A catheter hole having a flow breaking feature

ES 2 617 331 T3

DESCRIPTION

A catheter hole that has a flow-interrupting characteristic

BACKGROUND OF THE INVENTION

The present invention relates generally to systems and components for vascular infusion, including catheter assemblies and devices used with catheter assemblies. In particular, the present invention relates to systems and methods for improving the efficiency of catheter hole ordering to provide higher infusion flow rates, lower system pressures, and reduced catheter outlet jet velocities. Additionally, the present invention relates to the improvement of the energy dissipation of the fluid jets exiting the catheter holes.

Vascular access devices are used to communicate fluid with the anatomy of a patient. For example, vascular access devices, such as catheters, are commonly used to infuse fluid, such as saline, various medications, and / or total parenteral nutrition, into a patient, draw blood from a patient, and / or monitor various parameters of the patient's vascular system.

A variety of clinical circumstances, including massive trauma, major surgical procedures, massive burns, and some disease states, such as pancreatitis and diabetic ketoacidosis, can produce profound circulatory volume depletion. This depletion can be caused either by actual blood loss or by an internal fluid imbalance. In these clinical cases, it is often necessary to infuse blood and / or other fluid rapidly into a patient to avoid serious consequences.

Additionally, the ability to inject large amounts of fluid quickly can be convenient for other medical and diagnostic procedures. For example, some diagnostic imaging procedures use more intense contrast media to improve the visibility of the lesion in an effort to increase early diagnostic performance. These procedures require viscous contrast media to be injected by a specialized power injection pump intravenously at very high flow rates, which establishes a bolus of contrast or small plug of contrast media in the patient's blood stream resulting in better quality. of image.

Power injection procedures generate high pressures within the infusion system, thereby requiring specialized vascular access devices, extension sets, media transfer sets, pump syringes, and volumetric or pre-filled contrast media syringes. As the concentration (and therefore the viscosity) increases and the infusion rate of the contrast media increases, the bolus density also increases resulting in better image quality through attenuation of the computed tomography ( CT). Therefore, a current trend in healthcare is to increase the bolus density of contrast media by increasing the concentration of the contrast media and the rate at which the media is infused into the patient, all of which ultimately leads to higher system pressure requirements.

Intravenous infusion rates can be defined as either routine, generally up to 999 cubic centimeters per hour (cc / hr), or rapid, generally between approximately 999 cc / hr and 90,000 cc / hr (1.5 liters per hour). minute) or more. For some diagnostic procedures using viscous contrast media, an injection rate of approximately 1 to 10 ml / second is needed to ensure a sufficient bolus concentration. Power injections of viscous media at this injection rate produce significant back pressure within the infusion set that commonly results in failure of the infusion set components.

Traditionally, rapid infusion therapy comprises the use of an intravenous catheter attached to a peristaltic pump and a fluid source. A patient is infused as a tip portion of the catheter is inserted into a patient's vasculature and the pump pushes fluid through the catheter and into the patient's vein. Current rapid infusion therapies use a catheter and catheter tip with identical geometries to those used with traditional routine infusion rates. These geometries include a taper of the catheter tip, such that fluid is accelerated as fluid moves through the catheter tip and exits into the vasculature of a patient. This acceleration of the infused fluid is undesirable for a number of reasons.

For example, the tapered catheter results in increased back pressure for the remainder of the catheter assembly. This effect is undesirable due to the limitations of the pumping capacity of the infusion pump as well as the limited structural integrity of the components and sub-components of the infusion system. For example, if the back pressure becomes too great, the efficiency of the pump may decrease and some seals or connections within the infusion set may fail. Additionally, acceleration of the fluid at the catheter tip results in a recoil force that can cause the catheter tip to deflect within the patient's vein, thereby displacing the catheter and / or damaging the patient's vein and / or the injection site. Acceleration of the fluid also increases the velocity of the jet of fluid that is infused into the catheter tip. In some 2

In procedures, the jet of fluid can pierce the wall of the patient's vein, thereby leading to extravasation or infiltration. This is not only uncomfortable and painful for the patient, but the infiltration can also prevent the patient from receiving the required therapy.

Accordingly, the problem of increased discharge velocity of a fluid that is infused during rapid infusion procedures has yet to be resolved. Therefore, the present disclosure presents systems for reducing the exit rate of a fluid to be infused while maintaining a higher infusion rate, which is desirable during rapid infusion procedures. Additionally, the present disclosure features system modifications to increase the transfer pulse in jet streams of fluid exiting the catheter.

WO 01/51116 A2 discloses a catheter according to the concept of claim 1.

BRIEF SUMMARY OF THE INVENTION

The object of the invention is defined in the claims.

The systems of the present disclosure have been developed in response to problems and needs in the art that have not been fully solved heretofore by currently available infusion systems and methods. Therefore, these systems are developed to provide safer and more efficient rapid infusion procedures.

One aspect of the present invention provides an improved vascular access device for use in combination with a vascular infusion system capable of rapidly delivering a fluid to be infused into the vascular system of the patient. The vascular access device generally includes an intravenous catheter configured to access a patient's vascular system. The IV catheter is coupled to the vascular infusion system through an IV tubing section. The intravenous catheter material may include a polymer or metallic material compatible with infusion procedures.

In some embodiments, a tip portion of the IV catheter is modified to include a plurality of diffusion holes. The tip portion generally comprises a tapered profile, wherein the outer and inner surface of the tip tapers toward the distal end of the catheter. The tapered outer surface provides a smooth transition between the narrow diameter of the catheter tip opening and the larger diameter of the catheter tube. Thus, as the tip of the catheter is introduced into a patient's vein, the tapered outer surface facilitates easy insertion of the catheter through the access hole. The tapered inner surface is generally provided to be in close contact with the outer surface of an introducer needle housed within the lumen of the catheter. The introducer needle is provided to create an opening in the patient's vein through which the catheter tip is inserted. The tapered inner surface ensures a tight seal between the inner surface of the catheter and the outer surface of the needle. After catheter placement, the introducer needle is removed.

