catheter

Abstract

A catheter for insertion into a subject's blood vessel, the catheter comprising an elongated body extending between a proximal end configured to be connected to a central portion and a distal end configured to be inserted into a subject's blood vessel, the body having a tip portion at the distal end, the tip portion having an external tapered profile and comprising an outlet and a lumen extending from the proximal end to the outlet. The lumen is angled so as to direct flow from the outlet at an angle offset from an axis of the catheter, and / or at least a portion of the body comprises a blood vessel contacting portion that is softer than other portions of the catheter.

Description

Technical Field

[0001] The present invention relates to catheters, and in one example to a peripheral intravenous catheter (PIVC) or midline catheter for administering intravenous fluids, blood products and medications to a patient, or for withdrawing blood or fluids for sampling. In another example, the present invention relates to an arterial catheter for hemodynamic monitoring and blood sampling. Background Art

[0002] Reference in this specification to any previous publication (or information derived therefrom) or any known matter is not and should not be taken as an admission or recognition or any form of implication that the previous publication (or information derived therefrom) or known matter constitutes part of the common general knowledge in the technical field to which this specification relates.

[0003] A peripheral intravenous catheter (PIVC) or arterial line or line ("A-line") is an important tool in providing patient care within a hospital or nursing facility. 70% of hospitalized patients use a PIVC to administer intravenous (IV) medications, fluids, nutrition, and blood products, and PIVCs can be life-saving. Arterial lines are commonly used for hemodynamic monitoring and blood sampling.

[0004] Traditional PIVC and A-lines include a hollow tube, usually made of a polymer (eg, polyurethane), that is inserted peripherally into a patient's blood vessel. The catheter typically has a smooth, hydrophobic surface and a single lumen terminating in a tip portion with a fluid outlet.

[0005] Currently, up to 30%-40% of PIVCs fail due to occlusion, phlebitis, infiltration, infection, and migration, while up to 35% of peripheral arterial lines fail due to fibrin formation and microaggregation of blood components leading to thrombosis. An essential requirement for A-lines is patency to allow adequate hemodynamic monitoring.

[0006] Figure 1 An example of a prior art catheter 100 (PIVC or A-line) for insertion into a blood vessel 10 of a patient is shown in situ within the blood vessel 10 (which may be a vein or an artery).

[0007] In this example, the catheter 100 includes an open tube 110 extending between a proximal end 111 connected to a central portion 120 and a distal end 112 defining an opening that allows fluid 2 to flow into / out of the tube 110 .

[0008] Tube 110 defines a single lumen and includes a short outer tapered tip portion 113 terminating in an opening at distal end 112. The diameter of distal opening 112 at tip 113 is generally the same as the diameter of tube 110. Catheter 100 may be used to inject fluid into a patient's blood vessel 10 or to aspirate or withdraw blood for sampling.

[0009] The disadvantages of this conventional prior art catheter will now be described in more detail.

[0010] The first problem is the potential for interference between the catheter 100 and the tip 113 and the vessel wall 12. Typically, in use, the catheter 100 and the tip 113 will contact or drag against a portion A of the inner layer of the vessel wall 12 (referred to as the intima 12a). Lining this intima is a layer of sensitive endothelial cells (endothelium). This can cause damage to the vessel wall, including corrosion of the endothelium and intima 12a through friction, leading to phlebitis or infiltration. Phlebitis involves inflammation or irritation of the vessel wall, while infiltration involves the potential for the catheter to completely penetrate or puncture the vessel wall.

[0011] Phlebitis may also be due to the fact that fluid outflow is often concentrated in a small area of ​​the vessel wall. The force of the fluid ejected from the tip 113 onto the vessel wall 12a causes shear stress. Shear stress can damage endothelial cells and lead to phlebitis (inflammation). Irritants (such as intravenous medications) that are constantly discharged from the catheter into the lining of the vessel at the same location may also cause inflammation.

[0012] Figure 1 Conventional single lumen catheters of the type shown are also susceptible to thrombotic occlusions, whereby a thrombus forms in, around, or at the tip of the catheter, thereby preventing fluid from flowing into / out of the catheter. Occlusions may also occur during aspiration of blood or fluid using a conventional single lumen catheter. The combination of the catheter tip being close to the vascular intima and the negative pressure of the aspiration may produce a suction-like effect, resulting in occlusion of the ball valve at the catheter tip.

[0013] For example, peripheral arterial catheters used for hemodynamic monitoring may also be partially occluded by fibrin formation and microthrombi.

[0014] Prior art catheters also typically have smooth, hydrophobic surfaces that attract biofilms that can lead to microbial infection, especially if the biofilms break off and enter the bloodstream.

[0015] A final disadvantage of existing PIVC and arterial catheters relates to the shear forces exerted on the vessel wall as the outflow is directed against the vessel inner wall 12a, which may cause wall damage or irritation. Typically, when fluid is injected into the catheter from a prefilled syringe, the inflow pressure is constant.

[0016] It is against this background, and the problems and difficulties associated therewith, that the present invention has been developed. Summary of the invention

[0017] In a broad form, one aspect of the invention seeks to provide a catheter for insertion into a blood vessel of a subject, the catheter comprising: an elongated body extending between a proximal end configured to be connected to a central portion and a distal end configured to be inserted into a blood vessel of the subject, the body having: a tip portion at the distal end, the tip portion having an external tapered profile and including an outlet; and, an inner lumen extending from the proximal end to the outlet, wherein: the inner lumen is inclined to direct flow out of the outlet at an angle offset from the axis of the catheter; and / or, at least a portion of the body includes a blood vessel contacting portion that is softer than other portions of the catheter.

[0018] In one embodiment, the lumen is inclined in at least one of the following ways: asymmetrically; such that the lumen walls on opposite sides of the tip portion are inclined differently; such that the wall on one side of the tip portion is substantially aligned with the lumen in the elongated body and the wall on the opposite side of the tip portion is angled relative to the lumen in the elongated body; at the tip portion; at least a portion of the body; narrowing the lumen toward the outlet; and, having a curved profile.

[0019] In one embodiment, the lumen in the tip portion is disposed at an angle relative to the axis of the catheter that is at least one of: greater than 1°; greater than 2°; greater than 5°; greater than 10°; less than 15°; and, less than 20°.

[0020] In one embodiment, the outer tapered profile is at least one of: asymmetric; offset at an angle from the axis of the conduit; and such that the outlet is offset from the axis of the conduit.

[0021] In one embodiment, the angle of the lumen is configured to: direct flow from the outlet at an angle offset from the catheter axis; and direct flow toward the center of the vessel; and, direct flow away from the vessel wall.

[0022] In one embodiment, the vessel contacting portion is configured to at least one of: at least partially deform upon contact with a vessel; and distribute a load on a surface of the vessel.

[0023] In one embodiment, the vessel contacting portion is at least one of: made of a different material than other portions of the body; and, a surface layer applied to at least a portion of the body.

[0024] In one embodiment, the blood vessel contacting portion is made of polyurethane.

[0025] In one embodiment, the vessel contacting portion has a Shore durometer of at least one of: less than 50A; less than 40A; less than 30A; less than 20A; and, less than 10A.

[0026] In one embodiment, the non-vascular contacting portion has a Shore durometer of at least one of: greater than 50A; greater than 40A; greater than 30A; greater than 20A; and, greater than 10A.

[0027] In one embodiment, the ratio of the hardness of the non-vessel contacting portion to the vessel contacting portion is at least one of: greater than 0.01:1; greater than 0.05:1; greater than 0.1:1; and greater than 0.5:1.

