Patent Publication Number: US-2023133531-A1

Title: Cannulators and Methods Thereof

Description:
BACKGROUND 
     Existing dialysis needles are rigid (e.g., metal) with a sharp tip that is left in place during dialysis. The sharp tip of such dialysis needles can result in infiltration (e.g., puncture of a blood-vessel wall) when the sharp tip is incorrectly advanced or a patient moves during dialysis, the latter of which is likely due to the duration of a dialysis treatment procedure. A device is needed to reduce any potential for infiltration. Disclosed herein are cannulators and methods thereof that address the foregoing. 
     SUMMARY 
     Disclosed herein is a cannulator for cannulating an arteriovenous fistula . The cannulator includes, in some embodiments, a compound needle and a compound cannula. The compound needle includes a needle, a dilator, and a needle hub. The dilator is disposed over the needle with at least a tip of the needle extending beyond a distal end of the dilator. The needle hub is around a proximal-end portion of the dilator. The compound cannula includes a cannula and a cannula hub around a proximal-end portion of the cannula. The cannulator has a mated state of the compound needle and the compound cannula for at least cannulation with the cannulator. The mated state of the cannulator includes the dilator disposed in the cannula with a proximal-end portion of the cannula hub coupled to a distal-end portion of the needle hub. 
     In some embodiments, the needle hub includes a housing enclosing a cavity having a distal wall. Each of a proximal end of the needle and a proximal end of the dilator is coupled to the distal wall. 
     In some embodiments, the compound needle further includes an access guidewire disposed in the needle. The access guidewire extends from the cavity through a through hole in the distal wall of the needle hub. 
     In some embodiments, the compound needle further includes a guidewire actuator. The guidewire actuator is configured to advance a distal end of the access guidewire beyond the tip of the needle or withdraw the distal end of the access guidewire into a distal-end portion of the needle proximal of the tip of the needle. 
     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-end portion of the access guidewire in the cavity of the needle hub. 
     In some embodiments, the cannula is formed of a flexible polymeric material configured to increase patient comfort during a dialysis treatment procedure. 
     In some embodiments, a distal-end portion of the cannula includes a taper. The taper of the cannula is configured to continue from a taper of the dilator in the mated state of the cannulator. 
     In some embodiments, the cannula hub is furcated (e.g., bifurcated). When furcated, the cannula hub includes at least a primary arm and a secondary arm. 
     In some embodiments, the primary arm of the cannula hub includes a primary-arm lumen and the secondary arm of the cannula hub includes a secondary-arm lumen. Each lumen of the primary-arm lumen and the secondary-arms lumen is fluidly connected to a cannula lumen of the cannula. 
     In some embodiments, each arm of the primary arm and the secondary arm of the cannula hub terminates in a Luer connector. 
     In some embodiments, the proximal-end portion of the cannula hub coupled to the distal-end portion of the needle hub in the mated state of the cannulator is the Luer connector of the primary arm of the cannula hub disposed in a bore in the distal-end portion of the needle hub. 
     Disclosed herein is a cannulator for cannulating an arteriovenous fistula. The cannulator includes, in some embodiments, a compound needle and a compound cannula. The compound needle includes an access guidewire, a needle, a dilator, and a needle hub. The needle is disposed over the access guidewire. The dilator is disposed over the needle with at least a tip of the needle extending beyond a distal end of the dilator. The needle hub includes a housing enclosing a cavity having a distal wall. Each of a proximal end of the needle and a proximal end of the dilator is coupled to the distal wall. The guidewire actuator is configured to advance a distal end of the access guidewire beyond the tip of the needle or withdraw the distal end of the access guidewire into a distal-end portion the needle proximal of the tip 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 a proximal-end portion of the access guidewire that extends into the cavity of the needle hub through a through hole in the distal wall of the needle hub. The compound cannula includes a cannula and a cannula hub around a proximal-end portion of the cannula. The cannulator has a mated state of the compound needle and the compound cannula for at least cannulation with the cannulator. The mated state of the cannulator includes the dilator disposed in the cannula with a Luer connector in a proximal-end portion of the cannula hub disposed in a bore of a distal-end portion of the needle hub. 