As a fluid to be infused passes through the tapered portion of the inner surface, the fluid flow of the fluid to be infused is accelerated due to the decreased volume through the tapered tip. Thus, in some embodiments, a plurality of diffusion holes are formed through the thickness of the intravenous catheter wall so as to provide a plurality of pathways through the intravenous catheter wall. Thus, as the fluid to be infused flows through the catheter toward the tip of the catheter, a portion of the flow volume through the catheter is diverted through the diffusion holes rather than through the main opening of the catheter. catheter tip. Therefore, the pressure within the infusion system is reduced compared to systems incorporating the standard intravenous catheter. Additionally, the plurality of diffusion holes reduces the velocity of the jet exiting the catheter tip, thereby allowing higher flow rates as required for some diagnostic procedures without additional damage to the vein wall.

In some examples, the diffusion holes are located on the catheter tip in a stepped configuration such that an upstream diffusion hole is not aligned with a downstream hole. Therefore, the fluid flow of an infused fluid exiting a downstream diffusion hole is not disturbed by the fluid flow of an infused fluid exiting an upstream diffusion hole. This feature provides greater flow efficiency through the downstream diffusion holes.

In some examples of the present invention, a first set of diffusion holes is disposed in a first annular ring at an axial position upstream of the catheter tip. A second set of diffusion holes is disposed in a second annular ring at an axial position of the catheter tip that is downstream of the first annular ring. In some examples, the holes in the first annular ring are staggered with respect to the holes in the second annular ring so that they are generally not aligned. In other examples, the holes in the first annular ring are staggered axially with respect to the holes in the second annular ring by about 15 ° to about 60 °. Finally, in some examples the holes in the first annular ring are staggered axially with respect to the holes in the second annular ring by approximately 45 °.

In some embodiments, the diffusion holes are provided through the catheter wall at an angle of 3

ES 2 617 331 T3 predetermined perforation. Specifically, the diffusion holes of the present invention include an interior wall surface that can be angled relative to the interior surface of the catheter lumen. In some embodiments, the interior surface of a diffusion hole is oriented at an acute angle relative to the interior surface of the catheter lumen. In other embodiments, an interior surface of the diffusion hole is oriented at an angle of about 15 ° to about 75 ° relative to the interior surface of the catheter lumen. In some embodiments, the angle of perforation of the diffusion hole is selected in such a way as to optimize the efficiency of flow and through the diffusion hole, the tension of the catheter within the vein, the centralized positioning of the catheter tip within the vein, and reducing the system pressure and jet velocity at the tip within an infusion set.

In some embodiments, one or more diffusion holes are positioned in the distal end of a body element of the catheter. Specifically, the diffusion holes include a flow interruption feature. For example, in some embodiments, the flow interruption feature comprises the association of two or more diffusion holes, wherein the axis of each hole is oriented to cross the axis of another hole in outer space with respect to the catheter body. . Therefore, the jet streams of fluid exiting these holes will collide and disrupt the jet streams. The resulting scattered jet stream loses energy and momentum more rapidly than a single jet stream, thus reducing stress and impact on vessel walls.

In some examples, the flow disruption feature of the diffusion holes includes a flow disruptor. Specifically, in some examples, the flow disruptor includes a wedge-shaped extension in the hole. In other examples, the flow disruptor includes an inward projection. For example, in some examples, the inward projection is arranged on the surface of the inner wall of the hole. In some examples, the hole is substantially teardrop-shaped. In some examples, the hole has an elongated geometry. The flow disruptor will disrupt the jet stream flowing through the diffusion hole either by disrupting it or by flattening its shape. Consequently, a stream exiting the diffusion hole will have a thinner cross-section or an interrupted and dispersed flow. The resulting interrupted jet stream loses energy and momentum more rapidly than a single jet stream, thus reducing stress and impact on vessel walls.

BRIEF DESCRIPTION OF THE VARIOUS VIEWS OF THE DRAWINGS

In order for the above-mentioned and other characteristics and advantages of the invention obtained to be easily understood, a more particular description of the invention will be made briefly described above by reference to specific embodiments thereof which are illustrated in the accompanying drawings. These drawings illustrate only typical embodiments of the invention and are therefore not to be construed as limiting the scope of the invention.

Figure 1 is a perspective view of an infusion system in accordance with a representative example of the present invention.

Figure 2 is a detailed perspective view of a catheter in accordance with a representative example of the present invention.

Figure 3A is a perspective view of a catheter tip in accordance with a representative example of the present invention.

Figure 3B is a cross-sectional side view of the tip of the catheter of Figure 3A in accordance with a representative example of the present invention.

Figure 4A is a perspective view of a catheter tip in accordance with a representative example of the present invention.

Figure 4B is a cross-sectional side view of a catheter tip in accordance with a representative example of the present invention.

Figure 5 is a graphical representation of jet tip speeds at various flow rates in accordance with representative examples of the present invention.

Figure 6 is a graphical representation of system pressures at various flow rates in accordance with representative examples of the present invention.

Figure 7A is a perspective view of a catheter tip in accordance with a representative example of the present invention.

Figure 7B is a perspective view of a catheter tip in accordance with a representative example of the present invention.

Figure 8 is a perspective view of a catheter tip in accordance with a representative example of the present invention.

Figure 9 is a cross-sectional side view of the catheter tip of Figure 8.

Figure 10A is a perspective view of a catheter tip in accordance with a representative example of the present invention.

