Patent Publication Number: US-2020276430-A1

Title: Apparatus and method for cannulation of vascular access vessel

Description:
CROSS-REFERENCES 
     This application is a divisional application of U.S. patent application Ser. No. 16/175,698, filed Oct. 30, 2018, the contents of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     An apparatus and method is described for needle access of a surgically created vascular access for use as a means to receive hemodialysis and other procedures requiring vascular access and, more particularly, an apparatus and method for vascular access of an arteriovenous fistula or arteriovenous graft that enables location of cannulation sites post-implant. 
     Hemodialysis is a life-sustaining treatment for patients with end stage renal disease. Hemodialysis is a process whereby large amounts of blood are removed from the body, filtered through a machine that removes wastes, and then returned into the body. 
     A vascular access site on the body where blood will be removed and returned during hemodialysis is prepared before starting hemodialysis. High-flow access to a patient&#39;s circulation is achieved in a surgical anastomosis creating an arteriovenous fistula (“AVF”) in which a vein is connected directly to an artery. Alternatively, the connection between the artery and the vein may be formed using a prosthetic arteriovenous graft (“AVG”) made from a synthetic material and implanted just under the skin. Placement sites for AVG&#39;s include, without limitation, the forearm, upper arm, neck, chest, and thigh, in either straight or looped configurations. 
     Once a vascular access vessel is surgically positioned, the AVF or AVG becomes a conduit that can be used repeatedly for vascular access during hemodialysis. Needles are used to cannulate through the skin, directly puncturing the walls of the vascular access vessel. In conventional hemodialysis, two cannulas are placed in the vascular access vessel, with one efferent needle puncture being made in the graft wall in the arterial side and another afferent needle puncture being made in the venous side. During dialysis, blood is withdrawn from the arterial side via the first needle, passed through a hemodialysis machine, and then returned to the patient through the second needle inserted in the venous. 
     A significant step in the hemodialysis procedure is “finding” the proper position within along the vascular access vessel to perform the needle sticks. Moreover, conventional dialysis protocols require a patient to undergo a dialysis procedure at least three times a week. As a result, the skin and underlying tissue are punctured numerous times per week to gain entry into the vascular access vessel. The technique of cannulating an AVF or AVG for hemodialysis requires considerable skill. A vascular access vessel often lies several centimeters below the surface of the skin and cannot be located by visual inspection. A medical technician is required to locate the AVF or AVG by palpation, which can prove to be extremely difficult. The punctures of the vascular access are prone to error and complication. Punctures done incorrectly may promote rupture of the access, bleeding, hematoma formation, pseudoaneurysm formation, severe pain or the development of organized thrombi within the lumen of the graft. The formation of such blood clots may result not only in multiple graft thromboses, but may eventually lead to graft failure. Missing the vascular access entirely or improperly positioning of the needle within the lumen of the AVF or AVG device are two contraindications, which adversely affect the time the graft remains patent. Locating the cannulation area simply by using conventional methods of palpating through the skin is sometimes unreliable. 
     Chronic repeated insertion of the needles eventuates in traumatic breakdown of the skin, and traumatic breakdown and stenosis of the graft site, particularly in the vicinity of its venous anastomosis. Traumatic breakdown and stenosis requires thrombectomies, AVG salvage, surgical revision procedures and new surgical constructions. Vascular access life may be prolonged with patch angioplasty at venous outflow stenoses or by adding a new segment of the AVG to bypass areas of venous stenosis. Vascular access life may also be prolonged by rotating and tracking puncture sites to allow maximum healing between punctures at a particular site. 
     For the forgoing reasons, there is a need for an apparatus and method for proper cannulation of a vascular access fistula or graft, including correct identification of an access region of the vascular access following implantation. The new apparatus should improve access to the implanted AVF or AVG by allowing a user of the vascular access vessel to facilitate accurate and reproducible entry into the implanted AVF or AVG of dialysis needles, cannulas, and the like, which are introduced into the vascular access via insertion through the skin. Ideally, the new apparatus and method should minimize trauma, pain and risk of infection while also maximizing the functional integrity and longevity of the fistula or graft used in hemodialysis. 
     SUMMARY 
     An apparatus is provided for rotatable selection of sites for cannulation with a needle along a subcutaneous vascular access vessel. The cannulation site selection apparatus comprises a template having an inner surface and an outer surface, and a plurality of visible markings on the outer surface of the template. The template is adapted to be disposed adjacent the subcutaneous vascular access vessel such that the markings align with the cannulation sites along the vascular access vessel for selecting a site for cannulation with a needle into the vascular access vessel. 
