significant risk of accidental needle sticks. Clearly, this risk involves exposure to any number of blood borne diseases that may be transmitted by exposure to the patient's blood and other fluids. Such blood-borne diseases include, but are not limited to, Human Immunodeficiency Virus (HIV), Hepatitis B (HBV), and Hepatitis C (HCV).

There have been many prior attempts to shield the needle tip after catheter placement. Such devices may be found in US7658725 and US7736342 assigned to Smiths Medical ASD, inc. u.s, US9095683, US9861792 assigned to c.r.bard, and US 20180126125.

Needle closure devices that use an elongated needle shield to shield the tip of the needle by closing the needle cannula with a manually movable needle support have become widely accepted and widely used, requiring further improvements to make the mechanism simple and easy to manufacture. Accordingly, there remains a need for improved devices that allow for insertion of a needle catheter assembly that places the needle in a protective configuration while remaining simple and easy to use.

Brief description of several views of the drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

Fig. 1A-1B illustrate an exemplary catheter and needle, respectively, as essential components of a safety catheter-needle assembly.

Fig. 2A-2C illustrate a body member coupled to a needle hub.

Fig. 3A-3C illustrate protective sheaths for use with variations of the catheter needle assemblies disclosed herein.

Fig. 4A-4D illustrate the catheter needle assembly transitioning from an unprotected/ready state to a protected or shielded state.

Fig. 5A and 5B illustrate an example of operation of a variation of the security assembly of the present disclosure in use.

Fig. 6A-6C illustrate an improved valve for use with a catheter.

Fig. 7A-7C illustrate exemplary basic components of a safety catheter-needle assembly as discussed herein.

Fig. 8A and 8B illustrate the safety catheter-needle assembly after assembly, with the catheter positioned over the dilator and the dilator positioned over the needle.

Fig. 8C shows an enlarged view of the distal end of fig. 8B.

Fig. 9A and 9B illustrate an example of actuating the assembly to shield the sharp tip of the needle.

Fig. 10A and 10B are drawings illustrating the locking feature of the dilator relative to the needle.

Detailed description of the invention

Fig. 1A-5B (which are not necessarily drawn to scale for ease of illustration of the various components) illustrate various variations of a needle assembly that allow a needle to be secured in a protective configuration. The devices described herein provide an improved catheter-needle-dilator assembly (or just a dilator-needle assembly) that allows the needle to be inserted into a vein, access to the vein is determined by flashback (flashback), and then allows the needle to be in a protected configuration without the need for the needle to be removed from the vein. These devices should be simple and easy to use. The locking dilator safety devices described herein also allow for deep access and ultrasound guidance. The locked dilator is shielded on the needle bevel to reduce venous trauma, which provides a safety shield for safe needle sticks. The dilator described herein dilates the vein wall to "seal" the insertion site from infiltration.

Fig. 1A-1B illustrate exemplary basic components of a safety catheter-needle assembly as discussed herein. Fig. 1A illustrates a catheter 102, the catheter 102 having a catheter tube 104 or extrusion (extrusion) coupled to a catheter hub 106. The catheter hub 106 may include a commonly known internal luer fitting (male luer) with the valve 170 located within the lumen of the catheter hub 106. The catheter hub 106 may optionally include a threaded portion 108 located on the exterior of the hub or extending from the hub (not shown).

Fig. 1B illustrates a needle 120, the needle 120 having a cannula 122 or needle shaft (needle draft) terminating in a sharp tip 126. The needle 120 includes a needle hub 124. In the illustrated variation, the needle hub 124 includes a flash chamber 128 with a porous plug (not shown in fig. 1B). The plug may be positioned at the proximal end of the flash chamber 128, the flash chamber 128 facing the proximal end of the needle hub 124. The plug 130 is similar to those known in the art and described in US7736342, which is incorporated herein by reference. In one variation, the plug 130 includes a venting material that can allow gas (e.g., air) to pass through, but retain blood or other fluids within the flash chamber 128. Typically, the plug 130 remains in place and prevents fluid from passing through the flash chamber 128, but alternative variations include configurations in which the plug 130 may be removed so that medical care givers may enter and pass through the flash chamber 128 and the needle cannula 24 as needed. In some variations, the flash chamber and/or the needle hub may be completely or partially opaque to allow visualization of blood or fluid flow within the chamber and needle.

