Introducer and method thereof

Abstract

The introducer (100) may include a composite needle (104) and a composite cannula (102). The composite needle may include a needle (110), a dilator (108), and a needle hub (106). The dilator may be arranged above the needle, wherein at least the end of the needle extends beyond the distal end of the dilator. The needle hub may surround the proximal portion of the dilator. The composite cannula may include a cannula (140) and a cannula hub (142) surrounding the proximal portion of the cannula. The introducer may have a mating state of the composite needle and the composite cannula for at least intubation using the introducer. The mating state of the introducer may include a dilator arranged in the cannula, wherein the proximal portion of the cannula hub is coupled to the distal portion of the needle hub.

Description

Background Art

[0001] Existing dialysis needles are rigid (e.g., metal) with sharp tips that remain in place during dialysis. The sharp tips of such dialysis needles can cause penetration (e.g., perforation of the vessel wall) when the sharp tip is not advanced correctly or when the patient moves during dialysis, which can be due to the duration of a dialysis treatment. A device is needed to reduce the likelihood of any penetration. Disclosed herein is an introducer and method thereof that addresses the aforementioned issues. Summary of the Invention

[0002] Disclosed herein is an introducer for cannulating an arteriovenous fistula. In some embodiments, the introducer includes a composite needle and a composite cannula. The composite needle includes a needle, a dilator, and a needle hub. The dilator is arranged above the needle, wherein at least the end of the needle extends beyond the distal end of the dilator. The needle hub surrounds the proximal portion of the dilator. The composite cannula includes a cannula and a cannula hub surrounding the proximal portion of the cannula. The introducer has a mating state of the composite needle and the composite cannula for at least cannulation using the introducer. The mating state of the introducer includes the dilator arranged in the cannula, wherein the proximal portion of the cannula hub is coupled to the distal portion of the needle hub.

[0003] In some embodiments, the needle hub includes a housing enclosing a chamber having a distal wall. Each of the proximal end of the needle and the proximal end of the dilator are coupled to the distal wall.

[0004] In some embodiments, the composite needle further comprises an access guidewire disposed in the needle. The access guidewire extends from the lumen through a through-hole in the distal wall of the needle hub.

[0005] In some embodiments, the composite needle further comprises a guidewire actuator configured to advance the distal end of the entry guidewire beyond the tip of the needle or to withdraw the distal end of the entry guidewire into the distal portion of the needle proximal to the tip of the needle.

[0006] In some embodiments, the guidewire actuator includes a slider slidably disposed in a longitudinal slot of the needle hub. The slider includes an extension coupled to a proximal portion of the entry guidewire in a cavity of the needle hub.

[0007] In some embodiments, the cannula is formed from a flexible polymer material configured to increase patient comfort during a dialysis treatment procedure.

[0008] In some embodiments, the distal portion of the cannula includes a taper. The taper of the cannula is configured to continue from the taper of the dilator in the engaged state of the introducer.

[0009] In some embodiments, the cannula hub is bifurcated (eg, branched). When bifurcated, the cannula hub includes at least a first arm and a second arm.

[0010] In some embodiments, the first arm of the cannula hub comprises a first arm lumen and the second arm of the cannula hub comprises a second arm lumen. Each of the first arm lumen and the second arm lumen is fluidly connected to the cannula lumen of the cannula.

[0011] In some embodiments, each of the first and second arms of the cannula hub terminates in a Luer connector.

[0012] In some embodiments, the proximal portion of the cannula hub coupled to the distal portion of the needle hub in the mated state of the introducer is a luer connector of the first arm of the cannula hub disposed in the hole in the distal portion of the needle hub.

