U.S. patent application number 15/250479 was filed with the patent office on 2017-02-23 for catheter system with on-board temperature probe.
The applicant listed for this patent is ZOLL Circulation, Inc.. Invention is credited to Jeff P. Callister, Amy L. Hammack, Alex T. Roth, Paul M. Stull, William S. Tremulis.
Application Number | 20170049617 15/250479 |
Document ID | / |
Family ID | 25420740 |
Filed Date | 2017-02-23 |
United States Patent
Application |
20170049617 |
Kind Code |
A1 |
Hammack; Amy L. ; et
al. |
February 23, 2017 |
Catheter System with On-Board Temperature Probe
Abstract
A catheter system for controlling the body temperature of a
patient by modifying the temperature of blood flowing within a
blood vessel of the patient. The catheter system comprises a
catheter body having a heat exchange region in contact with the
blood; and a temperature probe having a distal end that extends
from the catheter body, thereby monitoring the temperature of blood
flowing within the blood vessel.
Inventors: |
Hammack; Amy L.;
(Sacramento, CA) ; Callister; Jeff P.; (Redwood
City, CA) ; Stull; Paul M.; (San Mateo, CA) ;
Roth; Alex T.; (Redwood City, CA) ; Tremulis; William
S.; (Redwood City, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZOLL Circulation, Inc. |
San Jose |
CA |
US |
|
|
Family ID: |
25420740 |
Appl. No.: |
15/250479 |
Filed: |
August 29, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11871931 |
Oct 12, 2007 |
9427353 |
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15250479 |
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10730861 |
Dec 9, 2003 |
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11871931 |
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09905389 |
Jul 13, 2001 |
6679906 |
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10730861 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/00084
20130101; A61B 2017/00867 20130101; A61F 2007/0054 20130101; A61F
2007/0096 20130101; A61F 2007/126 20130101; A61F 7/12 20130101;
A61B 2017/00088 20130101 |
International
Class: |
A61F 7/12 20060101
A61F007/12 |
Claims
1.-59. (canceled)
60. A heat exchange catheter system comprising: a heat exchange
catheter device comprising a catheter shaft and a temperature probe
lumen which extends between a proximal opening on the heat exchange
catheter device and a distal opening on the catheter device; and,
an elongate temperature probe having a proximal portion and a
distal end; the temperature probe being insertable into the
temperature probe lumen and, when so inserted, axially advanceable
from a non-deployed position in which the distal end resides within
the temperature probe lumen and the proximal portion extends out of
the proximal opening; to a deployed position in which some of the
proximal portion has been advanced through the proximal opening and
into the temperature probe lumen and the distal end has advanced
out of the distal opening to a position a spaced distance away from
the heat exchange catheter device.
61. A system according to claim 60 wherein said spaced distance is
a distance sufficient to allow the temperature probe to accurately
sense the body temperature of a subject in whom the heat exchange
catheter device has been inserted.
62. A system according to claim 60 wherein said spaced distance is
between 1.8 mm and 3.2 mm from the heat exchange catheter
device.
63. A system according to claim 62 wherein the temperature probe
further comprises indicia which indicates when the distal end of
the temperature probe has reached said spaced distance.
64. A system according to claim 63 wherein said indicia comprises
marking on the proximal portion of the temperature probe.
65. A system according to claim 64 wherein the heat exchange
catheter device has a proximal hub and wherein the proximal opening
comprises a port on the proximal hub.
66. A system according to claim 65 wherein distally advancing the
proximal portion of the temperature probe until the marking becomes
aligned with the port indicates that the distal end of the
temperature probe has reached said spaced distance.
67. A system according to claim 60 further comprising a locking
surface for locking the temperature probe in its current axial
position within the temperature probe lumen.
68. A system according to claim 67 wherein the locking surface is
useable to lock the temperature probe in position after its distal
end has been advanced to said spaced distance.
69. A system according to claim 60 wherein the heat exchange
catheter comprises a closed loop catheter through which a heat
exchange fluid is circulated.
70. A system according to claim 60 wherein the temperature probe
has at least one thermistor at or near its distal end.
71. A system according to claim 70 wherein said at least one
thermistor comprises first and second thermistors.
72. A system according to claim 1 wherein the temperature probe
comprises an elongate member having at least one temperature sensor
at or near the distal end and one or more wires for connecting said
at least one temperature sensor to an extracorporeal control
device.
73. A system according to claim 72 further comprising a control
device programmed to use signals received from said at least one
temperature sensor to control operation of the heat exchange
catheter.
74. A system according to claim 60 wherein at least a portion of
the temperature probe lumen is within the catheter shaft.
75. A system according to claim 60 wherein at least a portion of
the temperature probe lumen is external to the catheter shaft.
76. A system according to claim 60 wherein the temperature probe
lumen extends external of and along at least a portion of the
catheter shaft.