Figure 10B is a cross-sectional side view of the catheter tip of Figure 10A.

Figure 11A is a perspective view of a catheter tip in accordance with a representative example of the present invention.

Figure 11B is a cross-sectional side view of the catheter tip of Figure 11A.

ES 2 617 331 T3

Figures 12-19 are diffuser hole shapes in accordance with representative examples of the present invention.

Figure 20 is a cross-sectional side view of a catheter tip in accordance with a representative embodiment of the present invention.

Figure 21 is a perspective view of a catheter tip in accordance with a representative example of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The examples of the present invention will be better understood by reference to the drawings, where like reference numerals indicate identical or functionally similar elements. It will be readily understood that the components of the present invention, as generally described and illustrated in the figures herein, could be configured and designed in a wide variety of different configurations. Thus, the following more detailed description, as depicted in the figures, is not intended to limit the scope of the invention as claimed, but is merely representative of presently preferred embodiments of the invention.

The systems of the present invention are generally designed for use in combination with a vascular infusion system capable of rapidly delivering a fluid to be infused into the vascular system of a patient. Referring now to Figure 1, a vascular infusion system 100 is shown, in accordance with a representative example of the present invention. Infusion systems of this type are commonly configured to operate at internal pressures up to 2000 psi (13.8 MPa). Many systems operate in the 75 to 2000 psi (0.51 to 13.8 MPa) range, while specific devices of this type operate at 100, 200, and 300 psi (0.69, 1.38, and 2.07 MPa). ). Vascular infusion system 100 comprises a vascular access device 112 coupled to an injector pump 120 through a coiled extension assembly 130. In some examples, the infusion system 100 further comprises a safety device 140 positioned between the vascular access device 112 and the injection pump 120. In some examples, a safety device 140 is provided to automatically obstruct the fluid path of the system. infusion 100, thereby avoiding excessive pressure build-up in the downstream infusion components.

An injector pump 120 generally comprises a fluid pumping apparatus configured to rapidly deliver a fluid to be infused, such as blood, drugs, and CT contrast agents to a vascular system of the patient. Desirable fluids to be infused can also include various fluids often of high viscosity as required for medical and diagnostic procedures. In some examples, the injector pump 120 comprises a power injector capable of delivering a fluid to be infused into a patient at flow rates of about 10 mL / hour to about 1200 mL / minute. In some examples, a high infusion rate is desirable for medical procedures that require a higher bolus density of a fluid to be infused into a vascular system of the patient. For example, a trend in diagnostic imaging procedures is to use higher contrast media which requires more viscous contrast media to be introduced into a patient at a higher flow rate, thus resulting in higher image quality. Thus, in some examples, an injection pump 120 and a vascular access device 112 are selected to compatibly achieve a desired infusion rate.

A coiled extension assembly 130 generally comprises flexible or semi-flexible polymer tubes configured to deliver a fluid to be infused from the injection pump 120 to the vascular access device 112. The extension assembly 130 includes a first coupler 132 for connecting the extension assembly. 130 to a downstream device 112 or 140. Extension assembly 130 also includes a second coupler 134 for connecting extension assembly 130 to injection pump 120. A rolled configuration of extension assembly 130 generally prevents undesirable kinking or occlusion of assembly 130 during infusion procedures. However, one skilled in the art will appreciate that extension assembly 130 can include any configuration capable of efficiently delivering a fluid to be infused from an injector pump 120 to the patient through a vascular access device 112. In some examples, Extension assembly 130 is coupled between a syringe and a vascular access device, whereby a fluid to be infused is manually injected into a patient. In other examples, the infusion system comprises only a syringe and a vascular access device, in accordance with the present invention.

Vascular access device 112 generally comprises a peripheral intravenous catheter 114. A peripheral intravenous catheter 114 in accordance with the present invention generally comprises a short or truncated catheter (usually 13mm to 52mm) that is inserted into a small peripheral vein. Such catheters generally comprise a diameter of about 14 catheter gauge or smaller. Peripheral IV catheters 114 are typically designed for temporary placement. The short length of catheter 114 facilitates convenient catheter placement, but makes it prone to premature vein displacement due to patient movement and / or recoil forces experienced during infusion procedures. Furthermore, unlike central or midline peripheral catheters, peripheral intravenous catheters 114 in accordance with the present invention comprise a tapered catheter tip 146 to accommodate use with an introducer needle (not shown) designed to aid insertion. catheter 114.

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An introducer needle is typically inserted through catheter 114 such that a tip of the needle extends beyond tapered tip 146. The tapered geometry of tapered tip 146 conforms snugly to the outer surface of the introducer needle. Both the outer surface and the inner surface of tip 146 are tapered toward the distal end of catheter 114. The outer surface of tip 146 is tapered to provide a smooth transition from the smaller profile of the introducer needle to the larger profile of the outer diameter of the catheter. Insertion of the introducer needle into the patient's vein provides an opening in the vein through which the tapered tip 146 of the catheter 114 is inserted. The tapered outer surface of the tip 146 allows easy insertion of the catheter 114 into the opening. . Once peripheral intravenous catheter 114 is inserted into the patient's vein, the introducer needle (not shown) is removed from the lumen of catheter 114 to allow infusion through catheter 114.

The tapered inner surface of tip 146 provides a secure seal between the inner surface of the catheter tip 146 and the outer surface of the introducer needle (not shown). Additionally, the tapered inner surface of tip 146 causes an acceleration of the fluid to be infused into the catheter lumen as the fluid to be infused approaches and flows through the catheter tip 146. Specific details regarding the geometries of the tapered inner surface of tip 146 are provided with reference to Figures 3B and 4B below. Following an infusion procedure, peripheral intravenous catheter 114 is simply withdrawn from the vein and discarded.