[0013] Disclosed herein is an introducer for cannulating an arteriovenous fistula. In some embodiments, the introducer includes a composite needle and a composite cannula. The composite needle includes an access guidewire, a needle, a dilator, and a needle hub. The needle is positioned above the access guidewire. The dilator is positioned above the needle, wherein at least the distal end of the needle extends beyond the distal end of the dilator. The needle hub includes a housing enclosing a chamber having a distal wall. The proximal end of the needle and the proximal end of the dilator are each coupled to the distal wall. A guidewire actuator is configured to advance the distal end of the access guidewire beyond the distal end of the needle or to retract the distal end of the access guidewire into a distal portion of the needle proximal to the distal end of the needle. The guidewire actuator includes a slider slidably disposed in a longitudinal slot of the needle hub. The slider includes an extension coupled to the proximal end of the access guidewire, the extension extending through a through-hole in the distal wall of the needle hub into the chamber of the needle hub. The composite cannula includes a cannula and a cannula hub surrounding the proximal end of the cannula. The introducer has a mating state of a composite needle and a composite cannula for at least intubation using the introducer. The mating state of the cannula includes a dilator arranged in the cannula, wherein a Luer connector in a proximal portion of the cannula hub is arranged in a hole in a distal portion of the needle hub.

[0014] In some embodiments, the distal portion of the cannula includes a taper. The taper of the cannula is configured to continue from the taper of the dilator in the engaged state of the introducer.

[0015] In some embodiments, the cannula hub is bifurcated (eg, branched). When bifurcated, the cannula hub includes at least a first arm and a second arm.

[0016] In some embodiments, the first arm of the cannula hub comprises a first arm lumen and the second arm of the cannula hub comprises a second arm lumen. Each of the first arm lumen and the second arm lumen is fluidly connected to the cannula lumen of the cannula.

[0017] This document also discloses a method for intubating a patient using an introducer. In some embodiments, the method includes an introducer acquisition step, a perforation establishment step, an entry guidewire advancement step, a tissue expansion step, a cannula advancement step, and a needle withdrawal step. The introducer acquisition step includes obtaining the introducer. The introducer includes a composite needle and a composite cannula in a mating state with the introducer. The perforation establishment step includes establishing a percutaneous perforation by inserting the end of the composite needle's needle into the patient's blood vessel. The entry guidewire advancement step includes utilizing the composite needle's guidewire actuator to advance the distal end of the entry guidewire beyond the end of the needle and into the vascular lumen. The tissue expansion step includes utilizing the composite needle's dilator positioned above the needle to expand the tissue surrounding the perforation. The cannula advancement step includes advancing the cannula of the composite cannula over the dilator, needle, and entry guidewire into the vascular lumen. The needle withdrawal step includes withdrawing the composite needle from the vascular lumen, leaving the composite cannula in place.

[0018] In some embodiments, the access guidewire advancing step includes distally sliding a slider disposed in a longitudinal slot of the needle hub. The slider includes an extension coupled to a proximal portion of the access guidewire in a cavity of the needle hub.

[0019] In some embodiments, the method further comprises an access guidewire retraction step. The access guidewire retraction step comprises, prior to the needle retraction step, retracting the distal end of the access guidewire into a distal portion of the needle proximal to the tip of the needle using a guidewire actuator.

[0020] In some embodiments, the method further comprises an ensuring step. The ensuring step comprises ensuring that the composite needle and composite hub are properly mated with the luer connector of the first arm of the cannula hub disposed in the bore of the distal portion of the needle hub.

[0021] In some embodiments, the ensuring step includes ensuring that the taper of the distal portion of the dilator continues along the taper of the distal portion of the cannula.

[0022] In some embodiments, the tissue dilating step comprises dilating the tissue using a distal portion of the cannula.

[0023] In some embodiments, the blood vessel is an arteriovenous fistula.

[0024] In some embodiments, the method further comprises a dialysis machine connection step and a dialysis initiation step. The dialysis machine connection step comprises connecting the composite cannula to a tubing set of the dialysis machine. The dialysis initiation step comprises initiating dialysis through the composite cannula.

[0025] These and other features of the concepts provided herein will become more readily apparent to those skilled in the art in view of the accompanying drawings and the following description, which more particularly depict specific embodiments of such concepts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A first isometric view of an introducer according to some embodiments is shown.

[0027] Figure 2 A second isometric view of an introducer is shown, according to some embodiments.

[0028] Figure 3 Shown is a top view of an introducer according to some embodiments.

[0029] Figure 4 A side view of an introducer according to some embodiments is shown.

[0030] Figure 5 An isometric view of a composite cannula separated from a composite needle of an introducer is shown, according to some embodiments.

[0031] Figure 6 Shown is a side view of a composite cannula separated from a composite needle, according to some embodiments.

[0032] Figure 7 An isometric cross-sectional view of a proximal portion of a composite needle is shown, according to some embodiments.

