Catheter with stiff distal tip

Abstract

The catheter assembly may include an over-the-needle catheter and an introducer needle. The catheter may include a distal tip and an elongated tubular portion proximate the distal tip of the catheter. The distal tip may be constructed of a first material and may include at least a portion of a stepped surface. The tubular portion may be constructed of a second material having a harder durometer than the first material. The introducer needle may include a needle feature having another stepped surface configured to abut the stepped surface of the catheter when the introducer needle is in the insertion position such that proximal movement of the distal tip of the catheter relative to the introducer needle is inhibited.

Description

Technical Field

[0001] The present disclosure generally relates to catheter assemblies for insertion into a patient's vasculature, as well as related devices and methods.

Background Art

[0002] Intravenous (IV) catheters are commonly used in various infusion therapies. For example, an IV catheter can be used to inject saline, various drugs, or total parenteral nutrition into a patient. An IV catheter can also be used to draw blood from a patient.

[0003] A common type of IV catheter is an over-the-needle peripheral IV catheter. As its name indicates, an over-the-needle peripheral IV catheter can be attached over an introducer needle having a sharp distal tip. The introducer needle and the IV catheter are generally inserted through the patient's skin at a shallow angle into the vasculature such that the bevel of the introducer needle faces away from the patient's skin. During insertion, the sharp distal tip of the introducer needle may be distal to the distal end of the IV catheter. Thus, insertion of the IV catheter into the vasculature may follow puncture of the vasculature by the introducer needle.

[0004] Generally, the introducer needle is made of metal, while the IV catheter may be made of a soft material such as, for example, plastic. In contrast to a hard one, a soft catheter material can be more comfortable for the patient, less irritating, and can improve retention. However, if the IV catheter is too soft, its column strength may not be great enough to resist the force required to penetrate the patient's skin and tissue.

[0005] In some cases, as the introduction needle and IV catheter are inserted into the patient, the IV catheter may tend to buckle, detach, or move proximal to the distal tip of the introduction needle. This can occur because the patient's skin or tissue pushes against the distal tip of the IV catheter during the insertion process. If the IV catheter detaches or moves proximal to the distal tip of the introduction needle, the catheter may have an enlarged cross-section, requiring greater insertion force, increasing dilation at the insertion site, and / or increasing pain for the patient.

[0006] The general description and the following detailed description are illustrative and explanatory, and should be understood not to limit the invention, just as the claims do not limit it. [Overview of the Initiative] [Means for solving the problem]

[0007] As used in this disclosure, the term “distal” may refer to a part or component of the catheter assembly that is further away from the user. As used in this disclosure, the term “proximal” may refer to a part or component of the catheter assembly that is closer to the user. As used in this disclosure, the term “user” may refer to a clinician, physician, nurse, or any other caregiver, and may also include support personnel.

[0008] In some embodiments, the catheter assembly may include an over-the-needle catheter. In some embodiments, the catheter may include a distal tip made of a first material having a first durometer. In some embodiments, the catheter may be annular and may include a first stepped surface. In some embodiments, the first stepped surface may include a rigid or semi-rigid first distal surface having a first uniform inner diameter, a first proximal surface having a second uniform inner diameter greater than the first uniform inner diameter, and a rigid or semi-rigid first transition surface positioned between the first distal surface and the first proximal surface. In some embodiments, at least the first distal surface and the first transition surface of the first stepped surface may be part of the distal tip of the catheter and therefore may be made of the first material.

[0009] In some embodiments, the catheter may include an elongated tubular portion coupled close to the distal end of the catheter. In some embodiments, the tubular portion may be made of a second material. In some embodiments, the durometer of the first material may be harder than the durometer of the second material. In some embodiments, the distal end and tubular portion of the catheter may include a catheter lumen extending through them. In some embodiments, the first stepped surface may be located within the catheter lumen. In some embodiments, at least a portion of the outer surface of the distal end may be tapered.