Description
RELATED APPLICATIONS
[0001] This is a continuation of copending U.S. patent application
Ser. No. 11/871,931 filed Oct. 12, 2007 and issuing on Aug. 30,
2016 as U.S. Pat. No. 9,______, which is a continuation of U.S.
patent application Ser. No. 10/730,861 filed on Dec. 9, 2003 U.S.
patent application Ser. No. 10/730,861 filed on Dec. 9, 2003, now
abandoned, which is a continuation of U.S. patent application Ser.
No. 09/9,605,389 filed on Jul. 13, 2001, now issued as U.S. Pat.
No. 6,679,906, the entire disclosure of each such patent and
application being expressly incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to medical devices
and a method of using them for selectively affecting the
temperature of a patient's body, or a portion of the patient's
body, and more particularly, to a temperature control catheter
system including an on-board temperature probe and a method of use
thereof.
[0004] 2. Description of the Prior Art
[0005] Under ordinary circumstances, the thermoregulatory system of
the human body maintains a near constant temperature of about
37.degree. C. (98.6.degree. F.), a temperature generally referred
to as normothermia. For various reasons, however, a person may
develop a body temperature that is below normothermia, a condition
known as hypothermia, or a temperature that is above normothermia,
a condition known as hyperthermia. Accidental hypothermia and
hyperthermia are generally harmful, and if severe, the patient is
generally treated to reverse the condition and return the patient
to normothermia. Accidental hypothermia significant enough to
require treatment may occur in patients exposed to overwhelming
cold stress in the environment or whose thermoregulatory ability
has been lessened due to injury, illness or anesthesia. For
example, this type of hypothermia sometimes occurs in patients
suffering from trauma or as a complication in patients undergoing
surgery.
[0006] However, in certain other situations hyperthermia and
particularly hypothermia may be desirable and may even be
intentionally induced. For example, hypothermia is generally
recognized as being neuroprotective, and may, therefore, be induced
in conjunction with cardiac surgery where there is an interruption
or decrease of cardiac output of oxygenated blood, treatments for
ischemic or hemorrhagic stroke, blood deprivation caused by cardiac
arrest, intracerebral or intracranial hemorrhage, head and spinal
trauma, brain or spinal surgery, or any other situation where there
danger to neural tissue because of ischemia, increased intracranial
pressure, edema or other similar processes.
[0007] Other examples where hypothermia may be neuroprotective
include periods of cardiac arrest in myocardial infarction and
heart surgery, neurosurgical procedures such as aneurysm repair
surgeries, endovascular aneurysm repair procedures, spinal
surgeries, procedures where the patient is at risk for brain,
cardiac or spinal ischemia such as beating heart by-pass surgery or
any surgery where the blood supply to the heart, brain or spinal
cord may be temporarily interrupted.
[0008] Hypothermia has also been found to protective of cardiac
muscle tissue when that muscle tissue is at risk, for example
during or after a myocardial infract (MI), or during cardiac
surgery, cardiac arrest, or other situations where there is
deprivation of the normal blood supply to the cardiac tissue.
Indeed the tissue protective nature of hypothermia in general is
recognized in a vast array of situations.
[0009] Simple surface methods for cooling such as cooling blankets,
immersion in cold water or ice baths, or alcohol rubs are generally
ineffective for inducing hypothermia. The body's normal
thermoregulatory responses such as vasoconstriction of capillary
beds at the surface of the body and arterio-venous shunting of
blood away from the skin act to render such cooling methods
ineffective. Further, if the body temperature drops sufficiently
below normothermia, usually at about 35.5.quadrature. C, the body
begins to shiver as a thermoregulatory response to generate
additional metabolic heat and fight the induction of hypothermia.
This may increase the generation of metabolic heat by 200-500% and
generally makes induction of hypothermia in an awake patient
impossible by surface cooling alone. Further, the shivering itself
is so uncomfortable and exhausting for the patient that this is
altogether unacceptable for an awake patient. Only if the patient
is paralyzed, which necessitates the patient be intubated for
breathing and be placed under general anesthesia can the patient be
subjected to significant surface cooling. Even under these
conditions, surface cooling which necessitates cooling through the
skin and surface fat layers and the use of generally low power
surface cooling devices, is too slow and inefficient to be an
acceptable means of inducing therapeutic hypothermia.
[0010] Furthermore, if control of the patient's temperature is
desired so as to attain and maintain a target temperature
(sometimes but not always normothermia), or to reverse hypothermia
and re-warm the patient at a predetermined rate, surface cooling
and warming far too slow and inefficient to give the required level
of prompt and precise change in the patient's core temperature to
allow these methods to control the patient's thermal condition.