[0033] Figure 8 An isometric cross-sectional view of a composite cannula according to some embodiments is shown. DETAILED DESCRIPTION

[0034] Before disclosing some specific embodiments in more detail, it should be understood that the specific embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that the specific embodiments disclosed herein may have features that are easily separable from the specific embodiments and optionally combined with or substituted for the features of any of the many other embodiments disclosed herein.

[0035] About the terms used herein, it should also be understood that these terms are for describing some specific purposes, and these terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify the different features or steps in a set of features or steps, and do not provide sequential or numerical restrictions. For example, "first," "second," and "third" features or steps do not need to appear in this order, and the specific embodiment including such features or steps does not need to be limited to three features or steps. For convenience, marks such as "left," "right," "top," "bottom," "front," "back" etc. are used, and these marks are not intended to imply, for example, any specific fixed position, orientation or direction. On the contrary, such marks are used to reflect, for example, relative position, orientation or direction. The singular forms "a," "an," and "the" include plural references unless the context clearly indicates otherwise.

[0036] Reference to the "proximal side," "proximal portion," or "proximal end portion" of a catheter, for example, as disclosed herein, includes the portion of the catheter that is intended to be near a clinician when the catheter is in use with a patient. Similarly, reference to the "proximal length" of a catheter, for example, includes the length of the catheter that is intended to be near a clinician when the catheter is in use with a patient. For example, the "proximal end" of a catheter includes the end of the catheter that is intended to be near a clinician when the catheter is in use with a patient. The proximal portion, proximal portion, or proximal length of a catheter may include the proximal end of the catheter; however, the proximal portion, proximal portion, or proximal length of a catheter need not include the proximal end of the catheter. That is, unless the context suggests otherwise, the proximal portion, proximal portion, or proximal length of a catheter is not the terminal portion or terminal length of the catheter.

[0037] With respect to, for example, the "distal side," "distal portion," or "distal end portion" of a catheter as disclosed herein, this includes the portion of the catheter that is intended to be near the patient or within the patient's body when the catheter is used on a patient. Similarly, for example, the "distal length" of a catheter includes the length of the catheter that is intended to be near the patient or within the patient's body when the catheter is used on a patient. For example, the "distal end" of a catheter includes the end of the catheter that is intended to be near the patient or within the patient's body when the catheter is used on a patient. The distal portion, distal portion, or distal length of a catheter may include the distal end of the catheter; however, the distal portion, distal portion, or distal length of a catheter need not include the distal end of the catheter. That is, unless the context suggests otherwise, the distal portion, distal portion, or distal length of a catheter is not the terminal portion or terminal length of the catheter.

[0038] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

[0039] As described above, existing dialysis needles are rigid (e.g., metal) with sharp tips that remain in place during dialysis. The sharp tips of such dialysis needles can cause penetration (e.g., perforation of the blood vessel wall) when the sharp tip is not advanced correctly or when the patient moves during dialysis, which can be due to the duration of a dialysis treatment. A device is needed to reduce the likelihood of any penetration.

[0040] This document discloses an introducer and method thereof that solve the above problems.

[0041] Intubator

[0042] Figures 1 to 4 Different views of an introducer 100 are shown, according to some embodiments. Figure 5 and Figure 6 Different views of the composite cannula 102 are shown separated from the composite needle 104 of the introducer 100, according to some embodiments. Figure 7 An isometric cross-sectional view of a proximal portion of a composite needle 104 is shown, according to some embodiments. Figure 8 An isometric cross-sectional view of a composite cannula 102 is shown, according to some embodiments.

[0043] The introducer 100 is configured for cannulating at least an arteriovenous fistula. As shown, the introducer 100 includes a composite cannula 102 and a composite needle 104. The composite needle 104 and the composite cannula 102 are described in sequence in the following sections; however, due to the interrelationship between the composite needle 104 and the composite cannula 102 in the introducer 100, some overlap exists between the composite needle 104 and the composite cannula 102.

[0044] As shown, the compound needle 104 includes a needle hub 106, a dilator 108, a needle 110, and an access guidewire 112. The compound needle 104 may also include a guidewire actuator 114 for actuating (eg, advancing or retracting) the access guidewire 112.