[0010] In some embodiments, the catheter assembly may include an introduction needle, which may include a needle feature having a second stepped surface, which may be annular. In some embodiments, the second stepped surface may include a second distal surface, a second proximal surface, and a second transition surface positioned between the second distal surface and the second proximal surface. In some embodiments, when the introduction needle is in the insertion position, the second distal surface may be adjacent to the first distal surface, the second proximal surface may be adjacent to the first proximal surface, and the second transition surface may be in contact with the first transition surface so as to suppress proximal movement of the distal tip relative to the introduction needle.

[0011] In some embodiments, the second proximal surface may be generally cylindrical. In some embodiments, the second proximal surface may include a notch that can provide access to the lumen of the needle. In some embodiments, the second proximal surface may include at least a portion of a groove or flat section. In some embodiments, the catheter assembly may include a flashback path located within the catheter lumen. In some embodiments, the flashback path may include a groove or flat section.

[0012] In some embodiments, the groove may extend through a second transition surface, and the second distal surface may extend through the distal tip of the introduction needle. In some embodiments, the groove or flat portion may include a notch. In some embodiments, the notch may be located proximal to the second proximal surface. In some embodiments, the second proximal surface may extend through the proximal end of the catheter when the introduction needle is in the insertion position.

[0013] In some embodiments, the introduction needle may include a wall defining the lumen of the needle. In some embodiments, the second distal surface, the second transition surface, the second proximal surface, and the wall of the introduction needle may be formed monolithically as a single component. In some embodiments, the feature portion of the needle may be coupled to the wall of the introduction needle to form the second transition surface and the second proximal surface.

[0014] The general description and the following detailed description are illustrative and descriptive, and should be understood not to limit the invention, as are the claims. It should be understood that various embodiments are not limited to the arrangements and means shown in the drawings. Furthermore, it should be understood that embodiments can be combined or other embodiments can be utilized, and that the structure can be modified without departing from the scope of the various embodiments of the invention, unless otherwise claimed. Therefore, the following detailed description should not be interpreted as restrictive.

[0015] Exemplary embodiments are described and explained in more specific and detail with reference to the accompanying drawings: [Brief explanation of the drawing]

[0016] [Figure 1A] Figure 1A is a top view of an exemplary catheter assembly according to several embodiments; [Figure 1B] Figure 1B is a cross-sectional view of the distal end of an exemplary catheter of the catheter assembly shown in Figure 1A, according to several embodiments; [Figure 1C] Figure 1C is a top perspective view of the distal end of the catheter in Figure 1B, according to several embodiments; [Figure 2A] Figure 2A is a top perspective view of the distal end of an exemplary introduction needle of the catheter system of Figure 1A, according to several embodiments; [Figure 2B] Figure 2B is a cross-sectional view of the distal end of the introduction needle in Figure 2A, positioned at the insertion site within the catheter in Figure 1B, according to several embodiments; [Figure 2C] Figure 2C is a cross-sectional view of the distal end of the introduction needle in Figure 2A, partially withdrawn from the catheter in Figure 1B, according to several embodiments; [Figure 2D] Figure 2D is a top view of the introduction needle of Figure 2A, positioned within an exemplary needle hub of the catheter system of Figure 1A, according to several embodiments; [Figure 3A] Figure 3A is a top perspective view of the distal end of another exemplary introduction needle of the catheter system of Figure 1A, according to several embodiments; [Figure 3B] Figure 3B is a cross-sectional view of the distal end of the introduction needle in Figure 3A, positioned at the insertion site within the catheter in Figure 1B, according to several embodiments; [Figure 3C] FIG. 3C is a top view of the introducer needle of FIG. 3A disposed within an exemplary needle hub of the catheter system of FIG. 1A, according to some embodiments; [Figure 3D] FIG. 3D is a top perspective view of the distal end of another exemplary introducer needle of the catheter system of FIG. 1A, according to some embodiments; [Figure 4A] FIG. 4A is a top perspective view of the distal end of another exemplary introducer needle of the catheter system of FIG. 1A, according to some embodiments; [Figure 4B] FIG. 4B is a cross-sectional view of the distal end of the introducer needle of FIG. 4A disposed at the insertion position within the catheter of FIG. 1B, according to some embodiments; [Figure 5A] FIG. 5A is a top perspective view of the distal end of another exemplary introducer needle of the catheter system of FIG. 1A, according to some embodiments; [Figure 5B] FIG. 5B is a cross-sectional view of the distal end of the introducer needle of FIG. 5A disposed at the insertion position within the catheter of FIG. 1B, according to some embodiments; [Figure 5C] FIG. 5C is a top view of the introducer needle of FIG. 3A disposed within an exemplary needle hub of the catheter system of FIG. 5A, according to some embodiments; and [Figure 6] FIG. 6 is another cross-sectional view of the distal end of the catheter of FIG. 1B, according to some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