A desired fluid to be infused is typically delivered to catheter 114 through an IV tubing section 116 coupled to catheter 114. In some examples, an y-adapter 118 is coupled to one end of tube 116 opposite catheter 114, allowing the vascular access device 112 is coupled to the remainder of vascular infusion system 100. One skilled in the art will appreciate the possible variations and specific features of the available vascular access devices 112, as commonly used in the medical and research professions. For example, in some examples, a catheter 114 in accordance with the present invention may include additional access sites, clamps, parallel IV lines, valves, couplers, introducer needles, liners, and / or materials as desired to suit a specific application. .

Referring now to Figure 2, a catheter 214 is shown in accordance with a representative example of the present invention. Catheter 214 generally comprises a catheter adapter 218 configured to house a tubular body member 220. Catheter adapter 218 further includes an inlet port 230 that is coupled to an intravenous tube section 216. Intravenous tubing section 216 is further coupled to upstream infusion components, as shown and described in relation to Figure 1, above.

Catheter adapter 218 facilitates delivery of a fluid to be infused within intravenous tubing 216 to a patient through tubular body member 220. An interior lumen of catheter adapter 218 is in fluid communication with an interior lumen of intravenous tubing. 216 and an interior lumen of tubular body member 220. In some examples, catheter adapter 218 further comprises an access port 222. Access port 222 is generally provided to allow direct access to the interior lumen of catheter adapter 218. In some examples, access port 222 is accessed through a needle and syringe to deliver a fluid to be infused into a patient through tubular body member 220. In other examples, an introducer needle or guidewire is inserted into access port 222 and advanced through the interior lumen of tubular body member 220. In some examples, a tip portion of the introducer needle or of the guide wire (not shown) extends beyond a tip portion 240 of the tubular body member 220. Therefore, the tip portion of the introducer needle or guidewire can provide an opening in the vascular system of a patient into which the tubular body member 220 is inserted. After placement of tubular body member 220 in the patient's vein, the introducer needle or guidewire is withdrawn from access port 222 thereby establishing fluid communication between tubular body member 220, the catheter adapter. 218 and IV tubing 216.

In some examples, the tubular body member 220 comprises an intravenous catheter. Intravenous catheter 220 generally comprises a flexible or semi-flexible biocompatible material, as is commonly used in the art. In some examples, intravenous catheter 220 comprises a polymeric material, such as polypropylene, polystyrene, polyvinyl chloride, polytetrafluoroethylene, and the like. In other examples, intravenous catheter 220 comprises a metallic material, such as surgical steel, titanium, cobalt steel, and the like.

The tubular body member 220 can comprise any length, wherein the length is selected based on the intended application of the catheter 214. For some applications, the tubular body member 220 is inserted into a peripheral vein of the patient. In other applications, the tubular body member 220 is inserted into a central vein of the patient. For rapid infusion applications, the tip portion 240 of the tubular body member 220 is modified to include a plurality of diffusion holes 250. The diffusion holes 250 are generally provided to divert fluid from the main flow channel through the tube. inner lumen of tubular body member 220. Therefore, diffusion holes 250 effectively retard the jet of fluid to be infused exiting catheter tip 240 during rapid infusion procedures. Additionally, the plurality of diffusion holes 250 increases the cumulative area of ​​the catheter tip 242 opening to relieve overall pressure in the vascular infusion system 100.

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Referring now to Figure 3A, a distal end portion 320 of an intravenous catheter 314 is shown, in accordance with a representative example of the present invention. As previously discussed, an outer surface of tip 340 is tapered to provide a gradual transition from the opening of catheter 342 of tip 340 to the diameter of the body of catheter 314. In some examples, the tip 340 of the intravenous catheter 314 is modified to include a plurality of side holes 350. The side holes 350 are positioned generally on the tapered tip 340 of the catheter 314 to provide an access through which fluid can exit into infuse into catheter 314. The surface area of ​​the side holes 350 combines with the surface area of ​​the lumen opening 342 to increase the total surface area through which a fluid to be infused can exit the tip 340 of the intravenous catheter 314. Side holes 350 are arranged in an annular fashion at tip 340 of intravenous catheter 314 so as to align adjacent holes along a common axis 360. Therefore, an upstream hole 356 is directly aligned with downstream holes 358.

Referring now to Figure 3B, a cross-sectional view of intravenous catheter 314 of Figure 3A is shown. As previously discussed, a portion 334 of the inner surface of tip 340 is tapered, causing an acceleration in the flow of fluid 390 through tip 340. Side holes 350 of intravenous catheter 314 are formed through the wall of catheter 354 such that an interior surface 364 of each hole 350 is oriented at an angle 370 of approximately 90 ° relative to an interior surface 382 of the lumen. catheter 380. Side holes 350 are positioned generally within tapered portion 334 of tip 340 such that as fluid flow velocity 390 increases through tapered portion 334, infused fluid 394 can exit through the side holes 350. As the fluid to be infused exits through the side holes 350, the pressure of the fluid within the lumen 380 decreases. Additionally, as the fluid to be infused exits through the side holes 350, the jet velocity at the tip of the fluid to be infused also decreases.

Computational fluid dynamic analysis of the 90 ° side holes 350 reveals that only a first half 374 of each hole cross section 350 is utilized by fluid flow 390. In some examples, a second half 376 of the cross section of the 90 ° side holes 350 comprise a recirculation vortex 392. Thus, in some examples, the 90 ° side hole configuration 350 can demonstrate approximately fifty percent flow efficiency through each side hole 350.