     The vascular access vessel may be an arteriovenous dialysis access graft subcutaneously implanted in a body of a patient or an arteriovenous fistula in a body of a patient. 
     In one aspect, the plurality of visible markings on the template comprises an amount of cannulation site selection markings such that a user can cannulate the vascular access vessel at a different cannulation site selection marking for four weeks of treatment. The plurality of visible markings may be on a first side and a second side of a longitudinal axis of the template. 
     In a further aspect, the template may comprise a key on the template, the key describing the schedule for rotation of the cannulation site selection markings. The key can include a reproduction of an image of a forearm and a wrist of a patient and, further, a reproduction of an image of a torso of a patient. 
     In one aspect, the template has at least one passage opening, the template defines holes along an edge of the template, the holes spaced at set distances from one another, and is adapted to be disposed adjacent the subcutaneous vascular access vessel such that the holes align with the cannulation sites along the vascular access vessel for selecting a site for cannulation with a needle into the vascular access vessel. 
     In yet another aspect, the template is translucent. 
     A sleeve may be provided, the sleeve defining a pocket for receiving the template, wherein the sleeve is configured to accommodate the body of the subject adjacent the subcutaneous vascular access vessel such that the markings align with the cannulation sites along the vascular access vessel for selecting a site for cannulation with a needle into the vascular access vessel. In this embodiment, the vascular access vessel is an arteriovenous dialysis access graft subcutaneously implanted in a body of a patient, or an arteriovenous fistula in a body of a patient. 
     A kit is also provided, the kit comprising at least one dialysis needle for accessing a subcutaneous vascular access vessel in a body of a patient, a dispenser, a template having an inner surface and an outer surface, and a plurality of visible markings on the outer surface of the template. The template is adapted to be disposed adjacent the subcutaneous vascular access vessel such that the markings align with cannulation sites along the vascular access vessel for selecting a site for cannulation with the needle into the vascular access vessel. 
     In another embodiment, an apparatus for rotatable selection of a cannulation sites along a vascular access vessel comprises a template having an inner surface and an outer surface, the template defining at least one opening extending from the outer surface to the inner surface, and a skin marking device. The template is adapted to be disposed adjacent the subcutaneous vascular access vessel such that the at least one opening aligns with a cannulation site along the vascular access vessel for selecting the site for cannulation with a needle into the vascular access vessel by marking through the opening with the skin marking device. A spacer may be provided, the spacer defining a hole to be aligned with the last cannulation site for marking the arm beyond the periphery of the spacer. 
     A method is also contemplated for rotatable selection of sites for cannulation with a needle along a subcutaneous vascular access vessel. The cannulation site selection method comprises the steps of providing a template having an inner surface and an outer surface, disposing a plurality of visible markings on the outer surface of the template, positioning the template adjacent the subcutaneous vascular access vessel such that the markings align with the cannulation sites along the vascular access vessel, and selecting a site for cannulation with a needle into the vascular access vessel. 
     In one aspect, the cannulation site selection method further comprises the step of cannulating the vascular access vessel at a site corresponding to a second cannulation site selection marking, wherein the second cannulation site selection marking is spaced from the first cannulation site selection marking. Moreover, the step of cannulating the vascular access vessel at a site corresponding to a third cannulation site selection marking follows, wherein the third cannulation site selection marking is spaced from the second cannulation site selection marking. The plurality of visible markings on the template comprises an amount of cannulation site selection markings such that a user can cannulate the vascular access vessel at a different cannulation site selection marking for four weeks of treatment. 
     The cannulation site selection method may further comprise the step of implanting an arteriovenous dialysis access graft in a body of a patient, or the step of surgically forming an arteriovenous fistula in a body of a patient. 
     In another aspect of the method, the cannulation site is cannulated to provide access to the vessel for single-needle hemodialysis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present apparatus and method, reference should now be had to the embodiments shown in the accompanying drawings and described below. In the drawings: 
         FIG. 1  is a top plan view of an embodiment of an apparatus for cannulation of a vascular access vessel. 
         FIG. 2  is a top plan view of another embodiment of an apparatus for cannulation of a vascular access vessel. 
