U.S. patent application number 10/205066 was filed with the patent office on 2003-02-27 for heat exchange catheter having a helically wrapped heat exchanger.
Invention is credited to Huezo, Xochitl, Pham, Nora Tran, Walker, Blair D..
Application Number | 20030040782 10/205066 |
Document ID | / |
Family ID | 25153590 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030040782 |
Kind Code |
A1 |
Walker, Blair D. ; et
al. |
February 27, 2003 |
Heat exchange catheter having a helically wrapped heat
exchanger
Abstract
A heat exchange catheter has a catheter body with an inflow
lumen, an outflow lumen, and an infusion lumen. A first heat
exchange balloon helically wraps around at least a portion of the
catheter body in fluid communication with the inflow lumen. A
second heat exchange balloon helically wraps around at least a
portion of the catheter body in fluid communication with the
outflow lumen. The first and second balloons form a gap there
between to facilitate infusion of fluid into the blood stream of
the patient via an infusion port formed within the gap.
Inventors: |
Walker, Blair D.; (Mission
Viejo, CA) ; Pham, Nora Tran; (Lake Forest, CA)
; Huezo, Xochitl; (Lake Forest, CA) |
Correspondence
Address: |
ATTN: SARAH KIRKPATRICK, I.P. RIGHTS
ALSIUS CORPORATION
15770 LAGUNA CANYON ROAD, SUITE 150
IRVINE
CA
92618
US
|
Family ID: |
25153590 |
Appl. No.: |
10/205066 |
Filed: |
July 25, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10205066 |
Jul 25, 2002 |
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09791391 |
Feb 22, 2001 |
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6451045 |
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Current U.S.
Class: |
607/105 ;
607/113 |
Current CPC
Class: |
A61F 7/12 20130101; A61F
7/123 20130101; A61F 2007/126 20130101 |
Class at
Publication: |
607/105 ;
607/113 |
International
Class: |
A61F 007/00; A61F
007/12 |
Claims
1. A heat exchange catheter comprising: a catheter body having a
core, an inflow lumen, an outflow lumen, a proximal region and a
distal region; a balloon helically wrapping around at least a
portion of the catheter body and being in fluid communication with
the core and at least one of the inflow lumen or the outflow lumen;
the core fluidly communicating with the other of the at least one
of the inflow lumen or the outflow lumen; the balloon and the core
forming a fluid circuit to facilitate circulation of a heat
exchange fluid through the balloon and the core to exchange heat
with a patient.
2. The heat exchange catheter of claim 1 wherein the balloon is in
fluid communication with the inflow lumen.
3. The heat exchange catheter of claim 1 wherein the balloon is in
fluid communication with the outflow lumen.
4. The heat exchange catheter of claim 1 further comprising at
least one infusion port on the catheter body for infusing a fluid
such as nutrients, medication or saline into the patient.
5. The heat exchange catheter of claim 1 wherein the distal portion
includes a distal tip comprising a port opening located on the
distal tip for infusing a fluid such as nutrients, medication or
saline into the patient or for accommodating a guidewire.
6. A method of circulating a heat exchange fluid within a heat
exchange catheter, comprising: circulating the heat exchange fluid
through the catheter to exchange heat with the blood stream of a
patient, the heat exchange fluid being circulated from a fluid
source external to the catheter; returning the heat exchange fluid
through the core of the catheter to the fluid source; and infusing
an infusion fluid into the blood stream of the patient via the
catheter.
7. The method of claim 6 wherein the heat exchange fluid through
the catheter is circulated along a helical path.
8. The method of claim 6 wherein the heat exchange fluid through
the catheter is circulated along the balloon.
9. A method of circulating a heat exchange fluid within a heat
exchange catheter, comprising: circulating the heat exchange fluid
through the core of the catheter to exchange heat with the blood
stream of a patient, the heat exchange fluid being circulated from
a fluid source external to the catheter; returning the heat
exchange fluid through the balloon of the catheter to the fluid
source; and infusing an infusion fluid into the blood stream of the
patient via the catheter.
10. The method of claim 9 wherein the heat exchange fluid is
circulated at least partially through along a helical path.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 09/791,391, filed Feb. 22, 2001, the
disclosures of which are incorporated herein by reference in their
entirety.