     In some embodiments, a distal-end portion of the cannula includes a taper. The taper of the cannula is configured to continue from a taper of the dilator in the mated state of the cannulator. 
     In some embodiments, the cannula hub is furcated (e.g., bifurcated). When furcated, the cannula hub includes at least a primary arm and a secondary arm. 
     In some embodiments, the primary arm of the cannula hub includes a primary-arm lumen and the secondary arm of the cannula hub includes a secondary-arm lumen. Each lumen of the primary-arm lumen and the secondary-arms lumen is fluidly connected to a cannula lumen of the cannula. 
     Also disclosed herein is a method of cannulating a patient with a cannulator. The method includes, in some embodiments, a cannulator-obtaining step, a puncture-establishing step, an access guidewire-advancing step, a tissue-dilating step, a cannula-advancing step, and a needle-withdrawing step. The cannulator-obtaining step includes obtaining the cannulator. The cannulator includes a compound needle and a compound cannula in a mated state of the cannulator. The puncture-establishing step includes establishing a percutaneous puncture by inserting a tip of a needle of the compound needle into a blood vessel of the patient. The access guidewire-advancing step includes advancing a distal end of an access guidewire beyond the tip of the needle and into a blood-vessel lumen with a guidewire actuator of the compound needle. The tissue-dilating step includes dilating tissue surrounding the puncture with a dilator of the compound needle disposed over the needle. The cannula-advancing step includes advancing a cannula of the compound cannula over the dilator, the needle, and the access guidewire into the blood-vessel lumen. The needle-withdrawing step includes withdrawing the compound needle from the blood-vessel lumen leaving the compound cannula in place. 
     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-end portion of the access guidewire in a cavity of the needle hub. 
     In some embodiments, the method further includes an access guidewire-withdrawing step. The access guidewire-withdrawing step includes withdrawing the distal end of the access guidewire into a distal-end portion of the needle proximal of the tip of the needle with the guidewire actuator before the needle-withdrawing step. 
     In some embodiments, the method further includes an ensuring step. The ensuring step includes ensuring the compound needle and the compound hub are properly mated with a Luer connector of a primary arm of the cannula hub disposed in a bore of a distal-end portion of the needle hub. 
     In some embodiments, the ensuring step includes ensuring a taper of a distal-end portion of the dilator continues along a taper of a distal-end portion of the cannula. 
     In some embodiments, the tissue-dilating step includes dilating the tissue with the distal-end portion of the cannula. 
     In some embodiments, the blood vessel is an arteriovenous fistula. 
     In some embodiments, the method further includes a dialysis machine-connecting step and a dialysis-commencing step. The dialysis machine-connecting step includes connecting the compound cannula to a tubing set of a dialysis machine. The dialysis-commencing step includes commencing dialysis through the compound cannula. 
     These and other features of the concepts provided herein will become more apparent to those of skill in the art in view of the accompanying drawings and following description, which describe particular embodiments of such concepts in greater detail. 
    
    
     
       DRAWINGS 
         FIG.  1    illustrates a first isometric view of a cannulator in accordance with some embodiments. 
         FIG.  2    illustrates a second isometric view of the cannulator in accordance with some embodiments. 
         FIG.  3    illustrates a top view of the cannulator in accordance with some embodiments. 
         FIG.  4    illustrates a side view of the cannulator in accordance with some embodiments. 
         FIG.  5    illustrates an isometric view of a compound cannula separated from a compound needle of the cannulator in accordance with some embodiments. 
         FIG.  6    illustrates a side view of the compound cannula separated from the compound needle in accordance with some embodiments. 
         FIG.  7    illustrates an isometric cross-sectional view of a proximal-end portion of the compound needle in accordance with some embodiments. 
         FIG.  8    illustrates an isometric cross-sectional view of the compound cannula in accordance with some embodiments. 
     
    
    
     DESCRIPTION 
     Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments disclosed herein. 
     Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the 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 different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. Labels such as “left,” “right,” “top,” “bottom,” “front,” “back,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. 