[0028] In one embodiment, the vessel contacting portion is disposed at least one of: on an underside of the body; and, behind the tip portion.

[0029] In one embodiment, the body includes: a first portion extending a first length from the proximal end; a second portion extending a second length from an end of the first portion to the tip portion, and wherein the second portion includes a blood vessel contacting portion.

[0030] In one embodiment, the length of the second portion is at least one of: at least 30% of the catheter length; at least 40% of the catheter length; at least 50% of the catheter length; at least 60% of the catheter length; and at least 65% of the catheter length.

[0031] In one embodiment, the body includes at least one opening extending through the body.

[0032] In one embodiment, the at least one opening is configured to allow fluid to flow into or out of the body.

[0033] In one embodiment, at least one opening is disposed on a side of the body comprising the blood vessel contacting portion.

[0034] In one embodiment, the at least one opening is configured such that fluid exiting the at least one opening enters the region between the blood vessel and the blood vessel contacting portion, thereby at least one of: helping to cushion the blood vessel wall; and reducing blood flow stagnation in the region proximate the catheter.

[0035] In one embodiment, at least one opening is provided on a side of the body opposite to the side containing the blood vessel contacting portion.

[0036] In one embodiment, the at least one opening is configured such that fluid exiting the at least one opening is directed: towards the center of the blood vessel; and / or, away from the blood vessel wall.

[0037] In one embodiment, the at least one opening is configured to direct fluid exiting the catheter via the opening in a direction substantially parallel to the direction of blood flow within the vessel.

[0038] In one embodiment, at least one opening is provided behind the tip portion.

[0039] In one embodiment, the body includes: a first portion extending a first length from the proximal end; a second portion extending a second length from one end of the first portion to the tip portion, and wherein the second portion includes at least one opening extending through the body.

[0040] In one embodiment, the second portion is configured to be positioned entirely within the blood vessel in use.

[0041] In one embodiment, at least one of the openings is a self-closing opening operable between a resting closed position and a forced open position.

[0042] In one embodiment, the plurality of self-closing openings is at least one of: a cross-shaped slit; a U-shaped slit; an I-shaped slit; a curved slit.

[0043] In one embodiment, the plurality of self-closing openings are in the forced open position when at least one of the following conditions occurs: the internal pressure is greater than the external pressure; and the external pressure is greater than the internal pressure.

[0044] In one embodiment, the catheter body is made of at least one of: a flexible material; fluorinated ethylene propylene (FEP); polytetrafluoroethylene (PTFE); silicone; and, polyurethane.

[0045] In one embodiment, the tip tapers to a narrower distal end.

[0046] In one embodiment, the diameter of the narrow distal end is at least one of: less than 90% of the diameter of the body; less than 80% of the diameter of the body; less than 50% of the diameter of the body; between 40% and 10% of the diameter of the body; approximately 30% of the diameter of the body; and, approximately 20% of the diameter of the body.

[0047] In one embodiment, the catheter includes features configured to assist in orienting the catheter within a blood vessel.

[0048] In one embodiment, the proximal end of the catheter is connected to the hub and the features are used to control the orientation of the catheter relative to the hub.

[0049] In one embodiment, the feature includes a visual marker that is: provided near the proximal end; and / or, disposed on the first portion, wherein the visual marker indicates at least one of: a side of the catheter that should contact the blood vessel; a side of the catheter that should face away from the blood vessel; a position of the blood vessel contacting portion; a direction of the lumen angle.

[0050] In a broad form, one aspect of the present invention seeks to provide a catheter for insertion into a patient's blood vessel, the catheter comprising an elongated body extending between a proximal end for connection to a central portion and a distal end at a tip portion thereof, the body having a circumferential wall and comprising a first portion extending a first length from the proximal end and defining a closed portion of the wall and a second portion extending a second length from an end of the first portion toward the tip portion, the second portion defining an at least partially open portion of the wall having a plurality of self-closing openings arranged to allow fluid to flow into or out of the second portion of the body, wherein the self-closing openings are operable between a static closed position and a forced open position.

[0051] In one embodiment, the tip tapers to a narrower distal end.

[0052] In one embodiment, the diameter of the narrow distal end is at least one of: less than 90% of the diameter of the body; less than 80% of the diameter of the body; less than 50% of the diameter of the body; between 40% and 10% of the diameter of the body; approximately 30% of the diameter of the body; and, approximately 20% of the diameter of the body.

[0053] In one embodiment, the plurality of self-closing openings are at least one of: a cross-shaped slit; a V-shaped slit; a U-shaped slit; an I-shaped slit; a curved slit.

[0054] In one embodiment, the second portion is made of at least one of: a flexible material; fluorinated ethylene propylene (FEP); polytetrafluoroethylene (PTFE); silicone; and, polyurethane.

[0055] In one embodiment, the plurality of self-closing openings are in the forced open position when at least one of the following conditions occurs: the internal pressure is greater than the external pressure; and the external pressure is greater than the internal pressure.

[0056] It should be understood that the broad forms of the invention and their respective features can be used in combination and / or independently, and reference to the individual broad forms is not intended to be limiting. In addition, it should be understood that the features of the method can be performed using the system or device, and the features of the system or device can be implemented using the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Various examples and embodiments of the present invention will now be described with reference to the accompanying drawings, in which:-

[0058] Figure 1 is a schematic side view of a prior art catheter positioned in situ within a patient's blood vessel;

[0059] Figure 2 is a schematic side view of a first example of a catheter for insertion into a blood vessel of a patient;

[0060] Figure 3 is a schematic side view of a second example of a catheter for insertion into a blood vessel of a patient;

[0061] Figure 4 is a schematic side view of another example of a catheter inserted into a blood vessel and used to deliver fluid into the bloodstream;

[0062] Figure 5A is a schematic side view of another example of a catheter inserted into a blood vessel and used to deliver fluid into the bloodstream;

[0063] Figure 5B is along Figure 5A A schematic cross-sectional view taken along line AA' of FIG. 1 , showing fluid flowing out of the catheter into the blood vessel;

[0064] Figure 6 is a schematic side view of another example of a catheter;

[0065] Fig. 7A is a schematic side perspective view of another example of a catheter;

[0066] Figure 7B yes Fig. 7A A schematic end view of a catheter of;

[0067] Figure 7C yes Fig. 7A A schematic internal end view of a catheter of;

[0068] Fig.7D yes Fig. 7A A schematic close-up view of the catheter end of ;

[0069] Fig. 7E yes Fig. 7A A schematic perspective internal view of a catheter end portion of;

[0070] Figure 7F yes Fig. 7A a second schematic perspective interior view of a catheter end portion of;

[0071] Fig. 8A It shows that the Fig. 7A A schematic diagram of an example of fluid flow through a catheter-venous opening;

[0072] Figure 8B is a schematic diagram showing an example of saline diffusion during fluid flow during maintenance of a vein patency by a conventional catheter;

[0073] Figure 8C It is shown Fig. 7A Schematic diagram of an example of saline diffusion during fluid flow during the catheter to maintain vein patency;

[0074] Fig.8Dis a schematic diagram showing an example of blood flow around a conventional catheter during fluid flow to maintain a vein open;

[0075] Fig. 8E is shown during the fluid flow that keeps the vein open Fig. 7A A schematic diagram of an example of blood flow around a catheter;

[0076] Fig. 9A It is shown Fig. 7A A schematic diagram of an example of flushing fluid flow through a catheter;

[0077] Fig. 9B is a schematic diagram showing an example of saline diffusion during irrigation fluid flow in a conventional catheter;

[0078] Fig. 9C It is shown Fig. 7A A schematic diagram of an example of saline diffusion during irrigation fluid flow in a catheter;

