Patent Application
20220401644
Various types of modern medical devices include or employ one or more cannula tubing for conveying fluid media. A cannula may be employed for conveying fluid media to or from a patient, a sensor, a pump, an insertion set or other medical device, a reservoir or fluid container, an implanted or partially implanted device, or the like. A cannula may be included in a sensor, a pump, in insertion set or other medical device. In some contexts, a cannula may be configured to be inserted into or partially into a patient, for example, through the patient's skin.
Certain diseases or conditions may be treated, according to modern medical techniques, by delivering a medication or other substance to the body of a user, through a cannula tubing, either in a continuous manner or at particular times or time intervals within an overall time period. For example, diabetes is commonly treated by delivering defined amounts of insulin to the user at appropriate times. Some common modes of providing insulin therapy to a user include delivery of insulin through manually operated syringes and insulin pens. Other modern systems employ programmable fluid infusion devices (e.g., insulin pumps or other fluid delivery devices) to deliver controlled amounts of insulin to a user. In certain instances, these infusion devices employ an infusion set (or an insertion set) having one or more cannula to be coupled to the body of a user for the delivery of the insulin.
Typically, the infusion set includes a cannula having a cannula portion that can be inserted under the skin of the user to deliver controlled amounts of infusion media to the user. Various examples of infusions sets that include a flexible tubing cannula are described in U.S. Patent Application Publication No. 2018/0318550 (application Ser. No. 15/973,471 and U.S. Patent Application Publication No. 2020/0384187 (application Ser. No. 16/436,486), which is incorporated herein by reference, in its entirety. Example cannulas as described herein may be employed with or included in those or other suitable infusion set devices. Example cannulas as described herein may be employed with other medical devices and systems for conveying fluid media to or from a patient, a sensor, a pump, an infusion set or other device or system.
For example, a cannula (or an infusion set with a cannula) as described herein may be configured or employed in an infusion media delivery system that includes a pump or other delivery device and an infusion media reservoir. In those systems, the cannula provides at least a portion of the fluid flow path to deliver the infusion media. In other examples, a cannula or an insertion set with a cannula may be configured in or employed in a sensor set, to couple a sensor to a body of the user. For example, a sensor set may be configured to monitor glucose levels, or to measure glucose levels in blood or interstitial fluid. In particular examples, an infusion set (or insertion set) includes at least one (or multiple) first cannula for delivery of infusion media or at least one second cannula for a sensor (or one or more of both first and second cannulas).
The above and other aspects and features of the present invention will become more apparent to those skilled in the art from the following detailed description of the example embodiments with reference to the accompanying drawings, in which:
Hereinafter, example embodiments will be described in more detail with reference to the accompanying drawings. The present invention, however, may be embodied in various different forms, and should not be construed as being limited to only the illustrated embodiments herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the present invention to those skilled in the art. Accordingly, processes, elements, and techniques that are not necessary to those having ordinary skill in the art for a complete understanding of the aspects and features of the present invention may not be described. Unless otherwise noted, like reference numerals denote like elements throughout the attached drawings and the written description, and thus, descriptions thereof may not be repeated. Further, features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other example embodiments.
Certain terminology may be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, terms such as “top”, “bottom”, “upper”, “lower”, “above”, and “below” could be used to refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “side”, “outboard”, and “inboard” could be used to describe the orientation and/or location of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second”, and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context.
It will be understood that when an element or feature is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or feature, or one or more intervening elements or features may be present. In addition, it will also be understood that when an element or features is referred to as being “between” two elements or features, it can be the only element or feature between the two elements or features, or one or more intervening elements or features may also be present.
The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the present invention. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and “including,” “has, ” “have, ” and “having,” when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
As used herein, the term “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art. Further, the use of “may” when describing embodiments of the present invention refers to “one or more embodiments of the present invention.” As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present specification, and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.
Example embodiments relate to cannula for conveying fluid media. Further example embodiments relate to infusion sets, insertion sets, media delivery systems, sensors or other medical devices and systems that include one or more cannula.