FILED OF THE INVENTION
[0002] This invention relates to heat exchange catheters, and
particularly to catheters that exchange heat with the blood stream
of a patient.
BACKGROUND
[0003] Heat exchange catheters are used in many instances for a
variety of reasons. Some surgeries, for example, are better
performed when the patient cools to a hypothermic state. In other
instances, a patient may suffer from accidental hypothermia and may
need to be warmed to a normothermic temperature e.g. 98.6 F. Some
heat exchange catheters include the capability of infusing fluids
such as nutrition, medicine and contrast agents into the blood.
[0004] Post surgical patients risk infection and fever. A fever can
be controlled through the use of a heat exchange system having an
intravascular heat exchange catheter. One such system is disclosed
in U.S. Pat. No. 6,146,411. This US Patent is incorporated herein
by reference and teaches an exemplary system used to achieve
patient normothermia.
[0005] The principals of heat exchange applicable to any flowing
medium (including blood) dictates the amount of heat transfer. In
blood, the heat transferred depends on many things including the
volumetric flow rate of the blood, the geometry of the heat
exchanger and the temperature difference between the heat exchanger
and the blood.
[0006] Various heat exchange catheter designs have been developed.
U.S. Pat. No. 6,126,684, for example, teaches a heat exchange
catheter having tubular balloons in serial alignment to exchange
heat with the blood stream of a patient. This U.S. Patent is
incorporated herein by reference. The balloons allow for a
relatively large surface area of contact for heat exchange.
Infusion lumen exit ports are defined between the balloons.
Unfortunately, these exit port regions limit the effective heat
exchange surface area.
[0007] Heat exchange catheter balloons can be sized having an
external volume that optimally exchanges heat with the flowing
blood. The balloon internal volume, however, is large enough to
inhibit optimal mixing of the heat exchange fluid. Boundary layers
of heat exchange fluid can form in the interior of such balloons,
lowering the temperature gradient between the heat exchange fluid
at the balloon internal surface and ultimately reducing the
effective rate of heat transfer between the heat transfer fluid and
the flowing blood.
[0008] Heat exchange catheters have been developed that deliver the
heat exchange fluid to the distal end of the catheter via an
insulated delivery lumen, causing the heat exchange fluid to
maintain a relatively uniform temperature until the heat exchange
fluid returns via a return lumen to exchange heat with the flowing
blood. This improves the temperature gradient between the heat
exchange fluid within the interior balloon walls and the flowing
blood, unfortunately, the residence time that the heat exchange
fluid interacts with the flowing blood is limited.
[0009] Blood has a maximum desirable heating limit because above
certain temperatures blood proteins can degenerate and coagulation
may occurr. This limits the maximum operating temperature of known
intravasculature catheters. Because the operating temperature of an
intravascular catheter is limited, the catheter geometry takes on
an increased importance to effectuate overall heat transfer.
[0010] What is desired is a heat exchange catheter having a
geometry that is optimally designed for transferring heat to
flowing blood.
SUMMARY
[0011] A heat exchange catheter includes a catheter body having an
inflow lumen, an outflow lumen, a proximal region and a distal
region. A first balloon helically wraps around at least a portion
of the catheter body and maintains fluid communication with the
inflow lumen. A second balloon helically wraps around at least a
portion of the catheter body and maintains in fluid communication
with the outflow lumen. The first and second balloons forming a
fluid circuit to facilitate circulation of a heat exchange fluid
through the first balloon and the second balloon.
[0012] Optimally, the first and second balloons are inflatable from
a flattened configuration where the balloons lie flush with the
catheter body to an operational configuration where the heat
exchange fluid inflates the balloons. The flattened configuration
facilitates insertion of the catheter into the body of a patient.
Preferably, the catheter inserts into the central vasculature.
[0013] The catheter body defines a core extending between the
proximal region and the distal region. The inflow lumen and the
outflow lumen being defined within the core in the proximal region.
The balloons further define the inflow and outflow lumens in the
distal region. The core also defines a guidewire lumen.
