Patent Description:
This disclosure relates to an apparatus for use of a fluid flow control device and, more particularly, to a cannula apparatus for selective fluid flow in a removal direction and a return direction, opposite the removal direction.

Extracorporeal membrane oxygenation ("ECMO"), also known as extracorporeal life support, is an extracorporeal technique of providing prolonged cardiac and/or respiratory support to persons whose heart and/or lungs are unable to provide an adequate amount of gas exchange and/or perfusion to sustain life. For example, ECMO could be provided to a patient during or after a major surgical procedure, to help reduce the burden on the patient's own body to oxygenate the blood due either to heart or lung dysfunction, or both.

In ECMO, deoxygenated blood is removed from the vasculature of a patient's body via one lumen of a device, is perfused with oxygen and/or otherwise treated in a therapeutic manner, and then is returned to the patient's vasculature (either through a different lumen of the same device or a different device). <CIT> discloses a cannula apparatus suitable for selective fluid flow in a removal direction and a return direction, comprising the features of the the preamble of claim <NUM>.

In an aspect, a cannula apparatus for selective fluid flow in a removal direction and a return direction, opposite the removal direction is described. An outer sheath has proximal and distal outer sheath ends spaced apart by a longitudinal outer sheath body defining an outer sheath lumen. At least one fluid removal aperture extends entirely through the outer sheath body adjacent the distal outer sheath end to place the outer sheath lumen in fluid communication with an ambient space. The outer sheath includes a side access aperture extending entirely through the outer sheath body. An introducer has proximal and distal introducer ends spaced apart by a longitudinal introducer body. The introducer body at least partially defines a guidewire channel longitudinally therealong. The introducer is configured for selective insertion at least partially into the outer sheath lumen with the guidewire channel in fluid communication with the side access aperture. An inner tube has proximal and distal inner tube ends spaced apart by a longitudinal inner tube body defining an inner tube lumen. At least one fluid return aperture is located at least one of at and adjacent the distal inner tube end to place the inner tube lumen in fluid communication with an ambient space. The inner tube is configured for selective insertion into the outer sheath lumen, when the introducer is absent from the outer sheath lumen, with the inner tube body extending completely through the side access aperture to place the distal inner tube end in an ambient space outside the outer sheath.

For a better understanding, reference may be made to the accompanying drawings, in which:.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which the present disclosure pertains.

As used herein, the term "subject" can be used interchangeably with the term "patient" and refer to any warm-blooded organism including, but not limited to, human beings, pigs, rats, mice, dogs, goats, sheep, horses, monkeys, apes, rabbits, cattle, farm animals, livestock, etc..

As used herein, the singular forms "a," "an" and "the" can include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," as used herein, can specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

As used herein, the term "and/or" can include any and all combinations of one or more of the associated listed items.

It will be understood that when an element is referred to as being "on," "attached" to, "connected" to, "coupled" with, "contacting", "adjacent", etc., another element, it can be directly on, attached to, connected to, coupled with, contacting, or adjacent the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, "directly on," "directly attached" to, "directly connected" to, "directly coupled" with, "directly contacting", or "directly adjacent" another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "directly adjacent" another feature may have portions that overlap or underlie the adjacent feature, whereas a structure or feature that is disposed "adjacent" another feature might not have portions that overlap or underlie the adjacent feature.

Spatially relative terms, such as "under," "below," "lower," "over," "upper", "proximal", "distal", and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms can encompass different orientations of a device in use or operation, in addition to the orientation depicted in the figures.

As used herein, the phrase "at least one of X and Y" can be interpreted to include X, Y, or a combination of X and Y. For example, if an element is described as having at least one of X and Y, the element may, at a particular time, include X, Y, or a combination of X and Y, the selection of which could vary from time to time. In contrast, the phrase "at least one of X" can be interpreted to include one or more Xs.

It will be understood that, although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. Thus, a "first" element discussed below could also be termed a "second" element without departing from the teachings of the present disclosure. The sequence of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise.