         FIG. 3  is a top plan view of a third embodiment of an apparatus for cannulation of a vascular access vessel. 
         FIG. 4  is a top plan view of a fourth embodiment of an apparatus for cannulation of a vascular access vessel. 
         FIG. 5  is a top plan view of a fifth embodiment of an apparatus for cannulation of a vascular access vessel. 
         FIG. 6  is a top plan view of a sixth embodiment of an apparatus for cannulation of a vascular access vessel. 
         FIG. 7  is a top plan view of a seventh embodiment of an apparatus for cannulation of a vascular access vessel. 
         FIG. 8  is a perspective view of an eighth embodiment of an apparatus for cannulation of a vascular access vessel including a mobile telephone. 
         FIG. 9  is a perspective view of another embodiment of an apparatus for cannulation of a vascular access vessel including a mobile telephone. 
         FIG. 10  is a schematic perspective view of an embodiment of a wristband for use with an apparatus for cannulation of a vascular access vessel. 
         FIG. 11  is a top plan view of a ninth embodiment of an apparatus for cannulation of a vascular access vessel. 
     
    
    
     DESCRIPTION 
     As used herein, the term “vascular access” is used to mean access to a vessel comprising an intended surgical connection between an arterial and venous system through which blood flows from the artery to the vein. As noted above, this can be achieved by an anastomosis directly connecting a vein to an artery (AVF) or by utilizing a synthetic or autologous conduit for anastomosis to an artery at one end and a vein at the other end to connect the arterial and venous systems (AVG). Because there are many types of AVG&#39;s and associated components that are well known in the art and that may be utilized with the present apparatus and method, a more detailed description of these components is not required. It is understood that the present apparatus and method is not directed to only to AVF nor to any particular type of AVG. The vascular access apparatus and method described herein is for use in medical procedures requiring vascular access. Accordingly, the features described herein may be used with any conventional vascular access vessel including AVG&#39;s including, but not limited to, the AVG described by U.S. Pat. No. 9,585,998, the contents of which are hereby incorporated by reference herein in their entirety. A similar application is shown and described in U.S. Pub. Application No. 2014/0336682, the contents of which are also incorporated by reference herein in their entirety. Accordingly, detailed explanations of the functioning of all of the components and use of vascular grafts are deemed unnecessary for understanding of the present description by one of ordinary skill in the art. 
     Certain terminology is used herein for convenience only and is not to be taken as a limiting. For example, words such as “upper,” “lower,” “left,” “right,” “horizontal,” “vertical,” “upward,” “downward,” “top” and “bottom” merely describe the configurations shown in the FIGs. Indeed, the components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. The words “interior” and “exterior” refer to directions toward and away from, respectively, the geometric center of the core and designated parts thereof. The terminology includes the words specifically mentioned above, derivatives thereof and words of similar import. 
     Referring now to the drawings, wherein like reference numerals designate corresponding or similar elements throughout the several views, an apparatus for use in a method for cannulating a vascular access vessel connecting an artery to a vein is shown in  FIG. 1  and generally designated at  20 . The cannulation template  20  has markings  22  used to locate and implement cannulation at a site as well as for presenting a rotation plan for successive cannulations. The cannulation template  20  provides a device for rotatable selection of cannulation sites along a vascular access vessel for hemodialysis. As a result, the vascular access vessel is allowed increased healing time before re-cannulation occurs at a particular site. Properly spacing and rotating cannulation sites using the cannulation template  20  can extend the life of an arteriovenous fistula or arteriovenous graft and reduce the likelihood of failure of the vascular access. The cannulation template  20  as described herein can also be used to assist users with properly inserting a needle into a site to carry out hemodialysis treatments. 
       FIG. 1  shows a first outer side  24  of an embodiment of the cannulation template  20  to be used for a patient with, for example, an arteriovenous graft. The cannulation template has a left end  26  and a right end  28 . The outer side  24  surface has markings  22  for the user to plan and select cannulation sites. More particularly, the cannulation template  20  has a first marking  30   a  located, for example, at one end of the cannulation template  20 , and additional markings extending the length  31  thereof. In use, the first marking  30   a  is positioned adjacent the anastomosis made surgically between adjacent blood vessels, or other channels of the body, and indicates a first site for cannulation. 
