U.S. patent application number 09/791391 was filed with the patent office on 2002-08-22 for heat exchange catheter having a helically wrapped heat exchanger.
Invention is credited to Huezo, Xochitl, Pham, Nora, Walker, Blair.
Application Number | 20020116039 09/791391 |
Document ID | / |
Family ID | 25153590 |
Filed Date | 2002-08-22 |
United States Patent
Application |
20020116039 |
Kind Code |
A1 |
Walker, Blair ; et
al. |
August 22, 2002 |
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; (Mission
Viejo, CA) ; Pham, Nora; (Lake Forest, CA) ;
Huezo, Xochitl; (Rancho Santa Margarita, CA) |
Correspondence
Address: |
ARLYN L. ALONZO, ESQ.
15770 LAGUNA CANYON ROAD
SUITE 150
IRVINE
CA
92618
US
|
Family ID: |
25153590 |
Appl. No.: |
09/791391 |
Filed: |
February 22, 2001 |
Current U.S.
Class: |
607/105 ;
607/113 |
Current CPC
Class: |
A61F 2007/126 20130101;
A61F 7/123 20130101; A61F 7/12 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 an
inflow lumen, an outflow lumen, a proximal region and a distal
region; a first balloon helically wrapping around at least a
portion of the catheter body and being in fluid communication with
the inflow lumen; a second balloon helically wrapping around at
least a portion of the catheter body and being in fluid
communication with the outflow lumen; and 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.
2. A heat exchange catheter as set forth in claim 1, wherein the
first balloon and second balloon wrap around the distal region, the
first balloon and the second balloon define a gap, and the catheter
body defines at least one infusion lumen having an exit port
located in the gap between the balloons.
3. A heat exchange catheter as set forth in claim 1, wherein 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.
4. A heat exchange catheter as set forth in claim 2, wherein the
proximal region defines a portion of the inflow lumen and the
outflow lumen.
5. A heat exchange catheter as set forth in claim 1, wherein the
catheter body defines a guidewire lumen.
6. A heat exchange catheter as set forth in claim 1, wherein the
inflow lumen and the outflow lumen are defined within the proximal
region, the first balloon and second balloon wrap tightly around
the distal region.
7. A heat exchange catheter as set forth in claim 1, further
comprising a sheath surrounding the first and second balloons.
8. A heat exchange catheter as set forth in claim 7, wherein the
sheath is distanced from the first and second balloons.
9. A heat exchange catheter as set forth in claim 7, wherein the
sheath contacts the first and second balloons.
10. A heat exchange catheter as set forth in claim 1, wherein the
catheter body includes a transition region that interconnects the
inflow lumen and the outflow lumen in fluid communication.
11. A heat exchange catheter as set forth in claim 1, wherein the
catheter body includes a distal tip with a transition region that
interconnects the inflow lumen and the outflow lumen in fluid
communication.
12. A heat exchange catheter, comprising: a catheter's body having
an inflow lumen, an outflow lumen, a proximal end and a distal end;
a first balloon helically wrapping around at least a portion of the
catheter body and being in fluid communication with the inflow
lumen; a second balloon helically wrapping around at least a
portion of the catheter body and being in fluid communication with
the outflow lumen; the first and second balloons forming a fluid
circuit to facilitate circulation of heat exchange fluid through
the first and second balloons; and a sheath surrounding the first
and second balloons.
13. A heat exchange catheter as set forth in claim 12, wherein the
distal end includes a transition region that connects the inflow
lumen and the outflow lumen in fluid communication.
14. A heat exchange catheter as set forth in claim 12, wherein the
catheter body defines an infusion lumen.
15. A heat exchange catheter as set forth in claim 14, wherein the
first and second balloons define a gap, an infusion port in
communication with the infusion lumen is formed within the gap.
16. A method of circulating fluid within a heat exchange catheter,
comprising: circulating heat exchange fluid through a heat exchange
catheter along a helical path to exchange heat with the blood
stream of a patient; and infusing fluid into the blood stream via
the heat exchange catheter.