Alternatively, not shown, a guidewire may be positioned through the plug 130. In this variation, the guidewire slidably passes through the plug 130 while allowing the plug to prevent liquid from flowing out of the flash chamber 128 in the proximal direction. As discussed below, flash chamber 128 allows the medical caregiver to flash the chamber to observe the flow of blood into chamber 128 after the sharp tip 126 of needle 120 has penetrated the blood vessel. In alternative variations, the flash chamber 128 may be detachable from the needle hub 124 or may be separate from the needle hub 124. Alternatively, the flash chamber and/or the needle hub may include one or more windows to allow visual confirmation of any substance within the needle/flash chamber.

Fig. 1B also illustrates a needle having one or more rails/keyways 134 and a pocket 136. As described below, the track/keyway 134 allows the body unit to be coupled to the needle hub 1124.

Fig. 2A-2C illustrate the body member 140 coupled to the needle hub 120. Fig. 2A illustrates an exploded assembly view of the body member 140 separated from the needle hub 124 of the needle 120. The body member 140 may include a gripping surface 146, as described below, that allows for manipulation of the needle-catheter assembly and movement of a protective dilator or sheath (not shown) over the distal end of the needle 120. The body member 140 includes a channel 148, the channel 148 including one or more rail structures 142. As described below, the rail structure slidably receives the dilator hub or the sheath hub. As shown, the attachment feature or clip 144 is advanced over the track 134 of the needle hub 124.

Fig. 2B illustrates the body member 140 positioned on the needle hub 124 such that the locking feature 144 is secured into the pocket to prevent relative movement between the body member 140 and the needle 120.

Fig. 2C illustrates a bottom view of the body member 140. In some variations, the locking feature 144 extends from the rail 142. Alternatively, the locking feature 144 and the rail 142 may be separate structures. Fig. 2C also illustrates that the body member has a pocket 149. The pocket can receive a tab or other protrusion that is part of the dilator hub/sheath hub to lock the protective sheath/dilator in place relative to the needle 120.

Fig. 3A-3C illustrate protective sheaths for use with variations of the catheter needle assemblies disclosed herein. In this variation, the protective sheath 150 also functions as a dilator, as the tip of the dilator tube 160 expands the tissue after needle entry, as disclosed below. Fig. 3A illustrates an isometric view of a variation of the dilator 150, the dilator 150 having a hub 152 with protrusions 158, the protrusions 158 may be used to move the dilator 150 relative to the catheter needle assembly. Hub 152 includes a plurality of grooves or slots 162. In the illustrated variation, there are two slots 162 that extend through the wall of the hub 152. However, alternative variations include recesses that do not extend through the hub 152. Alternatively, the grooves 162 may be replaced with protrusions that define grooves or channels along the dilator hub 152.

Fig. 3B illustrates a side view of the dilator of fig. 3B. As shown, the dilator body 152 may optionally include one or more locking tabs 154. As discussed below, the locking tabs 154 are designed to prevent the dilator/sheath from moving relative to the needle once the dilator/sheath shields the sharp tip of the needle.

Fig. 3C illustrates dilator 150 positioned within channel 148 of body member 140. As shown, the slot 162 is aligned with the rail 142 in the body member 140. As shown in fig. 2B, the body member 140 is coupled to the needle 120.

