U.S. patent application number 13/025894 was filed with the patent office on 2011-06-09 for temperature management system and method for burn patients.
This patent application is currently assigned to ZOLL CIRCULATION, INC.. Invention is credited to SUZANNE WINTER.
Application Number | 20110137248 13/025894 |
Document ID | / |
Family ID | 39417813 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110137248 |
Kind Code |
A1 |
WINTER; SUZANNE |
June 9, 2011 |
TEMPERATURE MANAGEMENT SYSTEM AND METHOD FOR BURN PATIENTS
Abstract
Intravascular closed loop heat exchange catheters are used to
manage temperature in burn patients.
Inventors: |
WINTER; SUZANNE; (Grass
Valley, CA) |
Assignee: |
ZOLL CIRCULATION, INC.
|
Family ID: |
39417813 |
Appl. No.: |
13/025894 |
Filed: |
February 11, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11602738 |
Nov 21, 2006 |
7892270 |
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13025894 |
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Current U.S.
Class: |
604/113 ;
607/105; 607/113 |
Current CPC
Class: |
A61F 2007/126 20130101;
A61F 7/123 20130101; A61F 7/12 20130101 |
Class at
Publication: |
604/113 ;
607/113; 607/105 |
International
Class: |
A61F 7/12 20060101
A61F007/12 |
Claims
1. A method comprising: advancing a closed loop intravascular heat
exchange catheter into the vasculature of a burn patient; and
establishing a desired patient temperature using the catheter,
wherein the catheter includes plurral heat exchange elements
established by one or more hollow elongated segments that have
external surfaces which have turbulence-inducing exterior surfaces
that are shaped to alter the flow of blood flowing past the
elements.
2. The method of claim 1, wherein the catheter is used to warm the
patient during skin graft surgery.
3. The method of claim 2, wherein the catheter is used to establish
normothermia in the patient should the patient become febrile.
4,5. (canceled)
6. The method of claim 1, wherein the heat exchange elements are
metal.
7-14. (canceled)
15. A method for treating a burn patient while skin graft surgery
is being conducted on the patient, comprising: during surgery,
circulating working fluid through a catheter in the patient to
counter hypothermia in the patient; and controlling the temperature
of the working fluid.
16. The method of claim 15, wherein the catheter is used to
establish normothermia in the patient should the patient become
febrile.
17. The method of claim 15, wherein the catheter has plural heat
exchange elements.
18. The method of claim 17, wherein the heat exchange elements are
balloons or are metal.
19. The method of claim 15, comprising using the catheter to
undertake at least one central venous line function selected from
the group consisting of: infusing medicament into the bloodstream,
infusing saline into the bloodstream, and monitoring a patient
parameter.
20. The method of claim 19, wherein the act of countering
hypothermia is executed by circulating working fluid through the
catheter such that the working fluid does not enter the bloodstream
and exchanges heat therewith.
21. The catheter of claim 1, wherein the heat exchange elements are
made of gold.
22. The catheter of claim 1, wherein adjacent heat exchange
elements are separated by a flexible articulating joint.
23. The catheter of claim 1, wherein the heat exchange elements are
made of single piece of material.
24. The catheter of claim 1, wherein the heat exchange elements are
made of plastic.
25. The catheter of claim 1, wherein the heat exchange elements are
spiral.
26. The catheter of claim 1, wherein the heat exchange elements are
fluted.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to patient
temperature control systems.
BACKGROUND OF THE INVENTION
[0002] It has been discovered that the medical outcome for a
patient suffering from severe brain trauma or from ischemia caused
by stroke or heart attack or cardiac arrest is improved if the
patient is cooled below normal body temperature (37.degree. C.).
Furthermore, it is also accepted that for such patients, it is
important to prevent hyperthermia (fever) even if it is decided not
to induce hypothermia. Moreover, in certain applications such as
post-CABG surgery, it might be desirable to rewarm a hypothermic
patient.
