Catheter tip passive control device and related systems and methods

Abstract

We provide catheter assemblies. [Solution] A catheter assembly for passively opening a fluid pathway, comprising: a catheter adapter having a proximal end, a distal end, and a lumen extending between them; a catheter extending from the distal end, including the length of the tip and the tube, wherein the length of the tube includes an elastic vent portion having an initial shape including a first portion of the length of the tube, the first portion of the length of the tube being displaced relative to a second portion of the length of the tube; and a needle configured to extend through the length of the tube, wherein in response to the needle extending through it, the elastic vent portion and the tip of the catheter fit into the needle, and in response to the needle being withdrawn proximally, the elastic vent portion returns to its initial shape such that the tip of the catheter is displaced relative to the length of the tube in the vascular system.

Description

Technical Field

[0001] The present disclosure generally relates to vascular access devices or intravenous catheters for injecting fluids and / or withdrawing blood from a patient's vascular system.

Background Art

[0002] Catheters are generally used in various infusion therapies. For example, a catheter can be used to inject fluids such as saline, various drugs, and total parenteral nutrition into a patient. A catheter can also be used to withdraw blood from a patient to obtain a blood sample.

[0003] A common catheter is an over-the-needle type peripheral intravenous (「IV」) catheter. An over-the-needle catheter, as its name implies, is a catheter that can be mounted on an introducer needle having a sharp distal end. The catheter and the introducer needle can be assembled such that the distal tip of the introducer needle extends beyond the distal tip of the catheter and the bevel of the needle faces away from the patient's skin. The catheter and the introducer needle are typically inserted into the patient's vascular system at a shallow angle from the skin.

[0004] To verify proper placement of the introducer needle and / or catheter within the blood vessel, a clinician generally confirms that there is a 「flashback」 of blood within the flashback chamber of the catheter assembly. Once the needle placement is confirmed, the clinician can temporarily occlude the flow within the vascular system, remove the needle, and leave the catheter in place for subsequent blood sampling, infusion, or probe access.

[0005] However, catheter function can be impaired for several reasons, particularly if the catheter has a long residence time in the vascular system. More generally, over time, catheters can become susceptible to complications and occlusions that obstruct fluid flow. For example, a catheter may become occluded at its tip due to the presence of fibrin sheaths, thrombi, venous walls, or valves. Consequently, while catheters are commonly used to obtain blood samples during catheter placement, they are less frequently used to obtain blood samples during the catheter's residence period. If a blood sample is desired during the catheter's residence period, typically an additional needle stick is used to provide venous access for blood collection, causing additional pain to the patient and increasing material costs. However, applying traction to move or reposition the catheter tip within the vein has been shown to significantly improve blood collection success and catheter function by avoiding occlusion and obstruction.

[0006] The subject matter claimed herein is not limited to embodiments that resolve any shortcomings or embodiments that operate only in the environments described above. Rather, this background art is provided merely to illustrate an example of the technical area in which some of the embodiments described herein can be carried out. [Overview of the project] [Means for solving the problem]

[0007] However, various complications and occlusions can obstruct the flow of fluid through the catheter, thus impairing its function and / or performance. For example, a catheter can become occluded at its tip due to the presence of fibrin sheaths, thrombi, venous walls, or valves. Repositioning the catheter tip within the patient's vascular system to open the fluid pathway can significantly improve catheter function and enable successful blood collection.

[0008] Some embodiments of this specification disclose vascular access devices that enable aspiration, blood collection, and infusion by passively repositioning the tip of a catheter and opening a fluid pathway. In some embodiments, the vascular access device for passively opening a fluid pathway in the vascular system may include a catheter and a guidewire. In some embodiments, the catheter may include a proximal end, a tip, and the length of the tube between the proximal end and the tip. In some embodiments, the guidewire may extend along the length of the tube and may include a vented portion. In some embodiments, at least a portion of the length of the tube may substantially conform to the vented portion in the vascular system so that the tip of the catheter can avoid occlusion therein.

[0009] In some embodiments, the guidewire may be coupled to at least a portion of the surface of the catheter. Alternatively, in some embodiments, the guidewire may be embedded in at least a portion of the catheter. Some embodiments of the catheter may include one or more fenestrations placed therein to provide additional fluid pathways.

[0010] In some embodiments, the guidewire may contain a temperature-activated material such as nitinol or scandium fluoride (ScF3). In some embodiments, the catheter and guidewire may have their own thermal expansion properties. In some embodiments, the guidewire may be adapted along the length of the tube so that the tip of the catheter is oriented upward, downward, or laterally with respect to the horizontal axis of the vascular system.