[0017] This disclosure relates in general to catheter assemblies for insertion into a patient's vascular system, as well as related devices and methods. Referring now to Figure 1A, in some embodiments the catheter assembly 10 may include an over-the-needle catheter 12 and an introduction needle 14. Figure 1A shows the introduction needle 14 in the insertion position for insertion into a patient. In some embodiments, when the introduction needle 14 is in the insertion position, the sharp distal tip 16 of the introduction needle 14 may be positioned beyond the distal tip 18 of the catheter 12.

[0018] In some embodiments, the catheter assembly 10 may include a catheter adapter 20. In some embodiments, the proximal end of the catheter 12 may be fixed within the catheter adapter 20, and the catheter 12 may extend distally from the catheter adapter 20. In some embodiments, the proximal end of the introduction needle 14 may be fixed within a needle hub 22 of the catheter assembly 10.

[0019] The catheter assembly 10 may include any type of catheter assembly having a catheter and an introduction needle. The catheter assembly 10 shown in Figure 1A is integrated to have an integrated extension tube, but it is understood that the catheter assembly 10 may be straight or not integrated. Non-limiting examples of integrated IV catheter systems may include, for example, the BD NEXIVA® Closed IV Catheter System, the BD NEXIVA® DIFFUSICS® Closed IV Catheter System, or the Bcton Dickinson PEGASUSTM Safety Closed IV Catheter System. Non-limiting examples of straight or non-integrated catheter assemblies include the BDINSYTE® AUTOGUARD® Shielded IV Catheter. In some embodiments, the catheter assembly 10 may include any variety of needle safety mechanisms that can shield the distal tip 16 of the introduction needle 14.

[0020] In some embodiments, the catheter assembly 10 may include any suitable type of blood control septum that can be placed within the lumen of the catheter adapter 20. Figure 1A shows an exemplary blood control septum 24 according to some embodiments. In some embodiments, after the catheter 12 is properly positioned within the vascular system, the introduction needle 14 may be withdrawn proximal through the septum 24. In some embodiments, the septum 24 may be made of elastomer. In some embodiments, the septum 24 may divide the lumen of the catheter adapter 20 into a proximal chamber and a distal chamber.

[0021] Referring here to Figure 1B, in some embodiments, the catheter 12 may include a distal tip 18 which may be made of a first material having a first durometer. In some embodiments, the first material may be rigid or semi-rigid. In some embodiments, the catheter 12 may be annular and may include a first stepped surface 26. In some embodiments, the first stepped surface 26 may include a rigid or semi-rigid first distal surface 28 having a first uniform inner diameter 30, a first proximal surface 32 having a second uniform inner diameter 34 which is larger than the first uniform inner diameter 30, and a rigid or semi-rigid first transition surface 36 positioned between the first distal surface 28 and the first proximal surface 32.

[0022] In some embodiments, the entire distal tip may be made of the first material. In some embodiments, at least the first distal surface 28 and the first transition surface 36 of the first stepped surface 26 may be part of the distal tip 18 of the catheter and therefore may be made of the first material. In some embodiments, the first distal surface 28, the first transition surface 36, and the first proximal surface 32 of the first stepped surface 26 may be part of the distal tip 18 and therefore may be made of the first material.

[0023] In some embodiments, the catheter 12 may include an elongated tubular portion 38 coupled to the distal tip 18 of the catheter. In some embodiments, the tubular portion 38 may be made of a second material. In some embodiments, the durometer of the first material may be harder than the durometer of the second material. In some embodiments, the distal tip 18 and the tubular portion 38 may include a catheter lumen 40 extending through them. In some embodiments, the first stepped surface 26 may be located within the catheter lumen 40.