[0014] The first balloon and second balloon wrap around the distal
region. According to one aspect of the invention, the balloons
define a gap there between. According to an alternate aspect of the
invention, the balloons tightly wrap and forms a gap only to expose
an exit port. Both of these aspects of the invention include the
catheter body defining at least one infusion lumen having an exit
port located in the gap.
[0015] According to one aspect of the invention, the first balloon
and second balloon wrap tightly around the distal region of the
core without a gap between the first and second balloon.
[0016] According to another aspect of the invention, a sheath
surrounds the first and second balloons to inhibit coagulate
formation. The sheath is distanced from the first and second
balloons according to a variation of the invention. The sheath
contacts the first and second balloons according to an alternate
variation of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows a heat exchange catheter in accordance with the
present invention.
[0018] FIG. 2A shows a cross-section of the catheter as seen along
line A-A of FIG. 1
[0019] FIG. 2B shows a cross-section of the catheter as seen along
line B-B of FIG. 1.
[0020] FIG. 2C shows a cross-section of the catheter as seen along
line C-C of FIG. 1.
[0021] FIG. 3 shows a partial longitudinal-section of the distal
region per FIG. 1.
[0022] FIG. 4 shows an embodiment of the distal region in
accordance with the invention.
[0023] FIG. 5 shows an embodiment of the distal region in
accordance with the invention.
[0024] FIG. 6 shows an embodiment of the distal region in
accordance with the invention.
DETAILED DESCRIPTION
[0025] FIG. 1 shows a heat exchange catheter, generally designated
with the reference numeral 10. The catheter 10 includes a catheter
body 12 having an inflow lumen 14, an outflow lumen 16, a proximal
region 18, a distal region 20, and a distal tip 22. The catheter 10
also includes a first balloon 24 helically wrapping around the
distal region 20 of the catheter body 12 and being in fluid
communication with the inflow lumen 14. The catheter 10 further
includes a second balloon 26 helically wrapping around the distal
region 20 of the catheter body 12 and being in fluid communication
with the outflow lumen 16. The first balloon 24 and the second
balloon 26 connect in fluid communication in the tip 22 of the
catheter body 12 to form a fluid circuit.
[0026] The catheter 10 includes an infusion lumen 30 and an
infusion lumen 32, which terminate at infusion port 34 and infusion
port 36, respectively. The first balloon 24 and the second balloon
26 wrap in a helical pattern to form a helical gap there between.
Infusion port 34 and infusion port 36 are located in the helical
gap. The infusion lumens 30 and 32 facilitate infusion of fluids
such as nutrients, medicines, contrast agents and the like through
the infusion ports 34 and 36. According to one aspect of the
invention, the catheter 10 defines a centrally located guidewire
lumen that also functions to facilitate infusion of fluids.
[0027] A heat exchange fluid is pumped via the inflow lumen 14 into
the first balloon 24. The heat exchange fluid reaches the tip 22 of
the catheter body 12. From the tip 22, the heat exchange fluid
returns via the second balloon 26 and the outflow lumen 16.
[0028] The temperature, pressure, and flow rate of the heat
exchange fluid is regulated externally. It can be appreciated,
however, that the catheter 10 can be equipped with sensors and
supplemental heating/cooling elements to further monitor and
regulate the temperature, pressure and flow rate of the heat
exchange fluid. Optimally, the catheter 10 is designed for
intravascular use. It is conceivable, however, that the catheter 10
can be used in various internal regions of the body.
[0029] The catheter body 12 defines a core 27 extending between the
proximal region 18 and the distal region 20. The inflow lumen 14
and the outflow lumen 16 are defined within the core, in the
proximal region 18.
[0030] FIG. 2A shows a cross-section of the proximal region 18 of
the catheter body 12. The proximal region 18 defines a guidewire
lumen 28, two infusion lumens 30 and 32. The inflow lumen 14 and
the outflow lumen 16 are defined within the catheter body 12.
[0031] FIG. 2B shows a cross-section of the distal region 20 of the
catheter body 12. The balloons 24 and 26 are inflatable from a
flattened configuration where the balloons lie flush with the
catheter body to an operational configuration. As shown, the
balloons 24 and 26 are filled with heat exchange fluid 38, which
inflates the balloons 24 and 26 during operation of the heat
exchange catheter 10.