Fig. 4A-4D illustrate the catheter needle assembly 100 transitioning from the unprotected/ready state to the protected or shielded state. Fig. 4A shows a variation of the needle catheter assembly 100 as discussed herein, wherein the catheter 102 is positioned over a dilator or sheath 160. (As noted above, the term sheath is intended to include a dilator for purposes of the variations discussed herein.) the catheter 102 and sheath 160 are positioned over the needle 120, the needle 120 terminating in the distal sharp tip 126. In this variation, the catheter tube 104 extends to the proximal side of the dilator or sheath tube 160. The protrusion 158 of the dilator hub 152 is positioned between the catheter 102 (or valve) and the body member 140. As discussed herein, the body member 140 is coupled to the needle 120 such that moving or manipulating the body member 140 allows the catheter assembly 100 to be inserted to penetrate a blood vessel (as discussed below). The configuration shown in fig. 4A is considered to be an unprotected/ready state because the tip 126 of the needle protrudes from the dilator 160 and the catheter tube 104, so that the assembly 100 is ready to penetrate tissue.

Fig. 4B illustrates a cross-sectional view of the body member 140 and the dilator hub 152 positioned therein. As shown, dilator hub 154 includes tabs 154. In this variation, the tabs 154 are positioned on the exterior of the body member 140. However, alternative variations are also within the scope of the present disclosure. The configuration of catheter assembly 100 allows tab 154 to align with pocket 149 of body member 140.

Fig. 4C illustrates the catheter assembly 100 of fig. 4A, with the protrusion 158 of the dilator hub 152 moved relative to the body member 140. Protrusion 158 may be advanced distally of body member 140 or body member 410 may be moved proximally. In any event, because the needle 120 is coupled to the body member 140, relative movement between the protrusion 158/dilator hub 152 and the body member 140 results in the tip of the needle (not shown) being positioned within the dilator tube 160. This action places the assembly 100 in a protective or shielded state. Variations of the assembly 100 allow the catheter 102 to be positioned on the assembly 100 during shielding. Alternatively, the catheter may be removed from the assembly 100 during shielding.

Fig. 4D illustrates the cross-sectional view of fig. 4B with the dilator hub 152 moved relative to the body member 140. As shown, the tabs 154 of the dilator hub 154 are moved into the pockets 149 of the body member 140 to effectively lock the dilator 150 relative to the body member 140. Because the body member 140 is coupled to the needle (not shown), the dilator 150 is also locked relative to the needle.

Fig. 5A and 5B illustrate an example of operation of a variation of the security assembly 100 of the present disclosure in use. Fig. 5A illustrates a medical caregiver applying the assembly 100 directly into a blood vessel 22 through a patient's tissue 20. The component 100 is in a ready or unprotected state. The caregiver will confirm placement of the sharp tip 126 of the needle cannula within the blood vessel 22 by observing blood flashback within the needle hub. Flashback occurs when blood within the blood vessel 22 enters the lumen of the needle and flows into the flashback chamber. Alternatively, the needle cannula may have one or more spaced apart holes in the wall of the cannula to provide blood into the needle lumen and into the flash chamber. Once the caregiver observes flashback (or other liquid flowing into the chamber), the caregiver can hold the needle assembly 100 in place and advance the actuation tab of the dilator, as discussed above. FIG. 5b illustrates the device assembly 100 when flashback is observed and the actuation tab (not shown, 158 in FIG. 4A) causes relative movement between the dilator assembly including dilator tube 160 and the sharp tip 126 of the needle cannula. In one variation, the drive tab is driven forward to shield the needle. Pusher dilator tube 160 ensures that the distal end of device assembly 100 remains within blood vessel 22. In an alternative variation, the advancement tab may remain stationary while the needle hub may be moved to move the sharp distal tip 126 proximal to the opening of the dilator tube 160.

Fig. 6A-6C illustrate an improved valve for any of the conduits described herein. Typically, such a catheter 102 is used with a male luer. The catheter 102 includes a catheter hub 106, the catheter hub 106 having a lumen 112, the lumen 112 having a proximal surface 110 defining an open proximal end. The chamber 112 is in fluid communication with the conduit tube 104 to which the conduit is coupled. The tube includes one or more lumens in fluid communication with the chamber 112. The valve or diaphragm valve 170 includes a barrier layer (or diaphragm) 172 at the distal end. The barrier layer 172 may have one or more slits 174. The illustrated variation shows a barrier layer 174 having 3 slits that form three leaflet structures or flaps. However, variations of the valve 170 include any number of slits forming any number of leaflets. Barrier layer 172 typically comprises a flexible or semi-flexible material that is compatible with the blood, drugs, and other fluids typically encountered during catheterization/infusion procedures to which it is exposed.

