U.S. patent application number 15/115368 was filed with the patent office on 2017-01-12 for arterial cannula which allows proximal and distal perfusion within a cannulated vessel.
The applicant listed for this patent is NATIONAL UNIVERSITY HOSPITAL (SINGAPORE) PTE LTD, NATIONAL UNIVERSITY OF SINGAPORE, SINGAPORE HEALTH SERVICES PTE LTD. Invention is credited to Tar Toong Victor CHAO, Pei HO, Chong Hee LIM, Tze Kiat NG, Hock Heng Daniel TAN.
Application Number | 20170007800 15/115368 |
Document ID | / |
Family ID | 53759408 |
Filed Date | 2017-01-12 |
United States Patent
Application |
20170007800 |
Kind Code |
A1 |
CHAO; Tar Toong Victor ; et
al. |
January 12, 2017 |
ARTERIAL CANNULA WHICH ALLOWS PROXIMAL AND DISTAL PERFUSION WITHIN
A CANNULATED VESSEL
Abstract
A cannula includes a first segment configured to reside entirely
within a vessel. The first segment includes a proximal exit opening
disposed nearer to the heart, and multiple fenestrations disposed
distally away from the proximal exit opening near a cannulation
site. The fenestrations in combination with the proximal exit
opening enable simultaneous perfusion of blood into the cannulated
vessel along proximal and distal directions. During a medical
procedure, blood introduced into a vessel (e.g., the femoral
artery) by way of the cannula can exit the cannula in a manner that
provides concurrent blood flow in a first set of directions
proximally towards the heart and a second set of directions
distally away from the heart. Radially displaceable anchoring
elements positionable adjacent to the vessel's superficial wall aid
retention of the first segment in the vessel. The fenestrations
and/or anchoring elements can be arranged obliquely around portions
of the cannula's circumference.
Inventors: |
CHAO; Tar Toong Victor;
(Singapore, SG) ; LIM; Chong Hee; (Singapore,
SG) ; TAN; Hock Heng Daniel; (Singapore, SG) ;
NG; Tze Kiat; (Singapore, SG) ; HO; Pei;
(Singapore, SG) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SINGAPORE HEALTH SERVICES PTE LTD
NATIONAL UNIVERSITY HOSPITAL (SINGAPORE) PTE LTD
NATIONAL UNIVERSITY OF SINGAPORE |
Singapore
Singapore
Singapore |
|
SG
SG
SG |
|
|
Family ID: |
53759408 |
Appl. No.: |
15/115368 |
Filed: |
January 30, 2015 |
PCT Filed: |
January 30, 2015 |
PCT NO: |
PCT/SG2015/050010 |
371 Date: |
July 29, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 25/007 20130101;
A61M 25/04 20130101; A61M 25/10 20130101; A61M 1/3659 20140204;
A61M 2205/583 20130101 |
International
Class: |
A61M 25/00 20060101
A61M025/00; A61M 25/04 20060101 A61M025/04; A61M 25/10 20060101
A61M025/10; A61M 1/36 20060101 A61M001/36 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 30, 2014 |
SG |
2014008510 |
Claims
1. A cannula structure configured for cannulating an anatomical
vessel, the cannula structure comprising: a tube having an elongate
length and a lumen therethrough for channeling a fluid, the tube
having a distal fluid input configured for receiving the fluid, a
first segment having a first lumen therethrough aligned with the
lumen of the tube wherein the first segment is configured for
residing entirely internal to the cannulated anatomical vessel, and
a plurality of fluid outputs coupled to the distal fluid input and
configured for discharging the fluid into the vessel, wherein the
plurality of fluid outputs comprises: an exit opening disposed near
or at a proximal end of the first segment, the exit opening
configured for outputting or discharging a first portion of the
fluid into the vessel along a proximal flow direction; a plurality
of fenestrations carried by distal portions of the first segment
along portions of a length of the first segment and about portions
of a circumference of the first segment, the plurality of
fenestrations configured for outputting or discharging a second
portion of the fluid into the vessel such that the second portion
of the fluid flows along a distal flow direction opposite to the
proximal flow direction; and an anchoring assembly including at
least one structure that is distally carried by the first segment
near or adjacent to the plurality of fenestrations, and which is
outwardly or radially displaceable away from the lumen beyond an
exterior surface of the first segment, wherein at least one of (a)
the plurality of fenestrations and (b) the at least one outwardly
or radially displaceable structure is arranged obliquely with
respect to a lengthwise axis of the first segment or the proximal
fluid flow direction.
2. The cannula structure of claim 1, wherein the plurality of
fenestrations is configured to output the second portion of fluid
flow in multiple directions having a vector fluid flow component in
the distal direction.
3. The cannula structure of claim 1, wherein the plurality of
fenestrations comprises a first fenestration that is disposed
distally away from a second fenestration.
4. The cannula structure of claim 1, wherein each of (a) the
plurality of fenestrations and (b) the at least one outwardly or
radially displaceable element is disposed in an oblique arrangement
with respect to the lengthwise axis of the first segment or the
proximal flow direction.
5. The cannula structure of claim 1, wherein the plurality of
fenestrations is disposed around at most half of the circumference
of the first segment.
6. The cannula structure of claim 5, wherein the plurality of
fenestrations is disposed in a lower region of a lower half of the
circumference of the first segment.
7. The cannula structure of claim 1, wherein the anchoring assembly
is configured for selectively displacing the at least one outwardly
or radially displaceable structure away from or toward the first
lumen.
8. The cannula structure of claim 7, wherein the at least one
outwardly or radially displaceable structure when outwardly or
radially displaced has a cross sectional area that is larger than a
cross sectional area of the first segment.
9. The cannula structure of claim 7, wherein anchoring assembly
comprises a pressurizable, expandable, or inflatable cuff.
10. The cannula structure of claim 9, wherein the cuff is carried
external to the first lumen of the first segment such that the cuff
is exposed to the fluid in the vessel.
11. The cannula structure of claim 9, wherein the cuff is coupled
to a plurality of flange members that are outwardly or radially
displaceable away from the first lumen in response to
pressurization, expansion, or inflation of the cuff.
12. The cannula structure of claim 11, wherein the plurality of
flange members is disposed in an oblique arrangement with respect
to the lengthwise axis of the first segment or the proximal fluid
flow direction.
13. The cannula structure of claim 1, wherein the anchoring
assembly comprises a slidably displaceable switch coupled to a
plurality of thin flexible strips of material, wherein the at least
one structure comprises a plurality of petals, and wherein each of
the petals is coupled to or formed from end portions of a
corresponding strip of material.
14. The cannula structure of claim 13, wherein the plurality of
petals is disposed in an oblique arrangement with respect to the
lengthwise axis of the first segment or the proximal fluid flow
direction.
15. The cannula structure of claim 1, further comprising a flow
indicator assembly comprising: a fluid indicator port carried by
the first segment; a fluidic channel coupled to the flow indicator
port, the fluidic channel comprising a transparent or translucent
material capable of providing a visual indication of a flow of
fluid from the vessel into the fluid indicator port; and a luminous
portion disposed along the fluidic channel, the luminous portion
carrying a substance capable of reacting with the fluid within the
fluidic channel to thereby enhance the visual indication of the
flow of fluid in the fluidic channel.
16. The cannula structure of claim 1, wherein the first tube
further comprises at least one visible marking aligned with at
least one fenestration, the visible marking adapted to provide a
visual indication of contortion of the tube.
16. The cannula structure of claim 15, wherein the at least one
visible marking comprises a plurality of visible markings each of
which corresponds to a position of a fenestration of the plurality
of fenestrations.
17. The cannula structure of claim 1, wherein at least some of the
plurality of fenestrations are disposed on an angulatable material
carried by the first segment.
18. The cannula structure of claim 1, wherein the first tube
further comprises a second segment having a second lumen aligned
with the first lumen, the second segment distal to the first
segment, the second segment configured to substantially entirely
reside external to the vessel when the vessel is cannulated,
wherein the first and second lumens form the lumen of the tube.
19. The cannula structure of claim 1, further comprising a second
tube configured for mating engagement with the first tube and which
serves as a dilator relative to the first tube.
20. The cannula structure of claim 1, wherein the cannula structure
is configured for proximal infusion of blood into proximal portions
of the vessel by way of the exit opening concurrent with
maintaining distal perfusion of blood into distal portions of the
vessel to thereby distally deliver blood to a target organ or
tissue by way of the plurality of fenestrations.
Description
TECHNICAL FIELD
[0001] Defining proximal as toward the heart and distal as away
from the heart, aspects of the present disclosure are directed to a
cannula configured for enabling fluid (e.g., blood) flow in both
proximal and distal directions within a vessel by way of an
extravascular distal end opening for receiving a fluid, an
intravascular proximal end opening for outputting fluid in a
proximal direction towards the heart, and multiple intravascular
fenestrations disposed (e.g., obliquely) about portions of the
cannula's periphery and length for enabling distal fluid flow away
from the heart (e.g., down the limb in which the cannula is
placed). A set of selectively activatable/expandable intravascular
anchoring elements disposed (e.g., obliquely) distal to the
fenestrations aid precise positioning of the fenestrations and
secure retention of the cannula in the vessel.
BACKGROUND
[0002] Patients with cardiopulmonary failure can be treated with
mechanical circulatory support, such as extra-corporeal membrane
oxygenation (ECMO). In association with ECMO, a cannula having a
distal end and a proximal tip placed in an artery, which is
commonly the femoral artery, to infuse oxygenated blood into the
body. The cannula can be inserted into the artery by way of open
surgical or percutaneous puncture, such as through the Seldinger
technique. Blood that is directed into the cannula's distal end
exits the cannula at its proximal tip, and is directed up the aorta
towards the heart. Another context in which a cannula such as this
is used is cardiopulmonary bypass for heart surgery, including
minimally invasive cardiac surgery, where cannulation is performed
in a peripheral artery instead of the aorta (where cannulation is
performed for majority of heart operations).
[0003] In order to supply an adequate amount of blood, the cannula
needs to be sufficiently large in diameter. As a result, the
cannula itself obstructs blood flow into the extremities and limbs
that is cannulated, which is commonly a leg, though at times the
axillary/subclavian artery, or even the neck vessel (especially in
children/neonates) are accessed in certain clinical scenarios. For
patients on long-term support, the potential for ischemia to the
cannulated limb arises due to this obstruction of blood flow. There
are a number of existing devices that provide for an introduction
of catheters or cannulas into the artery or vessel.
[0004] U.S. Pat. No. 6,592,547 describes a device used for
placement inside the patient's heart or aorta. However, paragraph
[0052] mentions that a ring (46) is used to limit insertion of the
cannula into the vessel. There is a need to introduce an additional
step of suturing around the ring. In addition, paragraph [0054]
mentions that the cannula (28) is positioned in the ascending
aorta. The placement into the aorta might potentially lead to
rupture or undesirable effects. While paragraph [0070] mentions the
device needs to be curved or angled at a distal portion so that
fluid may be directed with or against natural flow, the natural
flow occurrence suggests that the fluid flows only through the
distal end.
[0005] U.S. Pat. No. 6,179,813 discloses a vascular access device
for infusing fluid into a patient. There are a number of holes
along the side of the vascular access device so that the fluid may
exit the side holes. There is no concerted fluid flow for perfusing
the vessel, nor is there an anchoring element in close relation to
the holes, which are not concentrated to be along the path of blood
flow, instead being positioned along the entire length of the
cannula. In addition, the vascular access device is elongated
without the need to be bendable, flexible, or capable of being
bent. The incapability of bending will inadvertently create rupture
to the artery when the vascular access device is twisted.