<FIG> depict a cannula apparatus <NUM> for selective fluid flow in a removal direction (arrow "-" in the Figures) and in a return direction (arrow "+" in the Figures), opposite the removal direction, within a patient's body. While a vasculature of a patient is used herein as an example use environment, one of ordinary skill in the art will be able to configure any cannula apparatus according to the present invention for a desired use environment (such as, but not limited to, flushing cerebrospinal fluid, ECMO (including pulmonary artery infusion), ECLS, right heart assist or RVAD, wound drainage and flushing, renal dialysis, peritoneal space drainage and flushing, delivery or removal of fluid based therapeutic treatments, and/or other medical and/or non-medical uses).

The cannula apparatus <NUM> includes an outer sheath <NUM> having proximal and distal outer sheath ends <NUM> and <NUM> spaced apart by a longitudinal outer sheath body <NUM> defining an outer sheath lumen <NUM>. At least one fluid removal aperture <NUM> extends entirely through the outer sheath body <NUM> at and/or adjacent the distal outer sheath end <NUM> to place the outer sheath lumen <NUM> in fluid communication with an ambient space. As shown in <FIG> and <FIG>, the fluid removal aperture <NUM> is at a distalmost tip of the outer sheath <NUM> and is simply an open end of the outer sheath body <NUM> tube. The ambient space within the patient's body may be, for example, an area of the patient's vasculature and/or an internal organ through which blood is flowing. The outer sheath <NUM> includes a side access aperture <NUM> and extends entirely through the outer sheath body <NUM>.

A deflector <NUM> is located within the outer sheath lumen <NUM> and has any desired configuration operative to steer or bias an inserted structure toward the side access aperture <NUM>. For example, the deflector <NUM> could be a rail or track which blocks at least a portion of the outer sheath lumen <NUM> cross-section to prevent a structure of a particular cross-sectional size and/or shape from traveling through the outer sheath lumen <NUM> past the deflector <NUM>. It is contemplated that, for most use environments of the cannula apparatus <NUM>, the deflector <NUM> will allow a desired amount of fluid pressure and fluid flow within the outer sheath lumen <NUM> in the removal direction, optionally in such a manner to minimize turbulent flow of fluid. It is also contemplated that one or more fluid removal apertures (not shown) could be located proximal to the deflector <NUM>.

<FIG> depicts an inner tube <NUM> having proximal and distal inner tube ends <NUM> and <NUM> spaced apart by a longitudinal inner tube body <NUM> defining an inner tube lumen <NUM>. At least one fluid return aperture <NUM> is located at least one of at and adjacent the distal inner tube end <NUM> to place the inner tube lumen <NUM> in fluid communication with an ambient space. The inner tube <NUM> is configured for selective insertion into the outer sheath lumen <NUM> with the inner tube body <NUM> extending completely through the side access aperture <NUM> of the outer sheath <NUM> to place the distal inner tube end <NUM> in an ambient space outside the outer sheath <NUM>. What is meant by "the inner tube body <NUM> extending completely through the side access aperture <NUM>" is that some portion of the inner tube body <NUM> passes through the side access aperture <NUM> during use of the cannula apparatus <NUM>, not that the entirety of the inner tube body <NUM> is, at some point, passed through the side access aperture <NUM>. The deflector <NUM> acts to guide or urge the inner tube <NUM>, during its insertion into the outer sheath lumen <NUM>, toward the side access aperture <NUM>. There may optionally be a membrane or other sealing structure (not shown) present within the side access aperture <NUM> to prevent fluid flow in the removal direction therethrough.

In use, the cannula apparatus <NUM> of <FIG> may be utilized to remove fluid from, and concurrently or consecutively return fluid to, a vasculature of a patient. The outer sheath <NUM> is inserted to a target removal site in the patient's body. The inner tube <NUM> could be at least partially held within the outer sheath <NUM> for concurrent insertion, or the inner tube <NUM> could be absent from the outer sheath <NUM> until the outer sheath <NUM> is placed as desired. Once the outer sheath <NUM> is at the target removal site, the inner tube <NUM> could be inserted (or further inserted) distally into the outer sheath lumen <NUM> until the deflector <NUM> directs the distal inner tube and <NUM> out the side access aperture <NUM> of the outer sheath <NUM>, into the configuration shown in <FIG> with the fluid return aperture <NUM> at a target returned site within the patient's vasculature. At that time, the outer sheath <NUM> can be used to remove fluid from the target removal site, and the inner tube <NUM> could be used, sequentially and/or simultaneously, to return fluid to the target returned site as desired.