[0079] Fig.9D is a schematic diagram showing an example of fluid velocity during flow of irrigation fluid in a conventional catheter;

[0080] Fig.9E It is shown Fig. 7A A schematic diagram of an example of a fluid velocity of a catheter during flushing fluid flow;

[0081] Fig.9F is a schematic diagram showing an example of shear stress in a conventional catheter during flow of irrigation fluid;

[0082] Figure 9G It is shown Fig. 7A A schematic diagram of an example of shear stress on a catheter during flow of an irrigation fluid;

[0083] Fig.10 is a graph showing the relationship between ramp size and shear stress within a blood vessel;

[0084] Fig.11 is a schematic side view of an example of a catheter tip for insertion into a patient's blood vessel;

[0085] Fig.12 is a schematic side view of a sixth example of a catheter for insertion into a blood vessel of a patient;

[0086] Fig.13 is a schematic side view of a seventh example of a catheter for insertion into a blood vessel of a patient;

[0087] Figures 14A to 14E is a schematic side view of an eighth example of a catheter for insertion into a blood vessel of a patient;

[0088] Fig.15is a schematic side view of a ninth example of a catheter for insertion into a blood vessel of a patient;

[0089] Fig.16 is a schematic side elevational view of a tenth example of a catheter for insertion into a blood vessel of a patient;

[0090] Fig.17 is a schematic side elevational view of an eleventh example of a catheter for insertion into a blood vessel of a patient. DETAILED DESCRIPTION

[0091] Now refer to Figure 2 An example of a catheter 200 for insertion into a blood vessel of a patient is described.

[0092] It should be understood that, as used herein, the term catheter refers to a range of medical devices for insertion into a patient's blood vessels, including peripheral intravenous catheters (PIVCs) or midline catheters for delivering intravenous (IV) fluids (e.g., medications, nutrients, etc.) to a patient or for withdrawing blood or fluids for sampling, arterial catheters for withdrawing blood and hemodynamic monitoring, and other types of catheters (e.g., renal arteriovenous fistula (AVF) catheters, central venous catheters, etc.).

[0093] A midline catheter (usually 7.5 cm to 20 cm in length) is inserted into the basilic, cephalic, or brachial vein near the antecubital fossa. The tip of the catheter does not extend beyond the distal axillary vein in the upper arm.

[0094] In this example, the catheter 200 includes a slender body 210, which extends between a proximal end 211 for connecting to a central portion 220 and a distal end 212 at a tip portion 213 thereof, the body 210 having a circumferential wall 215 and including a first portion 214 extending a first length L1 from the proximal end 211 and defining a closed portion of the wall and a second portion 216 extending a second length L2 from the end of the first portion 214 toward the tip portion 213, the second portion 216 defining an at least partially open portion of the wall 215 having a plurality of openings 230 arranged to allow fluid to flow into and out of the second portion 216 of the body 210.

[0095] The above arrangement provides a number of advantages.

[0096] By providing a plurality of openings in the circumferential wall in a portion of the catheter, fluid is permitted to enter / leave the catheter from a plurality of locations around the circumference in addition to the fluid outlet port disposed at the distal end of the catheter. Thus, fluid outflow is not concentrated at one point on the vascular intima of the vessel wall, thereby minimizing the potential for inflammation or phlebitis. Furthermore, because fluid is able to exit the catheter around the circumference of the body, in at least some examples during a flushing procedure, forces acting on the catheter body may cause the catheter to be substantially centered within the vessel, ensuring that the body is spaced apart from the vascular intima, thereby preventing drag and minimizing the potential for tissue damage or erosion and infiltration of the vessel wall.

[0097] Thrombotic occlusion at the catheter tip is also eliminated due to multiple alternative fluid entry / exit points in the catheter body in addition to the fluid outlet at the tip. Thus, the above arrangement is particularly suitable for use in conjunction with a Keep the Venous Open (TKVO) protocol and / or intermittent flushing. Ball valve occlusion during aspiration is also eliminated due to the ability of fluid to enter the catheter through multiple openings while bypassing the fluid inlet / outlet at the tip.

[0098] The plurality of openings in the catheter body further serve to reduce the surface area of ​​the body, which reduces the area on which biofilm can form. In addition, the openings in the body provide an alternative conduit for fluid flow, resulting in a reduction in outflow shear stress applied to the vessel wall at the distal outflow region 212, while also reducing the risk of biofilm migration into the bloodstream. The reduction in shear stress is beneficial because it limits irritation to the vessel wall and any potential inflammatory response.

[0099] A further benefit is reduced outflow or inflow resistance due to providing multiple fluid entry / exit points in the catheter body, which improves the transmission of the pulsatile arterial waveform.

[0100] It will be apparent from the above and the remaining description that centering of the catheter is not required, and in some embodiments, it may be desirable for the catheter to contact the vessel wall. However, the openings may still provide benefits, such as providing alternative fluid entry / exit points, etc.

[0101] It will also be noted that the above described arrangement includes an opening 230.1 in the tip region 213. However, it is not essential to include the opening 230.1 in the tip region 213, and in some cases it may be preferred to include an opening in the second portion 216 only behind the tip portion 213.

[0102] A number of further features will now be described.

[0103] In one example, a plurality of openings are arranged in a matrix or a mesh. In such an arrangement, the circumferential wall of the second portion of the catheter body can form a mesh (web), a mesh (mesh) or a lattice structure, which provides high rigidity, ensures the structural integrity of the wall, and simultaneously minimizes the surface area of ​​the wall, thereby causing the accumulation of biofilm to be reduced. The matrix structure can have a wavy pattern, which regularly repeats and promotes the uniform fluid inflow / outflow around the circumference of the catheter body. Matrix or mesh structure are usually fine grids, to ensure that an introducer needle (introducer needle) can not easily protrude through any one of a plurality of openings.

[0104] In another example, the plurality of openings are oval and extend in the elongated direction of the body. The plurality of openings may include openings having substantially the same length or openings having different lengths. The oval openings may help reduce the surface area of ​​the second portion of the body.

[0105] In other examples, the plurality of openings can have different sizes depending on their location on the second portion. For example, the plurality of openings can include a first arrangement of openings on a first side of the second portion and a second arrangement of openings on an opposite second side of the second portion, the openings on the first side being larger than the openings on the second side. In some examples, the diameter of the openings on the first side can be 1.5 to 2 times the diameter of the openings on the second side.

[0106] The plurality of openings can reduce the surface area of ​​the second portion of the body by 30-40%, 40-50%, 50-60%, 60-70% and 70-80%. More specifically, the surface area can be reduced by 30-35%, 35-40%, 40-45%, 45-50%, 50-55%, 55-60%, 60-65%, 65-70%, 70-75% and 75-80%.

[0107] In one example, the ratio of the first length to the second length is approximately in the range of 0.5 to 2. In other words, the first length is approximately between one-third and two-thirds of the total length of the catheter, and the second length is approximately two-thirds to one-third of the total length. This configuration allows the first length to vary to accommodate variable patient sizes and vessel depths. In addition, this also ensures that multiple openings are provided over a large portion of the body while maintaining a closed solid portion extending from the proximal end of the body, thereby preventing backtracking of fluid from the catheter.

[0108] In one example, the second part comprises a tip portion, however this is not necessary and the tip portion may have a closed circumferential wall or alternatively may have an opening arranged independently of the opening provided in the second part. In a preferred example, the second part is provided behind the tip region, in which case the opening in the tip region may be omitted.