In certain examples, the cannula includes a hollow tube or tubing and is configured to be inserted into (or partially into) a patient, such as, through the patient's skin. In other examples, the cannula tubing is configured to be included in (or is included in) an implantable device configured to be implanted within the body, limb or head of a patient. The cannula may be included in an insertion set, an infusion set, a sensor device, an infusion pump or other fluid delivery system, or other medical device or system, or the like. In certain examples, the cannula may be connected to or included in an infusion set or an insertion set that has a base or hub configured to adhere to the skin of a patient. In other examples, the cannula may be connected to or included in another external medical device or in an implantable (internal) medical device.
The cannula according to certain examples may be configured to receive an insertion needle, for assisting with insertion of the cannula into or through a patient's skin, a septum or another structure. In some examples, the cannula tubing has a hollow channel in which the insertion needle is received and can slide. In other examples, the cannula tubing is configured to fit and slide inside the channel of a hollow needle. The needle can provide sufficient rigidity and a pointed or sharp end, for assisting with inserting the cannula through the patient's skin, the septum or the other structure. In particular examples, the needle is withdrawn, after insertion of the cannula, leaving the cannula extending through the patient's skin, the septum or the other structure.
In the example in
The infusion set 12 includes the cannula 10 and a base 14 on which the cannula is held. In some examples, as shown in
The cannula 10 may be part of a cannula assembly 16 that includes the cannula 10 and a needle guide 18. In some examples, the cannula assembly 16 may also include or operate with a septum 20 and a port member, as shown in an exploded view in
In some examples, the infusion set 12 may include a port member 22 (
In the example in
When received in the receptacle 14a of the base 14, the cannula 10 extends through the opening 14c and out from the base 14 (from the downward-facing surface of the base in
In certain examples, the surface 14d of the base 14 from which the cannula 10 extends (i.e., the downward-facing surface in
In the illustrated example, the infusion set 12 has one cannula 10 coupled in fluid communication with a fluid source for infusion of fluid to a patient. In other examples, the infusion set may have more than one cannula for infusion of fluid, each connected to the same fluid source or respectively different fluid sources. The fluid source may include the tube 26 connected through the hub 24 and the port member 22, or may include a reservoir (not shown) located on the base 14.
In certain examples, the infusion set 12 may include one or more insertable sensor members configured to be inserted through the patient's skin, where each sensor member is connected to the same or different sensor electronics (not shown) located in the base 14. For example, in the example in
The cannula tubing having an axial length dimension (along axis A), a generally circular cross-section shape taken perpendicular to the axial length dimension, and a central passage through which fluid may flow. In other examples, the tubing may have a cross-section shape that is not a circle, such as, but not limited to an oval, another curved shape, a polygon or a shape having a combination of curved and straight edges. The cross-section shape of the central passage may have a circular or another shape, and may correspond to (be the same shape as) the outer cross-section shape of the tubing. In other examples, the cross-section shape of the central passage may be a different shape relative to the outer cross-section shape of the tubing.
The cannula tubing may be made of a material that is compatible with fluids intended to be conveyed through the tubing, and with other materials to which the tubing may come into contact or be connected, in the intended environment of use. In certain examples, the cannula tubing is made of a material that is biologically compatible, for use in contexts in which the tubing is in contact or connected with a biological entity (such as a human patient or another biological entity), or is implanted fully or partially in the patient (or other biological entity). In certain examples, the cannula tubing is treated in one or more processes for enhancing biologically compatible such as, but not limited to cleaning, sterilizing, coating with Heparin, or the like.
In certain examples the cannula tubing is made of a material that is suitable for medical uses, including but not limited to materials compatible with, and suitable for, implanting or partially implanting into a patient or other biological entity. Alternatively or in addition, the tubing material is selected to be compatible with and suitable for conveying one or more desired or predefined fluids (such as, but not limited to insulin, cancer or AIDs treatment media, pain treatment media, or other medications, drugs or therapy fluids). Such materials may include, but are not limited to an ethylene tetrafluoroethylene (ETFE), a polytetrafluoroethylene (PTFE), a fluorinated ethylene propylene (FEP), a perfluoroalkoxy (PFA), a polychloroprene (Neoprene), a polypropene (PP), a polypropylene, a polyethylene (PE), a fluorinated ethylene propylene (FEP) or other fluoropolymer, an ethylene vinyl acetate (EVA), a polyether block amide (PEBA) of thermoplastic elastomer (TPE) such as PEBAX™, a thermoplastic polyurethane (TPU) such as PELLETHAN™, a silicon material, other fluoropolymer, synthetic rubber, thermoplastic polymer, or the like. However, for other contexts and applications of use, the tubing may be made of other materials suitable and compatible with those contexts and applications. In particular examples in which the cannula tubing is made by injection molding, micromolding or other molding techniques, a tubing material compatible with such techniques.