<FIG> illustrate a second embodiment of a cannula apparatus <NUM>'. The cannula apparatus <NUM>' of <FIG> is similar to the cannula apparatus <NUM> of <FIG> and therefore, structures of <FIG> that are the same as or similar to those described with reference to <FIG> have the same reference numbers with the addition of a "prime" mark. Description of common elements and operation similar to those in the previously described first embodiment will not be repeated with respect to the second embodiment, but should instead be considered to be incorporated below by reference as appropriate.

<FIG> is a cross-sectional view of the cannula apparatus <NUM>'. Similarly to the first embodiment, the cannula apparatus <NUM>' of the second embodiment includes a deflector <NUM>'. However, in the second embodiment, the deflector <NUM>' takes the form of a channel tube <NUM> which extends a significant length of the outer sheath body <NUM>', within the outer sheath lumen <NUM>', between the proximal outer sheath end <NUM>' and the side access aperture <NUM>'. The channel tube <NUM> could be, for example, a smaller-diameter tube attached to an inner wall of the outer sheath body <NUM>'. The inner tube <NUM>' then has its own, "dedicated lane" within the outer sheath lumen <NUM>'. The inner tube <NUM>'can be inserted into the channel tube <NUM> and out the side access aperture <NUM>' as desired by a user, similarly to the operation of the first embodiment of the cannula apparatus <NUM>'. Stated differently, the second embodiment includes a reduced-diameter outer sheath lumen <NUM>' in cross-sectional areas of the outer sheath body <NUM>' through which the inner tube <NUM>' extends within the channel tube <NUM>.

It should also be noted, for the sake of illustration, that the outer sheath <NUM>' of the second embodiment includes a plurality of fluid removal apertures <NUM>' at differing longitudinal spacing along the outer sheath body <NUM>'. As with any embodiment of the present invention, there may be any number, location(s), and size(s) of fluid removal apertures <NUM>' as desired for a particular use environment in order to remove or "drain" fluid appropriately. For example, in an ECMO use environment, the fluid removal apertures <NUM>' could be configured to drain about one-third of the total removal volume from the head/SVC and about two-thirds from the IVC.

<FIG> illustrate a third embodiment of a cannula apparatus <NUM>". The cannula apparatus <NUM>" of <FIG> is similar to the cannula apparatuses <NUM>, <NUM>' of <FIG> and therefore, structures of <FIG> that are the same as or similar to those described with reference to <FIG> have the same reference numbers with the addition of a double "prime" mark. Description of common elements and operation similar to those in the previously described first and second embodiments will not be repeated with respect to the third embodiment, but should instead be considered to be incorporated below by reference as appropriate.

In the third embodiment of the cannula apparatus <NUM>", as shown in <FIG>, the deflector <NUM> takes the form of a spacer frame <NUM> which holds the inner tube <NUM>" away from the outer sheath body <NUM>" walls within the outer sheath lumen <NUM>". It is contemplated that one or more spacer frames <NUM> could be provided along the length of the outer sheath body <NUM>" , in order to "suspend" the inner tube <NUM>" within the outer sheath lumen". That is, fluid is removed concentrically around the inner tube <NUM>" through the outer sheath <NUM>"during use of the cannula apparatus <NUM>" of the third embodiment. The inner tube <NUM>" could be directed toward the side access aperture <NUM>" in any desired manner, such as, but not limited to, a spacer frame <NUM> configured to urge the inner tube <NUM>" and/or a steerable feature of the inner tube <NUM>".

<FIG> illustrate a fourth embodiment of a cannula apparatus <NUM>"'. The cannula apparatus <NUM>‴ of <FIG> is similar to the cannula apparatuses <NUM>, <NUM>', <NUM>" of <FIG> and therefore, structures of <FIG> that are the same as or similar to those described with reference to <FIG> have the same reference numbers with the addition of a triple "prime" mark. Description of common elements and operation similar to those in the previously described first through third embodiments will not be repeated with respect to the fourth embodiment, but should instead be considered to be incorporated below by reference as appropriate.