17. A method of circulating fluid within a heat exchange catheter
as set forth in claim 16, further comprising circulating the heat
exchange fluid through an inflow lumen along a helical path and
through an outflow lumen along a helical path.
18. A method of circulating fluid within a heat exchange catheter
as set forth in claim 17, further comprising inflating a first and
second heat exchange balloon with the heat exchange fluid.
19. A method of circulating fluid within a heat exchange catheter
as set forth in claim 18, wherein the first and second balloons
form helical a gap there between.
20. A method of circulating fluid within a heat exchange catheter
as set forth in claim 19, wherein the infusing fluid is
accomplished by infusing fluid through an infusion port defined
within the gap.
21. A heat exchange catheter, comprising: a catheter body having an
inflow lumen, an outflow lumen, a proximal region and a distal
region; a first heat exchange means helically wrapping around at
least a portion of the catheter body and being in fluid
communication with the inflow lumen; a second heat exchange means
helically wrapping around at least a portion of the catheter body
and being in fluid communication with the outflow lumen; and the
first heat exchange means and second heat exchange means forming a
fluid circuit to facilitate circulation of a heat exchange fluid
through the first heat exchange means and the second heat exchange
means.
22. A heat exchange catheter as set forth in claim 21, wherein the
first heat exchange means and second heat exchange means wrap
around the distal region, the first heat exchange means and the
second heat exchange means define a gap, and the catheter body
defines at least one infusion lumen having an exit port located in
the gap between the heat exchange means.
23. A heat exchange catheter as set forth in claim 21, wherein the
first heat exchange means and the second heat exchange means are
inflatable from a flattened configuration to an operational
configuration.
24. A heat exchange catheter as set forth in claim 22, wherein the
proximal region defines a portion of the inflow lumen and the
outflow lumen.
25. A heat exchange catheter as set forth in claim 21, wherein the
catheter body defines a guidewire lumen.
26. A heat exchange catheter as set forth in claim 1, wherein the
inflow lumen and the outflow lumen are defined within the proximal
region, the first heat exchange means and second heat exchange
means wrap tightly around the distal region.
27. A heat exchange catheter as set forth in claim 21, further
comprising a sheath surrounding the first heat exchange means and
the second heat exchange means.
28. A heat exchange catheter as set forth in claim 27, wherein the
sheath is distanced from the first heat exchange means and the
second heat exchange means.
Description
FIELD OF THE INVENTION
[0001] This invention relates to heat exchange catheters, and
particularly to catheters that exchange heat with the blood stream
of a patient.
BACKGROUND
[0002] 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.degree.
F. Some heat exchange catheters include the capability of infusing
fluids such as nutrition, medicine and contrast agents into the
blood.
[0003] 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 U.S. Patent is incorporated herein
by reference and teaches an exemplary system used to achieve
patient normothermia.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] What is desired is a heat exchange catheter having a
geometry that is optimally designed for transferring heat to
flowing blood.
SUMMARY
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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
[0016] FIG. 1 shows a heat exchange catheter in accordance with the
present invention.
[0017] FIG. 2A shows a cross-section of the catheter as seen along
line A-A of FIG. 1
[0018] FIG. 2B shows a cross-section of the catheter as seen along
line B-B of FIG. 1.
[0019] FIG. 2C shows a cross-section of the catheter as seen along
line C-C of FIG. 1.
[0020] FIG. 3 shows a partial longitudinal-section of the distal
region per FIG. 1.
[0021] FIG. 4 shows an embodiment of the distal region in
accordance with the invention.
[0022] FIG. 5 shows an embodiment of the distal region in
accordance with the invention.
[0023] FIG. 6 shows an embodiment of the distal region in
accordance with the invention.
DETAILED DESCRIPTION
[0024] 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.
[0025] 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.
[0026] 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. 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
* * * * *