[0045] The needle hub 106 is configured to be held in one hand because one person may not be strong enough to hold a flashlight. In fact, the needle hub 106 includes a housing 116 sized and shaped to be a handle that can be supported by the fingers of a single hand while establishing a percutaneous puncture using the introducer 100, as described below.

[0046] The housing 116 surrounds the chamber 118 and covers the chamber 118 with a proximal wall 120 and a distal wall 122, thereby forming a sterile enclosure for at least the proximal portion of the access guidewire 112. In addition, the distal portion of the needle hub 106 includes an extension 124 of the housing 116 that includes an aperture 126 configured to mate with a connector of a first arm 146 of the cannula hub 142, as described below.

[0047] The housing 116 may include a longitudinal slot 128 for a slider 136 of the guidewire actuator 114 when the guidewire actuator 114 is present in the compound needle 104. If the guidewire actuator 114 is not present, the guidewire 112 may be advanced or withdrawn through through-holes in the proximal and distal walls 120, 122, such as through-hole 130 in the distal wall 122.

[0048] The dilator 108 includes a distal portion having a tapered portion 132 configured to dilate tissue surrounding a puncture created by the needle 110. The proximal portion of the dilator 108 is disposed within the needle hub 106. In practice, the proximal end of the dilator 108 is coupled to the distal wall 122 of the housing 116 of the needle hub 106. The dilator 108 is disposed over the needle 110, with at least the distal end 134 of the needle 110 extending beyond the distal end of the dilator 108.

[0049] Needle 110 includes a distal portion having a tip 134 (e.g., a beveled tip) configured to establish a percutaneous puncture by inserting tip 134 of needle 110 into a patient's blood vessel. The proximal portion of needle 110 is disposed within needle hub 106. In practice, the proximal end of needle 110 is coupled to distal wall 122 of housing 116 of needle hub 106. Dilator 108 is disposed over access guidewire 112. Due to the presence of dilator 108, needle 110 can be smaller than existing dialysis needles. This, in turn, can reduce anxiety for patients and novice clinicians alike.

[0050] In some embodiments, the needle 110 is retractable. In such embodiments, the needle 110 passes through a through-hole 130 in the distal wall 122 and enters the chamber 118, where the needle 110 is disposed within and coupled to a compressed compression spring. When actuated, the needle retraction actuator releases the compressed compression spring, allowing the compression spring to extend, thereby withdrawing the needle 110 into the needle hub 106.

[0051] The access guidewire 112 is configured to facilitate a successful first puncture when establishing a percutaneous puncture with the needle 110 by ensuring that a novice clinician properly advances the needle 110 into the correct position. When the introducer 100 is engaged or in a ready-to-deploy state, the access guidewire 112 is disposed within the needle 110. In practice, the access guidewire 112 extends from at least the chamber 118 into the needle 110 through a through-hole 130 in the distal wall 122 of the housing 116 of the needle hub 106. For example, when the guidewire actuator 114 is present in the composite needle 104, a proximal portion of the access guidewire 112 is coupled to the slider 136 of the guidewire actuator 114, and the remainder of the access guidewire 112 extends from the chamber 118 into the needle 110 through the through-hole 130 in the distal wall 122 of the housing 116 of the needle hub 106. If the guidewire actuator 114 is not present, the entry guidewire 112 would otherwise extend into the chamber 118 through a through-hole in the proximal wall 120 of the housing 116 of the needle hub 106 .

[0052] In some embodiments, a successful first stab is further facilitated by visual confirmation of blood flashback, such as through a translucent portion of the housing 116 or a window in the housing 116 fluidly connected to the lumen of the needle 110 through a channel.

[0053] When present, the guidewire actuator 114 is configured to advance the distal end of the entry guidewire 112 beyond the tip 134 of the needle 110 or to withdraw the distal end of the entry guidewire 112 into the distal portion of the needle 110 proximal to the tip 134 of the needle 110. The guidewire actuator 114 may include a slider 136 slidably disposed in the longitudinal slot 128 of the housing 116 of the needle hub 106. The slider 136 includes an extension 138 coupled to the proximal portion of the entry guidewire 112 in the body chamber 118 of the needle hub 106.

[0054] The composite cannula 102 includes a cannula 140 and a cannula hub 142 surrounding a proximal portion of the cannula 140 .