     In one embodiment, the cannulation template  20  is made of a flexible material. The cannulation template  20  may, for example, be made of a flexible plastic, although paper, metal foil or a substantially equivalent material is suitable. The material from which the cannulation template  20  is formed is sufficiently flexible such that the apparatus can be bent around a patient&#39;s body part without breaking. This configuration of the cannulation template  20  allows a user to orient the cannulation template  20  appropriately along a patient&#39;s arteriovenous fistula or graft. As a result, the cannulation template  20  may be easily contoured along a vascular access vessel allowing selection of a cannulation site regardless of the vessel geometry. 
     Referring to  FIG. 1 , the cannulation template  20  has an array of markings  22  along the length  31 . The markings  22  include boundary lines  23  providing an exemplary hemodialysis access configuration comprising an array of twelve cannulation sites, indicated in  FIG. 1  by reference numerals  30   a  through  30   l . Each of reference numerals  30   a - 30   l  indicates a site where along the vascular access vessel cannulation should occur for hemodialysis treatment. The array of cannulation sites  30   a - 30   l  is used in a rotatable selection of a series of hemodialysis cannulation sites along an AVF or AVG for hemodialysis access of a patient. The user determines the number of available cannulation sites along the vascular access vessel based on the number of cannulation site markings corresponding to viable locations for cannulation along the vessel. Based on the number of available cannulation sites, the user has a defined number of treatments that can be completed before repeating a cannulation site. As shown in  FIG. 1 , the array includes twelve indicators  30   a - 30   l  for cannulation sites at which a hemodialysis needle may be cannulated. Each cannulation site corresponds with a cannulation site reference numeral  30   a - 30   l . Each correspondingly labeled access site is an indicator where an arterial access needle and a venous access hemodialysis needle may be independently or simultaneously cannulated. In this embodiment, the cannulation sites associated with reference numerals  30   a ,  30   e  and  30   j  will be cannulated during week 1, the cannulation sites associated with reference numerals  30   d ,  30   g  and  30   k  will be cannulated during week 2, the cannulation sites associated with reference numerals  30   b ,  30   f  and  30   i  will be cannulated during week 3, and the cannulation sites associated with reference numerals  30   c ,  30   h  and  30   l  will be cannulated during week 4. The indicated sites  30   a - 30   l  represent arterio-venous cannulation sites that are properly spaced and successively employed in an exemplary twelve successive hemodialysis sessions that comprise an exemplary hemodialysis cycle. With twelve available cannulation sites, given that the patient requires three hemodialysis treatments per week, a four week rotation plan for cannulation sites is provided. Each treatment may use a new site until treatment at the site  30   l  is completed. Then, at the next treatment, the user would return to re-cannulate site  30   a . The user will then cannulate at each of the subsequent chosen cannulation sites in the same rotation. By sequentially using the paired arterial and venous hemodialysis needles along the pathway of the vascular access vessel, the maximum number of available cannulation sites to be used in subsequent treatments and cannulation trauma to the vessel is evenly distributed over time and repeated cannulation of the same sites is avoided. The longevity of the vascular access vessel is accordingly extended. 
     The markings  22  on the cannulation template  20  may also be of different colors so as to make the markings  22  easier to read or distinguish from one another. For example, the cannulation site reference numerals  30   a - 30   l  for each week may be in contrasting colors, such as red, blue, green and gold for weeks 1-4, respectively. Instead of visual means the markings  22  for the cannulation zones may be delineated by physical means, raised or recessed material that physically separates the individual zones. 
     Similarly, the cannulation site reference numerals on the cannulation template may have differing shapes, for example, arrows for arterial access and lines for venous access. A cannulation template  60  is shown in  FIG. 3 , including an outer side  64  and having a left end  66  and a right end  68 . The cannulation template  60  has markings  62  which, in this embodiment, includes physical boundary lines  63  spanning the opening in the template  60  and defining zones for the user to plan and select cannulation sites. The cannulation zones do not need to be set in a grid fashion, thus the shapes can be abstract and non-typical to maximize cannulation area or increase separation between needle sticks. The shape could be chosen to accommodate any vascular access vessel. The shape of the cannulation template  60  could include, but is not limited to, any shape intended to accomplish the goal of rotating needle sites. 
     The rectangular cannulation template  20  shown in  FIG. 1  is about 2 inches long and about one-half inch wide. Adjacent cannulation sites are separated by about 0.5 centimeters to about 1 centimeter. However, these distances may differ based on a patient&#39;s condition. While the cannulation template  20  of the embodiment shown is rectangular in shape, other embodiments of the cannulation template  20  may be other shapes and dimensions. For example, as shown in  FIG. 1 , a cannulation template may have an ovular opening having a curved edge such that the apparatus could be placed along a curved vascular access vessel for determining available cannulation sites or measuring from one site to the next. 