The cannula apparatus <NUM>‴ shown in <FIG> helps provide selective fluid flow in both a removal direction and a return direction, opposite the removal direction, within a vasculature of a patient. As shown in <FIG>, the outer sheath <NUM>"', inner tube <NUM>"', and other structures of the cannula apparatus <NUM>‴ of the fourth embodiment may include connectors, couplers, control features, and/or other structures used to attach the components of the cannula apparatus <NUM>‴ to one another and/or to other, related devices. One of ordinary skill in the art can readily configure a cannula apparatus <NUM>"', and components thereof, for a particular use environment.

The cannula apparatus <NUM>‴ of the fourth embodiment includes an outer sheath <NUM>‴ having proximal and distal outer sheath ends <NUM>‴ and <NUM>‴ spaced apart by a longitudinal outer sheath body <NUM>‴ defining an outer sheath lumen <NUM>‴. At least one fluid removal aperture <NUM>‴ extends entirely through the outer sheath body adjacent the distal outer sheath end <NUM>‴ to place the outer sheath lumen <NUM>‴ in fluid communication with an ambient space. As shown in <FIG>, the outer sheath <NUM> includes a side access aperture <NUM>‴ extending entirely through the outer sheath body <NUM>"'. The side access aperture <NUM>‴ may be located proximal to all fluid removal apertures <NUM>"', or there may be one or more fluid removal apertures <NUM>‴ located proximal to the side access aperture <NUM>"'. The distal outer sheath end <NUM>‴ and/or the distal inner tube end <NUM>‴ may include a solid, nonapertured distalmost tip. Alternatively, the distal most tip of the outer sheath <NUM>‴ and/or the inner tube <NUM>‴ could be open, such as by a simple operation of the respective lumen ending at a cut-off the rim of the tube structure.

As shown in <FIG>, the cannula apparatus <NUM>‴ of the fourth embodiment may include an introducer <NUM> having proximal and distal introducer ends <NUM> and <NUM> spaced apart by a longitudinal introducer body <NUM>. The introducer body <NUM> at least partially defines a guidewire channel <NUM> longitudinally therealong, which may assist with placement of at least a portion of the cannula apparatus <NUM>‴. For example, at least one of the introducer <NUM> and the outer sheath <NUM>‴ may be present in a desired location, and then a balloon tipped catheter (serving as a guidewire) could be inserted through the "guidewire channel" in the introducer body <NUM>. Once the catheter distally exits the channel of the introducer body <NUM>, the balloon is inflated and the catheter is floated past the TV into the RV, through the RVOT and into the PA. The balloon tipped catheter could then be exchanged for a guidewire (without dislodging the guidewire as the catheter is withdrawn and/or as the introducer <NUM> is removed) over which the inner tube <NUM>‴ may be inserted and the guidewire removed. Alternately, it is contemplated that the guidewire may be placed first via the guidewire channel <NUM>, without the use of a balloon tipped catheter, in certain embodiments, or the guidewire may be placed first and backloaded into the guidewire channel <NUM>, in other embodiments. One of ordinary skill in the art will be able to readily substitute or supplement the guidewire, in the instant description, for a balloon tipped catheter, for a particular use environment.

The introducer <NUM> is configured for selective insertion at least partially into the outer sheath lumen <NUM>‴ with the guidewire channel <NUM> in fluid communication with the side access aperture <NUM>‴. As shown in the Figures, the introducer body <NUM> may include a guidewire groove <NUM> extending partially into the introducer body <NUM> from a laterally outermost surface thereof. In this case, and innermost wall of the outer sheath body <NUM>‴ will at least partially define, in cooperation with the guidewire groove <NUM> of the introducer body <NUM>, the guidewire channel <NUM> when the introducer <NUM> is at least partially located within the outer sheath lumen <NUM>"'. This is the situation shown schematically in <FIG>, with only a portion of the circumference of the outer sheath body <NUM>‴ shown, for clarity. As an alternative configuration, though not shown, the guidewire channel <NUM> could be a longitudinally extending "tunnel" provided within the introducer body <NUM>, such as by being a side lumen completely cross-sectionally enclosed by the structure of the introducer body <NUM>.