The cannula tubing may be made by any suitable manufacturing process including, but not limited to extrusion, molding, machining, shrinking over a mandrel, combinations thereof, or the like. However, in particular examples, the tubing is made with or by a micromolding process as described herein. While various manufacturing processes may be employed, micromolding can be an efficient way to make a cannula shape and wall dimensions as described herein. In particular, micromolding can be used to provide a flared end with an increased wall thickness (or without reducing wall thickness by an amount that would compromise strength) of the cannula tubing.
The cannula tubing has a distal end 10a and a proximal end 10b that are open to the passage of the tubing. The axial length of the cannula tubing extends from the open distal end 10a to the open proximal end 10b. The distal end 10a and at least a portion of the length of the cannula 10 is configured to be inserted into a subject (patient's skin, or in other examples, a septum or other pierced structure). The proximal end 10b is configured to be connected to the base 14 (and is shown in
The tubing of the cannula 10 has an OD that changes along its length. As shown in
In the example in
In particular examples, the OD of the cannula 10 is constant along the first length portion 10c. In other examples, the OD of the cannula 10 changes along the axial length of the first length portion 10c. Thus, in some examples, the OD of the cannula 10 may taper to a smaller OD at the distal end 10a, to a larger relative OD toward the second length portion 10d, as shown in
In particular examples, the ID of the cannula 10 is constant along the axial length of the first length portion 10c, from the distal end 10a to the second length portion 10d, as shown in
In particular examples, the tubing wall may have a wall thickness or width W1 that is relatively constant along the axial length dimension of the first length portion 10c. In some examples, the wall thickness or width W1 of the first length portion 10c is constant from the distal end 10a to the second length portion 10d (or to a location at which the cannula 10 tapers to transition to the second length portion 10d). In other examples, the wall thickness or width W1 may vary along the first length portion 10c, for example, from a smaller width to a greater width in the axial direction from the distal end 10a toward the second length portion 10d.
The second length portion 10d of the cannula 10 has an OD and ID that flares or expands outward to a larger OD and ID relative to the OD and ID of the first length portion 10c. The flared ID of the second length portion 10d of the cannula provides a recess 10f for receiving the needle guide 18.
The second length portion 10d has an OD size and shape that is configured to be received at least partially in the opening 14c to the chamber 14b of the base 14. In particular examples, cannula material has resiliency and the OD of the second length portion 10d is larger (or slightly larger) than the ID of the opening 14c, such that the second length portion 10d is press fitted or interference fitted into the opening 14c of the base. In particular examples, the interference fit of the second length portion 10d in the opening 14c may be sufficient to provide a reliable liquid-tight seal. However, in certain examples, the interference fit is not tight enough to cause a compression of the cannula wall in the second length portion 10d to an extent that causes cold flow of the cannula wall material in the second length portion 10d or to the extent that causes great enough cold flow to be undesirable (e.g., to reduce pull strength below that of the first length portion 10c). Thus, in particular examples, the OD of the section L and the OD of the opening 14c are selected or controlled to provide a desired sealing effect, without undesirable cold flow of the cannula material. In some examples, the interference fit and sealing function of the second length portion 10d in the opening 14c is created or enhanced when the needle guide 18 is received in the recess 10f, as shown in
In particular examples, the interference fit of the second length portion 10d includes engaging an outer surface of the second length portion 10d with an inner wall surface of the opening 14c. As shown in
The OD of a length section L of the second length portion 10d is larger than the OD of the opening 14c by a selected amount W3, to provide a level of compression along the section L of the second length portion 10d, for the interference fit. The amount W3 of difference in the ODs may be dependent, at least in part, on the size of the cannula 10, and the cannula material. The length L of the engaged surfaces can affect the sealing ability, such that a longer length L may provide a greater sealing ability than a shorter length L. Accordingly, in certain examples, the depth of the opening 14c of the receptacle 14, and the axial length of the outer surface of the second length portion 10d of the cannula (and, thus, the length L of the engaged surfaces) is selected to provide a desired or an enhanced sealing effect.