     The markings  22  on the cannulation template  20  are substantially permanent so as not to be smudged or wiped away upon sterilization between uses. Sterilization may be performed by submerging the cannulation template  20  in a 1% bleach solution for twenty minutes. The markings  22  may be designed to withstand degradation during other sterilization procedures, which may include sterilization by ultraviolet light, a higher or lower concentration of bleach for a longer or shorter soaking time, or hydrogen peroxide. As a result, the cannulation template  20  is reusable and easy to clean. The markings  22  on the cannulation template  20  may be obtained by reproductive means, such as, for example, conventional photography, digital photography, manual drawing, digital imaging or substantially equivalent means. The hemodialysis access configuration represented by the markings  22  may be transferred to the cannulation template  20  by transfer means such as, for example, printing, lithography, photocopying, or substantially equivalent means. It is understood that other information may be printed on either surface of the cannulation template  20 . For example, this arrangement allows for usage instructions to be printed on at least one side. Alternatively, the flexible member may be translucent. 
     The cannulation template  20  may be used with an arteriovenous fistula or arteriovenous graft. As described above, an arteriovenous graft hemodialysis access configuration surgically substitutes a conduit between an artery and a vein for a surgically created fistula. The description of the method that follows is in connection with the use of the AVG for hemodialysis. It is understood that the present vascular access configuration is equally applicable to a patient with the AVF for hemodialysis. 
     In use, a user places the cannulation template  20  on a patient&#39;s arm at the arteriovenous anastomosis, or another bodily area where vascular access is to be obtained. To determine a first cannulation site, the user orients the cannulation template  20  along the AVG used to create the vascular access. In orienting the cannulation template  20  along the vascular access vessel, the user places the left end  26  bearing the first markings  22  adjacent to the anastomosis. The flexibility of the material of the cannulation template  20  allows the user to contour the cannulation template  20  along the AVG. As the cannulation template  20  is contoured along the vessel, the first reference numeral  30   a  showing a label “M/T” indicates a first cannulation site in the array, creating a visual “stick zone” along the vessel indicating to the user that a pair of cannulation needles should be inserted in that area. 
     The user inserts a first cannulation needle at the site  30   a  for providing arterial vascular access to the patient. During hemodialysis treatment, the patient&#39;s blood will flow from the AVG, through the needle, and into tubing. The blood will pass through the tubing to an extracorporeal blood circuit and is returned through a venous needle inserted into the vascular vessel at the site  30   a . When treatment is completed, the needles are removed, and the cannulated site  30   a  may begin to heal. Because of the design of the cannulation template  20 , the first site  30   a  will typically not be re-cannulated until all other possible cannulation sites along the cannulation template  20  have been used. In this embodiment, site  30   a  will have four weeks to heal before re-cannulation. 
     When the patient requires a subsequent hemodialysis treatment, the user again begins by placing the first end of the cannulation template  20  at the anastomosis of the patient and orienting the cannulation template  20  along the AVG. The user will then select a different selection reference numeral  30   j  showing label “W/TH”. It is understood that the user may assess the viability of the available cannulation sites. For example, if the cannulation site associated with reference numeral  30   j  along the AVG as identified by cannulation site selection marking is not viable based on the condition of the AVG, the user would then select the next subsequent site for cannulation. 
     The user cannulates the selected site  30   j  with a first needle to provide arterial vascular access to the AVG for hemodialysis treatment and a second needle to provide venous vascular access to the AVG. Blood is removed from the patient through the first needle and returned through the second needle. When treatment is completed, the needles are removed and the cannulated site  30   j  may begin to heal. The second suite  30   j  will typically not be re-cannulated until all other possible cannulation sites have been used. In this embodiment, the site  30   j  will have four weeks to heal before re-cannulation. 
     While the cannulation template  20  of the embodiments shown and discussed above are discussed mainly for use in cannulating a patient for hemodialysis treatments, the cannulation template  20  may be used in cannulating patients for hemofiltration, hemodiafiltration, ultrafiltration, or other medical treatments where cannulation or insertion of an instrument into the body at a particular position or angle is necessary. 