As shown in fig. 6B, the valve includes a wall portion 176 extending proximally from the barrier layer 172 and defining a valve cavity 182. A flange portion 180 is formed around the wall 176 at the proximal end of the valve 170. The flange portion includes a diameter greater than a diameter of the wall portion. The variation of the valve 170 includes a flange portion 180 surrounding the valve 170. Alternatively, the flange portion 180 may include an opening or a break such that the flange portion 18 is not circumferentially continuous around the wall.

Fig. 6C shows the valve 170 coupled to the catheter hub 106 such that the flange portion 180 engages the proximal surface 110 of the catheter hub 106 and is located outside of the chamber 112 of the hub 106. The wall portion 176 of the valve 170 engages a surface of the chamber. The valve 170 may be attached to the conduit at different points. For example, variations of the assembly include a valve 170 that is attached to the catheter hub 106 using adhesive or bonding material only at the flange portion 180, with the wall portion 196 simply positioned against the wall of the chamber 140. Alternatively, or in combination, the valve 190 may be attached to the catheter hub 106 at the outer wall portion 176. In an alternative variation, the valve 170 may simply be press-fit into the catheter hub 106. Any number of features known to those skilled in the art may be used to facilitate placement of the valve 170 within the catheter hub 106 (e.g., pockets, ribs, increasing frictional resistance of the valve or chamber surfaces, etc.).

Fig. 7A-7C illustrate another example of a safety catheter-needle assembly as discussed herein. Fig. 7A illustrates a catheter 102 having a catheter tube 104 or extrusion coupled to a catheter hub 106.

Fig. 7B illustrates a needle 120 having a cannula 122 or body terminating in a sharp tip 126. The needle 120 includes a needle hub 124. In the illustrated variation, the needle hub 124 includes a flash chamber 128 with a porous plug 130. A plug 130 is positioned at the proximal end of the flash chamber 128, the proximal end of the flash chamber 128 facing the proximal end of the needle hub 124. The plug 130 is similar to those known in the art and described in US7736342(US7736342 is incorporated herein by reference). The plug 130 includes a venting material that is capable of passing a gas (e.g., air) therethrough, but retains blood or other fluid within the flash chamber 128. Typically, plug 130 remains in place against passage of fluid through flash chamber 128, but alternative variations include configurations in which plug 130 may be removed so that medical care givers may access and pass through flash chamber 128 and needle cannula 24 as desired. Alternatively, not shown, a guidewire may be positioned through the plug 130. In this variation, the guidewire slidably passes through the plug 130 while allowing the plug to prevent liquid from flowing out of the flash chamber 128 in the proximal direction. As discussed below, flash chamber 128 allows the medical caregiver to observe blood flow into chamber 128 after the sharp tip 126 of needle 120 has penetrated the blood vessel. In alternative variations, the flash chamber 128 may be detachable from the needle hub 124 or may be separate from the needle hub 124.

Fig. 7C shows dilator 150 with dilator hub 152 at the end of dilator tube 160. In the illustrated figures, the dilator hub 152 is shown as two pieces for illustrative purposes only. The dilator hub 152 also includes a locking feature, which in the illustrated variation includes a set of locking tabs 154, 156. However, the locking feature may comprise a single locking structure or tab or any similar structure that allows the dilator 150 to be locked relative to the needle 120, as described herein. The dilator hub 152 also includes a tab or protrusion 152 that allows the medical caregiver to move the dilator 150 relative to the needle 120.

Fig. 8A and 8B illustrate the safety catheter-needle assembly 100 assembled with the catheter positioned over the dilator and the dilator positioned over the needle. Fig. 8A illustrates a top view of the assembly 100, while fig. 8B provides an illustration of an isometric view of the assembly 100. In this arrangement, the dilator hub 152 is positioned over the flash chamber 128 in a sliding arrangement, as discussed below. Thus, the medical care provider can grasp the needle hub 124 and advance the actuation tab 158 with one hand to produce relative movement between the needle and the dilator to position the needle in the protected state, as discussed below. For purposes of illustration, the locking feature 154 shown in FIG. 8B is shown rotated over. As discussed below, the locking feature 154 engages a portion of the needle hub 124, which allows the medical caregiver to lock the dilator in a safe position such that the sharp tip is covered.