Accordingly, for a given cannula material and size, the amount W3 and length L may be selected or configured appropriately, such that the sealing surface of the cannula 10 create a sufficient liquid seal, but need not be forced in an axial direction or compressed to an undesired cold-flow state. Instead, the length L of the sealing surface of the second length portion 10d presses radially outward, against the inner surface of the opening 14c, by the resilience of the cannula material or by the needle guide received in the recess 10f of the cannula 10 (or both).
The flared or expanded OD and the ID of the second length portion 10d of the cannula can be formed by any suitable manufacturing method including, but not limited to micromolding, other types of molding, machining, pressing, extruding, or combinations thereof. However, by micromolding, the shape and wall thickness or width dimensions can be controlled such that the thickness or width W2 of the cannula wall in the second length portion 10d of the cannula is at least as great as (or greater than) the thickness or width Wi of the cannula wall in the first length portion 10c.
By providing a wall thickness or width W2 in the second length portion 10d that is greater than the thickness or width W1 in the first length portion 10c, the pull strength of the second length portion 10d of the cannula in the base 14 may be increased. The wall thickness or width W2 in the second length portion 10d is selected to provide a pull strength that is greater than the pull strength of the first length portion 10c. In particular examples, the wall thickness W2 is selected such that the expanded or flared second length portion 10d (the portion that forms the seal) is sufficiently strong to not limit or reduce the overall pull strength of the cannula 10.
The third length portion 10e of the cannula 10 has an OD that is larger than the OD of the second length portion 10d. In the example in
The third length portion 10e of the cannula 10 is located in the receptacle 14a of the base 14, when the cannula 10 is mounted on the base 14. The OD of the lip or flange of third length portion 10e is larger than the OD of the opening 14c in the base 14, such that the third length portion 10e of the cannula is inhibited from passing through the opening 14c, especially when the needle guide 18 is received in the recess 10f, as shown in
The lip or flange of the third length portion 10e may have a circular cross-section shape (taken perpendicular to the axis A), defining a curved, circular outer circumference. In certain examples, one or more sections of the circular outer circumference (represented by the section 10g) may be un-curved or non-circular, to match a correspondingly shaped surface in the receptacle 14a of the base 14. More specifically, the receptacle 14a may have an inner surface with a curved, circular inner circumference (corresponding to and engaging the outer circumference of the lip or flange of the third length portion 10e), and may also include one or more un-curved or non-circular sections that match and mate with the one or more un-curved or non-circular sections of the lip or flange. Accordingly, when the third length portion 10e of the cannula 10 is received in the receptacle 14a of the base 14, the one or more un-curved or non-circular sections of the lip or flange of the cannula 10 engage the one or more un-curved or non-circular surfaces of the receptacle 14a, and inhibit rotation of the cannula 10 about the axis A relative to the base 14.
The recess 10f in the cannula 10 forms a cup-shaped receptacle for the needle guide 18. The bottom of the recess 10f (in the orientation of
Also as shown in
The needle guide 18 includes a rigid body having a shaft section 18a extending from a lip or flange section 18b. The body of the needle guide 18 may be made of any material having sufficient rigidity to hold its shape and function as described herein, including, but not limited to plastic, metal, ceramic, composite material, combinations thereof, or the like.
The shaft and flange sections of the needle guide 18 form an annular body that has a central channel. The shaft section 18a has a generally cylindrical shape, while the lip or flange section 18b flares radially outward to a larger diameter relative to the shaft section 18a. In certain examples, the lip or flange section 18b has a generally circular outer circumference and one or more sections (represented by the section 18c) that are un-curved or non-circular, to match a correspondingly shaped surface in the receptacle 14a of the base 14. Accordingly, when the needle guide 18 is received in the recess 10f of the cannula 10, the one or more un-curved or non-circular sections of the lip or flange of the needle guide 18 engage one or more corresponding un-curved or non-circular surfaces in the receptacle 14a, and inhibit rotation of the needle guide 18 about the axis A relative to the base 14 and relative to the cannula 10.