[0024] In some embodiments, the first material and / or the second material may include a composite material. In some embodiments, the first material may include one or more of silicon, polyurethane, metal, plastic, and other suitable materials. In some embodiments, the second material may include one or more of silicon, polyurethane, metal, plastic, and other suitable materials. In some embodiments, the first material may include a first polyurethane, and the second material may include a second polyurethane. In some embodiments, the first material may include a first silicon, and the second material may include a second silicon. In some embodiments, the first material may include a metal, and / or the second material may include a plastic. In some embodiments, the second material may include a flexible material.

[0025] In some embodiments, the second material may include a material that is softer than the first material, which may be more comfortable for the patient and result in fewer placement problems. In some embodiments, the softer second material may allow the catheter 12 to be inserted into the vascular system for a longer period before complications occur. In some embodiments, the second stepped surface 44 may contact and support the first stepped surface 26 and the distal tip 16 when the introduction needle 14 is in the insertion position, thereby suppressing the proximal movement of the distal tip 16 relative to the introduction needle 14, and the compressive force required for the distal tip 16 to penetrate the skin is transmitted to the introduction needle 14, which may be made of metal. In some embodiments, the contact between the first stepped surface 26 and the second stepped surface 44 when the introduction needle 14 is in the insertion position may allow the second material to be even softer than a standard catheter body. In some embodiments, the second material may allow the tubular portion 38 to be bent when the catheter adapter 20 is fixed to the patient's skin, while the first material may facilitate the normal insertion of the catheter 12 into the vascular system.

[0026] In some embodiments, the first transition surface 36 may include a shoulder. In some embodiments, the first transition surface 36 may be positioned at approximately 90 degrees with respect to the longitudinal axis of the catheter assembly 10, as shown, for example, in Figure 1B. In some embodiments, the first transition surface 36 may be positioned at an angle other than 90 degrees with respect to the longitudinal axis of the catheter assembly 10. In some embodiments, the first transition surface 36 may be smooth and / or planar. In some embodiments, the first transition surface 36 may be uneven, rough, or irregular. In some embodiments, the first transition surface 36 may be curved.

[0027] Referring now to Figure 1C, in some embodiments, at least a portion of the outer surface of the distal tip 18 may be tapered, which may facilitate the entry of the catheter 12 into the patient's skin and tissue behind the distal end 16 of the introduction needle 14 when the distal tip 16 cuts through the pathway.

[0028] Referring here to Figures 2A to 2D, in some embodiments the catheter assembly 10 may include an introduction needle 14 and may include a needle feature portion 42. In some embodiments the needle feature portion 42 may be annular and may include a second stepped surface 44. In some embodiments the second stepped surface 44 may include a second distal surface 46, a second proximal surface 48, and a second transition surface 50 positioned between the second distal surface 46 and the second proximal surface 50. In some embodiments when the introduction needle 14 is in the insertion position, the second distal surface 46 may be adjacent to the first distal surface 28, the second proximal surface 48 may be adjacent to the first proximal surface 32, and the second transition surface 48 may be in contact with the first transition surface 36 so as to suppress proximal movement of the distal tip 18 relative to the introduction needle 14.

[0029] In some embodiments, the second transition surface 50 may include a shoulder. In some embodiments, the second transition surface 50 may be positioned at approximately 90 degrees with respect to the longitudinal axis of the catheter assembly 10, as shown, for example, in Figure 2B. In some embodiments, the second transition surface 50 may be positioned at an angle other than 90 degrees with respect to the longitudinal axis of the catheter assembly 10. In some embodiments, the second transition surface 50 may be smooth and / or planar. In some embodiments, the first transition surface 50 may be non-uniform, rough, or irregular. In some embodiments, the needle feature portion 42 may include a ridge, and / or the second transition surface 50 may be curved.