[0003] As recognized by the present invention, the above-mentioned
advantages in regulating temperature can be realized by cooling or
heating the patient's entire body. Moreover, the present invention
understands that since many patients already are intubated with
central venous catheters for other clinically approved purposes
anyway such as drug delivery and blood monitoring, providing a
central venous catheter that can also cool or heat the blood
requires no additional surgical procedures for those patients. The
following U.S. patents, all of which are incorporated herein by
reference, disclose various intravascular
catheters/systems/methods: U.S. Pat. Nos. 6,749,625, 6,786,916,
6,581,403, 6,454,792, 6,436,130, 6,146,411, 6,109,783, 6,419,643,
6,416,533, 6,409,747, 6,405,080, 6,393,320, 6,368,304, 6,338,727,
6,299,599, 6,290,717, 6,287,326, 6,165,207, 6,149,670, 6,146,411,
6,126,684, 6,306,161, 6,264,679, 6,231,594, 6,149,676, 6,149,673,
6,110,168, 5,989,238, 5,879,329, 5,837,003, 6,383,210, 6,379,378,
6,364,899, 6,325,818, 6,312,452, 6,261,312, 6,254,626, 6,251,130,
6,251,129, 6,245,095, 6,238,428, 6,235,048, 6,231,595, 6,224,624,
6,149,677, 6,096,068, 6,610,083, 6,042,559, and U.S. patent
application Ser. No. 10/355,776.
[0004] As understood herein the control of body temperature for
burn patients is also important, e.g., it would be advantageous to
prevent fever in burn patients and/or to prevent eaccidental
therapeutic hypothermia in burn patients. For example, heat loss is
a common finding in burned victims Severe hypothermia during
operation of debridement of bum wound, especially when patients are
sedated and mechanically ventilated, is associated with increased
mortality and morbidity. Studies showed almost 100% mortality in
severely burned patients who presented with core temperature less
than 32.degree. C. The present invention recognizes that current
therapeutic approaches such as warm blanket are limited.
SUMMARY OF THE INVENTION
[0005] A method includes advancing a closed loop intravascular heat
exchange catheter into the vasculature of a burn patient, and
establishing a desired patient temperature using the catheter. The
catheter may be used to warm the patient during skin graft surgery,
as well as to establish normothermia in the patient should the
patient become febrile.
[0006] In non-limiting implementations the catheter has plural heat
exchange elements. In one-non-limiting embodiment the heat exchange
elements are balloons. In another embodiment the heat exchange
elements are metal. In yet another embodiment they are established
by plural heat exchange fluid return tubes communicating with a
central supply lumen at a distal end of the catheter for carrying
heat, exchange fluid. In this last embodiment each return, tube is
formed spirally around the supply lumen such that a body fluid
flowing past the return tube exchanges heat with the heat exchange
fluid flowing therein.
[0007] In another aspect, a system for treating a burn patient
includes a heater/chiller and an intravascular catheter configured
for receiving working fluid from the heater/chiller and returning
working fluid thereto in a closed loop. A substrate is provided
bearing instructions for using the catheter to establish a desired
patient temperature in the patient.
[0008] In yet another aspect, a method for treating a burn patient
includes conducting skin graft surgery on the patient, and during
surgery, countering hypothermia in the patient using a
catheter.
[0009] The details of the present invention, both as to its
structure and operation, can best be understood in reference to the
accompanying drawings, in which like reference numerals refer to
like parts, and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic diagram of a system according to
present principles;
[0011] FIG. 2 is a perspective view of a first non-limiting
catheter, schematically showing a medicament source and coolant
source in an exploded relationship with the catheter;
[0012] FIG. 3 is a perspective view of a second non-limiting
catheter;
[0013] FIG. 4 is a cross-section as seen along the line 4-4 in FIG.
3;
[0014] FIG. 5 is a side view of a portion of a third non-limiting
catheter; and
[0015] FIG. 6 is a cross-section of the, catheter shown in FIG.