[0109] Typically, the circumferential wall defines an inner surface and an outer surface, and at least a portion of at least one of the inner surface and the outer surface is textured or roughened to reduce adhesion of biofilm to the body in use. Any suitable form of microtexture or surface roughness can be applied to reduce the smoothness of the polymer surface of the body. In some examples, the surface of the tip portion can be textured or roughened in a similar manner.

[0110] In some examples, an antimicrobial coating is applied to at least a portion of the circumferential wall to reduce biofilm adhesion. A suitable coating may be oil-impregnated polydimethylsiloxane (iPDMS).

[0111] Typically in use, when the catheter is inserted into a blood vessel and fluid outflow is at a constant rate, the force acting on the body may cause a spacing to be maintained between the body and the inner wall of the blood vessel. In one example, at least a portion of the body is substantially concentrated in the blood vessel. In fact, a "fluid cushion" is provided between the catheter body and the blood vessel wall, thereby preventing the catheter tip from dragging on the blood vessel intima and causing damage to it. Thereby avoiding tissue erosion and irritation, reducing the possibility of phlebitis and infiltration. However, this is not necessary, and in other examples, the catheter can be configured to contact the blood vessel wall in use.

[0112] In another broad form, there is provided a catheter for insertion into a patient's blood vessel, the catheter comprising an elongated body extending between a proximal end for attachment to a central portion and a distal end at a tip portion thereof, the body having a circumferential wall and including a portion defining an at least partially open portion of the wall, the portion having a plurality of openings arranged to permit fluid to flow out of the body into the blood vessel such that, in use, when the catheter is inserted into the blood vessel and fluid outflow is at a constant rate, forces acting on the body cause a spacing to be maintained between the body and the inner wall of the blood vessel.

[0113] In yet another more general form, a catheter assembly is provided, comprising a catheter tube for insertion into a patient's blood vessel, the catheter tube having an elongated body extending between a proximal end and a distal end at a tip portion thereof, the body having a circumferential wall and comprising a first portion extending a first length from the proximal end and defining a closed portion of the wall and a second portion extending a second length from an end of the first portion toward the tip portion, the second portion defining an at least partially open portion of the wall, having a plurality of openings arranged to allow fluid to flow into and out of the second portion of the body. The assembly also includes a central portion connected to the proximal end of the catheter tube; and an introducer needle inserted through the catheter tube, having an edge protruding beyond the distal end of the hose to penetrate the vessel wall.

[0114] Typically, the catheter assembly also includes a guidewire that extends through the lumen of the introducer needle for guiding the catheter tube into the blood vessel. This allows the catheter to be properly placed in the blood vessel using a modified Seldinger technique. Alternatively, the guidewire can be introduced into the blood vessel using a separate catheter using the conventional Seldinger technique.

[0115] exist Figure 2 In the example shown, the plurality of openings are oval in shape and have substantially the same length, and the length L l The length L is about one third of the total length of the main body, and the length L2 is about two thirds of the total length of the main body.

[0116] Now refer to Figure 3 A second example of a catheter 300 for insertion into a patient's blood vessel is described. The catheter 300 includes an elongated body 310 extending from a proximal end 311 connectable to the central portion 220 to a distal end 312, at which a fluid outlet is provided in a tip portion 313 thereof. The body 310 includes a first portion 314 and a second portion 316, the first portion 314 being a closed portion, and the second portion 316 defining an at least partially open portion having a plurality of openings 330, 332, 334 in a circumferential wall portion 315 thereof. In this example, the plurality of openings 330, 332, 334 are elliptical, configured to extend in the elongated direction of the body 310 and include openings of different lengths.

[0117] In this example, at least one of the inner and / or outer surfaces of the circumferential wall 315 of the body 310 is textured or roughened (indicated by cross-hatching) to reduce adhesion of biofilm to the body.

[0118] In another example, a catheter for insertion into a blood vessel of a subject includes a lumen that is angled to direct flow from an outlet at an angle that is offset from an axis of the catheter. Figure 4 An example of such an arrangement is described.

[0119] In this example, the catheter 400 includes an elongated body 410 extending between a proximal end 411 configured to be connected to a central portion 420 and a distal end 412 configured to be inserted into a blood vessel of a subject. The body also includes a tip portion 413 at the distal end 412, the tip portion having inner and outer tapered profiles and including an outlet 417. An inner lumen 418 extends from the proximal end 411 to the outlet 417.

[0120] In this example, the lumen 418 is angled at least in the tip portion 413 so as to direct the fluid flow from the outlet 417 at an angle that deviates from the axis A of the catheter, as shown by arrow F. Specifically, in one example, the inclined portion of the lumen defines a ramp 418.1 that is at a greater angle than the internal taper of the lumen on the opposite side of the catheter. In this arrangement, the catheter 400 can be arranged to contact the vessel wall 12, wherein the ramp 418.1 is oriented to direct the fluid leaving the catheter away from the vessel wall 12, toward the center of the vessel. This reduces fluid pressure and stress, particularly shear stress, on the vessel wall, thereby helping to reduce inflammation or irritation of the vessel wall.

[0121] It will therefore be appreciated that in this example, by directing outflow, this allows the catheter to come into contact with the vessel wall whilst still obtaining the benefit of reducing stress on the vessel wall.

[0122] A number of additional features of the angled lumen will now be described.

[0123] The angled portion of the lumen may be provided only in the tip portion 413 of the catheter body 410 including the tapered outer profile, but may additionally extend into at least a portion of the body 410 behind the tip portion, depending on the preferred implementation.

[0124] The angle can be defined as a portion of the lumen taper that allows the lumen to narrow toward the outlet 417, which can help maintain fluid pressure in the lumen. In one example, the lumen is asymmetrically angled, which can help ensure that the fluid is directed to the center of the vessel and in one example causes the outlet 417 to be offset from the axis A and optionally angled relative to the axis A. However, this is not required and other configurations can be used.

[0125] In one example, the walls of the lumen on opposite sides of the tip portion are tilted differently, so that, for example, the lumen on one side of the tip portion tapers inwardly to different degrees, thereby creating an inclined inner surface to thereby direct outflow toward the center of the blood vessel. In one specific example, the wall on one side of the tip portion is substantially aligned with the lumen in the elongated body, and the wall on the opposite side of the tip portion is angled relative to the lumen in the elongated body, and examples of such arrangements are described in more detail below.

[0126] Additionally, the angled portion of the lumen may be straight, but this is not required and a curved profile may instead be used.

[0127] exist Figure 4In the example shown, the inner cavity 410 in the tip region and the outer surface of the tip have similar complementary profiles, which means that the wall thickness of the catheter is similar throughout the body 410. In this case, the tip region can have an asymmetric outer tapered profile, at an angle offset from the axis of the catheter and / or arranged so that the outlet is offset from the axis of the catheter. However, it should be understood that this is not necessary, or, the change in the catheter wall thickness along the length of the catheter body 410 can be used to achieve the angle of the inner cavity.

[0128] In one example, the lumen in the tip portion is disposed at an angle relative to the axis of the catheter that is greater than 1°, greater than 2°, greater than 5°, greater than 10°, less than 15°, or less than 20°, although it will be appreciated that other angles may be used.

[0129] In another example, a catheter for insertion into a blood vessel of a subject includes a blood vessel contacting portion that is softer than other portions of the catheter.

[0130] Now refer to Figure 5A and Figure 5B An example of such arrangement is described.

[0131] In this example, catheter 500 includes an elongated body 510 extending between a proximal end 511 configured to be connected to a central portion 520 and a distal end 512 configured to be inserted into a blood vessel of a subject. The body also includes a tip portion 513 at the distal end 512 having an outer tapered profile and including an outlet 517. An inner lumen 518 extends from the proximal end 511 to the outlet 517.