[0006] U.S. Pat. No. 5,178,611 describes yet another device as
shown in FIG. 4 where there are at least two communication paths
adapted to channel fluid outwardly. A first fluid communication
path directs flow through at least one fenestration along a portion
of the device. A second fluid communication path channels fluid
towards a distal end of the device. Thus, there is a need to have
at least two fluid communication paths to channel flow within the
body. This would also mean a need to have a two-step approach for
fluid communication. There is also no anchoring system in relation
to the fenestrations. U.S. Pat. No. 5,542,936 describes a device
having anchor flaps, fenestrations, and a way to deploy the anchor
flaps. FIGS. 9a and 9b describe an anchor flap used for anchoring
the inner wall surface of the vessel. The anchoring of the device
may potentially distort the internal profile of the superficial
vessel wall, which is highly undesirable. The device has a line of
fenestrations on one aspect of the circumference to allow distal
perfusion, arranged along the length of cannula (longitudinally).
While FIG. 8 seems to suggest that the flow will be disrupted
heavily due to the concentration of the flow towards the wall of
the vessel especially from fenestrations more proximal to the entry
site (i.e., closer to the heart) and not in line with the line of
the vessel lumen; there would be turbulent flow which may result in
hemolysis (disruption of walls of red blood cells), also creating
minimal amount of flow towards the opposite direction. Because the
fenestrations are not circumferential, but only limited to one part
of the circumference of the cannula, should the device be inserted
in an oblique manner, i.e., not in line or parallel with the course
of the vessel, which may occur in certain clinical situations, or
be twisted, the fenestrations would direct flow toward the side
wall of the vessel, resulting in turbulence, hemolysis and reduced
flow.
[0007] U.S. Pat. No. 8,585,679 discloses an apparatus having
multiple stages whereby a second stage provides a plurality of
fenestrations where blood is directed inwardly axially along the
internal portion of a tube. There is an additional suction required
such that blood may be siphoned away from the heart. The apparatus
is purely meant for use at the heart and not along the veins or
artery.
[0008] U.S. Pat. No. 5,176,697 discloses a laparoscopic cannula for
operating in the abdomen through small incisions. FIGS. 1 and 2
disclose the laparoscopic cannula when in use inserted through the
body tissue. Thereafter, an inflatable balloon is inflated so that
the laparoscopic cannula is fixed within the internal surface of
the body tissue. The laparoscopic cannula is fixated in a
substantially perpendicular manner.
[0009] U.S. Pat. No. 6,099,506 discloses different types of closure
seals engaged at an incision to secure the cannula and prevent
leakage of blood from the incision. FIGS. 1 to 8 show that the
sealing effect must engage both a superficial vessel wall and a
wall before entry into the superficial vessel wall.
[0010] U.S. Pat. No. 8,840,636 describes a mesh for filtering blood
flow within a blood vessel. When the mesh is actuated, embolic
materials entrap at the mesh. However, due to the need to inflate
the mesh, the anchoring of the device creates an additional point
of contact within the artery at the circumferential joint (317) and
the entry point of the device. The additional point of contact
within the artery potentially creates unwanted rupture within the
artery. In addition, paragraph [0159] mentions that the cannula
optionally contains openings in its distal end to further diffuse
the cannula blood.
[0011] United States Patent Publication 2008/0294102 discloses a
device having a balloon to inflate within the superior vena cava
and inferior vena cava. The lateral openings that can presumably be
fenestrations are positioned close to the opening which does not
take into account of bi-directional flow as seen in FIG. 10. In
addition, upon inflation of the balloon, the balloon cannulas seem
to show that blood is only perfused in one direction and not
bi-directionally.
[0012] U.S. Pat. No. 6,958,076 describes a venous valve primarily
used for fluid flow in a first direction along a defined passageway
while a second closed position prevents fluid flow in a backward
direction opposite of the first direction. The venous valve is
primarily used for allowing one way flow of air into the inflatable
cuff. The venous valve is used as a way to allow fluid to flow in
only one direction.
[0013] U.S. Pat. No. 5,330,433 describes an arterial cannula which
includes a diverting side hole which simultaneously perfuses blood
to the body and the lower extremity. Two barbs on the cannula
exterior position the diverting hole just inside the blood vessel
and prevent the back wall of the blood vessel from blocking the
diverting hole. However, because these barbs form a fixed
protrusion from the otherwise smooth profile of the cannula,
insertion of the cannula into the artery-may cause the artery wall
to stretch and expand, thereby causing bleeding from around the
cannula after insertion, especially if the blood pressure is at a
higher level (practitioners in the art will know that bleeding from
around the cannula may occur even in patients who are treated with
existing standard arterial cannulae having smooth profiles).
Because the diverting hole is single thus being limited to one part
of the circumference of the cannula, should the device be inserted
in an oblique manner, not in line or parallel with the course of
the vessel, which may occur in certain clinical situations, or be
twisted, the diverting side hole could direct flow toward the side
wall of the vessel, resulting in turbulence, hemolysis and reduced
flow. The fixed protrusion of the barbs would mandate open surgical
removal of the cannula once its purpose is achieved, whereas the
defect in a vessel in which a smooth cannula has been placed, after
removal of said cannula, may be closed with percutaneous vessel
closure devices/techniques currently available in the market.
[0014] U.S. Pat. No. 8,795,253 describes a bi-directional perfusion
cannula that includes an elongate tube for insertion into an
artery. The elongate tube has a first aperture at an end of the
tube, an elbow formed in the elongate tube, and a second aperture
formed in or slightly rearward of the elbow. The second aperture is
the only aperture for distal blood flow, thus the second aperture
must be sufficiently large. However, because the elbow forms a
fixed protrusion from the otherwise smooth profile of the cannula,
insertion of the cannula into the artery may cause the artery wall
to stretch and expand, thereby causing bleeding from around the
cannula after insertion, especially if the blood pressure is at a
higher level (practitioners in the art will know that bleeding from
around the cannula may occur even in patients who are treated with
standard arterial cannulas with smooth profiles). Because the
second aperture is only limited to one part of the circumference of
the cannula, should the device be inserted in an oblique manner,
i.e., not in line or parallel with the course of the vessel, which
may occur in certain clinical situations, or be twisted, the second
aperture would direct flow toward the side wall of the vessel,
resulting in turbulence, hemolysis and reduced flow. The fixed
protrusion of the elbow would mandate open surgical removal of the
cannula once its purchase is achieved, whereas the defect in a
vessel in which a smooth cannula has been placed, after removal of
said cannula, may be closed with percutaneous vessel closure
devices/techniques currently available in the market.
[0015] PCT publication WO 2014/021786 describes a cannula with
multiple fenestrations that are maintainable in position
substantially immediately or slightly beyond a site or point of
cannula entry into a vessel. The fenestrations enable the
simultaneous perfusion of blood into the cannulated vessel along
multiple directions, including opposing or anti-parallel blood flow
directions relative to a central axis of the cannulated vessel.
However, the fenestrations are disposed transversely around the
whole of the circumference of the cannula. The arrangement of the
fenestrations may weaken the structural integrity of the
cannula.
[0016] Although some existing devices and cannulas have been
disclosed in the prior art, none of aforementioned devices and
cannulas provides the benefits of the present disclosure.
Therefore, a need exists for an arterial cannula that provides
adequate blood flow into the body, but which also enables blood
flow into the cannulated body extremity. The improved arterial
cannula thus provides improvements in cannulation of the artery,
thereby addressing at least some of the aforementioned
problems.
SUMMARY
[0017] In accordance with an aspect of the present disclosure, a
cannula structure configured for cannulating an anatomical vessel
includes: a tube having an elongate length and a lumen therethrough
for channeling a fluid. The tube has a distal fluid input
configured for receiving the fluid, a first segment having a first
lumen therethrough aligned with the lumen of the tube wherein the
first segment is configured for residing entirely internal to the
cannulated anatomical vessel, and a plurality of fluid outputs
coupled to the distal fluid input and configured for discharging
the fluid into the vessel. The plurality of fluid outputs includes:
an exit opening disposed near or at a proximal end of the first
segment, the exit opening configured for outputting or discharging
a first portion of the fluid into the vessel along a proximal flow
direction; a plurality of fenestrations carried by distal portions
of the first segment along portions of a length of the first
segment and about portions of a circumference of the first segment,
the plurality of fenestrations configured for outputting or
discharging a second portion of the fluid into the vessel such that
the second portion of the fluid flows along a distal flow direction
opposite to the proximal flow direction; and an anchoring assembly
including at least one structure that is distally carried by the
first segment near or adjacent to the plurality of fenestrations,
and which is outwardly or radially displaceable away from the lumen
beyond an exterior surface of the first segment, wherein at least
one of (a) the plurality of fenestrations and (b) the at least one
outwardly or radially displaceable structure is arranged obliquely
with respect to a lengthwise axis of the first segment or the
proximal fluid flow direction. For instance, each of (a) the
plurality of fenestrations and (b) the at least one outwardly or
radially displaceable element can be disposed in an oblique
arrangement with respect to the lengthwise axis of the first
segment or the proximal flow direction. The cannula structure is
configured for proximal infusion of blood into proximal portions of
the vessel by way of the exit opening concurrent with maintaining
distal perfusion of blood into distal portions of the vessel to
thereby distally deliver blood to a target organ or tissue by way
of the plurality of fenestrations.
[0018] The plurality of fenestrations is configured to output the
second portion of fluid flow in multiple directions having a vector
fluid flow component in the distal direction. The plurality of
fenestrations can include a first fenestration that is disposed
distally away from a second fenestration. In some embodiments, the
plurality of fenestrations is disposed around at most half of the
circumference of the first segment, for instance, in a lower region
of a lower half of the circumference of the first segment. At least
some of the plurality of fenestrations are disposed on an
angulatable material carried by the first segment.
[0019] The anchoring assembly is configured for selectively
displacing the at least one outwardly or radially displaceable
structure away from or toward the first lumen. The at least one
outwardly or radially displaceable structure when outwardly or
radially displaced has or defines a cross sectional area that is
larger than a cross sectional area of the first segment.
[0020] The anchoring assembly can include a pressurizable,
expandable, or inflatable cuff, which can be unflanged or flanged.
The cuff can be carried external to the first lumen of the first
segment such that the cuff is exposed to the fluid in the vessel.
The cuff, or an annular fluid transport channel can be coupled to a
plurality of flange members that are outwardly or radially
displaceable away from the first lumen in response to
pressurization, expansion, or inflation of the cuff. The plurality
of flange members can be disposed in an oblique arrangement with
respect to the lengthwise axis of the first segment or the proximal
fluid flow direction
[0021] The anchoring assembly can alternatively include a slidably
displaceable switch coupled to a plurality of thin flexible strips
of material, wherein the at least one structure comprises a
plurality of petals, and wherein each of the petals is coupled to
or formed from end portions of a corresponding strip of material.
The plurality of petals can be disposed in an oblique arrangement
with respect to the lengthwise axis of the first segment or the
proximal fluid flow direction.
[0022] The cannula structure can carry at least portions of a flow
indicator assembly including: a fluid indicator port carried by the
first segment; a fluidic channel coupled to the flow indicator
port, the fluidic channel comprising a transparent or translucent
material capable of providing a visual indication of a flow of
fluid from the vessel into the fluid indicator port; and a luminous
portion disposed along the fluidic channel, the luminous portion
carrying a substance capable of reacting with the fluid within the
fluidic channel to thereby enhance the visual indication of the
flow of fluid in the fluidic channel.
[0023] The first tube can include at least one visible marking
aligned with at least one fenestration, the visible marking adapted
to provide a visual indication of contortion of the tube. The at
least one visible marking can include a plurality of visible
markings, each of which corresponds to a position of a fenestration
of the plurality of fenestrations.