[0011] Some embodiments may include a catheter assembly for passively opening a fluid pathway. In some embodiments, the catheter assembly may include a catheter adapter having a proximal end, a distal end, and a lumen extending between the proximal and distal ends. In some embodiments, the catheter may extend from the distal end of the catheter adapter. In some embodiments, the catheter may include a tip and a tube length. In some embodiments, the tube length may include an elastic vent portion. Some embodiments of the elastic vent portion may include an initial shape in which a first portion of the tube length is offset relative to a second portion of the tube length.

[0012] Some embodiments of the catheter assembly may further include a needle configured to extend through the length of the tube. In some embodiments, the elastic vent portion and the tip of the catheter may conform to the needle in response to the needle extending through them. In some embodiments, in response to the needle being withdrawn proximally, the elastic vent portion may return to its initial shape so that the tip of the catheter is displaced along the length of the tube in the vascular system.

[0013] In some embodiments, the elastic vent portion may include an asymmetrical cross-section, an extended length, and / or one or more joints. In some embodiments, the catheter may include a guidewire extending along the length of the tube. In some embodiments, the guidewire may be bonded to at least a portion of the surface of the catheter. In some embodiments, the guidewire may be embedded in at least a portion of the wall of the catheter.

[0014] In some embodiments, the elastic vent portion may direct the tip of the catheter upward with respect to the horizontal axis of the vascular system. In some embodiments, the elastic vent portion may direct the tip of the catheter downward with respect to the horizontal axis. In some embodiments, the elastic vent portion may direct the tip of the catheter laterally with respect to the horizontal axis.

[0015] In some embodiments, a catheter assembly that passively opens a fluid pathway may include a catheter and a thermal element. In some embodiments, the catheter may include a proximal end, a tip, and the length of the tube between the proximal end and the tip. In some embodiments, the thermal element may be coupled to the length of the tube. Some embodiments of the thermal element may be temperature-activated to change shape in response to being placed in a vascular system. In some embodiments, the catheter and thermal element may be formed monolithically as a single unit.

[0016] It should be understood that both the above-mentioned general description and the following detailed description are illustrative and for illustrative purposes only, and do not limit the claimed invention. It should be understood that various embodiments are not limited to the arrangements and means shown in the figures. It should also be understood that embodiments may be combined, or other embodiments may be used, and structural modifications may be made without departing from the scope of the various embodiments of the invention, unless otherwise claimed. Accordingly, the following detailed description should not be interpreted as restrictive.

[0017] Exemplary embodiments are described and explained in more specific and detail with reference to the accompanying drawings. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a cross-sectional view of an exemplary vascular access device, showing an exemplary catheter with a pre-formed guidewire according to several embodiments. [Figure 2] Figure 2 is a cross-sectional view of another exemplary vascular access device according to several embodiments, showing an exemplary needle extending through it. [Figure 3] Figure 3 is a cross-sectional view of the vascular access device shown in Figure 2, where the cross-section is photographed along the indicated line. [Figure 4]FIG. 4 is a side perspective view of an exemplary vascular access device including an exemplary thermal element attached to an exemplary catheter according to some embodiments. [Figure 5] FIG. 5 is a side perspective view of another exemplary vascular access device including a bonding catheter disposed within a vascular system according to some embodiments. [Figure 6] FIG. 6 is a side perspective view of an exemplary vascular access device including a catheter having an extended length according to some embodiments. [Figure 7A] FIG. 7A is a cross-sectional view of an exemplary catheter having an asymmetric cross-section according to some embodiments. [Figure 7B] FIG. 7B is a cross-sectional view of an exemplary catheter embedded with an exemplary material having unique thermal properties according to some embodiments. [Figure 8] FIG. 8 is a top perspective view of an exemplary catheter adapter showing an exemplary guide wire extending along an exemplary catheter according to some embodiments. [Figure 9A] FIG. 9A is a perspective view of an exemplary guide wire having an exemplary bent portion according to some embodiments. [Figure 9B] FIG. 9B is a perspective view of another exemplary guide wire having another exemplary vent portion according to some embodiments. [Figure 9C] FIG. 9C is a perspective view of another exemplary guide wire having another exemplary vent portion according to some embodiments. [Figure 9D] FIG. 9D is a perspective view of another exemplary guide wire having another exemplary vent portion according to some embodiments. [Figure 9E] FIG. 9E is a perspective view of another exemplary guide wire having another exemplary vent portion according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0019] As used herein, the term "distal" refers to the direction away from the clinician who contacts and brings the device closer to the patient. The term "proximal" refers to the direction closer to the clinician who contacts the device with the patient and farther from the patient. Thus, for example, the end of the catheter that first touches the patient's body is the distal end, while the end on the opposite side of the catheter is the proximal end of the catheter.