[0132] In this example, the catheter body 510 includes a vessel contacting portion 510.1 that is softer than the rest of the catheter. In this regard, the vessel contacting portion 510.1 is arranged so that it will contact the vessel wall 12 preferentially over the rest of the catheter, which is typically accomplished by making the lower half of the catheter the vessel contacting portion. This portion of the catheter may be made of a different material, or of a material that has been treated and / or coated differently, such that the vessel contacting portion deforms when in contact with the vessel wall 12, e.g. Figure 5B This distributes the load, thereby reducing the forces and pressures on the surface of the vessel, which helps to reduce inflammation or irritation of the vessel wall. Nevertheless, the remainder of the catheter body 510 provides sufficient rigidity to allow the catheter to be used in a normal manner, in particular to maintain the overall shape of the catheter and to support the catheter during insertion into a vessel, allowing the catheter to be used in a substantially normal manner.

[0133] Another benefit of this arrangement is that stagnation is reduced in the area immediately adjacent to the catheter. In this regard, with conventional round catheters, there is a small spacing between the catheter and the vessel wall in a significant area. With reduced flow in this area, this can lead to stagnation, which can lead to coagulation, thrombosis, or occlusion. In contrast, in the current arrangement, the small spacing area is minimized, thereby minimizing the volume where stagnation can occur.

[0134] A number of further features of the vessel contacting portion will now be described.

[0135] In one example, the vessel contact portion is made of a different material than the rest of the body, which can be accomplished using dual extrusion or other similar manufacturing processes. However, this is not required, and in another example, the vessel contact portion can be a surface layer applied to at least a portion of the body. In one example, the vessel contact portion is made of polyurethane, but it should be understood that other suitable materials can be used.

[0136] In one example, the vessel contacting portion has a Shore hardness of less than 50A, less than 40A, less than 30A, less than 20A, or less than 10A. In this example, the non-vessel contacting portion of the catheter body has a Shore hardness of at least one of greater than 50A, greater than 40A, greater than 30A, greater than 20A, and greater than 10A. However, it should be understood that the vessel contacting material can have any range of stiffness lower than the non-vessel contacting portion of the catheter body. In another example, the stiffness ratio of the non-vessel contacting portion to the vessel contacting portion (including material stiffness or other overall mechanical properties, such as Young's modulus) is greater than 0.01:1, greater than 0.05:1, greater than 0.1:1, or greater than 0.5:1.

[0137] Typically, the blood vessel contact portion is disposed on the underside of the body, at least behind the tip portion, and optionally extends into the tip portion. In a specific example, the catheter body 510 includes a first portion 514 extending a first length from the proximal end 511 and a second portion 516 extending a second length from the end of the first portion 514 to the tip portion 513, wherein the blood vessel contact portion 510.1 is disposed in the second portion 516.

[0138] It should be understood that the angled lumen and vessel contacting portions described above may be used in combination, optionally with openings as previously described. An example of such an arrangement is Figure 6 shown.

[0139] In this example, catheter 600 includes an elongated body 610 extending between a proximal end (not shown) and a distal end 612. The body includes a tip portion 613 at distal end 612 having an outer tapered profile and including an outlet 617. A lumen 618 extends from the proximal end to the outlet 617.

[0140] In this example, only the second portion 616 of the catheter body is shown, extending from the end of the first portion (not shown) to the tip portion 613. The vessel contacting portion 610.1 is disposed on the underside of the second portion 616, and the lumen 618 includes an angled ramp 618.1, which in this example extends through the second portion 616 and the tip portion 613. As also shown, an opening 630 is disposed in the second portion 616 to allow inflow and / or outflow through the sidewall of the catheter body 610. Although only a single opening is shown, it should be understood that multiple openings may be provided and that the single opening is for illustrative purposes only.

[0141] It will therefore be appreciated that the above arrangement provides a combination of the benefits previously described for the various concepts. However, in this example, the opening 630 is not used to center the catheter within the vessel, but rather to facilitate flow and prevent blood stagnation and clotting.

[0142] A number of additional features will now be described.

[0143] In one example, the second portion is configured to be completely contained within the blood vessel, while the first portion generally extends only a minimum length in the blood vessel. This ensures that portions of the catheter that do not include the blood vessel contacting portion do not contact the inner wall of the blood vessel. In one example, the length of the second portion is at least 30% of the catheter length, at least 40% of the catheter length, at least 50% of the catheter length, at least 60% of the catheter length, and at least 65% of the catheter length.

[0144] In one example, the opening 630 is disposed on a side of the body containing the blood vessel contacting portion 610.1, and optionally may form a portion of the blood vessel contacting portion 610.1. Positioning the opening 630 near or in the blood vessel contacting portion 610.1 allows the opening to be configured such that fluid exiting the opening 630 enters the area between the blood vessel and the blood vessel contacting portion, which may help cushion the blood vessel wall and / or prevent stagnation of blood flow in the area near the catheter.

[0145] However, this is not required and the openings may alternatively be provided on a side of the body opposite the side containing the vessel contacting portion, for example to direct flow away from the vessel wall and / or towards the centre of the vessel.

[0146] The openings may also be opened to direct fluid exiting the catheter through the openings in a direction generally parallel to the direction of blood flow within the vessel, which also reduces flow agitation in the vessel.

[0147] In one example, the opening 630 is disposed rearwardly of the tip portion 613 and optionally in the second portion 616 of the catheter body 610. As will be described in more detail below, in one example, the opening is a self-occluding opening operable between a resting closed position and a forced open position.

[0148] When providing a lateral opening 630, the tip tapers toward the narrower distal end so that the lumen also tapers, thereby maintaining pressure in the lumen to promote flow through the lateral opening. In one example, the diameter of the narrow distal end is less than 90% of the body diameter, less than 80% of the body diameter, less than 50% of the body diameter, between 40% and 10% of the body diameter, about 30% of the body diameter, or about 20% of the body diameter, although other sizes can be used according to preferred implementations.

[0149] In a further example, the outlet 617 may also be self-closing, which may be used to facilitate increased flow through the side opening 630. In this regard, the outlet 617 may be configured to remain closed until a higher pressure is reached in the lumen, causing the side opening to open in preference to the outlet 617. In another example, the outlet may be configured to open only to allow for insertion of a guidewire or needle, such that all outflow is through the side opening, and wherein the outlet 617 is used only to facilitate insertion of a catheter.

[0150] In one example, the plurality of self-closing openings are cross-shaped slits, U-shaped slits, V-shaped slits, I-shaped slits, curved slits, or slits of other suitable shapes or configurations.

[0151] The second portion of the catheter is typically made of one or more of a flexible material, silicone, fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE) and / or polyurethane, depending on the desired properties, particularly whether it is to be used as a blood vessel contacting portion.

[0152] In one example, the plurality of self-closing openings are in a forced open position when the internal pressure is greater than the external pressure or when the external pressure is greater than the internal pressure.

[0153] In the above example, the catheter can include features configured to assist in orienting the catheter within a blood vessel. Specifically, this can be used to ensure that the catheter is oriented within the blood vessel so that the vessel contacting portion contacts the blood vessel (as opposed to other portions of the catheter body) and / or ensure that the angled lumen directs fluid away from the blood vessel wall.

[0154] In one example, a catheter is coupled to the hub and the features are used to control the orientation of the catheter relative to the hub, such as by having a coupling mechanism that engages the hub with the catheter in a specific orientation so that the hub can be used to orient the catheter within a vessel.