As shown in <FIG>, the introducer body <NUM> may be contoured along a longitudinal length thereof from a first cross-sectional area at the proximal introducer end <NUM> to a reduced second cross-sectional area at the distal introducer end <NUM>. This taper or reduced-diameter contour could be accomplished with a substantially constant reduction in diameter along the introducer body <NUM>, or, as shown in the Figures, the introducer body <NUM> may have a tapered distal portion <NUM> which, when the introducer <NUM> is at least partially located within the outer sheath lumen <NUM>"', protrudes distally from the outer sheath <NUM>‴ through an open portion of the distal outer sheath end <NUM>"'. In this case, the tapered distal portion <NUM> can act to help open up the vasculature of the patient, much in the manner of a traditional introducer, and ease the increased-diameter passage of the outer sheath <NUM>‴ without subjecting the vasculature to the relatively blunt distal outer sheath and <NUM>‴.

Also as shown in <FIG>, the introducer body <NUM>, when at least partially located within the outer sheath lumen <NUM>"', may have a substantially constant first cross-sectional area along a length thereof located proximal to the side access aperture <NUM>‴ of the outer sheath <NUM>‴, and the reduction to the second cross-sectional area occurs at least one of laterally adjacent to and distal to the side access aperture <NUM>‴ of the outer sheath <NUM>"'. Stated differently, and as shown in the Figures, an intermediate taper <NUM> may occur in the introducer <NUM> in approximate longitudinal alignment with the portion of the outer sheath <NUM>‴ which includes the side access aperture <NUM>"', when the introducer <NUM> is in place within the outer sheath lumen <NUM>"'. This arrangement is shown in magnified view in <FIG> and in the cross-sectional detail view of <FIG>, and, when present, this intermediate taper <NUM> may assist with avoiding interference with an already-placed guidewire during withdrawal of the introducer body <NUM>. It is contemplated, though, that a substantially constant-cross-section introducer body <NUM> could be instead provided, optionally including a longitudinal groove or notch therein to facilitate maintenance of the guidewire in place therein (i.e., avoiding dragging the guidewire backwards) when the introducer <NUM> is withdrawn in the proximal direction from the outer sheath lumen <NUM>‴. It is also contemplated that, when the introducer <NUM> is at least partially located within the outer sheath lumen <NUM>"', the distal introducer end <NUM> could be located a chosen one of laterally adjacent to, and distally to, the side access aperture <NUM>‴ of the outer sheath <NUM>‴.

As shown in <FIG>, the introducer <NUM> may be at least partially hollow to define an introducer lumen <NUM>, for any desired reason, such as, but not limited to, flexibility of the introducer <NUM> structure.

An inner tube <NUM>‴ has having proximal and distal inner tube ends <NUM>‴ and <NUM>‴ spaced apart by a longitudinal inner tube body <NUM>‴ defining an inner tube lumen <NUM>‴. At least one fluid return aperture <NUM>‴ is located at least one of at and adjacent the distal inner tube end <NUM>‴ to place the inner tube lumen <NUM>‴ in fluid communication with an ambient space. The inner tube <NUM>‴ is configured for selective insertion into the outer sheath lumen <NUM>"', when the introducer <NUM> is absent from the outer sheath lumen <NUM>‴, with the inner tube body <NUM>‴ (or portions thereof, as noted above) extending completely through the side access aperture <NUM>‴ to place the distal inner tube end <NUM>‴ in an ambient space outside the outer sheath <NUM>‴.

The inner tube <NUM>‴ might include only one fluid return aperture <NUM>"'. Further, and as shown in <FIG>, that one fluid return aperture <NUM>‴ may be located at a distalmost extent of the inner tube <NUM>"'. However, the inner tube <NUM>‴ may also or instead include at least one fluid return aperture (not shown in the Figures) located adjacent to, but not at, the distal inner tube end <NUM>‴.

As shown schematically in <FIG>, a guidewire <NUM> may be configured for selective introduction through the guidewire channel <NUM> while the introducer <NUM> is at least partially located within the outer sheath lumen <NUM>"'. A distalmost end of the guidewire <NUM> may egress the outer sheath lumen <NUM>‴ via the side access aperture <NUM>‴. That is, and as shown schematically in <FIG>, the guidewire <NUM> may travel along the guidewire channel <NUM>, which itself may be formed collectively by the guidewire groove <NUM> and innermost wall of the outer sheath body <NUM>"', as shown in <FIG>. Then, when the guidewire <NUM> reaches the side access aperture <NUM>"', it may be directed laterally outward through the side access aperture <NUM>"', where it may later be used to guide placement of the inner tube <NUM>"', as will be discussed in detail below.