[0020] As described above, particularly when the dwell time of a catheter within the vasculature is extended, the function of the catheter can be impaired for several reasons. For example, the catheter may become occluded at its tip due to the presence of a fibrin sheath, thrombus, venous wall, or valve. In particular, a catheter has a tendency to form an "S" shape when placed within a vein, fixing the tip of the catheter to the opposite venous wall. Such proximity between the venous wall and the catheter can facilitate relative movement between the two, resulting in the formation of thrombus on the venous wall and / or the catheter tip. Further, when the catheter tip is in proximity to the venous wall, it may come to rest near the catheter tip, thereby facilitating the formation of thrombus.

[0021] Applying traction to move or reposition the catheter tip within the vein can significantly improve the success of blood sampling and the function of the catheter by avoiding such occlusion and obstruction. The embodiments described herein passively reposition the tip of a catheter within the vasculature to a position away from the venous wall, minimizing the likelihood of thrombus formation near the catheter tip, thereby extending the patency of the fluid pathway and enabling aspiration, blood sampling, and / or injection.

[0022] Referring here to Figure 1, in some embodiments, the catheter access device 100 may be configured to control the position of the tip 106 of the catheter 102 within the patient's vascular system 122 to avoid occlusion and open a fluid pathway for blood collection or fluid delivery. In some embodiments, the catheter 102 may include a peripheral IV catheter 102, a peripherally inserted central catheter 102, or a midline catheter 102. In some embodiments, the catheter 102 may be pre-inserted into the patient's vascular system 122 and may be left in place within the vascular system 122. In such cases, the catheter 106 may be susceptible to occlusion by debris (e.g., fibrin or thrombus) and / or adhesion of the tip 106 of the catheter 102 to the vascular system 122. Therefore, blood collection using the catheter 102 may be difficult.

[0023] Several embodiments of this specification disclose a vascular access device 100 that facilitates aspiration, blood collection, and / or infusion by passively repositioning the tip 106 of a catheter 102 within a vascular system 122 to open a fluid pathway. As shown in Figure 1, in some embodiments, the vascular access device 100 for passively opening a fluid pathway within a vascular system 122 may include a catheter 102 and one or more guidewires 110. In some embodiments, the catheter 102 may include the length of a proximal end 104, a tip 106, and a tube 108 between the proximal end and the tip.

[0024] In some embodiments, the guidewire 110 may be embedded in at least a portion of the catheter 102. In some embodiments of the guidewire 110, the guidewire 110 may be co-extruded within the catheter 102 so that it extends partially or completely along the length of the tube 108. In other embodiments, the guidewire 110 may be bonded to at least a portion of the outer surface 116 or inner surface 124 of the catheter 102. In some embodiments, the guidewire 110 may, for example, prevent twisting of the catheter 102 at the insertion site.

[0025] In some embodiments, the catheter 102 may include one or more fenestrations 118 to provide additional fluid pathways. In some embodiments, the fenestrations 118 may be located along the length of the tube 108 and / or at the tip 106 of the catheter 102.

[0026] In some embodiments, the guide wire 110 may include a bent portion 112. In some embodiments, the guide wire 110 may include an elastic or shape memory wire, or other suitable material having its own pre-formed shape. In some embodiments, the guide wire 110 may be pre-formed into a curve or another suitable nonlinear shape. In some embodiments, the guide wire 110 may be pre-formed by thermoforming, mechanical forming, or another suitable forming technique.

[0027] In some embodiments, the guidewire 110 may include metal, a metal alloy, polycarbonate, plastic, or other suitable material. In some embodiments, at least a portion of the length of the tube 108 may substantially fit into the bent portion 112 of the guidewire 110 within the vascular system 122. In this way, the tip 106 of the catheter 102 may be passively directed away from any occlusion or obstruction 114 within the vascular system 122.

[0028] Referring now to Figure 2, in some embodiments, the catheter 102 may be configured to receive a needle 210 that may extend through the length of the catheter 102. In some embodiments, the sharp distal tip 212 of the needle 210 may be exposed at the distal end 206 of the catheter 102 in order to introduce the catheter 102 into the vascular system 122.