Referring now to Figure 4A, a distal end portion 420 of an intravenous catheter 414 is shown in accordance with a representative example of the present invention. Intravenous catheter 414 has been modified to include a plurality of staggered diffusion holes 450. One skilled in the art will appreciate that the number and dimensions of diffusion holes 350 and 450 can be varied and adjusted to achieve a desired flow rate, a reduction in jet velocity at the tip, a reduction in vascular damage, and an increase in bolus density. Diffusion holes 350 and 450 are generally provided by means of manufacturing methods known in the art. For example, in some embodiments, the plurality of diffusion holes 350 and 450 are provided with a laser perforation.

In some examples, a selected configuration of diffusion holes 450 increases the distance between adjacent holes 450 thereby structurally reinforcing tip 440 of intravenous catheter 414, compared to some linear hole configurations. In other examples, a selected configuration of the diffusion holes 450 further streamlines the fluid to be infused exiting the diffusion holes 450 thereby reducing the energy required to divert the volume of the main stream flow from the lumen of the catheter 490. in the diffusion holes 450.

For example, in some examples of the present invention the diffusion holes 450 have been arranged in a staggered configuration, as shown. Accordingly, an upstream hole 456 is not aligned with an adjacent downstream hole 458. Furthermore, a downstream hole 458 is not aligned with an adjacent downstream hole 460. In some examples, the upstream hole 456 is directly aligned with a downstream hole 460 along a common axis 480. In other examples, an upstream hole 456, a downstream hole 458, and a downstream hole 460 are not. aligned with each other such that neither hole is aligned along a common axis. In some examples, an upstream hole 456 is axially staggered with respect to a downstream hole 458 from about 15 ° to about 60 °. Finally, in some embodiments, an upstream hole 456 is axially staggered relative to a downstream hole 458 by approximately 45 °.

Diffusion holes 450 are arranged in an annular fashion in the tapered portion of tip 440 of intravenous catheter 414 in a stepped configuration, as previously discussed. A first annular ring 402 comprises a plurality of diffusion holes 450 that form a first ring upstream of diffusion holes. In some examples, the holes in the first annular ring 402 are axially spaced an equal distance from the adjacent holes in the first annular ring 402. In other examples, an axially non-uniform spacing is applied to the holes in the first annular ring 402. In some examples , a second annular ring 404 is provided downstream of the first annular ring 402, the diffusion holes of the second annular ring 404 are 7

ES 2 617 331 T3 positioned in a staggered fashion relative to the diffusion holes of the first annular ring 402. Finally, in some examples, a third annular ring 406 is provided downstream of the second annular ring 404, the diffusion holes of the third being annular ring 406 positioned staggered relative to the diffusion holes of the second annular ring 404.

A space 424 is provided between adjacent holes of the first annular ring 402. In some examples, the space 424 is provided to accommodate the width of the downstream hole 458, such that the downstream hole 458 and the space 424 are aligned therewith. along a common axis (not shown). In addition, a downstream space 428 is provided to accommodate the width of an upstream hole 466, such that upstream hole 466 and downstream space 428 are aligned along a common axis (not shown). The axial alignment of the upstream space 424 and the downstream hole 458 avoids the wake effect due to the absence of a diffusion hole directly upstream of the downstream hole 458. Similarly, the axial alignment of the downstream space 428 and the upstream hole 466 avoids the wake effect due to the absence of a diffusion hole directly downstream of the upstream hole 466.

The staggered configuration of the first, second, and third annular rings 402, 404, and 406 provides an elongated space 426 that forms a space between an upstream diffusion hole 452 of the first annular ring and an axially aligned downstream diffusion hole 454 of the third annular ring 406. The length of elongated space 426 generally provides sufficient distance between an upstream diffusion hole 452 and a downstream diffusion hole 454, such that the fluid pressure of a fluid to be infused from upstream hole 452 is approximately equal to fluid pressure of a fluid to be infused from the downstream hole 454. Thus, the staggered configuration of diffusion holes 450 ensures equal flow efficiency of upstream and downstream diffusion holes 452 and 454.

In some examples, diffusion holes 450 are formed through the catheter wall 474 such that an interior surface 464 of each hole 450 is oriented at an angle 470 that is acute relative to an interior tapered surface 482 of the catheter lumen 490, as shown in Figure 4B. In some examples, the angle 470 is between about 15 ° to about 75 °. In other examples, the angle 470 is approximately 45 °.

As noted above, diffusion holes and the configuration of diffusion holes decrease the force of fluid exiting a catheter tip. Attention will now be directed to the geometry of the diffusion holes (also referred to herein simply as holes), and specifically to the geometries that further decrease the force of fluid exiting the catheter tip. Figures 2-4B generally illustrate circular diffusion holes. However, in some examples, one or more diffusion holes may not be circular. As illustrated in Figure 7A, a substantially cylindrical jet of fluid 511 emerges from a circular hole 509 of a catheter 502 into the vasculature of a patient. In general, this jet 511 is concentrated and direct and is slowly interrupted within the vein. From this it follows that from a non-circular hole 510, as illustrated in Figure 7B, emerges a jet of fluid 513 having a substantially non-circular cross-section, and therefore a larger surface area. Increasing the surface area of ​​jet 513 increases the speed of the transfer pulse between jet 513 and the intravenous environment compared to that of a more cylindrical jet 511 of Figure 7A. Thus, the jet 513 exiting the non-circular hole 510 disperses and decelerates more rapidly, presenting a lower risk of extravasation to the vein walls.

In addition to employing non-circular hole geometries, flow disruption can also be facilitated by including an additional flow disruption feature in the diffusion hole. A flow interruption characteristic refers to a characteristic of the hole that substantially interrupts, thins or retards a jet of fluid exiting a hole so that the jet will lose velocity more rapidly within the vein. Flow interruption characteristics are characteristics of the hole that facilitate the interruption of the flow of a jet of fluid as it passes through and / or exits the hole. Flow interrupting features include a flow disruptor, elongated hole geometries, and hole orientations such that the flow axis of two or more holes collide. Non-limiting examples of hole interruption characteristics including two or more holes whose axis of flow collide are illustrated in Figures 20-21.