5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] Referring initially to FIG. 1, a system, generally
designated 10, is shown for managing and otherwise controlling
whole body temperature of a burn patient 12. The system 10 may be
used to establish normothermia in the burn patient 12, i.e., to
prevent undesired hypothermia during, e.g., surgery or to prevent
hyperthermia in the patient, and/or the system 10 may be used to
therapeutically cool the patient 12 to a hypothermic state, e.g.,
moderate hypothermia around thirty four degrees Celsius. In some
implementations discussed below, the system 10 may also be used to
provide central venous access to the burn patient 12. In
non-limiting implementations the burn patient 12 may be treated
with the system upon a predetermined burn threshold, e.g., the body
temperature of the burn patient 12 may be managed using the system
10 in the event that the bum patient 12 has suffered third degree
burns over thirty percent or more of the patient's body, it being
understood that this percentage is not limiting on present
principles.
[0017] As shown,, the system 10 includes an intravascular closed
loop heat exchange catheter 14 that receives a heat exchange fluid
(also referred to herein as "coolant") from a heater/chiller 16,
with the fluid circulating in a closed loop. The fluid can be
saline or other fluid such as refrigerant. Either the fluid flow
rate and/or the temperature of the fluid is controlled by a
controller associated with the heater/chiller 16 based on a patient
temperature feedback signal to control the amount and if desired
the rate at which heat is added or subtracted from the patient. The
controller can be implemented by a software-executing processor or
by discrete logic circuits or other electronic circuitry device to
establish a desired patient temperature by appropriately
controlling the flow rate and/or heat exchanger in response to a
temperature signal derived from a sensor in the patient 12.
Non-limiting examples of heater/chillers that can be used are
disclosed in U.S. Pat. Nos. 7,101,388; 6,878,156; 6,786,916;
6,454,792; 6,454,792; 6,146,411; and 6,019,783, all of which are
incorporated herein by reference. Further examples of non-limiting
heater/chillers are shown in U.S. Pat. Nos. 6,581,403, 6,436,130,
and 6,109,783, incorporated herein by reference.
[0018] As also shown in FIG. 1, in some non-limiting
implementations at least two central venous (CV) components can be
in communication with the catheter 16 for undertaking central
venous functions in addition to controlling the temperature of the
patient. These functions include and are not limited to drug
infusion and blood extraction for blood monitoring, as well as
blood pressure monitoring. For instance, a blood monitor 18 can
communicate with the catheter 14 via a line 20 to monitor blood
pressure or withdraw blood from the central venous system of the
patient 12. Also, a syringe 22 can engage the catheter 14 via a
connector line 24 for infusing drugs or other medicament such as
epinephrine into the patient 12. The components 16, 18, 22 can all
be connected to the catheter 14 via a proximal connector hub 26 of
the catheter 14. The hub 26 can be formed with a suture anchor 28
or other anchor structure such as tape for providing a means to
fasten the catheter 14 to the skin of the patient 14 for long-term
use.
[0019] The catheter 14 may be any suitable closed loop
intravascular temperature control catheter including without
limitation in addition to the specific structures disclosed herein,
the catheters disclosed in the following U.S. patents, all
incorporated herein by reference: U.S. Pat. Nos. 5,486,208,
5,837,003, 6,110,168, 6,149,673, 6,149,676, 6,231,594, 6,264,679,
6,306,161, 6,235,048, 6,238,428, 6,245,095, 6,251,129, 6,251,130,
6,254,626, 6,261,312, 6,312,452, 6,325,818, 6,409,747, 6,368,304,
6,338,727, 6,299,599, 6,287,326, 6,126,684.
[0020] In any case, once the patient 12 has been diagnosed as
suffering skin burns sufficient to warrant management of the
temperature of the patient 12, the catheter 12 may be placed in the
venous system, e.g., in the superior or inferior vena cava without
blocking the vessel so that blood can flow around the catheter to
effect, heat exchange. In non-limiting embodiments the catheter 14
may be advanced (possibly through an introducer sheath) into the
vena cava of the patient 12 through a groin entry point 32 or
through a neck entry point 34 to the central venous system of the
patient 12. When advanced through the groin the catheter is
advanced either through the saphenous vein or femoral vein to the
inferior vena cava, and when advanced through the neck through the
jugular or subclavian vein to the superior vena cava or inferior
vena cava. Less desirably, the catheter 14 may be advanced into the
arterial system of the patient 12.