[0030] In some embodiments, the first stepped surface 26 may include a shape corresponding to or mirroring the second stepped surface 44 such that there is no space between the first stepped surface 26 and the second stepped surface 44. In some embodiments, the outer diameter of the second proximal surface 48 may be larger than the first uniform inner diameter 30 of the catheter 12 so as to prevent the needle feature portion 42 from passing distally through the first distal surface 28. In some embodiments, the outer diameter of the second proximal surface 48 may be approximately equal to or slightly smaller than the second uniform inner diameter 34 so that the needle feature portion 42 is slidable through the tubular portion 38 but still in contact with the inner surface of the tubular portion 38 to provide support to the catheter 12. In some embodiments, the outer diameter of the second distal surface 46 may be approximately equal to or slightly smaller than the first uniform inner diameter 34 so that the first distal surface 28 can fit within and support the first distal surface 28.

[0031] In some embodiments, the second proximal surface 48 may be generally cylindrical in shape. In some embodiments, a notch 52 providing access to the needle lumen 54 may be located proximal to the second proximal surface. In some embodiments, a portion of the introduction needle 14 adjacent to the notch 52 may be spaced apart from the inner surface or tubular portion 38 of the catheter 12 to form a flashback path 56. In some embodiments, the second proximal surface may extend proximal to an opposing stepped surface so as to form the distal end of the flashback path 56, as shown, for example, in Figures 2B and 2D. In some embodiments, the flashback path 56 may be located within the catheter lumen 40 between the outer surface of the introduction needle 14 and the inner surface of the catheter 12. Figure 2D shows the introduction needle 14 removed from the catheter adapter 20 according to some embodiments.

[0032] To confirm the proper placement of the introduction needle and / or IV catheter within the vascular system, the user may generally observe a flashback of blood, which may be visible to the user. In some embodiments, another part of the catheter 12 and / or catheter assembly 10 may be at least partially transparent to help the user see the flashback. In some embodiments, in response to the distal tip 16 of the introduction needle 14 being positioned within the blood vessel, blood may flow proximally through the needle lumen 54, exit the needle lumen through the notch 52, and then move proximally between the outer surface of the introduction needle 14 and the inner surface of the catheter 12. Thus, the user may visualize a “flashback” of a small amount of blood, thereby confirming the placement of the catheter 12 within the vascular system. In some embodiments, once the placement of the introduction needle 14 within the vascular system is confirmed, the user may temporarily block the flow within the vascular system, withdraw the introduction needle 14 from within the vascular system, and leave the catheter 12 in place for future blood withdrawal and / or fluid injection. In some embodiments, the catheter assembly 10 may be ventilated to allow for the occurrence of flashback.

[0033] In some embodiments, the introduction needle 14 may include a wall defining the needle lumen 54. In some embodiments, the second distal surface 46, the second transition surface 50, the second proximal surface 48, and the wall of the introduction needle 14 may be formed monolithically as a single piece. In some embodiments, the needle feature portion 42 may be bonded to the wall of the introduction needle 14 to form the second transition surface 50 and the second proximal surface 48. For example, the needle feature portion 42 may include metal, plastic, or another suitable material bonded to the wall of the introduction needle 14. In some embodiments, the needle feature portion 42 may be created by partially crimping the introduction needle 14. In some embodiments, the needle feature portion 42 may be formed by removing portions of the distal and / or proximal wall of the needle feature portion 42.

[0034] Referring here to Figures 3A-3B, in some embodiments the second proximal surface 48 may include a flat portion or at least a portion of a groove 58. An exemplary flat portion 59 according to some embodiments is shown in Figure 3E. In some embodiments the flashback path 56 may include a groove 58. In some embodiments the groove 58 may include a notch 52. In these and other embodiments the second proximal surface 48 may extend to provide support to the tubular portion 38.

[0035] Referring here to Figure 3C, according to some embodiments, the introduction needle 14 is shown detached from the catheter adapter 20. In some embodiments, the second proximal surface 48 may extend from the second transition surface 50 to the proximal end of the introduction needle 14 and / or the needle hub 22, which may provide strength to the introduction needle 14. In some embodiments, the second proximal surface 48 may extend from the second transition surface 50 along a portion of the introduction needle 14. In some embodiments, the groove 58 may extend along any length of the introduction needle 14. In some embodiments, the proximal end of the groove 58 may be located distal to the septum 24. In some embodiments, the second proximal surface 58 may extend through the proximal end of the catheter 12 when the introduction needle 14 is in the insertion position.