[0024] The first tube further includes a second segment having a
second lumen aligned with the first lumen, where the second segment
distal to the first segment, and the second segment is configured
to substantially entirely reside external to the vessel when the
vessel is cannulated, wherein the first and second lumens form the
lumen of the tube. The second tube can be configured for mating
engagement with the first tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1A and FIG. 1B are diagrams of representative oblique
arrangements in accordance with the present disclosure.
[0026] FIG. 1C illustrates representative proximal fluid flow(s),
proximal vector fluid flow components, distal fluid flow(s), and
distal vector fluid flow components in a tubular structure in
accordance with an embodiment of the present disclosure.
[0027] FIG. 2A-2N illustrate aspects of representative catheters
that include anchoring assemblies having at least one
pressurizable/expandable/inflatable elements in accordance with
particular embodiments of the present disclosure.
[0028] FIG. 3A-3M illustrate aspects of representative catheters
that include anchoring assemblies having slidably displaceable
elements in accordance with particular embodiments of the present
disclosure.
[0029] FIG. 4 is a schematic illustration of representative
fenestration arrangements relative to a periphery, cross-sectional
area, or circumference of a first segment of a catheter in
accordance with particular embodiments of the present
disclosure.
[0030] FIG. 5 is a schematic cross-sectional illustration of a
cannula that carries at least one reinforcement structure, element,
or material along internal portions thereof.
[0031] FIG. 6 is a schematic illustration of a dilator
corresponding to a catheter in accordance with an embodiment of the
present disclosure.
DETAILED DESCRIPTION
[0032] In the present disclosure, depiction of a given element or
consideration or use of a particular element number in a particular
FIG. or a reference thereto in corresponding descriptive material
can encompass the same, an equivalent, or an analogous element or
element number identified in another FIG. or descriptive material
associated therewith. The use of "/" in a FIG. or associated text
is understood to mean "and/or" unless otherwise indicated. The
recitation of a particular numerical value or value range or the
use of terms such as approximately or about is understood to
include or be a recitation of an approximate numerical value or
value range (e.g., within +/-2%, +/-5%, +/-10%, or +/-20%).
[0033] As used herein, the term "set" corresponds to or is defined
as a non-empty finite organization of elements that mathematically
exhibits a cardinality of at least 1 (i.e., a set as defined herein
can correspond to a unit, singlet, or single element set, or a
multiple element set), in accordance with known mathematical
definitions (for instance, in a manner corresponding to that
described in An Introduction to Mathematical Reasoning: Numbers,
Sets, and Functions, "Chapter 11: Properties of Finite Sets" (e.g.,
as indicated on p. 140), by Peter J. Eccles, Cambridge University
Press (1998)). In general, an element of a set can include, be, or
be a portion of a system, an apparatus, a device, a structure, an
object, a process, a physical parameter, or a value depending upon
the type of set under consideration.
[0034] As used herein, proximal is defined as toward or closer to
the heart; and distal is defined as further away from the heart or
in a direction away from or opposite to proximal with respect to
fluid flow. The term "vessel" is taken to mean an anatomical
vessel, passage, or channel (e.g., a blood vessel, such as an
artery) of a patient or subject, or an anatomical chamber or
compartment. The term "perfusion" is taken to mean the injection,
transfer, or communication of blood and/or one or more other fluids
into a vessel for purpose of enabling the blood and/or other
fluid(s) to reach an organ or tissues (e.g., to supply nutrients
and oxygen thereto). The term "fluidically coupled" is taken to
mean coupled in a manner that provides for fluid (e.g., liquid/gas)
transfer or communication.
[0035] The term "oblique" or "obliquely" is taken to mean at an
angle that is neither a right angle nor a multiple of a right angle
relative to or along a lengthwise reference segment, section, or
axis (e.g., a central longitudinal axis or a peripheral edge,
border, or boundary) of a vessel or a tubular structure disposed
therein, and/or a direction of fluid flow (e.g., proximal fluid
flow) in the vessel or tubular structure. Representative examples
of oblique arrangements or orientations of structures within a
tubular structure or vessel 2 are shown in FIG. 1A-FIG. 1B. An
angle that is oblique can be measured relative to a lengthwise axis
or a fluid flow direction and a line or plane defined across or
through the tubular structure or vessel 2, for instance, a line or
plane corresponding to the positions of a plurality of structures
carried by the tubular structure or vessel 2. An individual having
ordinary skill in the art will readily understand that various
oblique arrangements or orientations are possible in accordance
with embodiments of the present disclosure.
[0036] The term "distal vector flow component" means a distally
directed component of a fluid flow vector V.sub.d within a vessel 2
where distally directed is defined as a direction that is parallel
to a lengthwise/longitudinal/central axis of the vessel 2 along
which fluid flows, and opposite to a proximally directed fluid flow
that is also parallel to the lengthwise/longitudinal/central axis
of the vessel 2. Correspondingly, the term "proximal vector flow
component" means a proximally directed component of a fluid flow
vector V.sub.p within the vessel 2, where proximally directed is
defined as a direction that is parallel to the
lengthwise/longitudinal/central axis of the vessel 2, and opposite
to a distally directed fluid flow. Representative proximal fluid
flows, proximal fluid flow vectors V.sub.p, proximal vector flow
components, distal fluid flows, distal fluid flow vectors V.sub.d,
and distal fluid flow components with respect to a representative
vessel 2 are illustrated in FIG. 1C.
Structural and Functional Overview
[0037] Embodiments in accordance with the present disclosure are
directed to a cannula or cannula structure (e.g., an arterial
cannula) providing (a) an exit opening at a proximal cannula
portion, segment, end, or tip that is configured for entry into a
vessel (e.g., an artery) at a cannulation site or point, and which
is configured for displacement or travel along internal portions of
the vessel and positioning away from the cannulation point; and (b)
a set of fenestrations, apertures, windows, or openings configured
to be positioned or maintained in position within the vessel
essentially, substantially, or nearly immediately beyond the
cannulation point. The cannula is configured to channel a flow or
volume of blood and/or another fluid along a least resistive
pathway through a lumen of the cannula with considerable laminar
flow in a first direction proximally towards the heart when a
portion of the lumen is positioned within the cannulated vessel.
The set of fenestrations, in association with the exit opening at
the cannula's proximal tip, enable simultaneous perfusion of blood
and/or another fluid into the cannulated vessel along multiple
fluid flow directions, including both proximal and distal fluid
flow directions. More particularly, a first amount, portion, or
volume of blood/fluid is discharged from the exit opening into the
vessel in a first flow direction towards the heart, and a second
amount, portion, or volume of the blood is discharged from the set
of fenestrations into the vessel in a set of flow directions away
from the heart. Thus, blood introduced into the vessel by the
cannula simultaneously flows towards the heart, i.e. proximally,
and away from the heart, i.e. distally.
[0038] FIG. 2A-FIG. 3M show schematic illustrations of portions of
representative cannula assemblies, cannula structures, cannula
devices, or cannulas (e.g., an arterial cannula) in accordance with
particular embodiments of the present disclosure. As indicated such
FIGs., the cannula includes at least a first tube, tubular member,
or tubular structure 10 providing a lumen therethrough and having
an elongate first portion 100 coupled to a second portion 200,
where the second portion 200 is distal to the first portion 100.
The first portion 100 spans, extends along, or defines an elongate
first fraction of the length of the first tube 10; and the second
portion 200 spans, extends along, or defines a second fraction of
the first tube's length. The first and second portions 100, 200 of
the first tube 10 are coupled, joined, or formed together (e.g.,
integrally formed together) to enable fluid flow from a distal
opening 220 disposed at a distal end 230 of the first tube 10
toward, to, and through a proximal exit opening, proximal end
opening, or proximal opening 120 disposed at, along, adjacent, or
contiguous to a proximal portion, segment, end, or tip 130 of the
first tube 10. In several embodiments, the proximal end portion/tip
130 is tapered to facilitate smooth insertion into a vessel. One
having ordinary skill in the art will readily understand that the
first tube 10 can itself be defined as the cannula, and hence the
first tube's distal opening 220 can be identified or defined as the
cannula's distal opening 220, and the first tube's proximal exit
opening 120 can be defined as the cannula's proximal exit opening
120.
[0039] The first portion 100 of the first tube 10 includes a first
or proximal segment 110 that spans or extends along a first section
of the first tube's elongate length, and which has a first lumen
therethrough which forms a portion of the first tube's lumen. The
first segment 110 is coupled (e.g., integrally and fluidically
coupled) to a second or distal segment 115 of the first portion
100, which spans or extends along a second section of the first
tube's elongate length, and which has a second lumen therethrough
(that is contiguous or aligned with the first lumen). The first
segment 110 is configured for entering into a vessel (e.g., an
artery) at a cannulation site or point, and being positioned or
displaced along or within the vessel such that the proximal tip 130
of the first tube 10 resides at an intended or predetermined
distance away from the cannulation point, at which blood and/or
another fluid is intended to be perfused or directed into the
cannulated vessel along a first or primary flow direction through
the first tube's proximal exit opening 120. The first flow
direction is the proximal direction going towards the heart.
[0040] The first segment 110 carries a set of fenestrations 140 and
a cannula retention or anchoring assembly 150. The set of
fenestrations 140 and the first tube's proximal exit opening 120
are configured for fluid communication with the first tube's distal
opening 220 and the second portion 200 by way of the first tube's
first and second segments 110, 115. Blood and/or another fluid
supplied to the first tube's distal opening 220 flows towards the
set of fenestrations 140 as well as the first tube's proximal exit
opening 120.
[0041] As further detailed below, the set of fenestrations 140
provide fluid output, discharge, or release sites, ports/portals,
or points other than the first tube's proximal exit opening 120 by
which blood and/or another fluid can enter into the cannulated
vessel from the first segment 110 and flow in a set of directions
away from, different than, or in opposition to a proximal
blood/fluid flow direction out of and beyond the first tube's
proximal exit opening 120 (or stated equivalently, the set of
fenestrations 140 provides sites at which blood/fluid can exit the
first segment 110, enter the cannulated vessel, and flow in a
distal direction). Hence, the set of fenestrations 140 provides
sites through which blood/fluid (e.g., oxygenated blood) that is
supplied to the first tube's distal opening 220 can flow into and
travel within the cannulated vessel along a second or secondary
direction that is different from or opposite to the aforementioned
first direction that is associated with the first tube's proximal
exit opening 120. The cannula of the present disclosure thus
advantageously eliminates the need for a second or separate cannula
to direct blood flow in the distal direction, as the cannula of the
present disclosure is able to enable or direct blood flow in both
proximal and distal directions in a simultaneous manner.
[0042] The anchoring assembly 150 includes a set of anchoring
elements configured for selective activation or deployment away
from and beyond outer or exterior portions of the first tube's
first segment 110, and subsequent abutment against or engagement
with the cannulated vessel's superficial wall, adjacent or just
internal to the cannulation point, to thereby facilitate reliable
retention or anchoring of the first tube 10 within the cannulated
vessel in a manner that facilitates or enables predictable/precise
positioning of the cannula's proximal exit opening 120 and the
fenestrations 140 within the cannulated vessel. Such anchoring
elements are also configured for selective deactivation or
retraction prior to withdrawal of the cannula from the cannulated
vessel. Depending upon embodiment details, the anchoring elements
can be coupled to or include outwardly or radially
displaceable/expandable and inwardly or radially
displaceable/retractable elements, such as fluid (e.g., gas or
liquid) pressurizable or inflatable/depressurizable or deflatable
elements, e.g., a balloon or cuff 160 and/or flange elements,
structures, or members 162, as indicated in FIG. 2A-2N and further
described in detail below; or slidably, progressably incrementally,
and/or stepwise displaceable structures that can laterally or
radially extend away from the outer or exterior surface of the
first tube's first segment 110, for instance, in the form of
projections, protrusions, or stub-like structures, e.g., petals
172, as indicated in FIGS. 3A-3M and further described in detail
below.
[0043] In some embodiments, a boundary or dividing line between the
first segment 110 and the second segment 115 of the first tube's
first portion 100 can be defined at a distal edge or border of the
anchoring assembly 150 or the set of anchoring elements associated
therewith (e.g., with respect to a distal-most edge or border of
the fenestrations 140). Portions of the anchoring assembly 150 or
the anchoring element(s) can be positioned at or approximately at
or generally near the middle of the first tube 10, depending upon
embodiment details. Depending upon embodiment details, the first
segment 110 can span up to approximately 70%-80% of the length of
the first portion 100. Typically, the second segment spans
approximately 20%-50% of the length of the first portion 100.
[0044] In various embodiments, the cannula also carries a
blood/fluid indicator assembly, which can include a blood/fluid
indicator port 190 disposed on the first segment 110 or second
segment 115 depending upon embodiment details, at a location near
or very near to the fenestrations 140 and/or the anchoring
assembly's anchoring elements When the cannula enters a vessel,
blood/fluid within the vessel can enter and flow into the
blood/fluid indicator port 190, and flow through portions of the
blood/fluid indicator assembly to provide an indication (e.g., a
visual indication) that the fenestrations 140 and the anchoring
elements are located at or approximately at an intended location,
and the cannula need not be advanced further into the vessel.
Additional details of representative blood/fluid indicator
assemblies are further described below.
[0045] The second portion 200 of the first tube 10 extends distally
away from the second segment 115 of the first tube's first portion
100, toward and to the first tube's distal opening 220. A distal
end 230 of the second portion 200 can provide or be a standard
physical interface, coupling, or connection configured for mating
engagement with and receiving blood and/or another fluid from a
structure or device (e.g., a portion of an ECMO or cardiopulmonary
bypass system) that is separate or separable from the first tube
10, in a manner readily understood by an individual having ordinary
skill in the relevant art.
[0046] With reference to FIG. 3L, when the cannula is in use (i.e.,
after the vessel is cannulated/after the first segment 110 of the
first tube 10 has been inserted into a patient or subject such that
blood and/or another fluid can flow or is flowing from the first
tube's distal opening 220 toward its proximal exit opening 120 and
out of the fenestrations 140 and the proximal exit opening 120),
the first segment 110 is configured to reside entirely within the
vessel. The second segment 115 and the second portion 200 are
configured to almost or essentially entirely reside external to the
vessel, outside of the patient's body. For instance, when the
cannula is in use, only a small portion of the second segment 115
that is distal to the anchoring element(s) provided by the
anchoring assembly 150 and which is very near or adjacent to the
inner surface of the cannulated vessel's superficial wall resides
within the vessel. The first segment 100 is flexible or pliable
along portions of its length, and the second segment 200 is at
least generally or somewhat flexible or pliable along portions of
its length. A lower or downward facing/downward oriented side of
the first tube 10 can be longer than the corresponding upper or
upward facing/upward oriented side of the first tube 10 to
facilitate an appropriate/predetermined amount of curvature or
bending for positioning the first tube 10 in a vessel 2, where
"lower"/"downward facing"/"downward oriented" refer to portions of
the first segment 110 that are opposite to and face away from the
site or point at which the first segment 110 entered into the
vessel, and which face away from the vessel's superficial wall
4.
[0047] In association with procedures such as heart lung bypass,
cardio pulmonary bypass, ECMO, or essentially any other means of
life support that requires the infusion of blood/fluid, the cannula
structure of the present disclosure can be adapted to proximally
infuse oxygenated blood into the body in a manner that maintains
distal perfusion during the procedure(s). For instance, a first
tube 10 in accordance with an embodiment of the present disclosure
can be inserted into an artery (e.g., the right femoral artery) of
a body extremity (e.g., the right leg, correspondingly). Blood
supplied to the first tube's distal opening 220 can flow through
the first tube 10 and simultaneously flow (a) out of the first
tube's proximal exit opening 120 into the body (e.g., directed up
the aorta towards the heart); and (b) out of the first tube's
fenestrations 140, away from the body and into the cannulated
extremity. Thus, blood leaving the first tube's proximal exit
opening 120 flows along a first direction (e.g., proximal direction
towards the heart), and blood leaving at least some of the first
tube's fenestrations 140 flows along a set of directions different
from or opposite to the first direction (e.g., distally away from
the heart). As a result, the risk of ischemia in the extremity is
substantially or greatly reduced, or essentially eliminated.
Aspects of Representative Fenestration Arrangements and
Fenestration Embodiments
[0048] The fenestrations 140 can be disposed along predetermined
portions of the length of the first tube 10 and around or about
predetermined portions of the circumference of first tube 10 in one
or more manners depending upon embodiment details. In several
embodiments, at least two fenestrations 140, each fenestration 140,
or at least two subsets of fenestrations 140 are disposed in an
oblique arrangement relative to the axial direction of the first
segment 110 of the first tube 10, and/or a given fluid flow
direction therethrough such as the first/primary fluid flow
direction. Representative oblique arrangements of fenestrations 140
about/along portions of the first tube's first segment 110 are
illustrated for the embodiments shown in FIG. 2A-2D; FIG. 2F-2I;
FIG. 2J-2L; and FIG. 2N, where such embodiments include anchoring
assemblies 150 having a set of selectively
pressurizable/expandable/inflatable elements (e.g., a set of
pressurizable/expandable/inflatable cuffs 160 and/or flange members
162); and also in the embodiments shown in FIG. 3A-3I, where such
embodiments include anchoring assemblies 150 having a set of
slidably displaceable elements (e.g., a slidably displaceable
switch 170 that selectively extends/retracts a plurality of petals
172).
[0049] Certain embodiments include fenestrations 140 that are
disposed in a non-oblique arrangement about predetermined portions
of the first segment's circumference, at a predetermined position
or location along the length of the first segment 110. For
instance, representative non-oblique arrangements of fenestrations
140 are illustrated for the embodiment shown in FIG. 2M, which
includes an anchoring assembly 150 having a set of
pressurizable/expandable/inflatable elements; and the embodiment
shown in FIG. 3J-3K, which includes an anchoring assembly 150
having a set of slidably displaceable elements.
Representative Aspects of Oblique Fenestration Arrangements
[0050] In various embodiments a plurality of fenestrations 140 are
disposed obliquely around portions of the first tube's
circumference. More particularly, with reference to FIG. 2B, FIG.
2H-2I, FIG. 2J-2L, and FIG. 3G-3H, a plane that extends or cuts
through multiple fenestrations 140 or each fenestration 140 forms a
non-parallel and non-perpendicular angle, i.e. an angle .alpha.
that is neither a right angle nor a multiple of a right angle, with
respect to the axial direction or a lengthwise/longitudinal axis of
the first segment 110 of the first tube 10 or a fluid flow
direction therethrough (e.g., the first/primary or proximal fluid
flow direction). In other words, a plane through a midpoint or
reference point of two or more fenestrations 140 (e.g., a
predetermined outermost point or corner thereof) that intersects a
centrally or peripherally defined longitudinal axis of the first
tube's first segment 110 forms an angle .alpha. that is neither a
right angle nor a multiple of a right angle with respect to the
longitudinal axis of the first segment 110 or a fluid flow
direction therethrough (e.g., the first/primary or proximal fluid
flow direction) at the point of intersection. In several
embodiments, the angle .alpha. formed by the plane of the set of
fenestrations 140 is 45.degree. relative to the axial direction or
fluid flow direction of the first tube 10. It should be apparent to
a person having ordinary skill in the relevant art that a variety
of other angles .alpha. are possible, such as between 30.degree.
and 60.degree..
[0051] In some embodiments having an oblique arrangement of
fenestrations 140 about and along portions of the first tube's
first segment 110, two or more fenestrations 140 need not be
disposed on a plane in a linear manner relative to each other;
rather, two or more fenestrations 140 can be disposed in a helical
or spiral arrangement along and about the first segment 110.
Consequently, a projection of a helical/spiral curve corresponding
to the locations of the fenestrations 140 onto the first segment's
longitudinal axis forms an oblique angle .alpha. that is neither a
right angle nor a multiple of a right angle with respect to this
longitudinal axis.
[0052] An oblique arrangement of fenestrations 140 can
advantageously allow for more streamlined and/or effective distal
flow of blood/fluid out of the fenestrations 140 as compared to a
non-oblique arrangement, thereby enhancing or improving the
efficiency of distal blood/fluid flow towards the patient's
extremities and limbs. Additionally, an oblique arrangement of
fenestrations 140 can result in enhanced structural integrity of
the first segment 110 of the first tube 10 compared to a
non-oblique fenestration arrangement, depending upon the number of
fenestrations 140 carried by the first segment 110.
Representative Aspects of Non-Oblique Fenestration Arrangements
[0053] Specific embodiments in accordance with the present
disclosure exhibit a non-oblique arrangement of at least some
fenestrations 140. FIG. 2M and FIG. 3J-3K illustrate representative
non-oblique or perpendicular fenestration arrangements, in which an
angle .alpha. formed by a plane through the set of fenestrations
140 equals 90.degree. relative to the lengthwise/longitudinal axis
of the first segment 110 of the first tube 10 or the proximal fluid
flow direction therethrough.
[0054] It should be noted that in certain embodiments, a plurality
of fenestrations 140 (e.g., at least one pair of fenestrations 140)
can be disposed non-obliquely about the first segment 110 at a
given location thereon, while other fenestrations 140 or the
overall/complete set of fenestrations 140 exhibit an oblique
arrangement about and along portions of the first segment's length.
Thus, in specific embodiments, a complete set of fenestrations 140
can include a plurality of fenestrations 140 disposed in a
non-oblique arrangement, as well as a plurality of fenestrations
disposed in an oblique arrangement with respect to the lengthwise
axis of the first segment 110 of the first tube 10 and/or a fluid
flow direction (e.g., the proximal fluid flow direction)
therethrough.
Representative Aspects of Fenestration Positions and Dimensions
[0055] Fenestrations 140 can be disposed about or around the
periphery, cross-sectional area, or circumference of the first
segment 110 of the first tube 10 in a variety of manners in
embodiments that exhibit non-oblique or oblique fenestration
arrangements. In some embodiments, fenestrations 140 reside in each
of a first or upper half of the first segment's cross-sectional
area and a second or lower half of the first segment's
cross-sectional area; however, in other embodiments, fenestrations
140 reside or approximately reside only in a particular half (e.g.,
the lower half) of the first segment's cross-sectional area. In
addition, depending upon embodiment details, each fenestration 140
can have an identical cross-sectional area and/or shape, or some
fenestrations 140 can have different cross-sectional areas and/or
shapes relative to other fenestrations 140 (e.g., particular
fenestrations 140 can have different dimensions compared to one or
more other fenestrations 140).
[0056] FIG. 4A-4D are schematic illustrations showing
representative manners in which fenestrations 140 can be disposed
relative to a cross-sectional area (e.g., a transverse or
perpendicular cross-sectional area), periphery, or circumference of
the first segment 110 of the first tube 10. As shown in FIG. 4A, in
some embodiments, a first through a fourth fenestration 140a-d are
uniformly disposed relative to the entire periphery of the first
tube's first segment 110. However, in other embodiments, such as
the representative embodiments shown in FIG. 4B-4D, fenestrations
140 are only partially disposed relative to the entire periphery of
the first segment 110, such as along, or at a particular fraction
or section of the first segment's cross-sectional area, periphery,
or circumference.
[0057] For purpose of simplicity and to aid understanding, in FIG.
4B-4D the set of fenestrations 140 include a first through a third
fenestration 140a-c that are not disposed uniformly relative to or
around the entire cross-sectional area, periphery, or circumference
of the first segment 110. Rather, the arrangement of fenestrations
140 is such that (a) approximately or up to at most half of the
cross-sectional area, periphery, or circumference of the first
segment 110 carries fenestrations 140, such as a lower or downward
facing/downward oriented half of the first segment's
cross-sectional area, periphery, or circumference, where
lower/downward facing/downward oriented are defined in a manner
identical or analogous to that described above; and (b) other
portions of the first segment's cross-sectional area, periphery, or
circumference do not carry fenestrations 140.
[0058] For instance, the first fenestration 140a can be disposed at
or approximately at a lower left portion of the cross-sectional
area or circumference of the first segment's lower half; the second
fenestration 140b can be disposed at or approximately at a bottom
portion of the cross-sectional area or circumference of the first
segment's lower half; and the third fenestration 140c can be
disposed at or approximately at a lower right portion of the
cross-sectional area or circumference of the first segment's lower
half. The fenestrations 140a-c are thus carried by or disposed on
(e.g., only carried by or disposed on) a lower or downwardly
facing/downwardly oriented region of the lower half section of the
cross-sectional area or circumference of the first tube's first
segment 110, while other portions (e.g., the upper half) of the
cross-sectional area or circumference of the first tube 10 exclude
or do not contain fenestrations 140.
[0059] As mentioned above, in various embodiments the fenestrations
140 are obliquely disposed around a portion of the circumference of
the first portion 110. After the cannula has been inserted into and
anchored within a vessel, such fenestrations 140 are slightly or
very slightly proximal or proximally adjacent/contiguous to the set
of anchoring elements provided by the anchoring assembly 150. In a
representative embodiment including three fenestrations 140a-c
disposed in an oblique arrangement such as in a manner shown in
FIG. 2H-2I or FIG. 2J-2L, the first fenestration 140a can be
closest to the cannula's distal end 230, the second fenestration
140b can be proximal to the first fenestration 140a, and the third
fenestration 140c can be proximal to the second fenestration 140b.
Various other oblique arrangements of fenestrations 140 are
possible, as will be readily recognized by an individual having
ordinary skill in the relevant art.
[0060] With additional conceptual reference to FIG. 3L, if a
cannula that includes fenestrations 140 carried on the upper half
of the first segment's cross-sectional area, periphery, or
circumference were inserted into a cannulation site or point 8 and
anchored within a vessel 2, portions of at least some of the
fenestrations 140 carried by this upper half section would face
upward, toward the vessel's superficial wall 4. Distal blood/fluid
flow through such fenestrations 140 is less efficient than for
fenestrations 140 that at least partially face in a downward
generally downward, or at least somewhat downward direction, away
from the cannulation site, and/or which at least partially face in
a distal direction. By limiting the positions of fenestrations 140
to approximately or at most a lower half of the cross-sectional
area, periphery, or circumference of the first tube's first segment
110, and in particular lower portions of the lower half of the
cross-sectional area, periphery, or circumference of the first
segment 110, blood/fluid flow out of the set of fenestrations 140
in the distal direction away from the heart is increased and/or
more efficient. Furthermore, such an arrangement of fenestrations
140 in only a particular half (e.g., the lower half) or region of
the first segment 110 can enhance the structural integrity of the
first segment 110, as there are fewer openings therein that can
reduce the first segment's structural integrity.
[0061] It will be apparent to an individual having ordinary skill
in the relevant art that the number of fenestrations 140 disposed
in a predetermined half-portion of the first tube's cross-sectional
area, periphery, or circumference is not limited to three; there
can be fewer than or more than three fenestrations 140 disposed in
such a manner. It will be apparent to such an individual that the
fenestrations 140 can also be arranged to reside around more than a
half portion of the cross-sectional area, periphery, or
circumference of the first segment 110, such as three-quarters
thereof, depending upon embodiment details.
[0062] Each fenestration 140 is configured or adapted to provide an
intended shape, size, or blood/fluid communication area, and not
all fenestrations 140 need to have an identical shape, size, or
blood/fluid communication area as indicated in FIGS. 4B and 4D. The
shape(s) and/or dimension(s) of particular fenestrations 140 can be
defined relative to the shape(s) and/or dimension(s) of other
fenestrations 140 carried by the first segment 110 (e.g., made
larger or smaller, depending upon the position(s) of certain
fenestrations 140 relative to other fenestrations 140) in order to
provide a cannula in accordance with an embodiment of the present
disclosure with an intended distal blood/fluid flow or output
relative to an expected proximal blood/fluid flow or output, and/or
an intended, target, or desired degree of structural integrity. In
a representative embodiment, a ratio of a total fenestration area
through which blood/fluid can exit the fenestrations 140 (e.g., a
total cross sectional area for blood/fluid flow provided by the
fenestrations 140) to a total proximal exit opening area through
which blood/fluid can exit the first tube's proximal exit opening
120 is not less than 10% and typically between 10% to 40% (e.g.,
20% to 40%, 25% to 35%, or 30%).
Aspects of Representative Anchoring Assemblies and Anchoring
Elements
Fluid Pressurizable/Expandable/Inflatable Anchoring Assemblies
[0063] In multiple embodiments such as shown in FIG. 2A-2N, the
anchoring assembly 150 includes a
pressurizable/expandable/inflatable cuff 160 and/or one or more
flange portions, sections, elements, structures, or members 162
that serve as anchoring elements by which the fenestrations 140 and
the proximal end opening 120 of the first segment 110 are retained
or maintained in an intended position within the vessel.
[0064] For instance, FIG. 2A-2D illustrate a representative first
embodiment of a cannula having an anchoring assembly 150 that
includes an expandable cuff 160 carrying and/or fluidically coupled
to a plurality of anchor members 162 in accordance with the present
disclosure. More particularly, FIG. 2A provides a representative
external perspective view of this first cannula embodiment; FIG. 2B
provides a representative plan view along portions of the first
portion 100 of this cannula's first tube 10; FIG. 2C provides a
representative interior or internal perspective view of this first
cannula embodiment; and FIG. 2D provides a magnified isometric
internal schematic illustration of the anchoring assembly 150 in
this first cannula embodiment.
[0065] In such an embodiment, the flange members 162 are configured
to radially/outwardly protrude through small openings or slots
formed in the first portion 100 of the first tube 10 in response to
pressurization/expansion/inflation of the cuff 160, such that the
flange members 162 extend slightly beyond the exterior surface of
the first segment 110 as the cuff 160 is
pressurized/expanded/inflated, while the cuff 160 is disposed and
remains internal to the exterior surface of the first segment 110.
Thus, from an external view, the cuff 160 remains hidden beneath
the exterior surface of the first tube 10, as indicated in FIGS. 2A
and 2B. Rather, only the anchoring assembly's flange members 162
selectively protrude away from and beyond the exterior surface of
the first portion 100 of the first tube 10 as a result of
pressurization/expansion/inflation of the cuff 160, whereas the
anchoring assembly's cuff 160 remains internal to the exterior or
outer surface of the first portion 100 of the first tube 10.
[0066] As shown in FIG. 2C and more clearly shown in FIG. 2D, the
cuff 160 in this first cannula embodiment resides and is retained
beneath the exterior surface of the first tube 10, for instance,
circumferentially disposed within or at least partially within
portions of the thickness of the wall of the first portion 100 of
the first tube 10, in a manner that avoids or substantially avoids
adversely affecting blood/fluid flow through the lumen(s) of the
first tube 10. When pressurized/expanded/inflated, the cuff 160 can
reinforce or aid the structural integrity of the first portion 100
of the first tube 10. As indicated in FIG. 2D, the cuff 160 is
fluidically coupled to a cuff pressurization/expansion/inflation
tube 168 that is fluidically couplable or coupled to a source of
pressurized gas or liquid (e.g., air) by which the cuff 160 can be
pressurized/expanded/inflated and the flange members 162 can
correspondingly be displaced outward beyond the exterior surface of
the first portion 100 of the first tube 10.
[0067] FIG. 2E is a cross-sectional illustration of a
representative cuff 160 and corresponding flange members 162
according to an embodiment of the present disclosure. In an
embodiment, the cuff 160 includes or is a generally elliptical or
circular ring or sleeve type structure having an outer surface or
layer 164, an inner surface or layer 166, and a chamber or cavity
165 therebetween. The outer layer 164 is expandable in response to
the delivery of positive fluid pressure (e.g., air or liquid
pressure) into the cavity 165. The cavity 165 is fluidically
coupled to the cuff pressurization/expansion/inflation tube 168 by
way of at least one activation port 169.
[0068] The flange members 162 can be integrally carried by or
formed from portions of the cuff's outer layer 164, or structurally
and/or fluidically coupled to or formed from portions of the cuff's
outer layer 164. For instance, the cuff's outer layer 164 can be
shaped such that the cavity 165 includes a plurality of outwardly
or radially directed extensions 163 therein, above which the flange
members 162 reside. Pressurization/inflation of the chamber 165
results in outward expansion of the cuff's outer layer 164 away
from its inner layer 166 and hence away from the interior or first
lumen of the first segment 110, resulting in outward or radial
expansion or displacement of the chamber's extensions 163 and the
flange members 162 away from the first lumen of the first segment
110, toward and slightly beyond the exterior surface of the first
segment 110. Analogously, appropriate depressurization/deflation of
the chamber 165 results in inward contraction of the cuff's outer
layer 164 toward its inner layer 166 and the first lumen of the
first segment 110, resulting in radial contraction or inward
displacement of the extensions 163 and the flange members 162
toward the first lumen of the first segment 110 until the outermost
surfaces of the flange members 162 are disposed below the exterior
surface of the first segment 110.
[0069] The outward or radial extent or height of each extension 163
and/or the thickness of those portions of the cuff's outer layer
164 that form the flange members 162 can be selected as required to
facilitate or enable reliable retention or anchoring of the cannula
in the vessel. In relation to the first segment 110 having a
predefined diameter suitably dimensioned according to the patient's
vessel size, the maximum cross-sectional area or diameter provided
by the activated or outwardly expanded flange members 162 can be
approximately 10% to 30% larger (e.g., about 15%-25% larger) than
the cross-sectional area or external diameter of the first segment
110. A person having ordinary skill in the relevant art will
understand that the extent or height to which the flange members
162 extend beyond the outer surface of the first segment 110 can
vary according to embodiment details and/or the nature and/or size
of the vessel under consideration. For instance, in a
representative embodiment in which the first segment has a diameter
of 21 French, complete pressurization/expansion/inflation of the
cuff 160 results in the radially outermost surfaces of the flange
members 162 being disposed a distance of approximately 1.5 mm away
from the exterior surface of the first segment 100. While the
embodiment shown in FIG. 2E includes four flange members 162a-d,
other embodiments can include additional or fewer flange members
162, in a manner readily understood by an individual having
ordinary skill in the relevant art.
[0070] In the first cannula embodiment shown in FIG. 2A-2D, the
fenestrations 140 are disposed in an oblique arrangement relative
to the lengthwise/longitudinal axis of the first segment 100 or a
blood/fluid flow direction therethrough, whereas the flange members
162 are disposed in a non-oblique arrangement relative to the
lengthwise/longitudinal axis of the first segment 100 or a
blood/fluid flow direction therethrough. In some embodiments, the
flange members 162 can be disposed in an oblique arrangement in a
manner analogous to that described above with respect to the
fenestrations 140, as further detailed hereafter.
[0071] FIG. 2F-2I illustrate a representative second embodiment of
a cannula in accordance with the present disclosure, which has an
anchoring assembly 150 that includes an expandable cuff 160 which
is fluidically coupled to a plurality of flange members 162 that
are obliquely arranged relative to the lengthwise/longitudinal axis
of the first segment 110 or a blood/fluid flow direction
therethrough. More particularly, FIG. 2F provides a representative
external perspective view of this second cannula embodiment; FIG.
2G provides a representative magnified view of portions of FIG. 2F;
FIG. 2H provides a representative internal view corresponding to
FIG. 2G; and FIG. 2I provides a representative cross-sectional view
corresponding to FIG. 2H.
[0072] In an oblique arrangement of flange members 162, a plane
that extends or cuts through multiple flange members 162 or each
flange member 162 forms a non-parallel and non-perpendicular angle,
i.e., an angle .beta. that is neither a right angle nor a multiple
of a right angle, with respect to the axial direction or a
lengthwise/longitudinal axis of the first segment 110 of the first
tube 10 or a fluid flow direction therethrough (e.g., the
first/primary or proximal fluid flow direction). In other words, a
plane through a midpoint or reference point of two or more flange
members 162 (e.g., a predetermined outermost point or corner
thereof) that intersects a centrally or peripherally defined
longitudinal axis of the first tube's first segment 110 forms an
angle .beta. that is neither a right angle nor a multiple of a
right angle with respect to the longitudinal axis of the first
segment 110 or a fluid flow direction therethrough. An oblique
arrangement of flange members 162 can enable activated or fully
deployed flange members 162 to be in a more planar orientation
relative to the superficial wall of the cannulated vessel when the
cannula is in use. This in turn can provide a more effective
abutment or anchoring of the flange members 162 on the superficial
wall, thereby aiding robust or reliable retention or anchoring of
the first segment 110 within the cannulated vessel. The angle
.beta. can be the same as or different than the angle .alpha.,
depending upon embodiment details, as will be readily understood by
an individual having ordinary skill in the relevant art.
[0073] As illustrated in FIGS. 2F, 2H, and 2I, in this embodiment
the cuff 160 is structurally separate or distinct from or
non-integral with at least some of the flange members 162. For
purpose of simplicity and to aid understanding, the representative
second embodiment 162 includes a first through a third flange
member 162a-c in an oblique arrangement, and a first through a
third fenestration 140a-c in an oblique arrangement. The first
flange member 162a is the distal-most flange member 162a; the
second flange member 162b is disposed in a proximal direction away
from the first flange member 162a; and the third flange member 162c
is disposed in a proximal direction away from the second flange
member 162b. Various other oblique arrangements of flange members
162 are possible, as will be readily understood by an individual
having ordinary skill in the relevant art.
[0074] In an embodiment, the first flange member 162a is carried by
or fluidically coupled to the cuff 160 (e.g., integrally formed
with or as a portion of the cuff 160) in a manner essentially
identical or analogous to that described above. For instance, the
second flange member 162b can include a
pressurizable/expandable/inflatable sleeve or channel that is
fluidically coupled to the cuff 160 by way of a first fluid
communication port/passage 161a. The third flange member 162c can
also include a pressurizable/inflatable sleeve or passage, which is
fluidically coupled to the second flange member 162b by way of a
second fluid communication passage 161b. Each fluid communication
passage 161a-b can reside or be formed in a portion of the
thickness of the first segment's wall.
[0075] Pressurization/inflation of the cuff 160 results in
pressurization of the first and second fluid communication passages
161a-b. Correspondingly, pressurization/inflation of the cuff 160
results in radial or outward expansion or displacement of the first
through third flange members 162a-c away from the first lumen of
the first segment 110, toward and slightly beyond the exterior
surface of the first segment 110. Analogously, appropriate
depressurization/deflation of the cuff 160 results in inward
depressurization/deflation of the first and second fluid
communication passages 161a-b. Correspondingly,
depressurization/deflation of the cuff results in radial
contraction or inward displacement of the flange members 162a-c
toward the first lumen of the first segment 100 until the outermost
surfaces of the flange members 162a-c are disposed flush with or
below the exterior surface of the first segment 110.
[0076] As an alternative to the foregoing, in some embodiments the
pressurizable/expandable/inflatable cuff 160 can simply be replaced
by annular/elliptical/circular fluid transport channel or air
channel 180, which is also shown in FIGS. 2D and 2F-2I. The annular
air channel 180 itself can be a rigid or generally rigid structure,
rather than an expandable structure. In such embodiments, the
annular air channel 180 resides internal to the outer/exterior
surface of the first portion 100 of the first tube 10 (e.g., within
internal portions of the wall of the first portion 100), and is
fluidically coupled to a plurality of
pressurizable/expandable/inflatable flange members 162 by way of a
set of fluid communication port/passages 161, such that the flange
members 162 are selectively outwardly/radially displaceable or
inwardly displaceable as a result of the application of positive
pressure or negative pressure to the annular air channel 180,
respectively.
[0077] It can be noted from the description above that in
embodiments such as those shown in FIGS. 2A-2I, flange members 162
can be pressurized/expanded/inflated collectively, such as in a
uniform or generally uniform manner for multiple or all flange
members simultaneously; or in a sequenced/sequential manner,
depending upon how positive pressure is communicated thereto (e.g.,
some flange members 162 may more fully or fully
pressurize/expand/inflate before other flange members 162).
Corresponding or analogous considerations apply to flange member
depressurization/contraction/deflation as a result of the
application of a negative pressure thereto.
[0078] In view of the embodiments shown in FIGS. 2A-2E and 2F-2I,
flange members 162 can be pressurized/expanded/inflated and
displaced beyond the exterior/outer surface, periphery,
cross-sectional area, circumference, or diameter of the first
portion 100 of the first tube 10 by way of
pressurization/expansion/inflation of the cuff 160, such as through
the introduction of air (or other type of fluid) into the cuff 160
from the cuff pressurization/expansion/inflation tube 168. Such
flange members 162 can be referred to as activated flange members
162. For instance, air can be introduced by a user such as a
clinician by applying a positive air pressure to a one-way valve
assembly 260 (which can include more than a single one-way valve
structure) disposed within the lumen of the first tube 10. A
one-way valve assembly 260 can include or be, for instance, a
duck-bill valve assembly such as illustrated in FIG. 2N.
[0079] As a result of radial displacement beyond the exterior
surface of the first tube's first portion 100, the activated flange
members 162 provide or define a cross-sectional area,
circumference, or diameter that is larger than an outer cross
sectional, circumference, or diameter area of the first segment 110
at a location around the first segment 110 at which the flange
members 162 are disposed. The activated flange members 162 can
subsequently abut or anchor to the internal surface or superficial
wall of the cannulated vessel, thereby aiding fixation, retention,
or maintenance of the first segment 110 and the fenestrations 140
and proximal end opening 120 thereof at a predictable or intended
position within the cannulated vessel. In order to retract the
cannula, the user/clinician can apply a negative pressure to or
deactivate the one-way valve assembly 260 that is sufficient to
overcome the valve assembly's one-way flow behavior, such that the
cuff 160 depressurizes/contracts/deflates/collapses to its minimal
volume or near-minimal volume configuration or shape. Consequently,
the user/clinician can safely retract or withdraw the cannula
through the cannulation site 8.
[0080] In still further embodiments, the cuff 160 can be carried by
an exterior or outer surface of the first segment 110 of the first
tube 10, such as in a manner indicated in FIG. 2J-2M. The cuff 160
can include or be an annular structure, which can be
contoured/tapered/flanged or unflanged, (e.g., the cuff 160 can
include a set of flange(d) regions, structures, or members 162
thereon or thereabout). The orientation/position of the cuff 160
around the first portion 100 of the first tube 10, the shape or
cross-sectional profile of the cuff 160, and/or the presence of
flanged regions, structure, or members 162 on the cuff 160 can
facilitate distal blood flow past the cuff 160 when the cuff 160 is
activated or deployed within the vessel, such that the cuff 160
does not impede or completely impede blood/fluid flow within the
vessel, especially when the cannula is accidentally advanced
further into the vessel (i.e., deeper than an intended or ideal
position).
[0081] In embodiments in which the cuff 160 is carried on the outer
surface of the first segment 110, at the location(s) at which the
first segment 110 carries the cuff 160 the thickness of the wall of
the first segment 110 can be reduced such that the cross-sectional
area corresponding to the cuff 160 (including its flange members
162) when the cuff 160 is depressurized/contracted/deflated is
nearly, approximately, or essentially the same as that of the
cross-sectional area of the first segment 110 adjacent to where the
cuff 160 resides, thereby aiding smooth insertion of the first
segment 110 into the vessel and smooth withdrawal therefrom.
[0082] As indicated in FIG. 2J-2K, in embodiments in which the cuff
160 is externally carried by the first segment 110, the cuff 160
can have an oblique orientation with respect to the
lengthwise/longitudinal axis of the first segment 110 or a fluid
flow direction therein. Consequently, a plane that extends or cuts
through the cuff 160 forms a non-parallel and non-perpendicular
angle, i.e. an angle .beta. that is neither a right angle nor a
multiple of a right angle, with respect to the axial direction or a
lengthwise/longitudinal axis of the first segment 110 of the first
tube 10 or a fluid flow direction therethrough (e.g., the
first/primary or proximal fluid flow direction), in a manner
analogous to that described above. Alternatively, as indicated in
FIG. 2L-2M, the cuff 160 can have a non-oblique orientation with
respect to the first segment's lengthwise/longitudinal axis or a
fluid flow direction therein, such that the angle .beta. equals
90.degree..
Slidably Displaceable Anchoring Assemblies and Elements
[0083] In alternative embodiments, the anchoring assembly 150 can
include slidably displaceable structures by which anchoring
elements such as a plurality of petals 172 can expand outwardly or
radially away from the first segment 110 and abut or anchor on the
inside surface of the cannulated vessel. The following description
provides details directed to particular representative embodiments
of such anchoring assemblies 150.
[0084] FIG. 3A is a representative perspective external view, FIG.
3B is a representative perspective internal view, FIG. 3C is a
representative plan view, and FIG. 3D is a representative cross
sectional view of a cannula that includes an anchoring assembly 150
having slidably displaceable elements in accordance with an
embodiment of the present disclosure. Additionally, FIG. 3E is a
representative magnified internal view showing such an anchoring
assembly 150 in an inactivated state, and FIG. 3F is a
representative magnified internal view showing this anchoring
assembly 150 in an activated state. Furthermore, FIG. 3G is a
representative magnified plan view and FIG. 3H is a representative
magnified cross sectional view of such an anchoring assembly 150.
FIG. 3I is a representative magnified perspective view of a cannula
that includes an anchoring assembly 150 having slidably
displaceable elements in accordance with another embodiment of the
present disclosure; and FIGS. 3J and 3K are representative
magnified cross-sectional views of a cannula that includes an
anchoring assembly 150 having slidably displaceable elements in
accordance with a further embodiment of the present disclosure.
FIG. 3L is a representative internal view showing a cannula that
includes an anchoring assembly 150 having slidably displaceable
elements after insertion into a vessel in accordance with an
embodiment of the present disclosure. Finally, FIG. 3M is a
cross-sectional view of slidably displaceable
elements/structures/elongate pieces of thin flexible material
disposed within passages that extend along sections of the wall of
the first portion 100 of the first tube 10, which correspond to or
form outwardly or radially extendable and inwardly retractable
petals 172, in accordance with an embodiment of the present
disclosure.
[0085] In embodiments such as those shown in FIG. 3A-3L, the
anchoring assembly 150 includes a slidable structure 170 such as a
slidably displaceable switch or activation element that is
mechanically coupled to the set of petals 172. The set of petals
172 can include, be coupled to, or be formed from portions (e.g.,
end or tip portions) of thin metal or polymer/plastic strips 171
(or any other significantly or highly flexible/pliable
biocompatible material) that are disposed along and within the wall
of the first portion 100 of the first tube 10, terminating just
distal to the fenestrations 140. A corresponding set of slits or
recesses and/or an intentionally formed defect or petal exit point
in the wall (e.g., a thin and/or puncturable region of the wall)
just distal to the set of fenestrations 140 (e.g., distally
adjacent or approximately adjacent to the fenestrations 140)
enables the petals 172 to protrude or extend outwardly beyond the
outer surface of the first segment 110 in response to activation of
the switch 170, that is, displacement of the switch 170 in the
proximal direction, allowing at least some of the petals 172 to
anchor to the superficial wall of the cannulated vessel. The
terminal end portions or ends of the petals 172 can be blunt or
curved in order to minimize the risk of damaging the vessel, in a
manner readily understood by an individual having ordinary skill in
the relevant art. Additionally, depending upon embodiment details,
the some or each of the petals 172 can exit or protrude from the
first segment 110 at an angle of approximately or nearly 90.degree.
with respect to the outer/exterior surface of the first segment
110, or another angle, such as within 15.degree.-30.degree. of
perpendicular to the outer/exterior surface of the first segment
110.
[0086] FIGS. 3B, 3D, 3E, 3F, 3H, and 3K illustrate thin strips of
material 171 (e.g., metal or plastic) disposed along and within
portions of the wall(s) of the first portion 100 of the first tube
10 in accordance with an embodiment of the present disclosure. FIG.
3M is a cross-sectional illustration of the first portion 100 of
the first tube 10, illustrating thin strips 171 disposed in slots
178 formed in the first portion's walls in accordance with an
embodiment of the present disclosure. Distal sections of the strips
171 are securely coupled to the switch 170, such that the strips
171 can be selectively displaced in a proximal or distal direction,
subject to physically imposed switch displacement limits, in
response to respective proximal or distal displacement of the
switch 170. In various embodiments, the proximal ends/tips of the
strips 171 form the petals 172 after (a) the switch 170 has been
displaced in a proximal direction; (b) the strips 171 have
correspondingly been displaced in the proximal direction; and (c)
the proximal ends/tips of the strips 171 protrude or extend
outwardly or radially away from the exterior surface of the first
segment 110 by a predetermined distance.
[0087] The switch 170 is configured to slide along the first tube
10, specifically the second segment 115 thereof. In some
embodiments, the second segment 115 and the switch 170 include male
and female structures that engage with each other and which
facilitate control of switch displacement. For instance, the second
segment 115 can include a set of grooves or channels formed therein
that match a set of teeth or bumps carried by the switch 170. The
set of grooves encircles a portion of the second segment 115, and
the set of bumps are disposed along portions of the inner diameter
and length of the switch 170. Each groove coincides with a bump.
The set of grooves can resemble the threading of a screw, while the
set of bumps can resemble the threading of a nut. The user or
clinician can push the switch 170 towards the cannula's proximal
end 130 to activate the petals 172. Stepwise advancement of the
switch 170 can cause interaction between the bumps and the grooves
in a manner that creates a frictional force that prevents the
switch 170 from sliding backwards (i.e. distally) to its original
position. Alternatively, the second segment 115 can have a set of
bumps and the switch 170 can have a corresponding set of
grooves.
[0088] FIGS. 3A, 3C, 3D, 3F, 3H, 3I, and 3K show petals 172 that
extended outwardly in directions away from the axis of the first
lumen of the first segment 110 and beyond the first segment's
exterior surface or cross-sectional area following user/clinician
activation of the switch 170. While the embodiments shown include
three or four petals 172, other embodiments can include additional
or fewer petals 172, in a manner readily understood by an
individual having ordinary skill in the relevant art. In general,
the anchor assembly 150 is suitably structured such that there are
at least two petals 172 that can act as anchoring points for
retaining or anchoring the first segment 110 at an intended
position within the cannulated vessel.
[0089] In an embodiment having three petals 172, the petals 172 and
their corresponding strips 171 can be uniformly separated from each
other about the entire periphery/circumference of the second
segment 110 by 120 degrees. In a representative embodiment having
four petals 172 such as that shown in FIG. 3M, the petals 172 and
their corresponding strips 171 can be uniformly separated from each
other about the entire periphery/circumference of the second
segment 110 by 90 degrees. Other arrangements of petals 172 are
also possible, as will be readily understood by an individual
having ordinary skill in the relevant art.
[0090] With further reference to FIG. 3M, each strip 171 resides in
a corresponding slot 178 that extends along a fraction of the
length of the first tube 10. One or more types of fluid impermeable
barriers can reside within the slots 178 in order to prevent the
backflow of blood/fluid therethrough when the petals 172 are
activated/deployed. For instance, one or more slots 178 can include
a compressible foam material (e.g., an open cell and/or closed cell
foam material) that extends along a predetermined short or
generally short length of the slot 178 (e.g., a few to several
millimeters, or up to 1 centimeter), which fills those portions of
the cross sectional area of the slot 178 that are not occupied by a
strip 171, and which provides a fluid impermeable barrier or seal
between the inner walls of the slot 178 and the outer periphery of
the strip 171 disposed therein. Such a foam material can be
disposed along one or more sections of a given slot 178, such as
slightly distal to the terminal end of the strip 171 that defines
the petal 172 thereof, and/or slightly proximal to a switch
displacement limit/stop structure. Alternatively or additionally, a
strip 171 can carry a set of bumps, kinks, or ridges that occupy
the internal cross-sectional area of its corresponding slot 178,
and which serve as fluid flow barriers within the slot 178.
[0091] In a manner essentially identical or analogous to that
described above for the flange members 162, the outward or radial
extent or height of each petal 172 can be defined or selected as
required to facilitate or enable reliable retention or anchoring of
the cannula in the vessel. In relation to the first segment 110
having a predefined diameter suitably dimensioned according to the
patient's vessel size, the maximum cross-sectional area or diameter
provided or defined by the activated or outwardly expanded petals
172 can be approximately 10% to 30% larger (e.g., about 15%-25%
larger) than the cross-sectional area or external diameter of the
first segment 110. A person having ordinary skill in the relevant
art will understand that the extent or height to which the petals
172 extend beyond the outer surface of the first segment 110 can
vary according to embodiment details and/or the nature and/or size
of the vessel under consideration. For instance, in a
representative embodiment in which the first segment has a diameter
of 21 French, complete activation or maximum outward/radial
displacement of the petals 172 results in the radially outermost
surfaces of the petals 172 being disposed a distance of
approximately 1.5 mm away from the exterior surface of the first
segment 100.
[0092] In a manner also essentially identical or analogous to that
described above, the petals 172 can be arranged obliquely or
non-obliquely/perpendicularly with respect to the axial or fluid
flow direction of the first segment 110. In an oblique arrangement,
a plane in which two or more petals 172 reside forms a non-parallel
and non-perpendicular angle .alpha., i.e. an angle that is neither
a right angle nor a multiple of a right angle, with respect to a
lengthwise/longitudinal axis of the first segment 110 and/or a
fluid flow direction therein. In one embodiment, the angle .alpha.
is 45.degree.; however, it will be apparent to the person having
ordinary skill in the relevant art that other angles .alpha. are
possible, such as between 30.degree. and 60.degree.. The effects or
advantages of an oblique arrangement of petals 172 is analogous or
essentially identical to the effects or advantages of an oblique
arrangement of flange members 162. Individual petals 172 can be
positioned in various manners in embodiments having an oblique
petal arrangement. For instance, in one oblique arrangement such as
that shown in FIG. 3I, a first petal 172a can be positioned closest
to the cannula's distal end 230, a third petal 172c can be
positioned furthest from the distal end 230, and a second petal
172b can be positioned between the first petal 172a and the third
petal 172c.
[0093] In a non-oblique/perpendicular arrangement, a plane in which
two or more petals 172 reside forms a perpendicular angle .alpha.
with respect to the lengthwise/longitudinal axis of the first
segment 110 and/or a fluid flow direction therein. In specific
embodiments, the first segment 110 can carry a first plurality of
petals 172 in an oblique arrangement, and a second plurality of
petals 172 in a non-oblique arrangement, in a manner analogous to
that described above with respect to the flange members 162.
[0094] FIG. 3L is a representative illustration showing portions of
the first tube's first and second segments 110, 115 positioned
relative to a vessel entry site or point 8 by which the first
segment 110 of the first tube 10 has been positioned within a
vessel 2. The vessel 2 includes a superficial wall 4 and a deep
vessel wall 6, in a manner readily understood by individuals having
ordinary skill in the relevant art. As indicated in FIG. 3L, in
various embodiments the fenestrations 140 are disposed on a
flexible or semi-flexible angulatable section, element, member, or
material 112 that is connected to or formed within or as a portion
of the first segment 110. The first tube 10 is configured to
channel a flow of blood/fluid along a least resistive pathway
through the lumen with considerable laminar flow in a first
direction (proximally out of the proximal exit opening 120). Once
the fenestrations 140 have entered into the vessel 2, a portion of
the first segment 110 distally adjacent or very near to the petals
172 can resemble a curve or an elbow by way of bending provided by
the angulatable section 112. The bending causes the first tube 10
to displace or angulate. The angulatable section 112 can establish
an intended or predetermined angular orientation or angle between
the first portion's first and second segments 110, 115, for
instance, approximately 45.degree.. Notwithstanding, the
angulatable section's range of angulation can be from 0.degree. to
180.degree., or a fraction thereof. The petals 172 are disposed on
the first segment 110, slightly distal to the angulatable section
112. The majority of the length of the first segment 110 extends
into the vessel 2, such that the first tube's proximal exit opening
120 reside at an intended or predetermined vascular location or
target site. In some embodiments, the angulatable section 112 can
be structurally reinforced to enhance structural reliability, for
instance, by way of one or more of material composition selection,
material thickness selection, and/or the incorporation of one or
more types of fibrous strands or materials (e.g., biocompatible
natural or synthetic bendable fibres such as carbon fibres, optical
fibres, or silk fibers), which can be oriented along predetermined
directions, such as lengthwise/cross-wise/spiral-wise, relative to
the elongate length of the first tube's first segment 110) in
and/or through one or more portions of the angulatable section
112.
[0095] As blood/fluid is pumped into the first tube 10, a first
portion of the blood/fluid exits the proximal exit opening 120 in a
first set of directions D1, and a second portion of the blood/fluid
exits the fenestrations 140 in a second set of directions D2, where
the set of directions D2 includes directions having a vector
blood/fluid flow component opposite to the set of directions D1.
More particularly, the set of directions D2 includes distal vector
flow components, whereas the set of directions D1 includes proximal
vector flow components. Similar, analogous, or essentially
identical considerations apply to embodiments in which the
anchoring assembly 150 includes flange members 162.
[0096] In order to withdraw the cannula from the cannulated vessel,
the user/clinician reverses the cannula insertion process by
displacing or releasing the switch 170 away from the cannula's
proximal end 130. The petals 172 thus retract or collapse into the
wall of the first segment 110, allowing smooth withdrawal of the
cannula from the vessel. Alternatively, a person having ordinary
skill in the relevant art can modify the switch 170 such that
advancing the switch 170 proximally towards the cannula's proximal
end 130 deactivates the petals 172, while retracting the switch 170
distally away from the proximal end 130 activates the petals
172.
Representative Aspects of Blood/Fluid Indicator Assemblies
[0097] As indicated above, the cannula can include a blood/fluid
indicator assembly including a blood and/or fluid indicator
interface 290, a blood/fluid indicator port 190, and a fluidic
passage or channel 195 therebetween. The fluid indicator interface
290, which is carried by second portion 200, is fluidically coupled
to the blood/fluid indicator port 190, which is carried by or
formed within an interior or inner surface of the first segment 110
of the first tube 10. The blood/fluid indicator port 190 is
positioned at a predefined distance distally away from the proximal
end 130, and adjacent to or near the set of fenestrations 140, but
in several embodiments not proximally beyond the positions of the
fenestrations 140. Different manners in which the blood/fluid
indicator port 190 can be positioned on the first segment 110 are
indicated in the FIGS. identified above.
[0098] Fluidic coupling of the fluid indicator interface 290 to the
blood/fluid indicator port 190 can be provided by way of the
channel 195, as will be readily understood by an individual having
ordinary skill in the relevant art. The blood/fluid indicator port
190 and the channel 195 fluidically connected thereto are adapted
to allow backward, i.e. distal, flow of blood, as well as for
retrieval or withdrawal of blood samples or specimens for testing
if needed. Additionally or alternatively, the channel 195 can be
attached to a manometer for measurement of intra-arterial blood
pressure, or to a pressure transducer device to measure vascular
pressure, thereby ensuring that the cannula is inserted into the
correct vessel. A person having ordinary skill in the art will
readily understand that blood/fluid flowing backward along the
channel 195 can be connected to any suitable blood pressure
measuring apparatus for providing the clinician with knowledge of
systolic and diastolic blood pressures. In various embodiments, the
channel 195 is made out of any suitable transparent or translucent
material, such that the presence of blood therein can be readily
visually observed by the clinician. The fluid indicator interface
290 and the channel 195 can thus provide a visual indication to a
clinician of the internal flow of blood/fluid within the channel
195, and also whether the anchoring elements and the fenestrations
140 have entered the cannulated vessel 2. In addition, contrast
agents can be injected into the vessel through fluid indicator port
190 by way of the fluid indicator interface 290 and the channel
195, in the opposite direction to that indicated above, to perform
contrast studies or angiograms of the vessel.
[0099] In some embodiments, the fluid indicator assembly can
include a luminous portion, which when contacted with blood/fluid
enhances the brightness thereof to create an enhanced visual
indication or direct attention to fluid flow along portions of the
channel 195, in a direction away from the blood/fluid indicator
port 190. The luminous portion carries therein a relatively small
amount of a substance that when reacted with blood/fluid causes the
blood/fluid to visually appear brighter. Such a substance can
include a garnet or borate single crystal containing thorium (Th)
or a liquid crystal material. The luminous portion can be disposed
in a variety of positions along the length of the channel 195. For
example, the luminous portion can be positioned adjacent to the
blood/fluid indicator port 190 so that the enhanced brightness
effect provided thereby upon the blood/fluid appears visually more
obvious essentially immediately after the blood/fluid has entered
the blood/fluid indicator port 190. Due to differential pressure,
the blood/fluid within the cannulated vessel 2 flows into the
blood/fluid indicator port 190 and interacts with the luminous
portion, thereby visually enhancing the brightness of the
blood/fluid. The visually enhanced portion of the blood/fluid is
gradually pushed along the length of the channel 195 in a distal
direction towards the fluid indicator interface 290.
[0100] In several embodiments, the blood/fluid indicator port 190
once inside the cannulated vessel allows backflow of blood/fluid
into and along the channel 195 to provide the clinician with a
visual indication that the fenestrations 140 and the anchoring
elements of the anchoring assembly 150 are in position within the
vessel lumen, indicating that they clinician may safely effectuate,
deploy, or activate the anchor assembly 150.
Representative Aspects of Cannula Positioning and Anchoring
[0101] Once the fenestrations 140 and the anchoring elements (e.g.,
flange members 162 or petals 172) of the anchoring assembly 150
have entered the vessel as indicated by one or more portions of the
fluid indicator interface, the anchoring elements can be activated
by the clinician, such that the anchoring elements (e.g. flange
members 162 or petals 172) expand to have a cross sectional area or
diameter that is larger than the entry site 8. The first tube 10
can then be partially or slightly withdrawn or displaced out of the
entry site 8, causing at least some anchoring elements to contact
or abut the inner surface of vessel's superficial wall 4. During
this partial withdrawal of the first tube 10, such contact of one
or more anchoring elements with the superficial wall 4 provides
perceptible tactile feedback to a clinician performing the
cannulation, such that the clinician knows that the fenestrations
140 are correctly positioned within the vessel 2. The first tube 10
can then be anchored to the patient's skin, thereby rendering the
first tube 10 substantially or essentially immobile relative to the
vessel 2 and fixating the cannula, in a manner readily understood
by one having ordinary skill in the relevant art.
[0102] When the first tube 10 is in a correct position and anchored
such as described above, an external pump, e.g. cardiopulmonary
bypass machine, can transfuse or transfer blood/fluid (e.g.,
oxygenated blood) through the distal opening 220 at the second
portion 200. The distal opening 220 is contiguous with the lumen in
the cannula structure. The transfused blood/fluid from the external
pump flows through the second portion 200 of the first tube 10
toward and into the first tube's first portion 100. The blood/fluid
further flows into the cannulated vessel 2 and exits the first
portion 100 by way of (a) the first tube's proximal exit opening
120, and (b) the fenestrations 140. That is, a first portion of the
blood/fluid flowing into the first portion 100 exits the first
segment 110 by way of the first tube's proximal exit opening 120,
while a second portion of the blood/fluid flowing into the first
portion 100 concurrently exits the first segment 110 by way of the
fenestrations 140. The first portion of the blood/fluid exits and
flows proximally towards the heart, while the second portion of the
blood/fluid exits and flows distally to the extremities and limbs
of the body. Therefore, when in use, the cannula simultaneously
directs blood/fluid flow in multiple directions, including both
proximal and distal directions, within the cannulated vessel 2.
[0103] An individual having ordinary skill in the relevant art will
further recognize that cannula assemblies, structures, and portions
thereof in accordance with embodiments of the present disclosure
can exhibit dimensions which are appropriate for the type of
patient or subject (e.g., an infant or child versus a full grown
adult) and/or the nature of a clinical situation under
consideration. Depending upon embodiment or situational details,
the first tube 10 can typically (but not exclusively) have an outer
diameter of Gauge 10 on the French Catheter Scale (approximately 4
millimeters which is suitable for infants), and up to Gauge 21 on
the French Catheter Scale (approximately 7 millimeters which is
suitable for adults). The length of the cannula may be based on
cannula products produced by Edwards Lifesciences Corporation
(Irvine, Calif. USA), Medtronic plc (Dublin, Ireland) or Maquet
Holding B.V. & Co. KG (Rastatt, Germany).
Additional/Other Design Considerations
[0104] There is a tendency for a cannula to bend out of shape prior
to use because of the relatively long length of the cannula. A
person having ordinary skill in the relevant art will readily
understand that the wavering of the cannula relates to kinking. The
cannula has a thickness between the lumen of the first tube 10.
There is typically at least one steel, plastic or other metal wire
strengthening portion 270 suitably positioned along the thickness
of the cannula. The at least one steel wire strengthening portion
270 is placed or suitably embodied by any suitable material such as
plastics, clear PVC, polyurethane, polyvinyl, or any other suitable
material that are commercially available. The at least one steel,
plastic or other metal wire strengthening portion 270 is adapted to
provide reinforcement along a portion of the first tube 10, as
shown in FIG. 5.
[0105] In some embodiments, the first tube 10 includes at least one
marking positioned along a surface thereof. The at least one
marking is adapted to provide a visual indication of contortion of
the first tube 10, i.e. whether the first tube 10 is positioned in
an undesired manner or twisted relative to a cannulated vessel.
Each of the at least one markings is positioned in a manner
correlated with or corresponding to the positions of the
fenestrations 140 to provide the clinician with a visual indication
of the directions the fenestrations 140 are facing within the
cannulated vessel. The at least one marking can include a first
mark site and a second mark site, wherein the alignment or
positioning together of both mark sites indicates that the first
tube 10 is substantially straight or is formed in a straight
manner. The presence of the at least one marking can mitigate the
risk of accidental contortion or twisting of the first tube 10, or
any part of the cannula device, while the cannula is in use or
being deployed. A cannula in accordance with an embodiment of the
present disclosure can thus be adapted to provide a quick
indication of an angle of twist or contortion while the first tube
10 is inside of the cannulated vessel.
[0106] FIG. 6 is a schematic illustration of a second tube 20
providable or provided by or in association with a cannula assembly
or structure in accordance with an embodiment of the present
disclosure. One having ordinary skill in the relevant art will
understand that the second tube 20 corresponds to or is a dilator
assembly or dilator 20. The second tube 20 has a diameter smaller
than the first tube 10, and is engageable therewith. The second
tube 20 includes a central guide wire channel 22 configured for
engaging with or passing a guide wire, as well as a tapered distal
end 24 having a diameter that occludes the proximal exit opening
120 of the first tube 10. The tapered distal end 24 includes a
through hole or opening therein 26 configured for passage of the
guide wire. The guide wire can be, for instance, 0.014 inch or
0.018 inch or 0.035 inch in diameter. The guide wire has a
frictional portion positioned at one end adapted to provide grip
while in use. Thus, the second tube 20 facilitates or enables
percutaneous insertion of the first tube 10 into the vessel 2. The
second tube 20 supports, straightens, and stiffens the first tube
10, thereby smoothening entry as the first tube 10 is inserted into
the vessel 2.
[0107] In a representative example femoral artery cannulation
procedure for ECMO, the first tube 10 and second tube 20,
henceforth simply referred to as the cannula 10 and the dilator
assembly 20, are inserted into the femoral artery 2 until the
blood/fluid indicator port 190 carried by the first tube's first
portion 100 is inside the femoral artery 2. At this point, blood
flows into the channel 195 and out through the blood/fluid
indicator interface 290, thereby visually indicating to a clinician
that the blood/fluid indicator port 190 is inside the femoral
artery 2.
[0108] With knowledge that the cannula 10 is within the artery 2,
the cannula 10 is advanced a short distance further (e.g.,
approximately or at least 1 centimeter), and the anchoring elements
(e.g., flange members 162 or petals 172) are effectuated or
activated. This further advancement of the cannula 10 into the
vessel 2 ensures that the anchoring elements are well away from the
superficial vessel wall 4 to avoid and prevent accidental damage to
the cannulated vessel 2 while activating the anchoring elements.
The cannula 10 is then gently pulled back until resistance is felt,
which indicates contact of the anchoring elements (e.g., flange
members 162 or petals 172) of the anchoring assembly 150 with the
superficial vessel wall 4 and thus correct positioning of the
cannula 10. The cannula 10 is then anchored into position to the
patient's skin externally, thus providing a two-point fixation. The
dilator assembly 20 is then withdrawn and the distal end 230 of the
cannula 10 is attached to a pump circuit. Thus, the proximal exit
opening 120 of the cannula 10 provides systemic blood flow to the
body, while the fenestrations 140 provide blood flow to the
extremities and limbs. The likelihood of limb ischemia is thereby
greatly reduced or avoided in patients undergoing extended
cardiopulmonary bypass procedures.
[0109] Aspects of particular embodiments of the present disclosure
address at least one aspect, problem, limitation, and/or
disadvantage associated with existing cannula designs, assemblies,
or structures. While features, aspects, and/or advantages
associated with certain embodiments have been described in the
disclosure, other embodiments may also exhibit such features,
aspects, and/or advantages, and not all embodiments need
necessarily exhibit such features, aspects, and/or advantages to
fall within the scope of the disclosure. It will be appreciated by
a person of ordinary skill in the art that several of the
above-disclosed systems, components, processes, or alternatives
thereof, may be desirably combined into other different systems,
components, processes, and/or applications. In addition, various
modifications, alterations, and/or improvements may be made to
various embodiments that are disclosed by a person of ordinary
skill in the art within the scope of the present disclosure.
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