As noted, one type of flow disruption characteristics is a flow disruptor. A flow disruptor refers to a deviation in a hole geometry from a rounded hole, a circular hole, or an elliptical hole. Thus, flow disruptors include inward projections and pointed extensions. A non-limiting example of a hole having a flow disruptor is a substantially teardrop-shaped hole that includes a pointed extension. Another non-limiting example of a hole that has a flow disruptor is a hole that has one or more inward projections. An inward projection refers to a part of a periphery of the hole that projects into the interior of the hole. Thus, there is a cross-sectional area of ​​the hole where a straight line interposed on the cross-section could cross the perimeter of the hole more than twice, as illustrated in Figure 12. Non-limiting examples of such inward projections are illustrated in Figures 8-16.

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Referring now to Figures 8-9, there is shown a distal end portion 514 of an intravenous catheter 502 in accordance with a representative example of the present invention. Intravenous catheter 502 has been modified to include a plurality of non-circular diffusion holes 508 and 510 in addition to the distal lumen opening 504. The number and dimensions of diffusion holes 508 and 510 can be varied and adjusted to achieve a desired flow rate, a reduction in jet velocity at the tip, a reduction in vascular damage, and an increase in bolus density. As illustrated, at least a portion of each diffusion hole is located in the tapered portion 506 of the catheter tip such that all fluid is introduced into the patient near the catheter tip. In other examples, a diffusion hole is disposed completely outside of the tapered portion of the catheter tip but near the distal portion 514 of catheter 502.

Referring now to Figure 9, there is illustrated a cross-sectional view of catheter 502 taken along the center of diffusion holes 508 and 510. As illustrated, holes 508 and 510 are oriented at an angle 528 with respect to to the central axis 512 of the catheter lumen. In some examples, the angle 528 between the central axis 512 of the catheter lumen and the distal surface of the hole 524 (the angle of the distal hole) is the same as the angle 526 between the central axis 512 of the catheter lumen and the distal surface of hole 524 (the angle of the proximal hole). In other examples, the angle of the distal hole 528 and the angle of the proximal hole 526 differ to provide a more diffuse jet of fluid from the hole. For example, if the angle of the distal hole 528 is greater than the angle of the proximal hole 526, fluid flowing into the hole collides, disrupting the exiting jet, and increasing the energy dissipation of the resulting jet. In other examples, the angle of the distal hole 528 is less than the angle of the proximal hole 526 such that a stream of fluid exiting the hole expands and disperses as it passes through the hole.

Fluid passing through catheter 508 generally travels through the lumen toward the lumen opening of catheter 504. The interior surface of the lumen includes one or more interior hole openings 530, through which some fluid. As fluid travels through the hole, the structures and geometries of the surface of the inner wall 520 of the hole modify the jet of fluid exiting through the opening of the outer hole 532. Additionally, the shapes of the inner and outer hole openings 530 and 532 affect the jet of fluid that exits. In some examples, the shape of the inner hole opening differs from the shape of the outer hole opening to modify the exiting fluid stream with higher dissipation properties.

Continuing with reference to Figures 8-9, the flow of fluid exiting diffusion holes 508 and 510 is interrupted by two flow disruptors associated with each diffusion hole. Specifically, holes 508 and 510 include a teardrop shape, or a teardrop shaped cross section, having a pointed extension 509 and 511. The pointed extension increases the surface area of ​​the exiting jet to improve rupture of the jet. flow. Holes 508 and 510 further comprise an inward projection 516 and 518 disposed on the inner wall surface of the diffuser hole. The inward projection extends inward toward an interior portion of the hole. As the fluid flows rapidly through the hole, the inward projection interrupts the direct flow, creating turbulence within the jet exiting the hole. Turbulence within the jet can cause jet interruption, jet expansion, jet lag, and will ultimately increase the speed of the impulse with which it is transferred from the jet to the intravenous environment.

Figures 10A-16 illustrate additional examples of inward projections causing a disruption within a jet of fluid exiting a diffusion hole. Referring now to Figures 10A-10B, a diffuser hole 542 in a catheter 540 includes an inward projection 544. The inward projection is disposed on the surface of the inner wall 548 of the hole 542 near the exit of the hole. In this way, fluid flow through hole 542 is interrupted by inward projection that forces fluid flow paths 546 into hole 542 to collide with each other, create turbulence, and thus create greater dispersion. and an expanded jet path 547 of the exiting fluid jet.

Referring now to Figures 11A-11B, a catheter 550 is illustrated, in accordance with some examples, having a diffusion hole 552 with an inward projection 554 on the surface of the inner wall 558 of the hole 552. The projection towards inside 554 extends between the inner and outer hole openings. The fluid flowing through hole 552 has a greater surface area than it would if flowing through a circular hole, therefore the jet that exits will be interrupted more quickly in the environment of the vein.

Reference is now made to Figures 12-16, which illustrate hole geometries having at least one inward projection. These structures project toward an interior portion of the hole, such that there is a cross-sectional area of ​​the hole in which a straight line interposed on the cross-section could cross the perimeter of the hole more than twice. This is illustrated in Figure 12. Reference is now made to Figure 12, which illustrates a cross section of a hole 570 having an inward projection. A line, which is not a structural component of the hole, and is indicated for illustration only, is shown as crossing the perimeter of the hole at four points 575, 576, 577, and 578. Consequently, structure 572 is presented as a inward projection because straight line 577 crosses the perimeter of the hole more than twice.