[0036] Referring here to Figure 3D, an example of a flat portion 59 is shown. In some embodiments, the flat portion 59 may be similar to the groove 58, except that the flat portion 59 does not include a wall. In some embodiments, the width of the flat portion 59 may be equal to the width of the cylinder that forms the second proximal surface 48 at the location of the flat portion 59. In some embodiments, the cross-sectional view shown in Figure 3B may also correspond to the cross-sectional view of the needle 14 in Figure 3D, positioned within the catheter 12 at the insertion position.

[0037] Referring here to Figures 4A–4B, in some embodiments, the groove 58 may extend through a second transition surface 50 and / or a second distal surface 46. In these and other embodiments, the groove 58 may extend through the distal tip 16 of the introduction needle 14 so that blood flows directly into the groove 58 to provide a flashback when the distal tip 16 is positioned within the patient's vascular system. As discussed with respect to Figure 3, in some embodiments, the second proximal surface 48 may extend to provide support to the tubular portion 38. In some embodiments, the groove 58 may extend along any length of the introduction needle 14. In some embodiments, the proximal end of the groove 58 may be positioned distal to the septum 24.

[0038] Referring here to Figures 5A–5B, in some embodiments, the second proximal surface 48 may include a notch 52 that can provide access to the needle lumen 54. In these and other embodiments, the inner surface of the tubular portion 38 may include a recess or channel 60 that can form a flashback pathway 56. In some embodiments, once the distal tip 16 is inserted into the patient's vascular system, blood may flow through the distal tip 16 out of the notch 52 and into the channel 60, which may be visible to the user. As discussed with respect to Figures 3–4, in some embodiments, the second proximal surface 48 may extend to provide support to the tubular portion 38. In some embodiments, the second proximal surface 48 may be smooth and generally uniform, as shown, for example, in Figure 5A.

[0039] Referring now to Figure 6, in some embodiments, the first distal surface 28 and the first transition surface 36 are part of the distal tip 18 and may be made of the first material, and the first proximal surface 32 may be part of the tubular portion and may be made of the second material. Thus, in some embodiments, the first transition surface 36 may be located near the second material. In some embodiments, the first distal surface 28, the first transition surface 36, and the first proximal surface 32 are part of the distal tip 18 and may be made of the first material, as shown, for example, in Figure 1B.

[0040] The present invention may be implemented in other specific forms without departing from its structure, method, or other essential features that are broadly described herein and claimed below. The embodiments and examples described are in all respects illustrative only and should not be considered limiting. Accordingly, the scope of the invention is indicated not by the above specification but by the accompanying claims. All modifications that fall within the meaning and scope equivalent to the claims should be included within the scope of the invention.

[0041] All examples and conditional language listed herein are intended for educational purposes to help the reader understand the present invention and the concepts provided by the inventors to advance the art, and should be construed as not being limited to such specifically listed examples and conditions. While the implementation of the present invention has been described in detail, it should be understood that various modifications, substitutions, and alternatives can be made without departing from the spirit and scope of the invention.

Claims

1. 1. An over-the-needle catheter comprising: a distal tip constructed of a first material having a first durometer; a first annular stepped surface having a rigid or semi-rigid first distal surface having a first uniform inner diameter, a first proximal surface having a second uniform inner diameter larger than the first uniform inner diameter, and a rigid or semi-rigid first transition surface disposed between the first distal surface and the first proximal surface, wherein at least the first distal surface and the first transition surface of the first annular stepped surface are part of the distal tip and are constructed of the first material; and an elongated tubular portion proximally coupled to the distal tip, the tubular portion being constructed of a second material, the durometer of the first material being harder than the durometer of the second material, the distal tip and the tubular portion comprising a catheter, the first annular stepped surface being disposed within a lumen of the catheter; an over-the-needle catheter comprising: an introducer needle including a needle feature having a second annular stepped surface, the second annular stepped surface comprising a second distal surface, a second proximal surface, and a second transition surface disposed between the second distal surface and the second proximal surface, wherein when the introducer needle is in an insertion position, the second distal surface is adjacent to the first distal surface, the second proximal surface is adjacent to the first proximal surface, and the second transition surface is adjacent to the first transition surface, such that proximal movement of the distal tip is inhibited; A catheter assembly comprising:

2. The catheter assembly of claim 1 , wherein the outer surface of the distal tip is tapered.

3. The catheter assembly of claim 1 , wherein the first material comprises a first plastic and the second material comprises a second plastic.