The flange end of the needle guide 18 has an enlarged recess opening 18c (having a diameter that is larger than the diameter of the central channel of the needle guide, and tapers inward to the diameter of the central channel. The enlarged, tapered recess opening 18c of the needle guide 18 provides a guide for a needle or other insertable member, for receiving the needle or other insertable member in fluid flow communication with the proximal end 10b of the cannula 10.
As discussed above, the first length portion 10c of the cannula is configured to be inserted into a patient's skin. In particular examples, the cannula tubing has sufficient flexibility to allow the cannula tubing to flex or move with the patient's skin, for improved comfort. In addition, the cannula tubing may be sufficiently rigid to withstand kinking or buckling during insertion or when bent or curved. In particular examples, the cannula tubing flexibility and rigidity is selected and controlled by selecting or controlling one or more of the tubing dimensions and configuration (including its outside diameter OD and its inside diameter ID), the material from which the tubing is made, and the process of manufacture. In certain examples, the tubing may include one or more additional structural features to either enhance flexibility or to enhance rigidity (and resistance to kinking or buckling).
In some examples, the cannula tubing may be relatively flexible along its length, but is also configured to have a relatively high degree of flexibility (or enhanced flexibility) in one or more selected sections of the length of the tubing, to allow bending at a controlled location or in a controlled manner (or both). Alternatively or in addition, the cannula tubing may be configured to have a relatively high degree of rigidity (or enhanced rigidity) in one or more selected sections of the length of the tubing, to inhibit bending or buckling at a controlled location or in a controlled manner (or both). In other examples, the flexible tubing may be relatively rigid along sections of its length but have one or more sections of enhanced flexibility, to allow bending only or primarily within the one or more sections of enhanced flexibility. Examples of configurations that may be employed to provide one or more sections of enhanced flexibility along a length of a flexible tubing cannula include, but are not limited to those described in U.S. Patent Application Publication No. 2020/0384187 A1 (application Ser. No. 16/436,496), which is incorporated herein by reference, in its entirety.
An example of a configuration providing one or more sections of enhanced rigidity (and resistance to buckling) is described with reference to
Cannula flexing can occur during or after insertion of the cannula. In some contexts, the cannula can tend to flex at the transition between the first length portion 10c and the second length portion 10d. Accordingly, in certain examples, each rib 10g extends from the second length portion 10d, toward the distal end 10a of the cannula, to provide enhanced resistance to buckling at in that portion of the cannula. In some examples, each rib 10g extends all of the way to the distal end 10a. In other examples, each rib 10g extends a portion, but not the entire length of the first length portion 10c. In particular examples, the one or more ribs 10g are located only on a section of the first length portion 10c that is adjacent the second length portion 10d, and extends toward the distal end 10a for about 5% to 40% of the length of the first length portion 10c. In other examples, the ribs extend from the second length portion 10d toward the distal end 10a for about 10% to 20% of the length of the first length portion 10c.
The flare or taper of the second length portion 10d of the cannula 10 may be formed by any suitable method. However, in some conventional tube flaring methods in which an end portion of a tubing is pressed into a flared shape, the tubing wall may stretch or cold flow (and be compromised in strength). In particular examples, a micromolding system or other molding system or procedure (or both) can be configured to form a wall thicknesses or widths of any desired dimensions along different portions of the length of the cannula. Micromolding or other molding systems and methods can be readily configured and controlled to define sufficiently precise cannula shapes and wall thickness dimensions, in an efficient manufacturing environment.
Alternatively a flared tubing end can be formed by other suitable processes, such as compressing or stretching an end portion over a mandrel or cone-shaped form, extruding, or machining. However, compressing or stretching processes tend to reduce the width or thickness of the tubing wall thickness or width. Accordingly, additional controls and variations of such other processes would be needed to form cannula shapes and wall thicknesses as described herein, which could increase manufacturing costs.
While various exemplary embodiments have been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiment or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope defined by the claims, which includes known equivalents and foreseeable equivalents at the time of filing this patent application.