[0021] Once disposed in the bloodstream of the patient 12, a target
patient temperature is input to the heater/chiller 16. The target
temperature can be, e.g., normothermia (i.e., approximately thirty
eight degrees Celsius), in which case the heater/chiller 16
controls the temperature and/or flow rate of the coolant
circulating through the catheter 14 in response to a patient
temperature signal as appropriate to heat or cool the patient to
achieve and maintain target temperature. It is to be understood
that the patient temperature signal may be generated by a sensor on
the catheter 14 and sent to the heater/chiller 16. Or the sensor
may be on another device that can be electrically connected to the
heater/chiller 16 for sending a patient temperature signal thereto.
For example, the sensor may be on a Foley catheter, a rectal
temperature probe, an esophageal probe, a tympanic temperature
device, or other suitable patient temperature generating
device.
[0022] Or, target temperature may be below normothermia for the
purpose of therapeutically establishing mild or moderate (or even
deeper) hypothermia in the patient, in which case the
heater/chiller 16 removes heat from the coolant as necessary to
achieve and maintain hypothermia for a therapeutic amount of
time.
[0023] Now referring to FIG. 2 for a description of a first
non-limiting catheter 14, commencing at the proximal end the
heater/chiller 16 provides coolant such as saline through a coolant
supply line 36, and coolant is returned from the catheter 14 via a
coolant return line 38. The non-limiting catheter 14 includes a
source tube 40 terminating in a fitting such as a female luer
fitting 42. Also, the catheter 14 has a return tube 44 terminating
in a fitting such a male luer fitting 46. The fittings 42, 46 can
be selectively engaged with complementary fittings 48, 50 of the
lines 36, 38 to establish a closed circuit coolant path between the
catheter 14 and heater/chiller 16.
[0024] Additionally, the non-limiting catheter 14 shown in FIG. 2
may include the primary infusion tube 20 as mentioned above that
can also be used as a guidewire tube. The tube 20 terminates in a
fitting such as a female luer 52. A guide wire 54 or the syringe 22
shown in FIG. 1 can be advanced through the tube 20 in accordance
with central venous catheter placement principles, or the monitor
18 shown in FIG. 1 may be engaged with the tube 20.
[0025] Moreover, the connector line 24, which can establish a
secondary infusion tube, can end in a female luer fitting 56 that
can be selectively engaged with, e.g., the syringe 22 for infusing
fluid from the syringe or other source such as an IV bag into the
patient.
[0026] The tubes 20, 24, 40, 44 are held in the hub 26, which may
be distally tapered as shown. As set forth in U.S. Pat. No.
6,368,304, incorporated herein by reference, the hub 26 establishes
respective pathways for fluid communication between the tubes 20,
24, 40, 44 and respective lumens in the body 46 of the catheter 14.
The suture anchor 28 advantageously may be formed on the hub 26 for
suturing the catheter 14 to a patient in accordance with central
venous catheter operating principles.
[0027] The non-limiting the catheter body 46 may include at least
two lumens, and in a preferred embodiment the catheter body 46
includes at least four lumens and, more preferably has five lumens.