4. 10. The catheter assembly of claim 1, wherein the second proximal surface is generally cylindrical and includes at least a portion of a groove or flat portion, and further includes a flashback path disposed within the catheter lumen, the flashback path including a groove.

5. 5. The catheter assembly of claim 4, wherein the second proximal surface includes at least a portion of the groove, the groove extending through the second transition surface, and the second distal surface extending through the distal tip of the introducer needle.

6. The catheter assembly of claim 4 , wherein the groove includes a notch that provides access to the needle lumen.

7. The catheter assembly of claim 1 , wherein the second proximal surface is generally cylindrical, and the second proximal surface includes a notch that provides access to a needle lumen.

8. 10. The catheter assembly of claim 1, wherein the second proximal surface is generally cylindrical and the introducer needle further includes a notch disposed proximally of the second proximal surface, the notch providing access to a needle lumen.

9. 10. The catheter assembly of claim 1, wherein the second proximal surface is generally cylindrical, and the second proximal surface extends through the proximal end of the catheter when the introducer needle is in the insertion position.

10. 10. The catheter assembly of claim 1, wherein the introducer needle further includes a wall defining a needle lumen, and wherein the second distal surface, the second transition surface, the second proximal surface, and the wall of the introducer needle are integrally formed as a single piece.

11. 2. The catheter assembly of claim 1, wherein the introducer needle further includes a wall defining a needle lumen, and the needle feature is integrated into the wall of the introducer needle to form the second transition surface and the second proximal surface.

12. 2. The catheter assembly of claim 1, wherein the first distal surface, the first transition surface, and the first proximal surface of the first annular stepped surface are part of the distal tip and are constructed of the first material.

13. 1. An over-the-needle catheter for insertion into a patient's vascular system comprising: a distal tip constructed of a first material having a first durometer; an annular stepped surface having a rigid or semi-rigid distal surface having a first uniform inner diameter, a proximal surface having a second uniform inner diameter greater than the first uniform inner diameter, and a rigid or semi-rigid transition surface disposed between the distal and proximal surfaces, wherein the distal and transition surfaces of the annular stepped surface are at least a portion of the distal tip and are constructed from the first material; and an elongated tubular portion proximally coupled to the distal tip, the tubular portion being constructed of a second material, the durometer of the first material being harder than the durometer of the second material, the distal tip and the tubular portion comprising a catheter, the annular stepped surface being disposed within the catheter lumen; An over-the-needle catheter comprising:

14. 14. The catheter of claim 13, wherein the distal surface, the transition surface, and the proximal surface are part of the distal tip and are constructed of the first material.

15. The catheter of claim 13, wherein the transition surface is disposed proximate the second material.

16. 1. An introducer needle for insertion into a patient's vascular system, comprising: a needle feature having an annular stepped surface, the annular stepped surface including a distal surface, a proximal surface, and a transition surface disposed between the distal surface and the proximal surface, the proximal surface being generally cylindrical in shape.

17. 17. The introducer needle of claim 16, wherein the proximal face includes at least a portion of a groove or flat that defines a flashback path.

18. 17. The introducer needle of claim 16, wherein the groove extends through the transition surface and the distal surface extends through the distal tip of the introducer needle, or the groove includes a notch that provides access to a needle lumen.

19. The introducer needle of claim 16 , wherein the proximal face includes a notch that provides access to the needle lumen.

20. 17. The introducer needle of claim 16, further comprising a notch disposed proximally on the proximal face, the notch providing access to a needle lumen.

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