[0155] In another example, the feature can include a visual marker provided near the proximal end and / or on the first portion. In this case, the visual marker can indicate the side of the catheter that should contact the blood vessel, the side of the catheter that should be away from the blood vessel, the location of the blood vessel contacting portion, or the angular direction of the lumen. In this case, it should be understood that the catheter can be visually inspected before or after insertion to ensure that the catheter is properly positioned.

[0156] Now refer to 7A to 7F Another specific example of a catheter is described.

[0157] In this example, the catheter includes an elongated body 710 extending between a proximal end (not shown) and a distal end 712. The body includes a tip portion 713 at the distal end 712 having an outer tapered profile and including an outlet 717. A lumen extends from the proximal end to the outlet 717.

[0158] In this example, only the second portion 716 of the catheter body is shown, extending from the end of the first portion (not shown) to the tip portion 713. The vessel contacting portion 710.1 is provided on the underside of the second portion 717, while the lumen includes an angled ramp 718.1, which in this example extends through the tip portion 713 and optionally through some or all of the second portion.

[0159] As also shown, openings 730 are provided in the second portion 716 to allow inflow and / or outflow through the sidewall of the catheter body 710, with the openings being angled to direct flow along the vessel generally parallel to the direction of blood flow.

[0160] The operation of this arrangement will now be described in more detail with reference to FIGS. 8 and 9 .

[0161] In this regard, susceptibility to thrombosis is generally caused by three considerations, namely blood stasis, endothelial damage, and hypercoagulability. Blood stasis is slow-moving, stagnant blood caused by a cannula blocking the blood and causing an area of ​​recirculating blood flow (i.e., stagnation). Endothelial damage is caused by the friction of the cannula rubbing against the important endothelial cells lining the vein and the force of infusing saline, while hypercoagulability is a patient-specific factor that is related to a person's blood and other aspects that may make their blood more likely to clot.

[0162] The above-described catheters are specifically arranged to address blood stasis and endothelial damage, particularly by preventing stasis, reducing the effects of contact between the catheter and the blood vessel, and the outflow of fluids that have entered the blood vessel.

[0163] In this regard, the angled lumen 718.1 directs fluid (e.g., saline) into the moving blood flow, thereby reducing the impact of the flow on the vessel walls, while the vessel contacting portion formed of a softer material allows the device to conform to the vessel, thereby reducing both the forces on the vessel and the area beneath a traditional circular cross-section catheter that may promote stagnation.

[0164] In use, the device is typically used during TKVO (keep the vein open) or irrigation.

[0165] TKVO is a common practice worldwide and involves the use of a continuous infusion of saline to "keep the vein open" so that the cannula does not clot. TKVO rates of 5-50 ml / h are insufficient to maintain a "patent tip" (i.e. a good outflow of saline from the tip) in some conventional catheters. In contrast, 7A to 7F The above catheter works well at 40 ml / h, and the flow example is as follows Fig. 8A 7, which highlights sufficient fluid flow through the outlet 717 and the opening 730 to ensure that blood moves around the cannula and reduce the amount of stagnant blood.

[0166] Figure 8B and Figure 8C Shown are the results from conventional catheters and 7A to 7F Comparison of the outflow of the above catheter. In this example, 7A to 7F The catheter results in similar diffusion of saline under TKVO, but the outflow is angled upward from the angled lumen 718.1, reducing disturbance to the vessel.

[0167] Fig.8D and Fig. 8E shows the conventional catheter and 7A to 7F Comparison of blood flow around the catheter above. In this example, 7A to 7F The catheter results in improved flow around the catheter and reduced stagnation through a combination of increased contact surface area between the catheter and the vessel (which reduces areas where stagnation may occur) and outflow through openings 730 which promote blood flow.

[0168] Despite these benefits, there is no significant effect on high or low shear stresses, which means 7A to 7F The catheter has no obvious disadvantages.

[0169] Flushing is the practice of infusing a certain amount of saline (e.g. 3-10 ml) at regular intervals throughout the day to clean the blood cannula, which is a common practice worldwide and included in clinical guidelines. There is no prescribed infusion rate to follow, but in general a 5 ml syringe can be used and 5 ml will be infused in a few seconds. However, this infusion rate affects the fluid dynamics and thus the shear stress and endothelial injury.

[0170] The flushing was modeled using a flushing rate of 1 ml / s, which is commonly used in the scientific literature, and 7A to 7F An example of the resulting flow rate of a catheter is Fig. 9A shown.

[0171] Fig. 9B and Fig. 9C Shown are the results from conventional catheters and 7A to 7F Comparison of the saline diffusion of the above catheters. In this example, 7A to 7F The catheter results in similar diffusion of saline during flushing, but the angled flow upward from the angled lumen 718.1 reduces disturbance to the vessel.

[0172] Fig.9D and Fig.9E Shown are the results from conventional catheters and 7A to 7F Comparison of flow rates during flushing of the above catheters. In this example, 7A to 7F The catheter results in increased flow rates due to a reduced outflow diameter compared to conventional catheters, but has an angle that prevents vessel wall rupture.

[0173] Fig.9F and Figure 9G shows the conventional catheter and 7A to 7F Comparison of shear stress during irrigation in the above catheters. In this example, 7A to 7F The catheter results in a significant reduction in wall shear stress, thereby reducing vascular inflammation and irritation. For example, compared with conventional catheters ( Fig.9F and Figure 9G ) compared to FIG. 7A to FIG. 7F In the catheter, the shear stress on the vessel wall near the tip area was reduced by 50%.

[0174] When flushing is performed, the cannula is used with either TKVO or zero infusion after flushing. If zero infusion is used, blood will creep back into the cannula after flushing. FIG. 7A to FIG. 7F The catheter changes the profile of blood flowing around the device and results in less stagnation volume around the cannula regardless of TKVO or zero infusion, but at zero infusion blood can flow into the cannula and the holes allow more blood to enter.

[0175] It will therefore be appreciated that this results in an improved catheter which reduces problems associated with vascular inflammation and blood stasis.

[0176] Further testing was performed to evaluate the ideal angle of the internal taper of the tip lumen wall, and modeling results are shown in Fig.10 This is for Fig.11 The tip arrangement shown in is performed.

[0177] In this example, the tip includes an upper wall aligned with the lumen in the elongated portion of the catheter. The length of the tip is 1600 μm compared to the total catheter length of 32000 μm, but it will be appreciated that these values ​​are for illustrative purposes only and that different lengths may be used in practice, e.g. depending on the preferred embodiment and / or intended use. The main elongated body of the catheter also has an inner lumen diameter of 800 μm and an outer diameter of 1100 μm. Different ramp heights R were tested, such as Fig.10 As shown, the optimal ramp height selected was 125 μm, resulting in a ramp angle of approximately 4.5°. Based on these dimensions, this resulted in an exit diameter of 675 μm for the lumen and an external exit diameter of 825 μm for the tip. This arrangement achieved a 60% reduction in shear stress (12.7v5.1 Pa) compared to the control PIVC and effectively directed the injected fluid away from the vein wall and into the flowing venous blood.

[0178] As previously mentioned, catheters may be used in conjunction with openings, and further examples of these will now be described in more detail.

[0179] Now refer to Fig.12 Another example of a catheter 1200 for insertion into a blood vessel of a patient is described.

[0180] exist Fig.12 In the example of the present invention, the catheter 1200 includes an elongated body 1210 extending from a proximal end 1211 that can be connected to the central part 220 to a distal end 1212 at its tip portion 1213, wherein a fluid outlet may also be provided. The body 1210 includes a first portion 1214 and a second portion 1216, wherein the first portion 1214 is a closed portion and the second portion 1216 defines an at least partially open portion having a plurality of openings 1230 in its circumferential wall portion.