Two of the lumens are coolant supply and return lumens through
which coolant is circulated to and from one more distally-located,
axially-spaced thin-walled heat exchange membranes 66, 68 (two
shown) that are arranged along the last fifteen or so centimeters
of the catheter body 46 and are bonded to the outer surface of the
catheter body 46, with an infusion port 64 being located between
the heat exchange membranes 66, 68. Essentially, the heat exchange
membranes 66, 68 extend along most or all of that portion of the
catheter 46 that is intubated within the patient. The heat exchange
membranes can be established by a medical balloon material. When
coolant is circulated through them the heat exchange membranes may
define a diameter of about ten French, and preferably no more than
twelve French in non-limiting embodiments. Thus, the heat exchange
membranes 66, 68 are relatively long and comparatively thin, to
advantageously avoid excessively blocking blood flow through the
vena cava while nevertheless effecting patient cooling. If desired,
a temperature sensor 70 such as a thermistor or other suitable
device can be attached to the catheter 14 as shown by solvent
bonding at a point that is proximal to the membranes 66, 68. The
sensor 70 provides patient temperature feedback to the
heater/chiller 16 through a wire disposed in the catheter 14. Or,
the sensor 70 can be disposed in a lumen of the catheter 14, or
attached to a wire that is disposed in a lumen of the catheter 14,
with the sensor hanging outside the catheter 14. Alternatively, a
separate temperature probe can be used, such as an esophageal
probe, a rectal probe or tympanic temperature sensor.
[0028] FIGS. 3 and 4 show another non-limiting intravascular closed
loop heat exchange catheter that can be used, generally designated
114. As shown in FIG. 3, the catheter 114 can include plural heat
exchange elements 130. The heat exchange elements 130 can be
established by one or more metal, preferably gold, hollow elongated
segments that have external surfaces which have turbulence-inducing
irregular exterior surfaces that are shaped to induce gentle
turbulence in blood flowing past the elements. Separating adjacent
heat exchange elements 130 can be a flexible articulating joint
131, it being understood that the heat exchange elements 130 and
joints 131 can be formed from a single piece of material such as
plastic or metal, e.g., gold. The details of the heat exchange
elements 130 and their configuration are set forth in U.S. Pat.
Nos. 6,554,797 and 6,096,068, incorporated herein by reference. In
any case, coolant is circulated in a closed fluid communication
loop between the heat exchange elements 130 and heater/chiller 16
to remove heat from the patient 12 or to add heat to the patient to
rewarm the patient.
[0029] Now referring to FIG. 4, it can be seen that in non-limiting
implementations the catheter 114 if desired may establish a tubular
conduit that is disposed substantially coaxially within the heat
exchange. elements 130, with the conduit having a supply lumen 136
for supplying a pressurized working fluid (represented by arrows
138) to a distal end 140 of the catheter 114. As the fluid exits
the supply lumen 138, it flows out and around the supply lumen 138
in a proximal direction as shown in an annular return lumen 142. It
may readily be appreciated that heat is exchanged between the fluid
138 and bloodstream into which the catheter 114 is placed across
the walls of the heat exchange elements 130 to heat or cool the
patient as desired.
[0030] In addition to the supply and return lumens 136, 142, the
catheter 114 if desired may have at least two and possibly more
infusion or working lumens (only two shown for clarity) for
undertaking CV functions simultaneously with controlling patient
temperature. Specifically, as shown in FIG. 4, a first infusion or
working lumen 144 terminates in a first outlet port 146, and a
second infusion or working lumen 148 terminates in a second outlet
port 150. Both lumens 144, 148 are separated from the fluid 138 and
both lumens 144, 148 preferably extend to the hub 26 shown in FIG.
1. The second infusion or working lumen 148 can be coaxial with the
body of the catheter 114 as shown. The second port 150 can be
located on the distal tip of the catheter 114 as shovvn. In any
case, to provide for mixing of infused drugs in the bloodstream if
two drugs are to be administered, the ports 146, 150 are
longitudinally separated from each other as shown. With the above
in mind, the monitor 18 (FIG. 1) or other CV device such as an
infusion device can communicate with one of the infusion or working
lumens 144, 148 while the syringe 22 can communicate with the other
infusion or working lumen 148, 144.