[0032] FIG. 2C shows a cross-section of the distal tip 22 of the
catheter body 12. The distal tip 22 includes the guidewire lumen 28
and a transition region 40. The transition region 40 joins the
inflow lumen and the outflow lumen in fluid communication.
[0033] FIG. 3 shows a portion of the distal region 20. The balloon
24 carries the heat exchange fluid in the direction of the arrow
42, towards the distal tip 22. The balloon 26 carries heat exchange
fluid in the direction of the arrow 44, away from the distal tip
22. The balloon 24 and the balloon 26 define a gap 46 there
between. The gap 46 extends along a helical path between the
balloons 24 and 26. The infusion ports 34 and 36 are formed on the
distal region 20, within the gap 46.
[0034] The gap 46 distances the balloons 24 and 26 to maximize the
surface area of the balloons 24 and 26 for heat transfer. Typically
blood from a patient's blood stream would flow by the balloons 24
and 26 to heat or cool the patient's body. The gap 46 also enables
positioning of the infusion ports 34 and 36 at any desired location
along the proximal region 20. According to one aspect of the
invention, the guidewire lumen 28 functions to infuse fluids
through the distal tip 22.
[0035] FIG. 4 shows a sheath 50 surrounding the balloon 24. The
sheath 50 prevents coagulum from forming within the gap 46. The
sheath 50 is distanced from the balloon 24 in a radial direction
from the distal region 20 according to one aspect of the invention.
According to an alternate aspect of the invention, the sheath 50
contacts the balloon 24. According to a further aspect of the
invention, an infusion port or ports can be formed within the gap
46.
[0036] FIG. 5 shows a single balloon 26 on the distal region 20.
The balloon 26 has ends 60 and 62 and is helically wrapped to form
a gap 46 between successive coils. The gap 46 extends along a
helical path between the ends 60 and 62. Infusion ports 34 and 36
are positioned near each end 60 and 62 of the balloon 26, and
within the gap 46.
[0037] FIG. 6 shows a single balloon 36 on the distal region 20.
The balloon 36 wraps tightly around the distal region 20,
maintaining contact with itself without forming a helical gap. It
can be appreciated that when an infusion port formed on the
catheter 10 requires exposure, the balloon 36 is conformed with a
small gap to expose the infusion port.
IN OPERATION
[0038] A method of circulating fluid within a heat exchange
catheter includes inserting the heat exchange catheter into the
central vasculature of a patient. The proximal portion of the
catheter is secured to the patient to prevent catheter
movement.
[0039] The next step includes circulating a heat exchange fluid
through the inflow lumen of a heat exchange catheter. The heat
exchange fluid circulates along a helical path to exchange heat
with the blood stream of a patient. One benefit of circulating the
heat exchange fluid along a helical path is that the residence time
that the heat exchange fluid transfers heat is increased compared
with tubular heat exchanger systems. Another benefit circulating
the heat exchange fluid along a helical path is that the helical
path causes fluid mixing within the catheter. This mixing causes
vortices, which disrupts the heat exchange fluid at the boundary
layer located at the wall of the inflow and out flow lumens.
Further, the helical shape causes blood to flow, turbulently under
some conditions, past the heat exchange catheter to improve heat
transfer between the heat exchange catheter and the blood.
[0040] To add medicine, nutrition, contrast agents and the like,
the step of infusing fluid into the blood stream via the heat
exchange catheter is performed.
[0041] According to one aspect of the invention, the heat exchange
occurs through dual helical balloons. One helical balloon
circulates fluid from the inflow lumen, the other circulates fluid
through the outflow lumen along a helical path. The heat exchange
fluid inflates both balloons from a flattened configuration to an
operational configuration. Preferably, the operational
configuration includes inflating the balloons to a round or an oval
cross-sectional configuration.
[0042] It can be appreciated that the core of the catheter can
inflow heat exchange fluid to the distally mounted heat exchange
balloon(s). Alternatively, the balloon(s) can inflow the heat
exchange fluid and the core can outflow the heat exchange fluid.
Optimally, however, the present invention includes two helical
balloons, one inflows heat exchange fluid and the other outflows
the heat exchange fluid. Many variations of this concept are
possible. Accordingly, the present invention should be limited only
by the following claims.
* * * * *