[0055] Cannula 140 includes a distal portion having a tapered portion 144. Similar to the tapered portion 132 of dilator 108, the tapered portion 144 of cannula 140 is configured to expand the tissue surrounding the perforation established using needle 110. In fact, the tapered portion 144 of cannula 140 is configured to continue from the tapered portion 132 of dilator 108 when the introducer 100 is engaged. Cannula 140 is formed of a flexible material, such as a flexible polymer material, which is configured to increase patient comfort during dialysis. In fact, cannula 140 contrasts with existing rigid (e.g., metal) dialysis needles, which have sharp tips that remain in place during dialysis. The sharp tips of such dialysis needles may cause penetration (e.g., perforation of the vessel wall) when the sharp tips are not advanced correctly or the patient moves during dialysis, the latter of which may be due to the duration of the dialysis treatment process.

[0056] The cannula hub 142 can be bifurcated (e.g., branched). When bifurcated, the cannula hub 142 includes at least a first arm 146 and a second arm 148 or side arm. The first arm 146 of the cannula hub 142 includes a first arm lumen 150, and the second arm 148 of the cannula hub 142 includes a second arm lumen 152. Each lumen in the first arm lumen 150 and the second arm lumen 152 is fluidly connected to the cannula lumen 154 of the cannula 140. As shown, each arm in the first arm 146 and the second arm 148 of the cannula hub 142 terminates in a connector, such as a Luer connector, which may include a valve to seal the lumen after the composite needle 104 is removed from the composite cannula 102 according to the needle withdrawal step described below. This allows the dialysis treatment process to be performed without contaminating the immediate area with blood or other body fluids, thereby avoiding the health risks associated therewith. Additionally, the valve prevents air from entering the composite cannula 102 when the connector is not connected to a closed system, such as when a dialysis component is disconnected or withdrawn from the composite cannula 102 .

[0057] The introducer 100 has a mated or ready-to-deploy state of the composite needle 104 and the composite cannula 102 for at least intubation using the introducer 100. The mated state of the introducer 100 includes the dilator 108 of the composite needle 104 disposed within the cannula 140 of the composite cannula 102, with the proximal portion of the cannula hub 142 coupled to the distal portion of the needle hub 106. Specifically, the proximal portion of the cannula hub 142, which is coupled to the distal portion of the needle hub 106 in the mated state of the introducer 100, is a connector of the first arm 146 of the cannula hub 142 disposed within the aperture 126 in the distal portion of the needle hub 106.

[0058] method

[0059] The method of introducer 100 includes intubating a patient using introducer 100. The method includes an introducer obtaining step, a perforation establishing step, an access guidewire advancing step, a tissue dilating step, a cannula advancing step, and a needle retracting step.

[0060] The introducer obtaining step includes obtaining the introducer 100. As described above, the introducer 100 includes the composite needle 104 and the composite cannula 102, preferably in a mated state of the introducer 100.

[0061] The method may also include a ensuring step. The ensuring step includes ensuring that the composite needle 104 and the composite needle hub are properly mated with the connector of the first arm 146 of the cannula hub 142 disposed in the aperture 126 of the distal portion of the needle hub 106. The ensuring step may also include ensuring that the tapered portion 132 of the distal portion of the dilator 108 continues along the tapered portion 144 of the distal portion of the cannula 140. The ensuring step may also include ensuring that the distal end of the guidewire 112 does not extend past the tip 134 of the needle 110 of the composite needle 104. When performed, the ensuring step should be performed before the perforation establishment step.

[0062] The perforation creation step includes creating a percutaneous perforation by inserting the distal end 134 of the needle 110 of the composite needle 104 into a blood vessel (eg, an arteriovenous fistula) of the patient.

[0063] The access guidewire advancing step includes utilizing the guidewire actuator 114 of the composite needle 104 to advance the distal end of the access guidewire 112 beyond the tip 134 of the needle 110 and into the lumen of the blood vessel.

[0064] The access guidewire advancing step includes distally sliding a slider 136 disposed in the longitudinal slot 128 of the needle hub 106. The slider 136 includes an extension 138 coupled to a proximal portion of the access guidewire 112 within the cavity 118 of the needle hub 106.