[0031] As an alternative to the catheters 14, 114, a catheter 214
shown in FIGS. 5 and 6 and disclosed in U.S. Pat. Nos. 6,585,692
and 6,610,083, both of which are incorporated herein by reference,
may be used. The catheter 214 can include plural heat exchange
elements 230. The heat exchange elements 230 can be established by,
e.g., three coolant return tubes made of hollow plastic, with each
tube establishing a respective coolant return lumen. As shown best
in FIG. 6, a central coolant supply lumen 232 that is established
by a center tube 234 is also provided. It is to be understood that
the supply lumen 232 conveys coolant from the heater/chiller 16 in
a distal direction along the catheter 214, whereas the heat
exchange elements 230 (the coolant return tubes) convey coolant
back to the heater/chiller 216 in a proximal direction as indicated
by the arrows 236 in FIG. 5. With this structure, blood 238 in a
central venous system vein 240 into which the catheter 214 is
advanced is cooled (or heated) by exchanging heat with the coolant
across the walls of the heat exchange elements 230. Thus, coolant
is circulated in a closed fluid communication loop between the heat
exchange elements 230 and heater/chiller 16 to remove heat from the
patient or to add heat to the patient to rewarm the patient after
surgery or after the termination of therapeutic hypothermia
treatment.
[0032] The coolant return tubes are spirally formed around the
center tube 234, and can be adhered thereto or not. That is,
non-limiting heat exchange elements 230 define spirals. The length
"L" of the heat exchange region of the catheter 214 can be about
250 millimeters, with the pitch of the spiral heat exchange
elements 230 being about 64 millimeters. In any case, the coolant
supply lumen 232 terminates in a hollow distal tip, as do the
lumens of the heat exchange elements 230. Accordingly, coolant
passes from the supply tube to the return tubes at the distal
tip.
[0033] Additionally, as best shown in FIG. 6, the center tube 234
can establish one or more working lumens (only two shown in FIG. 6
for clarity of disclosure) for undertaking CV functions
simultaneously with controlling patient temperature. In the
embodiment shown, the center tube 234 establishes first and second
working lumens 244, 246 that have any suitable cross-sectional
shape and that can respectively communicate with the central venous
components 18, 22 discussed above. Both working lumens 244, 246 are
separated from the coolant and both working lumens preferably
extend to the hub 26 shown in FIG. 1. The working lumens 244, 246
can terminate in respective exit ports that may be longitudinally
spaced from, each other, e.g., one port can be at the distal tip of
the catheter 214 and the other port can be located somewhat
proximal to the tip.
[0034] Any of the catheters disclosed herein can be used to
maintain normothermia in the burn patient 12, typically by warming
the patient. For example, the catheters 14, 114, 214 can be used
during surgery to keep patient temperature above 36 C when
replacing necrotic skin with grafts. Without the present invention,
it is often the case that patient temperature drops so that only
one limb at a time may be repaired with grafts, but with the
present invention grafts on all limbs may be completed during the
same surgery.
[0035] Temperature management of the patient 12 may be maintained
after surgery using the system 10 for, e.g., thirty days, with a
catheter change every few days if desired, with the patient in the
burn unit and/or hospital ICU.
[0036] In one non-limiting treatment protocol, the patient is older
than 18 years and presents with a core temperature of under
37.degree. C. Target temperature can be set to 36.5.degree. C. and
warming rate to maximum. A core temperature monitor is established
by, e.g., placing an esophageal/Foley/rectal temperature probe in
the patient, with the monitor connected to the heater/chiller 16.
Warming is commenced as early as possible to prevent core
temperature drop. The catheter 14 can also be used as a multi-lumen
central venous catheter to deliver warm fluid such as saline,
medications, to withdraw blood or conduct other monitoring acts of
patient parameters. All of these steps can take place during and
after skin graft surgery. Subsequently, should the patient develop
fever, the catheters 14, 114, 214 can also be used to control
hyperthermia. A substrate 300 (FIG. 1) may be provided that bears
instructions for using the present catheter to establish a desired
patient temperature in the burn patient 12 in accordance with
principles set forth herein.
[0037] While the particular temperature management system and
method for burn patients is herein shown and described in detail,
it is to be understood that the subject matter which is encompassed
by the present invention is limited only by the claims.
* * * * *