     With respect to “proximal,” a “proximal portion” or a “proximal-end portion” of, for example, a catheter disclosed herein includes a portion of the catheter intended to be near a clinician when the catheter is used on a patient. Likewise, a “proximal length” of, for example, the catheter includes a length of the catheter intended to be near the clinician when the catheter is used on the patient. A “proximal end” of, for example, the catheter includes an end of the catheter intended to be near the clinician when the catheter is used on the patient. The proximal portion, the proximal-end portion, or the proximal length of the catheter can include the proximal end of the catheter; however, the proximal portion, the proximal-end portion, or the proximal length of the catheter need not include the proximal end of the catheter. That is, unless context suggests otherwise, the proximal portion, the proximal-end portion, or the proximal length of the catheter is not a terminal portion or terminal length of the catheter. 
     With respect to “distal,” a “distal portion” or a “distal-end portion” of, for example, a catheter disclosed herein includes a portion of the catheter intended to be near or in a patient when the catheter is used on the patient. Likewise, a “distal length” of, for example, the catheter includes a length of the catheter intended to be near or in the patient when the catheter is used on the patient. A “distal end” of, for example, the catheter includes an end of the catheter intended to be near or in the patient when the catheter is used on the patient. The distal portion, the distal-end portion, or the distal length of the catheter can include the distal end of the catheter; however, the distal portion, the distal-end portion, or the distal length of the catheter need not include the distal end of the catheter. That is, unless context suggests otherwise, the distal portion, the distal-end portion, or the distal length of the catheter is not a terminal portion or terminal length of the catheter. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art. 
     As set forth above, existing dialysis needles are rigid (e.g., metal) with a sharp tip that is left in place during dialysis. The sharp tip of such dialysis needles can result in infiltration (e.g., puncture of a blood-vessel wall) when the sharp tip is incorrectly advanced or a patient moves during dialysis, the latter of which is likely due to the duration of a dialysis treatment procedure. A device is needed to reduce any potential for infiltration. 
     Disclosed herein are cannulators and methods thereof that address the foregoing. 
     Cannulators 
       FIGS.  1 - 4    illustrate different views of a cannulator  100  in accordance with some embodiments.  FIGS.  5  and  6    illustrate different views of a compound cannula  102  separated from a compound needle  104  of the cannulator  100  in accordance with some embodiments.  FIG.  7    illustrates an isometric cross-sectional view of a proximal-end portion of the compound needle  104  in accordance with some embodiments.  FIG.  8    illustrates an isometric cross-sectional view of the compound cannula  102  in accordance with some embodiments. 
     The cannulator  100  is configured for at least cannulating an arteriovenous fistula. As shown, the cannulator  100  includes the compound cannula  102  and the compound needle  104 . The compound needle  104  and the compound cannula  102  are described, in turn, in sections set forth below; however, some crossover between the sections for the compound needle  104  and the compound cannula  102  exist in view of the interrelatedness of the compound needle  104  and the compound cannula  102  in the cannulator  100 . 
     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  can further include a guidewire actuator  114  for actuating (e.g., advancing or withdrawing) the access guidewire  112 . 
     The needle hub  106  is configured to be held in a single hand as one might underhandedly hold a flashlight. Indeed, the needle hub  106  includes a housing  116  sized and shaped as a handle that can be cradled by fingers of a single hand while establishing a percutaneous puncture with the cannulator  100  as set forth below. 
     The housing  116  surrounds a cavity  118  and caps the cavity  118  with a proximal wall  120  and a distal wall  122 , thereby forming a sterile enclosure for at least a proximal-end portion of the access guidewire  112 . In addition, a distal-end portion of the needle hub  106  includes an extension  124  of the housing  116  including a bore  126  configured to mate with the connector of the primary arm  146  of the cannula hub  142  as set forth below. 
     The housing  116  can include a longitudinal slot  128  for the 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 access guidewire  112  can be advanced or withdrawn by way of through holes in the proximal and distal walls  120  and  122  such as the through hole  130  in the distal wall  122 . 