[0065] The tissue dilation step includes dilating the tissue surrounding the puncture using the tapered portion 132 of the dilator 108 disposed above the needle 110. The tissue dilation step also includes dilating the tissue using the tapered portion 144 of the cannula 140.

[0066] The cannula advancement step includes advancing the cannula 140 of the composite cannula 102 over the dilator 108 , the needle 110 , and the access guidewire 112 into the lumen of the blood vessel.

[0067] The method may further include an access wire withdrawal step. The access wire withdrawal step includes withdrawing the distal end of the access wire 112 into the distal portion of the needle 110 proximal to the tip 134 of the needle 110 using the guidewire actuator 114, preferably prior to the needle withdrawal step.

[0068] The needle withdrawal step includes disconnecting the connector of the first arm 146 of the cannula hub 142 from the aperture 126 of the distal portion of the needle hub 106 and withdrawing the composite needle 104 from the lumen of the blood vessel, leaving the composite cannula 102 in place.

[0069] The method may further include a dialyzer connection step and a dialysis start step. The dialyzer connection step includes connecting the composite cannula 102 to a tubing set of the dialyzer. The dialysis start step includes starting dialysis via the composite cannula 102.

[0070] Although some specific embodiments have been disclosed herein, and although specific embodiments have been disclosed in considerable detail, these specific embodiments are not intended to limit the scope of the concepts provided herein. Additional adaptations and / or modifications may be envisioned by those of ordinary skill in the art, and in broader aspects, these adaptations and / or modifications are also encompassed. Therefore, changes may be made to the specific embodiments disclosed herein without departing from the scope of the concepts provided herein.

Claims

1. An introducer for cannulating an arteriovenous fistula, comprising: A composite needle, comprising: Needle; a dilator disposed over the needle, wherein at least the distal end of the needle extends beyond a distal end of the dilator; and a needle hub surrounding a proximal portion of the dilator; and A composite cannula, comprising: intubation; and A cannula hub surrounding a proximal portion of the cannula, the introducer being arrangable in a mating state of the composite needle and the composite cannula for at least cannulation using the introducer, the mating state comprising the dilator being arranged in the cannula, wherein the proximal portion of the cannula hub is coupled to the distal portion of the needle hub, wherein the needle hub comprises a housing enclosing a chamber having a distal wall, to which each of the proximal ends of the needle and the dilator are coupled.

2. The introducer of claim 1, the compound needle further comprising an access guidewire disposed in the needle, the access guidewire extending from the lumen through a through-hole in a distal wall of the needle hub.

3. The introducer of claim 2, the composite needle further comprising a guidewire actuator configured to advance the distal end of the entry guidewire beyond the tip of the needle or to withdraw the distal end of the entry guidewire into a distal portion of the needle proximal to the tip of the needle.

4. The introducer of claim 3, the guidewire actuator comprising a slider slidably disposed in the longitudinal slot of the needle hub, the slider comprising an extension coupled to a proximal portion of the access guidewire in the cavity of the needle hub.

5. The introducer of claim 1, wherein the cannula is formed of a flexible polymer material configured to increase patient comfort during a dialysis treatment procedure.

6. The introducer of claim 1, wherein the distal portion of the cannula includes a taper configured to continue from the taper of the dilator in the mated state of the introducer.

7. The introducer of claim 1, wherein the cannula hub is bifurcated, the cannula hub comprising at least a first arm and a second arm.

8. The introducer of claim 7, wherein the first arm of the cannula bushing includes a first arm lumen, the second arm of the cannula bushing includes a second arm lumen, and each of the first arm lumen and the second arm lumen is fluidly connected to the cannula lumen of the cannula.

9. The introducer of claim 7 or 8, wherein each of the first and second arms of the cannula hub terminates in a Luer connector.

10. The introducer of claim 9, wherein the proximal portion of the cannula hub coupled to the distal portion of the needle hub in a mated state of the introducer is the Luer connector of the first arm of the cannula hub arranged in a hole in the distal portion of the needle hub.

11. The introducer of claim 1 , wherein the cannula has a luer connector in a proximal portion of the cannula hub, the luer connector being disposed in a bore in a distal portion of the needle hub.

12. The introducer of claim 11, wherein the distal portion of the cannula includes a taper configured to continue from the taper of the dilator in the mated state of the introducer.

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