[0029] In some embodiments, the catheter 102 may conform to the shape of the guidewire 110, including a bent portion 112. In some embodiments, at least a portion of the catheter 102, including the bent portion 112, may conform to the shape of the needle 210 as the needle 210 extends through it. For example, in some embodiments, the bent portion 112 of the catheter 102 and / or the guidewire 110 may be straightened as the needle 210 is inserted into the catheter 102 and advances distally through it.

[0030] In some embodiments, when the needle 210 is removed from the catheter 102, the vented portion 112 may return to its initial shape. Then, some embodiments of the catheter 102 may conform to the pre-formed shapes of the guidewire 110 and the vented portion 112. In some embodiments, the vented portion 112 of the guidewire 110 may include one or more bends. For example, in some embodiments, the vented portion 112 may include a bend at or near the tip 106. In some embodiments, the vented portion 112 may provide one or more bends more proximal along the length of the tube 108. In one embodiment, for example, the vented portion 112 may include multiple bends to provide an "s" curve shape along the length of the tube 108.

[0031] In this way, some embodiments of the catheter 102 passively move the tip 106 of the catheter 102 so that the tip 106 of the catheter 102 is misaligned with the length and position of the tube 108 in the vascular system 122. In some embodiments, the pre-formed shape of the guidewire 110 may lift the tip 106 of the catheter 102 toward the center of the vascular system 122. In this way, the tip 106 of the catheter 102 may be directed away from a perivenous occlusion 114, such as a thrombus.

[0032] In some embodiments, the guidewire 110 may include a strip of material bonded to the outer surface of the catheter 102. In other embodiments, the guidewire 110 may be extruded in a stripe-like manner from the catheter 102. Some embodiments of the guidewire 110 may be configured to bend in response to being placed within the vascular system 122. For example, as will be described in more detail below, in some embodiments, the guidewire 110 may be configured to bend in response to a temperature rise in the vascular system 122. In some embodiments, such bending may lift the tip 106 away from the wall, ceiling, or floor of the vascular system 122 when the needle 210 is removed from the catheter 102.

[0033] In some embodiments, the guidewire 110 may include a thermal element or any suitable temperature-activated material. In some embodiments, the temperature-activated material may include a pre-formed or other shape-memory metal or plastic strip configured to return to its pre-formed shape when the needle 210 is removed from the catheter 102. In some embodiments, the catheter 102 and guidewire 110 may have their own thermal expansion properties. For example, in some embodiments, the guidewire 110 may include scandium fluoride (ScF3) or another such material that can shrink with increasing temperature. In some embodiments, scandium fluoride or other suitable material may be placed along its circumference in the upper section of the tube of the catheter 102. Thus, in some embodiments, the shrinkage of the material may lift the catheter tip 106 away from the vein wall. In other embodiments, the guidewire 110 may include nitinol or other similar or suitable material.

[0034] In some embodiments, more than one guidewire 110 may be embedded in or connected to the catheter 102. As shown in Figures 2 and 3, in some embodiments, multiple guidewires 110a, 110b may be embedded on the opposite side of the outer surface 116 of the catheter 102. In some embodiments, multiple guidewires 110 may be similarly shaped to increase the force applied to reshape the catheter 102 when removing the needle 210.

[0035] In some embodiments, one or more guidewires 110 may be adapted along the length of the tube 108 so that the tip 106 of the catheter 102 can be oriented upward, downward, or laterally with respect to the horizontal axis 120 of the vascular system 122. In some embodiments, one or more guidewires 110 may be adapted similarly or uniquely with respect to one or more other guidewires 110 along the length of the tube 108. Figure 3 shows a cross-section of the catheter 102 and guidewires 110 of Figure 2 taken along line 300. As shown, the multiple guidewires 110A, 110B may be spaced evenly relative to the catheter wall. In other embodiments, the multiple guidewires 110a, 110b may be grouped together to facilitate passive bending and / or the formation of a bent portion 112 along the length of the tube 108, or otherwise, they may be arranged or adapted as desired.

[0036] Referring now to Figure 4, some embodiments may include a catheter assembly 200 for passively opening a fluid pathway. In some embodiments, the catheter assembly 200 may include a catheter adapter 202 having a proximal end 204, a distal end 206, and a lumen extending between the proximal and distal ends. In some embodiments, the catheter 102 may extend from the distal end 206 of the catheter adapter 202.