     The dilator  108  includes a distal-end portion having a taper  132  configured to dilate tissue surrounding a puncture established with the needle  110 . A proximal-end portion of the dilator  108  is disposed in the needle hub  106 . Indeed, a 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 tip  134  of the needle  110  extending beyond a distal end of the dilator  108 . 
     The needle  110  includes a distal-end portion having a tip  134  (e.g., a beveled tip) configured to establish a percutaneous puncture by inserting the tip  134  of the needle  110  into a blood vessel of a patient. A proximal-end portion of the needle  110  is disposed in the needle hub  106 . Indeed, a proximal end of the needle  110  is coupled to the distal wall  122  of the housing  116  of the needle hub  106 . The dilator  108  is disposed over the access guidewire  112 . Due to the presence of the dilator  108 , the needle  110  can be smaller than existing dialysis needles. This, in turn, can reduce anxiety in patients and novice clinicians alike. 
     In some embodiments, the needle  110  is retractable. In such embodiments, the needle  110  passes through the through hole  130  in the distal wall  122  and into the cavity  118  where the needle  110  is disposed within and coupled to a compressed compression spring. When actuated, a needle-retraction actuator releases the compressed compression spring allowing the compression spring to extend, thereby withdrawing the needle  110  into the needle hub  106 . 
     The access guidewire  112  is configured to facilitate first-stick success upon establishing a percutaneous puncture with the needle  110  by ensuring novice clinicians that they are properly advancing the needle  110  into the correct location. The access guidewire  112  is disposed in the needle  110  in a mated or ready-to-deploy state of the cannulator  100 . Indeed, the access guidewire  112  extends into the needle  110  from at least the cavity  118  by way of the 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 compound needle  104 , a proximal-end portion of the access guidewire  112  is coupled to the slider  136  of the guidewire actuator  114  and a remainder of the access guidewire  112  extends into the needle  110  from the cavity  118  by way of 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 access guidewire  112  additionally extends into the cavity  118  by way of the through hole in the proximal wall  120  of the housing  116  of the needle hub  106 . 
     In some embodiments, first-stick success 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 by a channel to a lumen of the needle  110 . 
     When present, the guidewire actuator  114  is configured to advance a distal end of the access guidewire  112  beyond the tip  134  of the needle  110  or withdraw the distal end of the access guidewire  112  into a distal-end portion the needle  110  proximal of the tip  134  of the needle  110 . The guidewire actuator  114  can 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-end portion of the access guidewire  112  in the body cavity  118  of the needle hub  106 . 
     The compound cannula  102  includes a cannula  140  and a cannula hub  142  around a proximal-end portion of the cannula  140 . 
     The cannula  140  includes a distal-end portion having a taper  144 . Like the taper  132  of the dilator  108 , the taper  144  of the cannula  140  is configured to dilate tissue surrounding a puncture established with the needle  110 . Indeed, the taper  144  of the cannula  140  is configured to continue from the taper  132  of the dilator  108  in the mated state of the cannulator  100 . The cannula  140  is formed of a flexible material such as a flexible polymeric material configured to increase patient comfort during dialysis. Indeed, the cannula  140  is in contrast to existing dialysis needles that are rigid (e.g., metal) with a sharp tip that is left in place during dialysis. The sharp tip of such dialysis needles can result in infiltration (e.g., puncture of a blood-vessel wall) when the sharp tip is incorrectly advanced or a patient moves during dialysis, the latter of which is likely due to the duration of a dialysis treatment procedure. 
     The cannula hub  142  can be furcated (e.g., bifurcated). When furcated, the cannula hub  142  includes at least a primary arm  146  and a secondary arm  148  or side arm. The primary arm  146  of the cannula hub  142  includes a primary-arm lumen  150  and the secondary arm  148  of the cannula hub  142  includes a secondary-arm lumen  152 . Each lumen of the primary-arm lumen  150  and the secondary-arm lumen  152  is fluidly connected to a cannula lumen  154  of the cannula  140 . As shown, each arm of the primary arm  146  and the secondary arm  148  of the cannula hub  142  terminates in a connector such as a Luer connector, which can include a valve to seal the lumen after the compound needle  104  is removed from the compound cannula  102  in accordance with the needle-withdrawing step set forth below. This allows a dialysis treatment procedure to be performed without contaminating the immediate area with blood or other bodily fluids, thereby obviating health risks associated therewith. In addition, the valve keeps air from entering the compound cannula  102  when the connector is not connected to a closed system such as when dialysis components are disconnected or withdrawn from compound cannula  102 . 