A method, not forming part of the present invention, of placing a cannula apparatus <NUM>‴ for selective fluid flow in a removal direction and a return direction, opposite the removal direction, within a vasculature of a patient will now be described, using the fourth embodiment, of <FIG>, as an example. The cannula apparatus <NUM>‴ as described above is provided. The introducer <NUM> is introduced at least partially into the outer sheath <NUM>‴. With the introducer <NUM> maintained at least partially within the outer sheath lumen <NUM>‴, and optionally inserted therein to sufficiently to protrude distally from the distal outer sheath and <NUM>"', whether or not the introducer <NUM> is tapered as described, the distal outer sheath and <NUM>‴ and distal introducer and <NUM> are advanced to a predetermined target removal location within the vasculature of the patient.

The distal outer sheath end <NUM>‴ and distal introducer and <NUM> are maintained at the target removal location, once achieved. When a guidewire <NUM> is used, the outer sheath <NUM>‴ and/or the introducer <NUM> maintained there in our adjusted to place the guidewire channel <NUM> in fluid communication with the side access aperture <NUM>"'. This step could be performed whether the guidewire channel <NUM> is of the tunnel type, through the wall of the introducer body <NUM>, or whether the guidewire channel <NUM> is collectively formed by the guidewire groove <NUM> and the innermost wall of the outer sheath body <NUM>"'. Once the guidewire channel <NUM> is aligned in fluid communication with the side access aperture <NUM>"', as shown in <FIG>, the guidewire <NUM> may be advanced distally through the guidewire channel <NUM>.

The guidewire <NUM> is then extended completely through the side access aperture <NUM>‴ (by "completely through" as previously noted, at least some portion of the guidewire <NUM> is concurrently located on both and inside and outside of the outer sheath lumen <NUM>‴ and penetrates through the side access aperture <NUM>‴). This places a distal guidewire end adjacent a target return location in the vasculature outside the outer sheath <NUM>"'.

The introducer <NUM> can then be withdrawn from the outer sheath <NUM>‴ while the distal guidewire end is maintained adjacent a target return location, and the distal outer sheath and <NUM>‴ is maintained at the target removal location.

When a guidewire <NUM> is not being used, once the distal outer sheath end <NUM>‴ and distal introducer end <NUM> have achieved their placement at the target removal location, the introducer <NUM> can be withdrawn from the outer sheath <NUM>"'. The inner tube <NUM>‴ is then inserted into the outer sheath lumen <NUM>‴ (with the introducer <NUM> absent therefrom) and advanced therethrough. The distal inner tube end <NUM>‴ is steered, in any desired manner, completely through the side access aperture <NUM>‴ to a placement at a target return location of the vasculature outside the outer sheath <NUM>‴.

When a guidewire <NUM> is being used, however, steering of the inner tube <NUM>‴ toward, and through, the side access aperture <NUM>‴ may be simplified. As above, the guidewire <NUM> is left extending through the side access aperture <NUM>‴ when the introducer <NUM> is withdrawn. In this case, the inner tube <NUM>‴ is manipulated to place the guidewire <NUM> within the inner tube lumen <NUM>"', and the inner tube <NUM>‴ may then be passed along the previously-placed guidewire <NUM>, as if along a rail, and the distal inner tube and <NUM>‴ will be guided directly to, and out, the side access aperture <NUM>‴ into the ambient space of the vascular outside the outer sheath <NUM>‴. The guidewire <NUM> may then be removed as desired from the outer sheath <NUM>‴ with the inner tube body <NUM>‴ maintained through the side access aperture <NUM>"'.

Once emplaced as just described, the outer sheath <NUM>‴ and inner tube <NUM>‴ can be adjusted as desired, and then fluid can be selectively removed from the target removal location through the outer sheath lumen <NUM>"', and, more specifically, through at least one fluid removal aperture <NUM>"'. Likewise, and concurrently or consecutively (or both at different times during operation of the cannula apparatus <NUM>), fluid can be selectively returned to the target return location through the inner sheath lumen <NUM>‴ and, more specifically through at least one fluid return aperture <NUM>‴ thereof.