In some examples, as in Figure 13, a hole 580 includes two inward projections 582 and 584. At 9

In other examples, as in Figure 14, a hole 590 includes three inward projections 592, 594, and 596. In other examples, a hole includes more than three inward projections. As an inward projection increases the surface area of ​​the resulting fluid stream, it turns out that each further inward projection increases the surface area equally. Accordingly, the number and dimensions of the inward projections disposed in a diffuser hole can be varied and adjusted to achieve a desired jet interruption, jet thinning, and jet retardation. Additionally, in some examples, as illustrated in Figure 15, a hole 600 may include a non-round inward projection 602, such as a square projection. Alternatively, in other examples, the inward projection is triangular, trapezoidal, rectangular, etc. Furthermore, in some examples, multiple inward projections 612 are disposed adjacent to each other or substantially adjacent to each other, such as illustrated in hole 610 of Figure 16, which forms a serrated edge of the hole.

Referring now to Figure 17, an elongated diffuser hole 620 is illustrated that has a length 624 greater than a width 622. As noted above, non-circular diffuser holes have a greater surface area and therefore the fluid that flows through it has higher energy dissipation properties. However, holes with very substantial lengths relative to the thickness of the peripheral catheter act as cuts within the catheter body that can weaken the catheter body. Accordingly, with peripheral catheters, one or more elongated diffuser holes can be included in the distal portion of the catheter body having a hole length 624 that is between 1.2-3.0 times the width of hole 622. In other examples, the length of the hole is between 1.3 - 2.5 times the width of the hole. In still other examples, the length of the hole is between 1.4 - 2.2 times the width of the hole.

Figures 18-19 illustrate other elongated holes 630 and 640 having wedge-shaped extensions 6365 and 646, in accordance with some examples. Specifically, Figure 18 illustrates a hole 630 that is generally teardrop-shaped, which facilitates insertion into a patient. The hole is elongated, it has a length 636 and 632 which is generally greater than the width 634. The hole 630 includes a main hole portion 632 and a wedge-shaped extension 636, which includes two straight surfaces or semi-straight surfaces 635 and 637 that extend from the main body portion 632 toward a point 638 remote from the body portion. main 632. In some examples, hole 630 is oriented such that point 638 of the wedge-shaped extension is on the proximal side of the hole. As the catheter is inserted through a patient's skin, the skin can naturally sink into the hole. As the catheter advances, the straight surfaces 635 and 637 gradually push the skin out of the hole 630 and prevent the skin from snagging, which may otherwise occur if the proximal side of the hole comprises a large flat surface perpendicular to the insertion direction. Figure 19 illustrates another teardrop-shaped hole 640 having a rounded wedge-shaped extension 646, a main hole portion 644, and a hole width, in accordance with some examples. The rounded wedge-shaped extension 646 reduces the overall length 644 and 646 of the hole 640 to increase the strength of the catheter body.

Reference is now made to Figure 20, which illustrates a cross-sectional view of a catheter 700 having a catheter body 702 comprising two diffuser holes 704 and 706. As illustrated, the two holes are oriented such that the jet of fluid exiting first hole 704 collides with jet of fluid exiting second hole 706. Accordingly, the angles between the lumen and the first axis of the hole 708 is generally greater than the angle between the lumen and the second axis of the hole 710 such that the two axis orientations cause the exiting fluid jets to collide. As these jets of fluid collide, the force and orientation of each jet disrupts the other jet, dispersing the fluid, retarding the fluid, and / or causing turbulence within the resulting area of ​​interrupted flow 716.

To achieve effective collisions, the location of the collision may be closer to the catheter surface than the distance between the location of the holes in the catheter body 702 and a wall of the vein such that the impact actually occurs instead. the two jets impact the wall of the vein. Accordingly, in some embodiments, the location of the collision is configured to be a distance away from the outer surface of the catheter, where the distance is less than the total thickness of the catheter body 702. In other examples, the distance is less. than 150% of the thickness of the catheter body 702. In other examples, the distance is less than 200% of the thickness of the catheter body 702. In other examples, the distance is less than 300% of the thickness of catheter body 702. In still other examples, the distance is less than 50% of the thickness of catheter body 702. Also, in some embodiments, the angle 718 between the first axis of hole 708 and second axis of hole 710 is between ninety 15-90 degrees.

In some examples, flow can be interrupted by the collision of flow exiting a first diffuser hole and flow exiting a second, smaller diffuser hole. For example, one or more small diffuser holes are included in the catheter tip, and oriented so that fluid exiting there collides with fluid exiting a larger diffuser hole. In this way, a greater number of holes can be included in the catheter tip without substantially weakening the tip with numerous holes of the same size.

Additionally, in some examples, fluid exiting one diffuser hole collides with fluid exiting two or more other diffuser holes. Referring now to Figure 21, which illustrates a catheter 720 having three holes 10

ES 2 617 331 T3 diffusers 722, 724, and 726, each having a hole axis 728, 730, and 732, respectively, which causes the fluid to leave there to collide with the fluid that leaves one of the other holes . Thus, in some examples, the three holes are located in a generally triangular configuration. In other examples, the three holes are located in a generally linear configuration such that a jet from an upstream hole collides with a jet from a downstream hole and the resulting stream further collides with a jet from another downstream hole. Additionally, in some examples, the diffuser hole assembly configuration comprises a set of holes oriented such that jets exiting almost each hole collide with at least one jet exiting another hole. Therefore, the sum of the jets that come out will produce a fluid infusion with less impact energy and that represents a lower risk for the walls of the vessels.

In some examples, a single diffuser hole includes more than one flow interruption characteristic. Examples of jet interruption characteristics are described herein, including at least inward projections, wedge-shaped extensions, elongated hole geometry, and hole axis orientations that result in collisions with other fluid jets. For example, in some examples, a hole includes an inward projection and has an axis orientation that collides with that of another hole. Furthermore, in some examples, the hole further includes a wedge-shaped extension. In other examples, other combinations of flow interruption characteristics are combined to provide a less disruptive, more effective catheter diffuser hole and set of diffuser holes.