     The cannulation template  20  and method as described herein identifies successive hemodialysis needle cannulation sites along a marked pathway of a corresponding vascular access vessel. The cannulation template assists the user, whether an in-center dialysis technician or a self-cannulator, to use best practice in cannulating a vascular access vessel for hemodialysis to ensure proper needle site rotation to maximize tissue healing, reduce graft degradation, and provide a clear protocol for where and when to cannulate a vascular access vessel. Cannulation trauma to the vessel is evenly distributed over time and space, and repeated cannulation of the same sites is minimized. As a result, the longevity of the vascular access vessel is extended. 
       FIG. 2  shows a second embodiment of a cannulation template generally designated at  40 . The cannulation template  40  has an oval opening and includes markings  42  on an outer side  44  surface having a left end  46  and a right end  48 . The cannulation template comprises boundary lines  43  spanning the opening and separating the template  40  into twelve cannulation zones  50   a - 50   l . In use, the first marking  50   a  is positioned adjacent the anastomosis made surgically between adjacent blood vessels, or other channels of the body, and indicates a first site for cannulation. The array of markings  42  along the cannulation template  40  provides an exemplary hemodialysis access configuration comprising an array of twelve cannulation sites, indicated in  FIG. 2  by labels A through L at reference numerals  50   a  through  50   l . Each label  50   a - 50   l  indicates a site where cannulation should occur along the vascular access vessel for hemodialysis treatment. The array of cannulation sites is used in a rotatable selection of a series of hemodialysis cannulation sites along an AVF or AVG for hemodialysis access of a patient. Cannulation protocols can be developed based on the separate zones, which would facilitate the creation of a prospective cannulation ‘schedule’ to ensure the appropriate cannulation separation between needle sticks. The cannulation template  40  shown in  FIG. 2  may be used to design a needle rotation schedule for one or two needles. In single needle dialysis, one needle is inserted into a vascular access vessel. The dialysis machine cycles between removing blood from the patient and delivering blood to the patient through the single needle. If the cannulation template  40  is used for one needle, for example, zones “A”  50   a , “I”  50   i , and “E”  50   e  can be used sequentially over the course of one week to ensure that each needle stick is spaced far enough apart to allow adequate tissue healing between sticks. 
     The cannulation template shown in  FIG. 4 , generally designated at  70 , has an outer side  74  and a left end  76  and a right end  78 . The cannulation template  70  has markings  72  including a boundary  73  spanning the opening and showing two areas of the template  70  that should be cannulated as indicated at reference numerals  80 ,  81 . In this embodiment, the user employs a circular spacer  82  defining a central hole  83  and creates a marking on a patient&#39;s skin through the cannulation template where they intend to cannulate the patient&#39;s vascular access. The user thus has some freedom on where to cannulate next, given that the spacer always ensures adequate separation from a previous cannulation. In use, the hole  83  in the spacer  82  is aligned with the last cannulation site. The user can then cannulate anywhere outside of the spacer area. This distance is approximately 0.5 cm to about 1.0 cm to ensure appropriate separation and tissue healing between previous cannulation sites. The cannulation template  70  is then removed, and cleaned for dialysis initiation. Thus, the cannulation template  70  is not present when the dialysis session occurs and the needles are inserted into the patient&#39;s vascular access. 
       FIG. 5  shows a cannulation template generally designated at  90  wherein the cannulation area is unmarked. The cannulation template  90  has an outer side  94  and a left end  96  and a right end  98 . Markings  92  and twelve labels  100   a - 1001  separated by boundary lines  93  surround the cannulation area. 
     Another embodiment of a cannulation template not including markings is shown in  FIG. 6  and generally designated at  110 . The cannulation template  110  has an outer side  114  and a left end  116  and a right end  118 . The cannulation template  110  has markings  112  spanning the opening. In this embodiment, tracking a hemodialysis configuration occurs on the cannulation template  110  itself. The cannulation template  110  comprises physical features to aid the user in selecting cannulation sites in lieu of, or in addition to, cannulation site markings. The cannulation template  110  has holes  120  along opposed longer edges which aid the user in visualizing cannulation sites as the holes may help to frame the cannulation sites. The holes  120  allow a physical item to be clipped, or a marker used to mark, or any other visual or physical component can be used to indicate a progression of previous cannulation sites. If a previous cannulation site is completely healed, other information is necessary to determine the previous cannulation site. In addition, holes in the body of the cannulation template  110  could allow cannulation through the flexible member. For example, the user could lay the cannulation template  110  against the vessel, determine cannulation sites, and cannulate through the hole  120  at that designated cannulation site. 