Particularly when the cannula apparatus <NUM> is being used for an ECMO procedure, or any other filtering or fluid treatment procedure, the removed fluid could be therapeutically treated (e.g., could be oxygenated and/or filtered) after its removal from the vasculature and before its return to the vasculature. Any desired treatment devices, with appropriate connectors, could be provided to, and/or used with, the cannula apparatus <NUM> as desired. For example, both the outer sheath <NUM> and inner tube <NUM> could have hubs provided with two ports each (one for draining or infusing, and the other to allow over-the-wire/catheter movement, and in the case of the outer sheath <NUM>, to allow the inner tube <NUM> to be inserted). That is, for the inner tube <NUM>, by having two ports, a user can move the inner tube <NUM> without disconnecting the blood flow to it, so a two-port hub will help facilitate adjustability over a wire/catheter of the device in-situ while still infusing blood.

While aspects of this disclosure have been particularly shown and described with reference to the example aspects above, it will be understood by those of ordinary skill in the art that various additional aspects may be contemplated. In an effort to maintain clarity in the Figures, certain ones of duplicative components shown have not been specifically numbered, but one of ordinary skill in the art will realize, based upon the components that were numbered, the element numbers which should be associated with the unnumbered components; no differentiation between similar components is intended or implied solely by the presence or absence of an element number in the Figures. Any of the described structures and components could be integrally formed as a single unitary or monolithic piece or made up of separate sub-components, with either of these formations involving any suitable stock or bespoke components and/or any suitable material or combinations of materials; however, the chosen material(s) should be biocompatible for many applications. Any of the described structures and components could be disposable or reusable as desired for a particular use environment. Any component could be provided with a user-perceptible marking to indicate a material, configuration, at least one dimension, or the like pertaining to that component, the user-perceptible marking potentially aiding a user in selecting one component from an array of similar components for a particular use environment. A "predetermined" status may be determined at any time before the structures being manipulated actually reach that status, the "predetermination" being made as late as immediately before the structure achieves the predetermined status. The term "substantially" is used herein to indicate a quality that is largely, but not necessarily wholly, that which is specified--a "substantial" quality admits of the potential for some relatively minor inclusion of a non-quality item. Though certain components described herein are shown as having specific geometric shapes, all structures of this disclosure may have any suitable shapes, sizes, configurations, relative relationships, cross-sectional areas, or any other physical characteristics as desirable for a particular application. Any structures or features described with reference to one aspect or configuration could be provided, singly or in combination with other structures or features, to any other aspect or configuration, as it would be impractical to describe each of the aspects and configurations discussed herein as having all of the options discussed with respect to all of the other aspects and configurations. A device incorporating any of these features should be understood to fall under the scope of this disclosure as determined based upon the claims below.

Claim 1:
A cannula apparatus (<NUM>) for selective fluid flow in both a removal direction and a return direction, opposite the removal direction, the apparatus comprising:
an outer sheath (<NUM>) having proximal and distal outer sheath ends (<NUM>, <NUM>) spaced apart by a longitudinal outer sheath body (<NUM>) defining an outer sheath lumen (<NUM>), at least one fluid removal aperture (<NUM>) extending entirely through the outer sheath body adjacent the distal outer sheath end to place the outer sheath lumen in fluid communication with an ambient space, the outer sheath including a side access aperture (<NUM>) extending entirely through the outer sheath body wall;
an introducer (<NUM>) having proximal and distal introducer ends (<NUM>, <NUM>) spaced apart by a longitudinal introducer body (<NUM>), and
an inner tube (<NUM>) having proximal and distal inner tube ends (<NUM>, <NUM>) spaced apart by a longitudinal inner tube body (<NUM>) defining an inner tube lumen (<NUM>), at least one fluid return aperture (<NUM>) located at least one of at and adjacent the distal inner tube end to place the inner tube lumen in fluid communication with an ambient space, the inner tube being configured for selective insertion into the outer sheath lumen, when the introducer is absent from the outer sheath lumen, with the inner tube body extending completely through the side access aperture to place the distal inner tube end in an ambient space outside the outer sheath,
characterized in that the introducer body at least partially defines a guidewire channel (<NUM>) longitudinally therealong, and in that the introducer is configured for selective insertion at least partially into the outer sheath lumen with the guidewire channel in fluid communication with the side access aperture.