     The cannulator  100  has a mated or ready-to-deploy state of the compound needle  104  and the compound cannula  102  for at least cannulation with the cannulator  100 . The mated state of the cannulator  100  includes the dilator  108  of the compound needle  104  disposed in the cannula  140  of the compound cannula  102  with a proximal-end portion of the cannula hub  142  coupled to the distal-end portion of the needle hub  106 . Specifically, the proximal-end portion of the cannula hub  142  coupled to the distal-end portion of the needle hub  106  in the mated state of the cannulator  100  is the connector of the primary arm  146  of the cannula hub  142  disposed in the bore  126  in the distal-end portion of the needle hub  106 . 
     Methods 
     A method of the cannulator  100  includes cannulating a patient with the cannulator  100 . Such a method includes a cannulator-obtaining step, a puncture-establishing step, an access guidewire-advancing step, a tissue-dilating step, a cannula-advancing step, and a needle-withdrawing step. 
     The cannulator-obtaining step includes obtaining the cannulator  100 . As set forth above, the cannulator  100  includes the compound needle  104  and the compound cannula  102 , preferably in the mated state of the cannulator  100 . 
     The method can further include an ensuring step. The ensuring step includes ensuring the compound needle  104  and the compound hub are properly mated with the connector of the primary arm  146  of the cannula hub  142  disposed in the bore  126  of the distal-end portion of the needle hub  106 . The ensuring step can also include ensuring the taper  132  of the distal-end portion of the dilator  108  continues along the taper  144  of the distal-end portion of the cannula  140 . The ensuring step can also include ensuring the distal end of the guidewire  112  is not extended past the tip  134  of the needle  110  of the compound needle  104 . When performed, the ensuring step should be performed prior to the puncture-establishing step. 
     The puncture-establishing step includes establishing a percutaneous puncture by inserting the tip  134  of the needle  110  of the compound needle  104  into a blood vessel (e.g., arteriovenous fistula) of the patient. 
     The access guidewire-advancing step includes advancing the distal end of the access guidewire  112  beyond the tip  134  of the needle  110  and into a blood-vessel lumen with the guidewire actuator  114  of the compound needle  104 . 
     The access guidewire-advancing step includes distally sliding the slider  136  disposed in the longitudinal slot  128  of the needle hub  106 . The slider  136  includes the extension  138  coupled to the proximal-end portion of the access guidewire  112  in the cavity  118  of the needle hub  106 . 
     The tissue-dilating step includes dilating tissue surrounding the puncture with the taper  132  of the dilator  108  disposed over the needle  110 . The tissue-dilating step also includes dilating the tissue with the taper  144  of the cannula  140 . 
     The cannula-advancing step includes advancing the cannula  140  of the compound cannula  102  over the dilator  108 , the needle  110 , and the access guidewire  112  into the blood-vessel lumen. 
     The method can further include an access guidewire-withdrawing step. The access guidewire-withdrawing step includes withdrawing the distal end of the access guidewire  112  into the distal-end portion of the needle  110  proximal of the tip  134  of the needle  110  using the guidewire actuator  114 , preferably before the needle-withdrawing step. 
     The needle-withdrawing step includes disconnecting the connector of the primary arm  146  of the cannula hub  142  from the bore  126  of the distal-end portion of the needle hub  106  and withdrawing the compound needle  104  from the blood-vessel lumen leaving the compound cannula  102  in place. 
     The method can further include a dialysis machine-connecting step and a dialysis-commencing step. The dialysis machine-connecting step includes connecting the compound cannula  102  to a tubing set of a dialysis machine. The dialysis-commencing step includes commencing dialysis through the compound cannula  102 . 
     While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein.