U.S. patent application number 17/004384 was filed with the patent office on 2021-04-22 for high efficiency heat exchange catheters for control of patient body temperature.
The applicant listed for this patent is Zoll Circulation, Inc.. Invention is credited to Masoumeh Mafi, James D. Mazzone.
Application Number | 20210113368 17/004384 |
Document ID | / |
Family ID | 1000005307285 |
Filed Date | 2021-04-22 |
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United States Patent
Application |
20210113368 |
Kind Code |
A1 |
Mazzone; James D. ; et
al. |
April 22, 2021 |
High Efficiency Heat Exchange Catheters for Control of Patient Body
Temperature
Abstract
Disclosure includes fluid-circulating heat exchange catheters,
systems and related methods useable for controlling a patient's
body temperature.
Inventors: |
Mazzone; James D.; (San
Jose, CA) ; Mafi; Masoumeh; (Mountain View,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zoll Circulation, Inc. |
San Jose |
CA |
US |
|
|
Family ID: |
1000005307285 |
Appl. No.: |
17/004384 |
Filed: |
August 27, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15395923 |
Dec 30, 2016 |
10758406 |
|
|
17004384 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 25/10 20130101;
A61F 2007/0096 20130101; A61F 2007/126 20130101; A61M 2206/10
20130101; A61M 2230/50 20130101; A61F 7/123 20130101; A61F
2007/0054 20130101; A61M 2025/1086 20130101; A61F 7/12
20130101 |
International
Class: |
A61F 7/12 20060101
A61F007/12; A61M 25/10 20060101 A61M025/10 |
Claims
1. A catheter device comprising: an elongate catheter having a
proximal end, a distal end, at least one inflow lumen, at least one
outflow lumen and a longitudinal axis; a first tube having a
proximal end and a distal end, said first tube being coiled in a
series of elongated loops each of which has a length axis and a
width axis; and a second tube having a proximal end and a distal
end, said second tube being coiled in a series of elongated loops
each of which has a length axis and a width axis; at least one
elongated loop of the first tube being positioned so that it
extends around a section of the catheter such that its length axis
is transverse to the longitudinal axis of the catheter; and at
least one elongated loop of the second tube being positioned such
that it extends around said section of the catheter with its length
axis transverse to the longitudinal axis of the catheter and
nonparallel to the length axis of said at least one elongated loop
of the first tube; wherein the first and second tubes are connected
to the inflow and outflow lumens such that a fluid will circulate
in the inflow lumen, through said first and second tubes and out of
the outflow lumen, and wherein the first and second tubes improve
the heat exchange efficiency of the catheter device.
2. A catheter device according to claim 1 wherein elongated loops
have shapes selected from: rectangular, rounded-corner rectangular,
oval, ovoid, triangle, and oblong polygonal.
3. A catheter device according to claim 1 wherein: a plurality of
elongated loops of the first tube extend around said section of the
catheter such that the length axis of each is substantially
perpendicular to the longitudinal axis of the catheter; and a
plurality of elongated loops of the second tube extend around said
section of the catheter such that the length axis of each is
substantially perpendicular to the longitudinal axis of the
catheter and nonparallel to the length axes of the elongated loops
of the first tube.
4. A catheter device according to claim 3 wherein said plurality of
elongated loops of the first tube comprise all elongated loops of
the first tube and said plurality of elongated loops of the second
tube comprise all elongated loops of the second tube.
5. A catheter device according to claim 3 wherein the elongated
loops are in a row wherein elongated loops of the first tube
alternate with the elongated loops of the second tube.
6. A catheter device according to claim 1 wherein the length axis
of said at least one elongated loop of the second tube is
substantially perpendicular to the length axis of said at least one
elongated loop of the first tube.
7. A catheter device according to claim 1 wherein the elongated
loops are configured such that when the catheter device is inserted
into the vasculature of a patient, the elongated loops will cause
blood to flow in a non-laminar or self-mixing manner
8. A catheter device according to claim 7 wherein the elongated
loops are configured such that blood may flow through the elongate
loops.
9. A method for controlling a subject's body temperature using a
catheter device according to claim 1, said method comprising the
steps of: inserting the catheter into the subject's vasculature;
and causing warmed or cooled heat exchange fluid to circulate
through the elongated loops thereby resulting in exchange of heat
between blood flowing through the subject's vasculature and the
heat exchange fluid circulating through the elongated loops.
10. A catheter device comprising: an elongate catheter having a
heat exchange balloon attached thereto: said heat exchange balloon
comprising a central passageway and a plurality of heat exchange
protuberances which extend outwardly from the central passageway;
wherein the catheter has at least an inflow lumen for circulation
of heat exchange fluid into the heat exchange balloon and an
outflow lumen for circulation of heat exchange fluid out of the
heat exchange balloon.
11. A catheter device according to claim 10 wherein the balloon
comprises a low pressure balloon formed of expandable material.
12. A catheter device according to claim 11 wherein the expandable
material comprises a material selected from: Chloroprene, Latex,
Silicone, Polyurethane (PU), Styrene Butadiene Styrene (SBS), and
Styrene Isoprene Styrene (SIS).
13. A catheter device according to claim 10 wherein the interior of
the balloon comprises separate flow paths for inflow and outflow of
heat exchange fluid.
14. A catheter device according to claim 10 wherein each heat
exchange protuberance has an inflow channel through which heat
exchange fluid circulates into that heat exchange protuberance and
an outflow channel through which heat exchange fluid flows out of
that heat exchange protuberance.
15. A method for controlling a subject's body temperature using a
catheter device according to claim 10, said method comprising the
steps of: inserting the catheter into the subject's vasculature;
and circulating warmed or cooled heat exchange fluid through the
heat exchange balloon, thereby causing the balloon to expand and
resulting in exchange of heat between blood flowing through the
subject's vasculature and the heat exchange fluid circulating
through the heat exchange balloon.
16. A catheter device comprising: an elongate catheter body having
a proximal end, a distal end, an inflow lumen and an outflow lumen;
a plurality of heat exchange tubes disposed in arcuate loops
extending away from the catheter body; the inflow and outflow
lumens being such that heat exchange fluid will circulate from the
inflow lumen, through the heat exchange tubes and then out of the
outflow lumen.
17. A catheter device according to claim 16 wherein heat exchange
fluid flows distally through the inflow lumen to a location distal
of the heat exchange tubes and then returns in the proximal
direction through the heat exchange tubes and out of the outflow
lumen.
18-20. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present disclosure relates generally to the fields of
medicine and biomedical engineering and more particularly to
fluid-circulating catheters and related methods useable for
controlling a patient's body temperature by endovascular heat
exchange.
BACKGROUND
[0002] Pursuant to 37 CFR 1.71(e), this patent document contains
material which is subject to copyright protection and the owner of
this patent document reserves all copyright rights whatsoever.
[0003] In modern medicine there are numerous clinical situations in
which it is desirable to control or modify body temperature of a
patient. For example, hypothermia can be induced in humans and some
animals for the purpose of protecting various organs and tissues
against the effects of ischemic, anoxic or toxic insult. For
example, hypothermia can have neuroprotective and/or
cardioprotective effects in patients who suffer an ischemic event
such as a myocardial infraction or acute coronary syndrome,
post-anoxic coma following cardiopulmonary resuscitation, traumatic
brain injury, stroke, subarachnoid hemorrhage, fever or
neurological injury. Also, studies have shown that hypothermia can
ameliorate nephrotoxic effects of radiographic contrast media
(e.g., radiocontrast nephropathy) in patients who have pre-existing
renal impairment.
[0004] One method for inducing hypothermia--or otherwise modifying
or controlling a patient's body temperature--involves insertion of
an endovascular heat exchange catheter into the patient's
vasculature and circulation of a heat exchange fluid, such as
warmed or cooled saline solution, through a heat exchanger located
on the catheter. This results in exchange of heat between the
circulating heat exchange fluid and blood that is coursing through
the patient's vasculature. Because the blood circulates throughout
the patient's entire body, this technique can be effective to
change the patient's core body temperature to a desired target
temperature and to thereafter maintain the target core body
temperature for a period of time.
[0005] In some clinical situations, it is desirable to induce
hypothermia as rapidly as possible. Once such example is in the
treatment of acute myocardial infarction. Patients who are
diagnosed with acute myocardial infarction are often treated with a
coronary intervention or surgery (e.g., angioplasty or coronary
artery bypass surgery) to reperfuse the ischemic myocardium. In at
least one study, it was observed that patients with anterior wall
infarctions whose core body temperature had been lowered to at
least 35.degree. C. prior to reperfusion by angioplasty had
significantly smaller median infarct size than other patients with
anterior wall infarctions whose core body temperature was greater
than 35.degree. C. at the time of reperfusion. This observation is
not explained by other factors such as time-to-presentation, lesion
location or quantity of antegrade coronary flow (TIMI Flow) prior
to the angioplasty. This would suggest that, at least in acute
myocardial infarction cases, it is desirable to lower the patient's
body temperature to at least 35.degree. C. as rapidly as practical
so that reperfusion may also be accomplished as rapidly as
practical after such hypothermia has been induced.
SUMMARY
[0006] In accordance with the present disclosure, there are
provided catheter devices and systems useable for endovascular heat
exchange and related methods for using such catheter devices and
systems. The catheters, systems and methods described herein may
provide high-efficiency heat exchange and the ability to rapidly
raise or lower a patient's body temperature.
[0007] In accordance with one embodiment, there is provided a heat
exchange catheter device which comprises an elongate catheter
having a proximal end, a distal end, at least one inflow lumen, at
least one outflow lumen and a longitudinal axis. At least first and
second tubes having proximal and distal ends are coiled to form a
series of elongated loops in each. Each such elongated loop has a
length axis and a width axis. At least one elongated loop of the
first tube extends around a section of the catheter such that the
length axis of that elongated loop is substantially perpendicular
or transverse to the longitudinal axis of the catheter. At least
one elongated loop of the second tube also extends around the
section of the catheter such that its length axis is also
substantially perpendicular or transverse to the longitudinal axis
of the catheter but nonparallel to the length axis of the elongated
loop(s) of the first tube that also extend around the catheter. In
at least some embodiments, the length axes of the first tube's
elongated loops may be substantially perpendicular or transverse to
the length axes of the second tube's elongated loops. In at least
some embodiments the first tube's elongated loops may be aligned in
a row with the second tube's elongated loops and/or the first
tube's elongated loops may alternate with the second tube's
elongated loops. The first and second tubes are connected to the
inflow and outflow lumens such that heat exchange fluid will
circulate in the inflow lumens, through the elongated loops and out
of the outflow lumens. The elongated loops may be of any suitable
elongate shape such as, for example, rectangular, rounded-corner
rectangular, oval, ovoid or other oblong polygonal shapes.
Catheters of this embodiment may be useable for controlling a
subject's body temperature by a) inserting the catheter into the
subject's vasculature and b) causing warmed or cooled heat exchange
fluid to circulate through the elongated loops thereby resulting in
exchange of heat between blood flowing through the subject's
vasculature and the heat exchange fluid circulating through the
elongated loops.
[0008] In accordance with another embodiment, there is provided a
catheter device which comprises an elongate catheter having a heat
exchange balloon attached thereto. Such heat exchange balloon
comprises a central passageway and a plurality of heat exchange
protuberances which extend outwardly from the central passageway.
The catheter has at least an inflow lumen for circulation of fluid
into the heat exchange balloon and an outflow lumen for circulation
of heat exchange fluid out of the heat exchange balloon. The
balloon may be a low pressure balloon formed of expandable material
such as, for example, an expandable material selected from:
Chloroprene, Latex, Silicone, Polyurethane (PU), Styrene Butadiene
Styrene (SBS), and Styrene Isoprene Styrene (SIS). In at least some
embodiments, the interior of the balloon may comprise separate flow
paths for inflow and outflow of fluid. Such flow paths may include
inflow and outflow channels within individual protuberances such
that fluid will circulates into each protuberance through an inflow
channel and out of each protuberance through an outflow channel.
Catheters of this embodiment may be useable for controlling a
subject's body temperature by a) inserting the catheter into the
subject's vasculature and b) causing warmed or cooled heat exchange
fluid to circulate through the heat exchange balloon, thereby
causing the balloon to expand and resulting in exchange of heat
between blood flowing through the subject's vasculature and the
heat exchange fluid circulating through the heat exchange
balloon.
[0009] Still further there is provided a catheter device which
comprises an elongate catheter body having a proximal end, a distal
end, an inflow lumen and an outflow lumen and a plurality of heat
exchange tubes disposed in arcuate loops extending away from the
catheter body. The inflow and outflow lumens are such that fluid
will circulate from the inflow lumen, through the heat exchange
tubes and then out of the outflow lumen. Catheters of this
embodiment may be useable for controlling a subject's body
temperature by a) inserting the catheter into the subject's
vasculature and b) causing warmed or cooled heat exchange fluid to
circulate in the inflow lumen, through the heat exchange tubes and
out of the outflow lumen.
[0010] Still further there is provided a catheter device which has
an elongate body with one or more tubular member(s) located on a
distal portion of the elongate body. Such tubular member(s) may
comprise heat exchange members through which heat exchange fluid
may be circulated. The tubular member(s) are initially deployable
in non-coiled configuration(s) and subsequently transitionable to
coiled configuration(s). Advanceable coiling member(s) is/are used
to facilitate such transition. The coiling member(s) may be formed
of superelastic (e.g., nickel-titanium alloy, chromium cobalt) wire
or any other suitable material or polymeric material that is
pre-set or biased to assume a coiled configuration when relaxed but
to become straight or substantially non-coiled when drawn taught.
The coiling member(s) extend through or are affixed to exterior
locations on the tubular member(s). The distal end(s) of the
coiling member(s) is/are held at fixed locations on the elongate
body of the catheter, distal to the tubular member(s). The proximal
end(s) of the coiling member(s) is/are engaged with a coiling
member advancement controller, such as a rotatable spooling device.
The coiling member advancement controller is useable to initially
draw the coiling member(s) to taught (preshaped), straight
configuration(s), thereby causing the associate tubular members to
assume non-coiled configurations. When the tubular members are in
such non-coiled configuration(s) and not filled with fluid, they
may be folded, furled, compressed, compacted, sleeved or otherwise
disposed in low profile configurations suitable for initial
insertion of the catheter device into a subject's body. Thereafter,
the coiling member advancement controller is useable to advance the
coiling member(s) distally, causing the coiling member(s) to
slacken and assume their coiled configurations. The slackening and
coiling of the coiling member(s) causes the tubular members to also
assume corresponding coiled shapes. When in such coiled shapes,
fluid (e.g., heat exchange fluid) may be circulated through the
tubular member(s).
[0011] Still further aspects and details of the present invention
will be understood upon reading of the detailed description and
examples set forth herebelow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The following detailed description and examples are provided
for the purpose of non-exhaustively describing some, but not
necessarily all, examples or embodiments of the invention, and
shall not limit the scope of the invention in any way.
[0013] FIG. 1 shows an endovascular temperature management system
which includes one embodiment of an endovascular heat exchange
catheter.
[0014] FIG. 2 is a broken side view of the embodiment of FIG.
1.
[0015] FIG. 2A is a distal end view of the embodiment shown in FIG.
1 and FIG. 2.
[0016] FIG. 2B is a longitudinal sectional view through the distal
tip member of the embodiment shown in FIGS. 1 and 2.
[0017] FIG. 2C is a cross sectional view through line 2C-2C of FIG.
2.
[0018] FIG. 3 is an enlarged, broken perspective view of the
embodiment shown in FIGS. 1 and 2.
[0019] FIG. 4 is a side view of another embodiment of a
endovascular heat exchange catheter.
[0020] FIG. 4A is a cross sectional view through line 4A-4A of FIG.
4.
[0021] FIG. 4B is a cross sectional view through line 4B-4B of FIG.
4.
[0022] FIG. 4C is a cross sectional diagram showing a variant of
the embodiment of FIG. 4 having heat exchange projections extending
around the circumference of the catheter.
[0023] FIG. 5 is a side view of another embodiment of a
endovascular heat exchange catheter.
[0024] FIG. 5A is a cross sectional view through line 4A-4A of FIG.
4.
[0025] FIG. 5B is a cross sectional diagram showing a variant of
the embodiment of FIG. 5 having arcuate heat exchange tubes
extending around the circumference of the catheter.
[0026] FIG. 6 is a side view of another embodiment of an
endovascular heat exchange catheter having heat exchange members in
non-coiled configurations.
[0027] FIG. 6A is an enlarged cut-away view of the coiling member
advancement controller of the catheter of FIG. 6 rotated in a
counterclockwise direction to cause the coiling members to retract
proximally and be drawn to a taught, thereby causing the coiling
members and the heat exchange members to be in non-coiled
configurations.
[0028] FIG. 6B is a cross-sectional view through line 6B-6B of FIG.
6.
[0029] FIG. 7 is a side view of the heat exchange catheter of FIG.
6 with its heat exchange members in coiled configurations.
[0030] FIG. 7A is an enlarged cut-away view of the coiling member
advancement controller of the catheter of FIG. 7 rotated in a
clockwise direction to cause the coiling members to advance
distally and slacken, thereby causing the coiling members and the
heat exchange members to assume coiled configurations.
[0031] FIG. 7B is a cross-sectional view through line 7B-7B of FIG.
7.
DETAILED DESCRIPTION
[0032] The following detailed description and the accompanying
drawings to which it refers are intended to describe some, but not
necessarily all, examples or embodiments of the invention. The
described embodiments are to be considered in all respects only as
illustrative and not restrictive. The contents of this detailed
description and the accompanying drawings do not limit the scope of
the invention in any way.
[0033] FIG. 1 shows an endovascular temperature management system
10 which generally includes a control console 10a and an
endovascular heat exchange catheter 10b. FIGS. 2 and 2A show
further details of the embodiment of the endovascular heat exchange
catheter 10b seen generally in FIG. 1.
[0034] The console 10a comprises a housing 31 within which, or on
which, there are positioned heating/cooling apparatus 32 for
alternately heating and cooling a heat exchange fluid, a pump 34
for pumping the heat exchange fluid and a programmable controller
36. A user interface 38, such as a liquid crystal display (LCD), is
in communication with the controller 36. The user interface
displays system information and also receives user input as well as
sensor data, as described more fully herein.
[0035] A source of heat exchange fluid 8, such as a bag or
container of sterile 0.9% NaCl solution, is connected by tubing to
the heater/cooler 32. Also connected to the heater/cooler 32 are
proximal ends of a heat exchange fluid outflow line OL and a heat
exchange fluid inflow line IL.
[0036] At least one body temperature sensor TS is connected by way
of a temperature lead TL, or alternatively by wireless
connectivity, to the controller 36. This body temperature sensor TS
may be positioned at any suitable location on or in the patient's
body to monitor body temperature. In some embodiments, a plurality
of temperature sensors TS may be employed. In some embodiments the
temperature sensor TS may be positioned on or in the heat exchange
catheter 10b or may be inserted through a lumen of the heat
exchange catheter 10b as represented by dotted lines on FIG. 1. In
other examples, the temperature sensor TS may be positioned
elsewhere in or on the patient's body, such as on the patient's
skin (e.g., axillary temperature sensor) or in the patient's
vasculature, esophagus, rectum, bladder, ear canal or other
suitable location.
[0037] In some embodiments, a temperature sensor TS may be inserted
through a catheter and a second temperature sensor TS may be
positioned at any other suitable location on or in the subject's
body.
[0038] This embodiment of the endovascular heat exchange catheter
10b generally comprises a proximal catheter body 12 and an
endovascular heat exchange assembly 14 attached to and/or extending
distally from the proximal catheter body 12. In this particular
embodiment, the proximal catheter body 12 has three lumens, an
inflow lumen 15a, an outflow lumen 15b and an optional through
lumen 13.
[0039] A hub 16 is mounted on the proximal end PE of the proximal
catheter body 12. The hub 16 has an inflow connector 18 that is
connected to the inflow lumen 15a of the catheter body 12 and an
outflow connector 20 that is connected to the outflow lumen 15b of
the proximal catheter body 12. Though not shown in the drawings,
any catheter embodiment described herein may optionally include one
or more additional lumens and such additional lumens may or may not
be accessible by way of one or more additional connectors on the
hub 16. Such optional additional lumens may extend through the
entire length of the catheter or may terminate distally at an
opening at the distal end DE of the heat exchange assembly 14 or
may terminate at other opening(s) or ports(s) located at other
location(s) on the catheter. Depending on their size, construction
and opening/port location, any such optional lumen(s), when
present, may be useable for passage of a guidewire or other device
(e.g., temperature sensor, other type of sensor, etc.) and/or
infusion or delivery of a substance (e.g., a medicament, fluid,
radiographic contrast solution, etc.) or withdrawal of blood
samples.
[0040] As may be fully appreciated from FIGS. 2 through 3, the heat
exchange assembly 14 of catheter 10b comprises at least first and
second coiled heat exchange tubes 30a, 30b. In some embodiments,
additional (e.g., third, fourth) heat exchange tubes may be used.
The heat exchange tubes 30a, 30b may be formed of any suitable
material. In the particular example shown in FIGS. 1 through 3, the
heat exchange tubes may be advantageously formed of a noncompliant
polymeric material, such as polyethylene terephthalate (PET),
Pebax, Polyolefin, Polyurethane and/or Nylon, or other suitable
compliant or noncompliant material. In some embodiments the heat
exchange tubes 30a, 30b may expand and collapse depending on
whether or not they are filled with fluid and, in such embodiments,
the heat exchange tubes 30a, 30b may be referred to a "balloons."
For some applications, the heat exchange tubes 30a and 30b may have
outer diameters in the range of 2 mm-19 mm and wall thicknesses in
the range of 0.0127 mm-0.1 mm.
[0041] In one example, the distal end of the first tube 30a is
connected to the inflow lumen 15a at the distal end of the catheter
body 12, and the distal end of the second tube 30b is connected to
the inflow lumen 15a at the distal end of the catheter body 12. The
first and second heat exchange tubes 30a and 30b are disposed on
the catheter body 12 such that heat exchange fluid will flow in the
distal direction through the inflow lumen 15a, which extends to the
distal end of the catheter body 12, and then into the first and
second heat exchange tubes 30a and 30b (either directly or via a
recirculating tip), then in the proximal direction through the
first and second heat exchange tubes 30a and 30b and then into the
outflow lumen 15b of the catheter body 12.
[0042] In this non-limiting example, the recirculating distal tip
member 40 comprises a generally bullet-shaped or blunt-tipped
cylindrical structure which comprises a wall 42 which encloses an
inner cavity 44. The distal end of inflow lumen 14 is connected to
an inflow port 48 on the proximal portion of the recirculating tip
member 40. In some embodiments, the catheter device 10b may include
an optional through lumen that extends through the recirculating
distal tip member 40 but is fluidly sealed from the inner cavity 44
such that fluid circulating through the inner cavity 44 will not
leak into or enter the through lumen. One example of such a
modified recirculating distal tip member having a through lumen is
described in U.S. patent application Ser. No. 15/395,858 entitled
Fluid-Circulating Catheters Useable For Endovascular Heat Exchange
filed by Applicant on even date herewith, the entire disclosure of
such copending application being expressly incorporated herein.
Additionally incorporated herein by reference are the entire
disclosure of U.S. Pat. No. 9,492,633 (Dabrowiak) and the entire
disclosures of U.S. patent application Ser. No. 13/631,076 (US PG
Pub. 2013/0178923) and Ser. No. 13/631,324 (US PG Pub.
2013/0090708).
[0043] The distal ends of the heat exchange tubes 30a, 30b are
connected to outflow ports 46, 49 on the proximal portion of the
distal tip member 40. Warmed or cooled heat exchange fluid will
flow in the distal direction through inflow lumen 48 and into the
inner chamber 44 of the recirculating tip member 40. Such warmed or
cooled heat exchange fluid then exits though outflow ports 46, 49
and flows in the proximal direction through the coiled heat
exchange tubes 30a, 30b where heat exchange occurs between the
warmed or cooled heat exchange fluid and the patient's blood which
flows in heat exchange proximity to the heat exchange tubes 30a,
30b. Causing the blood flow to be non-laminar or self-mixing can
enhance the efficiency of the heat exchange. In this regard, the
shape, spacing and arrangement of the elongate loops in heat
exchange tubes 30a, 30b may be designed to increase blood
contacting surface area on the tubes 30a, 30b and to disrupt
laminarity of blood flow and improve the heat exchange, heating or
cooling efficiency of the catheter 10b. For example, in the
embodiment shown, the blood will flow not only around the heat
exchange assembly 14 but will also course through blood flow
channels 34 within the elongate loops of heat exchange tubes 30a,
30b, thereby enhancing the efficiency of heat exchange. However, at
least in applications wherein the patient has not received
anticoagulant medication, it may also be desirable for the shape,
spacing and arrangement of the elongate loops in heat exchange
tubes 30a, 30b to be designed so as to avoid creating so much
turbulence or disruption of laminarity in the blood flow as to
result in unwanted thrombogenesis.
[0044] After the heat exchange fluid has flowed in the proximal
direction through the coiled heat exchange tubes 30a, 30b it will
enter outflow lumen, 15b. Outflow lumen, 15b will extend within the
proximal portion of the catheter body 12 or within the hub 16 such
that all of the outflowing heat exchange fluid will pass through
the outflow connector 20 and through outflow line OL back to the
heater/cooler 32. It is to be appreciated that the inflow/outflow
lumens 15a, 15b, the inflow/outflow connectors 18, 20 and the
inflow/outflow lines IL, OL may be specifically sized to
accommodate the volume and flow rate of fluid being channeled
therethrough.
[0045] In operation of the system 10, the catheter 10b is inserted
into the patient's vasculature such that the heat exchange assembly
14 is positioned within a blood vessel without fully blocking blood
flow through that vessel. In the example of FIG. 1, the catheter is
inserted through a femoral vein FV and advanced to a position where
the entire heat exchange assembly 14 is in the inferior vena cava
IVC. The temperature sensor(s) is/are positioned on or in the
patient's body and connected to the controller 36. A user inputs a
target body temperature to the controller 36 via the user interface
38. The controller then controls the pump 34 and/or heater/cooler
36 to circulate warmed or cooled heat exchange fluid through the
catheter 10b, thereby causing the sensed patient body temperature
to be adjusted to or maintained within a desired range of the input
target body temperature for a desired period of time. In this
manner the system 10 may be used to induce hypothermia, induce
hyperthermia or attain normothermia.
[0046] In another example of a catheter 10b, the proximal end of
the first tube 30a is connected to the inflow lumen 15a at the
proximal end of the catheter body 12, and the proximal end of the
second tube 30b is connected to the inflow lumen 15a at the
proximal end of the catheter body 12. The first and second heat
exchange tubes 30a and 30b are disposed on the catheter body 12
such that heat exchange fluid will flow in the distal direction
through the inflow lumen 15a, and in the distal direction into and
through the first and second heat exchange tubes 30a and 30b. The
distal ends of the first and second heat exchange tubes 30a and 30b
are coupled to the outflow lumen 15b at the distal end of the
catheter body. The fluid flows from the first and second heat
exchange tubes 30a and 30b into the outflow lumen 15b (either
directly or via a recirculating tip), and through the outflow lumen
15b in the proximal direction.
[0047] In another example of a catheter 10b, the proximal end of
the first tube 30a is connected to the inflow lumen 15a of the
proximal catheter body 12. The proximal end of the second tube 30b
is connected to the outflow lumen 15b of the catheter body 12. The
distal ends of the first and second tubes 30a, 30b are coupled to
each other by a connection piece or directly. These interconnected
first and second heat exchange tubes 30a and 30b are disposed on
the catheter body 12 such that heat exchange fluid will circulate
from the inflow lumen of the catheter body 12, in the distal
direction through the first heat exchange tube 30a, to the second
heat exchange tube 30b (either directly or via a recirculating
tip), then in the proximal direction through the second heat
exchange tube 30b and into the outflow lumen 15b of the catheter
body 12. In certain embodiments, the distal end of each heat
exchange tube 30a, 30b may be connected to an inner cavity 44 of a
recirculating tip member 40.
[0048] The system 10 may also be used with heat exchange catheters
that incorporate heat exchange assemblies 14 that differ from the
specific embodiment 14 used on the catheter 10b of FIGS. 1 through
3. For example, FIGS. 4 through 4C show another embodiment of a
heat exchange assembly 14a and FIGS. 5 through 5B show another
embodiment of a heat exchange assembly 14b.
[0049] The heat exchange assembly 14a seen in FIGS. 4 through 4C
comprises a low pressure/high surface area balloon having a central
passageway 60 with heat exchange protrusions 62 extending outwardly
from the central passageway 60. The protrusions 62 in FIG. 4 are
shown extending toward the distal end of the catheter, in the
typical direction of blood flow, however, in other embodiments the
protrusions may extend in other directions relative to the
catheter, e.g., perpendicular, or toward the proximal end of the
catheter. This balloon may comprise a flexible molded part formed
of an expandable material (e.g. Chloroprene, Latex, Silicone,
Polyurethane (PU), Styrene Butadiene Styrene (SBS), and Styrene
Isoprene Styrene (SIS), etc.) which allows a significant increase
in the balloon surface area when the balloon is filled with heat
exchange fluid. This will contribute to a higher heat transfer.
Once the fluid is injected through the catheter shaft into the
balloon, the finger-like protrusions on the balloon surface are
inflated and thus create very high surface area for the heat
transfer. The wall thickness of this balloon will also reduce as
the balloon inflates, thereby improving efficiency of heat
transfer. In some embodiments, the balloon may have a through lumen
68 that extends through the central shaft and useable for passage
of a guidewire GW or for other purposes such as passage of a
temperature sensor TS or other device, infusion of substances or
withdrawal of blood samples. In some embodiments warmed or cooled
heat exchange fluid may simply be circulated into an open inner
cavity and the protrusions 62 of the balloon, e.g., through an
inflow lumen 64, into the protrusions 62 and then into an outflow
lumen 66. Optionally, the inflow lumen 62 and the outflow lumen 66
may be arranged concentrically, with the inflow lumen surrounding
the outflow lumen or vice versa. In other embodiments, as seen in
the sectional diagram of FIG. 4B, the inner cavity of the balloon
may be portioned by walls 70 to define continuations of the inflow
and outflow lumens 64, 66 thereby causing heat exchange fluid to
circulate in specific flow paths or patterns within the balloon.
Also, although the diagram of FIG. 4 shows only two rows of heat
exchange protuberances 62 extending from opposite sides of the
central passage 60, it is to be appreciated that such heat exchange
protuberances 62 may be formed fully or partially around the
circumference of the central passageway 60. For example, FIG. 4C
shows a variant of this heat exchange assembly 14a wherein the
balloon has heat exchange protuberances 62 which extend from
locations all the way around the central passageway 60.
[0050] FIGS. 5 through 5B show yet another embodiment of a heat
exchange assembly 14b which comprises a catheter body 70 having an
inflow lumen 74, an outflow lumen 76, an optional through lumen 78
through which a guidewire GW is shown to be inserted and arcuate
heat exchange tubes 72. The arcuate heat exchange tubes 72 may be
of the same size and material and the heat exchange tubes 30a, 30b
of the first embodiment described above. As shown, the arcuate heat
exchange tubes extend in arcuate loops outboard of or away from the
catheter body 70. The inflow and outflow lumens 74, 76 may be
arranged such that warmed or cooled heat exchange fluid flows
distally through the inflow lumen 74 to a location distal to the
heat exchange tubes 72 and then returns in the proximal direction
through the heat exchange tubes 72 and then into the outflow lumen
76. Alternatively, the inflow and outflow lumens 74, 76 may be
arranged such that warmed or cooled heat exchange fluid flows
distally through the inflow lumen, and then into and distally
through the heat exchange tubes 72 to a location distal to the heat
exchange tubes 72 and then returns in the proximal direction
through the outflow lumen 74. Although the diagram of FIG. 5 shows
only two rows of arcuate heat exchange tubes 72 extending from
opposite sides of the catheter body 70, it is to be appreciated
that such arcuate heat exchange tubes 72 may be arranged fully or
partially around the circumference of the central catheter body 70.
For example, FIG. 5B shows a variant of this heat exchange assembly
14b wherein arcuate heat exchange tubes 72 are provided all the way
around the central catheter body 70.
[0051] FIGS. 6 through 7B show a catheter device 80 having a distal
portion 82, a proximal hub 84, an elongate body 98, and tubular
members 100a, 100b positioned on the distal portion 82 of the
elongate body 98. In the non-limiting example shown, the elongate
body 98 comprises a braided tube having a lumen extending
longitudinally therethrough. A connector 88 is connected to the
proximal end of that tubular elongate body 98. The distal end of
the elongate body 98 opens through an aperture in the distal tip
member 94 of the catheter 80. Thus, the lumen of the elongate body
98 extends through the length of the catheter device 80 and may be
used as a guidewire lumen, infusion lumen, medicament delivery
lumen, temperature sensor lumen or as a utility lumen for various
other purposes understood by those of skill in the art.
[0052] Coiling members 102a, 102b are embedded in the walls of
tubular members 100a, 100b. The distal ends of the coiling members
102a, 102b are attached to the elongate body 98 and/or distal tip
member 94. Proximal portions of the coiling members 102a, 102b
extend through hub 84 and are windable onto and off of a spool
within coiling member advancement controller 96. Each coiling
member 102a, 102b is formed of superelastic (e.g., nickel-titanium
alloy, chromium cobalt) wire or any other suitable material or
polymeric material that is pre-set or biased to coiled
configuration. The present coiled configurations of the coiling
member(s) may be the same or different in size and/or shape. When
the spool of the coiling member advancement controller 96 is
rotated in a counterclockwise direction, the proximal portions of
the coiling members 102a, 102b wind onto the spool, thereby drawing
the coiling members 102a, 102b to taught non-coiled configurations
and causing the tubular members 100a, 100b to also assume
non-coiled configurations in which they may be folded, furled,
compressed, compacted, sleeved or otherwise disposed in a low
profile (e.g., reduced diameter) configuration as seen in FIGS. 6,
6A and 6B.
[0053] When the coiling member advancement controller 96 is rotated
in the clockwise direction, proximal portions of the coiling
members 102a, 102b will unwind from the spool and advance distally,
thereby causing the coiling members 102a, 102b to slacken and
assume their pre-set coiled configurations. This likewise causes
the tubular members 100a, 100b to assume coiled configurations
which correspond to the size(s) and shape(s) of the coils formed in
the coiling members 102a, 102b as seen in FIGS. 7, 7A and 7B. With
the tubular members 100a, 100b in such coiled configurations, heat
exchange fluid may be circulated through the tubular members 100a,
100b to exchange heat with the subject's flowing blood. In
alternative embodiments, the coiling member may be a
nickel-titanium alloy wire or other material having a shape memory
transition temperature of about 4-10 degrees C. or below 20 degrees
or above 35 degrees, which transitions from a non-coiled to coiled
configuration and vice versa. Transition from one configuration to
the desired second configuration may be accomplished by changing
the temperature of the coiling member to cause the coiling member
to transition from a first configuration to a second
configuration.
[0054] In the example shown, the distal tip 94 comprises a
recirculating distal tip member which may be of the type described
in U.S. patent application Ser. No. 15/395,858 entitled
Fluid-Circulating Catheters Useable For Endovascular Heat Exchange
filed on even date herewith, the entire disclosure of which is
expressly incorporated herein by reference. Tubular member 100a is
connected proximally to heat exchange fluid inflow connector 86 and
distally to the recirculating distal tip member 94. Tubular member
100b is connected proximally to heat exchange fluid outflow
connector 92 and distally to the recirculating distal tip member
94.
[0055] During typical operation, the catheter device 80 is inserted
into the subject's vasculature while its tubular members 100a, 100b
are in their collapsed, non-coiled configurations as shown in FIGS.
6, 6A and 6B. After the distal portion 82 has been advanced into
the desired blood vessel (e.g., the inferior vena cava), the
coiling member advancement controller 96 is rotated in the
clockwise direction, causing the coiling members 102a, 102b and
tubular members 100a, 100b to assume coiled configurations as seen
in FIGS. 7, 7A and 7B. With the tubular members 100a, 100b in such
coiled configurations, heat exchange fluid from inflow connector
86, through the first tubular member 100a in the distal direction,
through the recirculating distal tip member 94, through the second
tubular member 102b in the proximal direction and then out of
outflow connector 92. In other embodiments, the tubular members
100a and 100b may be arranged such that fluid flows in the distal
direction through both tubular members and flows in the proximal
direction through an outflow lumen, or fluid may flow in a distal
direction through an inflow lumen, and then in a proximal direction
through the tubular members.
[0056] In many cases, the time required to raise or lower a
patient's body temperature using an endovascular heat exchange
catheter is dependent to at least some degree on the
heat-exchanging efficiency of the heat exchange catheter. The
catheters, systems and methods described herein may provide
high-efficiency heat exchange and the ability to rapidly raise or
lower a patient's body temperature.
[0057] Although the example of FIGS. 6 through 7B shows two tubular
members 100a, 100b with two coiling members 102a, 102b, any
suitable number of such tubular members and coiling members may be
used and the relative number of tubular members 100a, 100b used for
distally directed inflow and proximally directed outflow may
vary.
[0058] It is to be appreciated that, although the invention has
been described hereabove with reference to certain examples or
embodiments of the invention, various additions, deletions,
alterations and modifications may be made to those described
examples and embodiments without departing from the intended spirit
and scope of the invention. For example, any elements, steps,
members, components, compositions, reactants, parts or portions of
one embodiment or example may be incorporated into or used with
another embodiment or example, unless otherwise specified or unless
doing so would render that embodiment or example unsuitable for its
intended use. Also, where the steps of a method or process have
been described or listed in a particular order, the order of such
steps may be changed unless otherwise specified or unless doing so
would render the method or process unsuitable for its intended
purpose. Additionally, the elements, steps, members, components,
compositions, reactants, parts or portions of any invention or
example described herein may optionally exist or be utilized in the
absence or substantial absence of any other element, step, member,
component, composition, reactant, part or portion unless otherwise
noted. All reasonable additions, deletions, modifications and
alterations are to be considered equivalents of the described
examples and embodiments and are to be included within the scope of
the following claims.
* * * * *