From the foregoing, it will be appreciated that one or more flow interruption features can be included in one or more catheter diffuser holes in a catheter tip. The flow interruption feature can substantially interrupt, thin, or retard a jet of fluid exiting a hole such that the jet will lose velocity more rapidly within the vein and cause less damage to the vessel walls. In particular, the flow-interrupting characteristics are particularly advantageous when used in rapid infusion therapy that uses high rates of fluid to be infused to rapidly introduce a bolus of fluid into a patient through the catheter tip. During these procedures, one or more flow-interrupting features of a diffuser hole can increase patient comfort during infusion, decrease patient pain, allow higher infusion rates, and prevent damage to vessels.

EXAMPLES

To decrease the amount of contrast media required for a diagnosis, the concentration of contrast media per unit volume of blood has to be increased by increasing the volumetric flow rate of the contrast media without increasing the speed of the catheter tip. The elements of the present invention achieve these required objectives, as demonstrated in the examples below.

Example 1: Comparison of jet speed at the tip

Jet velocities at the tip of a standard catheter are in excess of 1,000 in / sec for a volumetric flow rate setting of 5 ml / sec, which results in a large force applied to the wall of a patient's vein. This force is treacherous for patients with suboptimal venous structure conditions, increasing the possibility of extravasation or intimate damage with increasing flow rates.

Jet velocities at the tip of a standard 22 GA X 1.00 catheter (V_Current tip) were compared to a 22 GA X 1.00 catheter (V_tip Ex. 1 - V_tip Ex. 4) modified to include a plurality of holes diffusion, as described in relation to Figures 4A and 4B, above. Quadruplicate samples of the modified catheter were tested at flow rates of 1 ml / sec, 2 ml / sec, 3 ml / sec, 4 ml / sec, and 5 ml / sec. The jet velocity at the tip was then recorded for each sample and compared to the jet velocity of the standard catheter at each flow rate. The experiment showed that the jet velocity at the total tip of the modified catheter decreased by 36% compared to the standard catheter. The results of the experiment are shown in Figure 5.

Example 2: Comparison of system pressure

Internal pressures within an infusion set were compared between an infusion system using a standard 22 GA X 1.00 catheter and an infusion system using a modified 22 GA X 1.00 catheter (P_iny # 1 and P_iny # 2). to include a plurality of diffusion holes, as described in relation to Figures 4A and 4B, above.

System pressure was measured within each infusion pump (P_iny Actual, P_iny 1, and P_iny 2) and the interior lumen of each catheter (P_sept Actual, P_sept 1, and P_sept 2). System pressure was tested and recorded at flow rates of 1 ml / sec, 2 ml / sec, 3 ml / sec, 4 ml / sec and 5 ml / sec. The system pressures at each flow rate were then plotted, as shown in Figure 6.

The results of the experiment demonstrate an increase in the volumetric flow rate decreasing the system pressure by approximately 30%, with the greatest pressure reduction within the lumen of the modified catheters.

Example 3: Computational fluid dynamic analysis

Computational fluid dynamic analysis was carried out with a standard 22 GA X 1.00 catheter modified for 11

ES 2 617 331 T3 include a plurality of diffusion holes drilled approximately 45 ° relative to the surface of the inner wall of the catheter. The analysis revealed a 6% addition deviation of the volume flow of the main stream in the diffusion holes, compared to a standard 22 GA X 1.00 catheter having a plurality of diffusion holes drilled 90 ° relative to the surface of the inner wall of the catheter. The analysis further revealed a significant increase in fluid flow 492 through the cross section of diffusion hole 450, compared to the straight holes of the standard catheter. While the diffusion holes 450 of the present invention exhibited a slight recirculation vortex 494, the recirculation vortex 494 was significantly weaker compared to the circulation vortex 392 of the standard catheter. A representative sample of fluid flow 492 is shown in Figure 4B.

Example 4: Stabilization of the catheter and centering of the vein

In standard peripheral intravenous catheters, the inner lumen of the catheter tapers toward the tip of the catheter resulting in a recoil force as a fluid to be infused accelerates through the constriction. This force is similar to the force felt when holding a fire hose. Like the fire hose, a catheter tip under compressive recoil force is unstable and can swing violently within the vein (also known as a catheter whip) damaging the vein, as previously discussed. If enough fluid to be infused is deflected from the axial direction through the diffusion holes, then the recoil force will turn negative and actually puts the catheter tip under tension; the stressed state of the catheter tip provides great stability to the inserted catheter. Therefore, in some embodiments the perforation angle is strategically selected to balance between the increased flow through the diffusion holes and the decreased recoil force at the catheter tip by reducing the axial direction of the fluid to be infused flowing through. diffusion holes.

The angle of perforation also affects the positioning of the catheter within the vein. For example, when inserted into a vein, the venous catheter generally extends through the skin and into the vein at approximately 30 °. Therefore, the tip of the venous catheter commonly contacts or abuts against the inner wall of the vein opposite the catheter insertion site. As fluid flow increases, a high jet velocity from the catheter tip is exerted directly on the inner wall of the vein. However, when the venous catheter tip is modified to include diffusion ports, the diverted fluid to be infused exiting the diffusion ports pushes the catheter tip away from the vein wall resulting in a centralized position of the vein. catheter tip into the vein. Thus, the velocity of the tip jet is directed into the vein fluid stream rather than the vein wall.

The present invention may be practiced in other specific ways without departing from its structures, methods, or other essential features as widely described herein and claimed below. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is therefore indicated by the appended claims.