       FIG. 7  shows a cannulation template  130  defining an oval opening  133 . A key  132  on the template  130  indicates location and orientation of the cannulation template  130 . In this embodiment, the cannulation template  130  is used on a forearm  132  for vascular access, which is shown on the template  130 . The cannulation template  130  also includes a partial picture of a body of a person to indicate appropriate orientation, wherein one end  138  of the cannulation template  130  is oriented towards a user&#39;s hand and the other end  136  is oriented towards the user&#39;s body. Other visual cues may be used, such as using a permanent or temporary marking on a user&#39;s body or clothing to align with a feature on the cannulation template  130  such as a hole  140 . The background of the cannulation template  130  on the surface  134  of the cannulation template  130  could also be printed to match with the location of a user&#39;s skin on which it is located (e.g. elbow crease, forearm veins, etc.). 
     An embodiment of a cannulation template, generally designated at  150  in  FIG. 8 , can also be integrated with a software application for cannulation in a hemodialysis configuration. For example, a user could take a picture of a patient&#39;s arm, dialysis session, cannulation template  150 , or other related item. The cannulation template  150  is similar to the embodiment shown in  FIG. 2 , having an oval opening  154  and includes markings  155  on an outer side  152  surface having a left end  158  and a right end  160 . The markings  155  comprise boundary lines spanning the opening  154  and separating the template  150  into eight cannulation zones. The picture could be uploaded to a mobile device  162  or server to provide a procedural history of cannulation to allow an assessment of factors such as: A) where the graft has been cannulated most frequently, B) identification of cannulation sites around the time that adverse events are identified, C) evaluation of whether density of graft punctures may lead to adverse events such as pseudoaneurysms, D) total history of cannulation and location, E) a way to transmit data to care providers, etc. The platform could incorporate machine learning and/or artificial intelligence to aid in the tracking and diagnosing of medical events. A picture taken prior to a dialysis session and uploaded provides a recommendation to the user for where to cannulate based on a combination of, for example, previous cannulation sites, previous adverse events, rates of tissue healing, graft integrity, and the like. 
       FIG. 9  shows an embodiment of a cannulation method  170  similar to  FIG. 8  wherein a physical cannulation template is not necessary. A picture  176  of the vascular access vessel  174  in forearm  172  is uploaded to a mobile device  162  including software provides a digital cannulation template interface and recommends cannulation site for vascular access. 
       FIG. 10  shows an embodiment of a cannulation method  180  comprising an armband  182  or any other flexible, semi-rigid or rigid item. The armband is adapted to receive the cannulation template  20  for attachment to the forearm  172  of a patient. The armband  182  may be secured around the forearm  172  using attachment means  184 , such as Velcro, at the free ends of the armband  182 . 
     In  FIG. 11 , a slightly arcuate embodiment of a cannulation template is generally designated at  190 . The cannulation template  190  has an openings  194  in an outer side  192  surface having a left end  196  and a right end  198 . The cannulation template  190  comprises boundary lines  193  between the openings  194  for separating the template  190  into twelve cannulation zones. It is contemplated that each of the  193  boundary lines comprise different colors to indicate cannulation sites and protocols to ensure appropriate needle rotation. 
     Although cannulation templates and method have been shown and described in considerable detail with respect to only a few exemplary embodiments thereof, it should be understood by those skilled in the art that we do not intend to limit the apparatus and method to the embodiments since various modifications, omissions and additions may be made to the disclosed embodiments without materially departing from the novel teachings and advantages, particularly in light of the foregoing teachings. For example, the present cannulation template  20  and method is suitable for use in a number of vascular access devices and applications. While the cannulation template  20  shown and described are discussed in the context of cannulating a patient&#39;s arm, the cannulation template  20  may be used with other vascular access positions on a patient. These other positions may include, the leg, the neck, the chest, or the groin. Moreover, while the cannulation templates of the embodiments shown and discussed above are described mainly in the context of a two-needle vascular access procedure, the cannulation templates can also be used for single needle dialysis. Accordingly, we intend to sticker all such modifications, omission, additions and equivalents as may be included within the spirit and scope of the cannulation template  20  and method as defined by the following claims. In the claims, means-plus-function clauses are intended to sticker the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.