[0037] In some embodiments, the catheter 102 may include the length of a proximal end 104, a tip 106, and a tube 108 between the proximal end and the tip. In some embodiments, the length of the tube 108 may include one or more mechanical features to facilitate flexibility along the length of the tube 108. In some embodiments, the mechanical features may facilitate flexibility to create a vented portion 112 when the length of the tube 108 is positioned within the vascular system 122.

[0038] For example, as shown in Figure 4, some embodiments of the catheter 102 may include a catheter 102 having an extended length 400 to allow the tip 106 to rest in a substantially central position within the vascular system 122 during the waiting period. In some embodiments, the extended length 400 may facilitate the passive lifting of the tip 106 of the catheter 102 within the vascular system 122. In some embodiments, the extended length 400 may facilitate the passive repositioning of the tip 106 of the catheter 102 within the vascular system 122 to avoid obstruction 202.

[0039] Referring here to Figure 5, some embodiments of the catheter 102 may include one or more joints 500, hinges, bends, or other suitable mechanical joints for forming a vent portion 112 when the catheter 102 is placed in the vascular system 122. In some embodiments, one or more joints 500 may be coupled to or integrated with the length of the tube 108. Some embodiments of the joints 500 may be positioned close to the tip 106 of the catheter 102 to facilitate the movement of the tip 106 along the length of the tube 108. In other embodiments, the joints 500 may be positioned along the length of the tube 108. Some embodiments of the joints 500 may be bidirectional or multidirectional. In some embodiments, one or more joints 500 may guide the tip 106 of the catheter 102 in a single direction.

[0040] Referring now to Figure 6, in some embodiments, the catheter 102 may include one or more thermal elements 600 coupled or integrated to the length of the tube 108. In some embodiments, the catheter 102 and the thermal elements 600 may be formed monolithically as a single unit.

[0041] In some embodiments of the thermal element 600, it may be positioned close to the tip 106 to facilitate the passive movement and / or repositioning of the tip 106 relative to the length of the tube 108. For example, in some embodiments, the thermal element 600 may change shape in response to the temperature within the vascular system 122. In some embodiments, this shape change may cause the tip 106 of the catheter 102 to move relative to the length of the tube 108. Of course, in some embodiments, one or more of the thermal elements 600 may be positioned along the length of the tube 108 at any intermediate position between the tip 106 and the proximal end 104.

[0042] As previously mentioned with reference to Figure 2, some embodiments of the thermal element 600 may include a metal, plastic, or other suitable material having thermal properties that respond to temperature changes by changing its shape. In some embodiments, the thermal element 600 may expand or contract in response to the ambient temperature. For example, in some embodiments, the thermal element 600 may include nitinol, scandium fluoride (ScF3), or another suitable material.

[0043] Referring here to Figure 7A, in some embodiments, the catheter 102 may include a catheter wall 700 having an asymmetric cross-section 702, thereby resulting in a vented portion 112 along the length of the tube 108. In some embodiments, the vented portion 112 may arise from one or more other mechanical features or a thermal element 600 bonded to or integrated therewith, in addition to the catheter 102 having the asymmetric cross-section 702.

[0044] For example, in some embodiments, the catheter 102 may include a guidewire extending along the length of the tube 108. In some embodiments, the length of the tube 108 may include an asymmetric 702 catheter wall 700 in which the guidewire 110 is embedded. Thus, the elastic vent portion 112 may arise from both the shape and adaptation of the guidewire 110 and the asymmetric cross-section 702 of the catheter wall 700.

[0045] Referring here to Figure 7B, in other embodiments, the catheter 102 may include one or more thermal elements 600 that are coupled to or embedded in the catheter wall 700. In some embodiments, the catheter wall 700 may be asymmetrical 702 to further support the movement of the thermal elements 600 within the vascular system 122 and form a vented portion 112. In other embodiments, the catheter wall 700 may include a substantially symmetrical cross-sectional profile.

[0046] As shown, in some embodiments, the multiple thermal elements 600 may be embedded in the catheter wall 700 or co-extruded with the catheter wall 700. In some embodiments, the multiple thermal elements 600 may be bonded to the catheter wall 700. In some embodiments, the multiple thermal elements 600 may be kept evenly spaced around the catheter wall 700. In other embodiments, the multiple thermal elements 600 may be grouped together to facilitate passive bending and / or the formation of a vented portion 112 along the length of the tube 108, or otherwise arranged or adapted as desired.

[0047] Referring here to Figure 8, in some embodiments, the vascular system 122 may include a horizontal axis 120. In some embodiments of the vent portion 112 of the catheter 102, the tip 106 of the catheter 102 may be directed substantially laterally upward with respect to the horizontal axis 120 within the vascular system 122. In some embodiments, the vent portion 112 may direct the tip 106 of the catheter 102 substantially laterally downward with respect to the horizontal axis 120 within the vascular system 122. In some embodiments, the vent portion 112 may direct the tip 106 of the catheter 102 laterally with respect to the horizontal axis 120 within the vascular system 122. In any case, the vent portion 112 may be substantially elastic and / or thermally activated so that the tip 106 of the catheter 102 can be passively re-adapted within the vascular system 122 to clear the fluid pathway after the needle 210 is withdrawn or otherwise removed.

[0048] Referring here to Figures 9A-E, some embodiments of the elastic vent portion 112 may include initial shapes 900a, 900b, 900c, 900d, and 900e. In some embodiments, the initial shapes 900a, 900b, 900c, 900d, and 900e may include the length of tube 108 having a first portion 902 that is offset relative to a second portion 904 of the length of tube 108, thereby forming the vent portion 112. In some embodiments, the second portion 904 may extend from the first portion 902. In some embodiments, the length of tube 108 may further include a third portion 906 that extends from the second portion 904. In some embodiments, the third portion 906 may be offset relative to the second portion 904. In some embodiments, the third portion 906 may be aligned with or substantially aligned with the first portion 902. In other embodiments, the third portion 906 may be offset relative to the first portion 902.

[0049] In any case, the elastic vent portion 112 may include initial shapes 900a, 900b, 900c, 900d, and 900e configured to push the tip 106 of the catheter 102 upward in a substantially lateral direction with respect to the horizontal axis 120 of the vascular system 122. In some embodiments, the initial shapes 602 900a, 900b, 900c, 900d, and 900e may push the tip 106 of the catheter 102 upward with respect to a first portion 902 and / or a second portion 904 of the catheter 102. In this way, some embodiments of the catheter 102 may allow the tip 106 of the catheter 102 to passively avoid interference with obstructions 202 located or positioned within the vascular system 122.

[0050] All examples and conditional statements described herein are intended for educational purposes to help understand the concepts provided by the inventors to advance the invention and the art, and should be construed as not being limited to the examples and conditions specifically listed herein. While embodiments of the invention are described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of the invention.

Claims

1. A catheter assembly that passively opens a fluid pathway, A catheter adapter comprising a proximal end, a distal end, and a lumen extending between them, A catheter extending from the distal end, including the length of the tip and the length of the tube, wherein the length of the tube includes an elastic vent portion having an initial shape including a first portion of the length of the tube, and the first portion of the length of the tube is offset relative to a second portion of the length of the tube, A catheter assembly comprising: a needle configured to extend through the length of the tube, wherein in response to the needle extending through it, the elastic vent portion and the tip of the catheter fit into the needle, and in response to the needle being withdrawn proximally, the elastic vent portion returns to its initial shape such that the tip of the catheter is misaligned with the length of the tube in the vascular system.

2. The catheter assembly according to claim 1, wherein the elastic vent portion includes an asymmetrical cross-section.

3. The catheter assembly according to claim 1, wherein the elastic vent portion includes an extended length.

4. The catheter assembly according to claim 1, wherein the elastic vent portion includes at least one joint.

5. The catheter assembly according to claim 1, wherein the catheter comprises a guidewire extending along the length of the tube.

6. The catheter assembly according to claim 5, wherein the guide wire is coupled to at least a portion of the surface of the catheter.

7. The catheter assembly according to claim 5, wherein the guide wire is embedded in at least a portion of the wall of the catheter.

8. The catheter assembly according to claim 1, wherein the elastic vent portion directs the tip of the catheter upward within the vascular system with respect to its horizontal axis.

9. The catheter assembly according to claim 1, wherein the elastic vent portion directs the tip of the catheter downward within the vascular system with respect to its horizontal axis.

10. The catheter assembly according to claim 1, wherein the elastic vent portion directs the tip of the catheter laterally within the vascular system with respect to its horizontal axis.

11. A catheter assembly that passively opens a fluid pathway, A catheter comprising a proximal end, a tip, and the length of a tube between them, A catheter assembly comprising: a thermal element coupled to the length of the tube, which is temperature-activated to change shape in response to being placed within the vascular system.

12. The catheter assembly according to claim 11, wherein the catheter and the thermal element are formed monolithically as a single unit.

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