[0181] Based on the previous example, the length of the first portion 1214 is approximately two-thirds of the total length of the body 1210, and the combined length of the tip portion 1213 and the second portion 1216 is approximately one-third of the total length of the body 1210, although the ratios of these lengths may vary depending on the intended use of the catheter 1200.

[0182] In this case, the openings 1230 are defined as circular holes, but it should be understood that any suitable shape of openings 1230 may be used. The plurality of openings 1230 may be arranged in an array or any other repeating pattern with regular spacing between adjacent openings. The openings 1230 may have different sizes depending on their positioning on the catheter. Specifically, in this example, the plurality of openings 1230 include a first arrangement of relatively larger holes across a first side of the second portion 1216 and a second arrangement of relatively smaller holes on an opposite second side of the second portion 1216.

[0183] In use, catheter 1200 can be inserted into the patient's blood vessel so that the first side with relatively large holes will be oriented upwards, and the second side with relatively small holes will be oriented downwards. In this way, the different sizes of the holes can be used to explain the change of the flow through the first side and the second side under the influence of gravity. For example, compared with the upwardly oriented (i.e. top) side of the inserted catheter 1200, it can be expected that a larger flow will pass through the downwardly oriented (i.e. bottom) side of the inserted catheter 1200, which may cause an uneven flow around the circumference of the inserted catheter 1200, so that the inserted catheter 1200 may not be properly concentrated in the blood vessel. However, this effect can be offset by using smaller holes at the bottom of the inserted catheter 1200 and using larger holes at the top of the inserted catheter 1200, thereby changing the relative flow ratio, thereby helping to properly concentrate the inserted catheter 1200 in the blood vessel, although as previously mentioned, it may not be necessary to concentrate.

[0184] In some embodiments, the diameter of the holes on the first side of the second portion 1216 can be 1.5 to 2 times the diameter of the holes on the second side of the second portion 1216. In one particular embodiment using a standard 20G catheter size (having an outer diameter of about 1.1 mm and an inner diameter of about 0.9 mm), the larger hole on the first side of the second portion 1216 can have a diameter of about 0.4 mm, while the smaller hole on the second side of the second portion 1216 can have a diameter of about 0.25 mm. It should be understood that the size of the holes can vary depending on the specifications of the catheter 1200 and the specific application.

[0185] In some examples, more than two holes of different sizes may be used and arranged so that the size of the holes gradually transitions from the first side to the second side. These arrangements of holes of different sizes may have the same or different spacing between adjacent holes. It should be understood that similar size variations may be applied to the construction of openings arranged in a matrix or mesh configuration as in the previous examples.

[0186] According to the previous example, the second portion 1216 terminates at the beginning of the solid and narrowly tapered tip portion 1213. The inner and outer circumferential walls of the first portion 1214, along with the solid tip portion 1213, are micro-textured or roughened (indicated by cross-hatching).

[0187] Now refer to Fig.13 A seventh example of a catheter 1300 for insertion into a blood vessel of a patient is described.

[0188] exist Fig.13In the example of the present invention, the catheter 1300 includes an elongated body 1312 extending from a proximal end 1311 that can be connected to the central portion 220 to a distal end 1312 at its tip portion 1313, wherein a fluid outlet may also be provided. The body 1310 includes a first portion 1314 and a second portion 1316, wherein the first portion 1314 is a closed portion and the second portion 1316 defines a portion having a plurality of self-closing openings 1330 in its circumferential wall portion.

[0189] Based on the previous example, the length of the first portion 1314 is approximately two-thirds of the total length of the body 1310, and the combined length of the tip portion 1313 and the second portion 1316 is approximately one-third of the total length of the body 1310, although the proportions of these lengths may vary depending on the intended use of the catheter 1300.

[0190] In this example, the second portion 1316 is a flexible material, such as silicone or polyurethane. The second portion 1316 ends at the start of the tip portion 1313 and is therefore located behind the tapered tip portion 1313.

[0191] In this case, the self-occluding opening 1330 is defined as a slit, but it should be understood that any suitable shape of self-occluding opening 1330 can be used. A plurality of self-occluding openings 1330 can be arranged in an array or any other repeating pattern with regular spacing between adjacent openings. The self-occluding openings 1330 can have different sizes depending on their positioning on the catheter. In particular, in this example, the plurality of self-occluding openings 1330 include a plurality of cross-shaped slits. The self-occluding opening 1330 has a static closed position and a forced open position.

[0192] In use, in addition to the fluid outlet in the tip portion 1313, the fluid also exits the catheter 1300 through the plurality of self-closing openings 1330. In this example, the diameter of the fluid outlet in the tip portion is smaller than the inner diameter of the body 1310 and / or the second portion 1316. The smaller outlet causes the internal pressure of the catheter to increase and creates an internal pressure greater than the external pressure of the catheter 1300. The fluid thereby forces the plurality of self-closing openings 1330 to open and exit the catheter 1300.

[0193] Similarly, in the example of suction, when the external pressure is greater than the internal pressure of the catheter 1300, the fluid forces the plurality of self-closing openings 1330 to open and enter the catheter 1300.

[0194] In one example, the diameter of the fluid outlet in the tip portion can be less than 50% of the body diameter. More specifically, it can be between 40% and 10% of the body diameter. In one example, the diameter of the fluid outlet in the tip portion is approximately 30% of the body diameter. In another example, the diameter of the fluid outlet in the tip portion is approximately 20% of the body diameter. In a specific embodiment using a standard 20G catheter size (with an outer diameter of approximately 1.1mm and an inner diameter of approximately 0.9mm), the fluid outlet in the tip portion can have a diameter between 0.1mm and 0.4mm or approximately 0.2mm or approximately 0.3mm. In one example, the diameter of the catheter body is between 0.4mm and 2mm, and the self-occluding opening is forced to open, and the opening diameter is between 0.01mm and 1.0mm, or between 0.05mm and 0.5mm, or between 0.11mm and 0.2mm.

[0195] Now refer to FIG. 14A to FIG. 14E An eighth example of a catheter 1400 for insertion into a patient's blood vessel is described. It should be understood that FIG. 14A to FIG. 14E The example is roughly similar to Fig.13 except for the differences in the specific arrangements of the respective second parts. FIG. 14A to FIG. 14E In the example of , the plurality of self-closing openings 1430 include a plurality of U-shaped or V-shaped slits. It should be understood that other orientations of the U-shaped or V-shaped slits may also be suitable.

[0196] Now refer to Fig.15 A ninth example of a catheter 1500 for insertion into a patient's blood vessel is described. It should be understood that Fig.15 Examples with Fig.13 The examples are generally similar except for the differences in the specific arrangements of the respective second parts. Fig.15 In the example of FIG. 1 , the plurality of self-closing openings 1530 comprises a plurality of I-shaped slits.

[0197] Now refer to Fig.16 A tenth example of a catheter 1600 for insertion into a patient's blood vessel is described. It should be understood that Fig.16 Examples with Fig.13 The examples are generally similar except for the differences in the specific arrangements of the respective second parts. Fig.16 In the example of FIG. 1 , the plurality of self-closing openings 1630 comprises a plurality of curved slits.

[0198] It should be understood that the plurality of self-closing openings may be in the form of different sizes and shapes. Fig.17 In the example of FIG. 1 , the catheter 1700 has a mixture of U-shaped slits and curved slits of varying sizes to form a plurality of self-occluding openings 1730. It should also be understood that the self-occluding openings may be arranged in rows and columns in the second portion or randomly dispersed in the second portion.

[0199] The above arrangement provides a number of advantages.