In the variation shown in fig. 8A and 8B, the catheter hub 106 is positioned over the dilator hub such that the device is in a "ready state" in which the sharp tip is exposed at the distal end of the dilator tube 160 adjacent the catheter tube 104. Fig. 8C shows an enlarged view of the distal end of fig. 8B to further illustrate the sharp tip 126 of the needle cannula extending beyond dilator tube 122, with catheter tube 104 adjacent the end of dilator tube 122.

Although not shown, the assembly 100 may include any number of protective guards on the sharp tip 126. For example, the assembly 100 may be provided with a disposable guard positioned over the sharp tip 126, and optionally over the dilator 160 and catheter tube 104, in the ready configuration. Thus, when the medical caregiver is ready to insert the assembly 100, the caregiver can remove and discard the disposable guard and insert the device.

Fig. 9A and 9B illustrate an example of actuating the assembly to shield the sharp tip of the needle. Fig. 9A illustrates the needle and dilator (catheter omitted for illustration purposes). As shown, movement 12 of actuator tab 158 relative to needle hub 124 causes movement of dilator hub 152 and dilator tube 160 relative to the needle such that the needle is shielded by dilator tube 160. Fig. 9B illustrates the device in a protective configuration with the sharp tip 126 within the catheter tube 104 and dilator tube 160.

Fig. 10A and 10B are drawings illustrating the locking feature of the dilator 150 relative to the needle 120. For clarity, the catheter is not shown, but typically is positioned over the dilator 150 as described above. In addition, the dilator 150 is shown outside of the needle hub 124 and rotated relative to the needle hub 124 to better illustrate the locking action. As described below, during assembly, dilator 150 is rotated 90 degrees about the axis of dilator tube 160 such that the alignment slot 162 of the dilator slides around flash chamber support member 132. In the ready or initial configuration, the locking features 154 and 156 of the dilator hub 152 are positioned proximal to the flash chamber 128 and the support 132. Once the sharp tip is placed in the blood vessel, blood will enter the chamber 128, which confirms proper placement of the needle cannula within the blood vessel. At this point, the caregiver holds the needle assembly in place and secures the sharp tip 126 of the needle cannula 122 within the dilator tube 160 using the actuator tab (not shown) (see fig. 4B).

This action causes the dilator hub 152 to move distally 14 (or relative movement between the dilator hub 152 and the needle hub 124) as shown in fig. 10B. This movement also causes the locking tabs 154 and 156 to deflect away from each other when urged against the rearmost flash chamber support 132. Continued advancement 14 of the dilator hub 152 (or actuation tab) moves the locking features (tabs 154, 156) distal to the rearmost flash chamber support 132 such that the support 132 is now positioned within the clearance opening 164 adjacent the locking features (154, 156) and the locking features are no longer deflected by the support such that the locking features return to their original positions and provide a "lock" on the dilator since the features are now on opposite sides of the support. As discussed above, this effectively locks the dilator hub 152 and dilator tube 160 distal to the sharp tip of the needle while the needle remains within the blood vessel 22. Once locked, the needle is shielded within the dilator and the two components are removed and disposed of with the catheter remaining in the vessel.

In a further variation, the catheter hub can engage the dilator such that advancement of the catheter hub from the assembly will pull the dilator relative to the needle assembly, causing the dilator to enter the locked configuration and shield the distal tip of the needle. The catheter will then be separated or detached from the locked dilator and moved into the vein or artery to the desired length. The locked dilator/needle assembly will then be withdrawn from the catheter. Alternatively, such a configuration may also allow for the act of withdrawing the needle and dilator to move the dilator relative to the needle such that the needle and dilator are positioned in a protective state shielding the tip of the needle.