[0200] By providing a plurality of self-occluding openings in the circumferential wall in a portion of the catheter, thrombotic occlusions at the catheter tip are eliminated due to a plurality of alternative fluid entry / exit points in the catheter body in addition to the fluid outlet at the tip. In the above arrangement, when no fluid / intravenous medication or blood products are infused or when used at a TKVO rate, the self-occluding openings are in a static closed position because the internal pressure will not be sufficient to overcome the external pressure. This prevents the formation of blood components or microthrombi on the uncovered openings, resulting in occlusion in the second portion.

[0201] It should be understood that the above features can be applied to catheters having a variety of catheter gauge sizes and lengths, and that the sizes and proportions of particular features can be selected based on the size of any given catheter and taking into account the intended use of the catheter. For example, if desired, the second portion including the plurality of openings can be longer or shorter than shown in the previous examples, while the size of the openings and the diameter of the fluid outlet in the tip portion can vary depending on the catheter gauge size and other requirements.

[0202] It should also be understood that the features depicted in the figures are not necessarily shown to scale. For example, the relative size of a particular feature may be enlarged or reduced for better understanding. Similarly, simplified shapes may be used to represent features in the figures or shading or the like may be used to indicate features to avoid unnecessarily complicating the view.

[0203] It should therefore be appreciated that, in at least one example, the above-described PIVC, midline or arterial catheters can eliminate or reduce catheter "drag," occlusions, phlebitis, infiltration, biofilm adhesion, shear stress, outflow resistance, and fibrin deposition.

[0204] Throughout this specification and the claims that follow, unless the context requires otherwise, the word "comprises" and variations, will be understood to imply the inclusion of stated integers or groups of integers or steps but not the exclusion of any other integers or groups of integers.

[0205] Those skilled in the art will appreciate that many variations and modifications will become apparent. All such variations and modifications apparent to those skilled in the art should be considered to fall within the broad spirit and scope of the invention as previously described.

Claims

1. A catheter or cannula for insertion into a blood vessel of a subject, the catheter or cannula comprising: a) an elongated body extending between a proximal end configured to be connected to the central portion and a distal end configured to be inserted into a blood vessel of a subject, the body having: b) a tip portion at the distal end, the tip portion having an outer tapered profile and including an outlet; and, c) a lumen extending from the proximal end to the outlet, wherein the lumen is angled asymmetrically at the tip portion such that the lumen narrows toward the outlet and directs flow from the outlet at an angle offset from the axis of the catheter or cannula such that the fluid is directed toward the center of the blood vessel, wherein a wall on one side of the tip portion is substantially aligned with a lumen in the elongated body and a wall on an opposite side of the tip portion is angled relative to the lumen in the elongated body such that the lumen is asymmetrically angled in the tip portion.

2. The catheter or cannula of claim 1, wherein the lumen is angled with a curved profile.

3. The catheter or cannula of claim 1, wherein: a) the lumen in the tip portion is disposed at an angle greater than 1° and less than 20° relative to the axis of the catheter or cannula; and / or b) At least a portion of the lumen wall in the tip portion is disposed at an angle greater than 1° and less than 10° relative to the axis of the catheter or cannula. The catheter or cannula of claim 1 , wherein the outer tapered profile is asymmetrical.

5. The catheter or cannula of claim 1, wherein the outer tapered profile is offset at an angle from the catheter or cannula axis.

6. The catheter or cannula of claim 1, wherein the outer tapered profile causes the outlet to be offset from the axis of the catheter or cannula.

7. The catheter or cannula of claim 1, wherein at least a portion of the elongated body comprises a vessel contacting portion that is softer than other portions of the catheter, wherein at least one of: a) the vessel contacting portion is configured as at least one of the following: i) at least partially deforms upon contact with a blood vessel; and, ii) distribute the load over the vessel surface; b) wherein the blood vessel contacting portion is at least one of: i) is made of a different material from the rest of the body; and, ii) a surface layer applied to at least a portion of the body; c) The blood vessel contact part is made of polyurethane; d) the blood vessel contacting portion has a Shore hardness of less than 50A; e) the non-vascular contact portion has a Shore hardness greater than 10A; f) The ratio of the hardness of the non-vascular contact part to the vascular contact part is greater than 0.01:1; g) The blood vessel contact portion is configured as at least one of the following: i) on the underside of the body; and, ii) Behind the tip portion.

8. The catheter or cannula of claim 1, wherein the body comprises: a) a first portion extending from the proximal end to a first length; and b) a second portion extending a second length from an end of the first portion to the tip portion, and wherein the second portion includes a blood vessel contacting portion.

9. The catheter or cannula of claim 8, wherein the length of the second portion is at least 30% of the length of the catheter or cannula.

10. The catheter or cannula of claim 1, wherein the body includes at least one opening extending through the body, wherein the at least one opening is configured to allow fluid to flow into or out of the body.

11. The catheter or cannula of claim 10, wherein the at least one opening is disposed on a side of the body that includes the blood vessel contacting portion and wherein the at least one opening is configured such that fluid exiting the at least one opening enters an area between the blood vessel and the blood vessel contacting portion, thereby achieving at least one of: a) Helps cushion blood vessel walls; and b) Reduce blood flow stagnation in the area near the catheter or cannula.

12. The catheter or cannula of claim 11, wherein at least one opening is configured as one of: a) directing the fluid exiting the at least one opening in at least one of the following ways: i) towards the centre of the vessel; and, ii) away from the vessel wall; and, b) directing fluid exiting the catheter or cannula through the opening in a direction substantially parallel to the direction of blood flow within the vessel.

13. The catheter or cannula according to any one of claims 10 to 12, wherein at least one opening is provided rearwardly of the tip portion.

14. The catheter or cannula of claim 1, wherein the body comprises: a) a first portion extending from the proximal end to a first length; b) a second portion extending a second length from the end of the first portion to the tip portion, and wherein the second portion is configured to be positioned entirely within the blood vessel in use and includes at least one opening extending through the body.

15. The catheter or cannula of claim 10, wherein at least one of the openings is a self-occluding opening operable between a resting closed position and a forced open position.

16. The catheter or cannula of claim 15, wherein the plurality of self-closing openings are each one of: a) Cross-shaped slits; b) U-shaped slit; c) I-shaped slit; d) curved slits; and, e) When one of the following conditions occurs, it is in the forced open position: i) the internal pressure is greater than the external pressure; and, ii) External pressure is greater than internal pressure.

17. The catheter or cannula of claim 1, wherein the catheter or cannula body is made of a flexible material.

18. The catheter or cannula of claim 1, wherein the tip tapers toward a narrower distal end.

19. The catheter or cannula of claim 18, wherein the diameter of the narrow distal end is less than 90% of the diameter of the body.

20. The catheter or cannula of claim 1, wherein the catheter or cannula includes features configured to assist in orienting the catheter or cannula within a blood vessel.

21. The catheter or cannula of claim 20, wherein the proximal end of the catheter or cannula is connected to the central portion and the feature is used to control the orientation of the catheter or cannula relative to the central portion.

22. The catheter or cannula of claim 20 or 21, wherein the feature comprises a visual marker having one of the following configurations: a) disposed proximate to the proximal end; and, b) disposed on the first portion, wherein the visual indicia indicates at least one of: i) The side of the catheter or cannula that should contact the blood vessel; ii) The catheter or cannula should be pointed away from the side of the blood vessel; iii) the location of the vascular contact part; iv) Direction of lumen angle.

23. The catheter or cannula of claim 1, wherein the catheter or cannula body is made of one of: a) Fluorinated ethylene propylene (FEP); b) Polytetrafluoroethylene (PTFE); c) silicone; and, d) Polyurethane.

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