[0011] A patient's temperature may be controlled by a very invasive
method of adding heat to or removing heat from a patient's blood,
particularly in the case of heart surgery. Blood is removed from a
patient, circulated through a heart-lung by-pass system, and
reintroduced into the patient's body. The equipment generally has a
temperature control unit that heats or cools the blood as it is
circulated out of the patient before it is reintroduced into the
patient. Because a large volume of blood is circulated through the
machine in a short time, this by-pass method may be both fast and
effective in changing the patient's core temperature and in
controlling that temperature, but has the disadvantages of
requiring a very invasive medical procedure which requires the use
of complex equipment, a team of highly skilled operators, is
generally only available in a surgical setting where the patient
has undergone a thoracotomy (had its chest split and opened), and
involves mechanical pumping of a huge quantity of the patient's
blood and channeling that blood through various external lines and
conduits, all of which is generally very destructive of the blood
tissue resulting in the cytotoxic and thrombolytic problems. In
fact, most surgeons using such by pass machinery tend to avoid its
use for longer than four hours, much less if at all possible, which
is an inadequate period of time for treatment of some conditions
such as stroke.
[0012] One method for adding or removing heat from a patient by
adding or removing heat from the patient's blood that does not
involve pumping the blood with an external, mechanical pump is by
placing a heat exchange catheter in the bloodstream of a patient
and exchanging heat through the catheter. This endovascular
temperature management (ETM) technique was described in U.S. Pat.
No. 5,486,208 to Ginsburg, the complete disclosure of which is
incorporated herein by reference. The Ginsburg patent discloses a
method of controlling the temperature of a body by adding or
removing heat to the blood by inserting a heat exchange catheter
having a heat exchange region into the vascular system and
exchanging heat between the heat exchange region and the blood to
affect the temperature of a patient. One method disclosed for doing
so includes inserting a catheter having a heat exchange region
comprising a balloon into the vasculature of a patient and
circulating warm or cold heat exchange fluid through the balloon
while the balloon is in contact with the blood.
[0013] In successful ETM, in addition to fast and precise changes
in a patient's body temperature, fast and precise control over a
patient's thermal condition is very important whether the patient
is being cooled, warmed, or maintained at a constant temperature. A
general apparatus and method of ETM control based on temperature
management responsive to feedback from temperature probes in or on
the patient is disclosed in U.S. Pat. No. 6,149,673 to Ginsburg,
the complete disclosure of which is incorporated herein by
reference. A similar method is described in PCT publication WO
01/10494 to Radiant Medical Inc., the complete disclosure of which
is also incorporated herein by reference. In such methods, a signal
representing the temperature of a target tissue, which as mentioned
may be the core body temperature, is directed to a controller from
a temperature probe inserted on or in the patient, and the
controller then controls the exchange of heat between the heat
exchange catheter and the patient's blood flowing past that
catheter. That in turn controls the temperature of the patient.
With such a method, it is clear that precise, accurate and
convenient control is dependent to a large extent on the precise,
accurate, and convenient temperature measurement of the temperature
of the target tissue (which may be the core body temperature) and
thus dependent on a precise, accurate and convenient temperature
probe.
[0014] Currently, the patient's temperature may be measured by any
one or several generally available temperature probes. These
include, for example, skin temperature probes, tympanic probes that
may be placed in the ear canal and perhaps even in physical contact
with the ear drum, esophageal probes including nasoesophageal
probes, rectal probes, bladder probes, temperature sensors placed
on an insertion sheath, and temperature probes that may be inserted
by needle directly into the target tissue. Each of these
techniques, however, suffers from significant shortcomings.
[0015] Some probes may not give an accurate temperature of the
target tissue and therefore may not provide the information
necessary for controlling the ETM procedure. For example, if the
target is the core temperature of the patient, a skin temperature
is generally not an accurate representation of the core
temperature; if cardiac muscle is the target tissue, a bladder
probe might not be sufficiently accurate. The probe might not be
sufficiently responsive to changes in temperature to provide a
current temperature of the target temperature. For example, a
rectal temperature probe is generally very slow to respond to
temperature changes in the core, and thus if the controller is
receiving its temperature signal from a rectal probe, it might not
be able to respond with sufficient speed and precision to changes
in the core temperature. Bladder temperature probes also tend to
suffer from this problem. Some probes are awkward and too difficult
to use. For example, tympanic probes are difficult to place and
tend to fall out and thus not provide an accurate temperature
measure. Where a temperature probe is controlling an ETM procedure
and thus in the patient at the same time as an ETM catheter, it may
reflect the temperature of the ETM catheter rather than the target
tissue if the probe is located too close to the catheter. Probes
placed on the insertion sheath, for example, may tend to be unduly
influenced by the heat exchange catheter placed through the sheath.
Other probes may measure the temperature of the target tissue, but
have other disadvantages that make their use undesirable. For
example, needle temperature probes that are stuck directly into the
target tissue, of course, measure the temperature of the target
tissue, but are invasive and require the patient suffer an
additional needle stick. They are also dependent on accurate
placement in the first instance which may be a difficult and highly
skilled procedure, and require that they do not move after
placement, requiring constant monitoring and taping or the like
which may be obtrusive and awkward.
[0016] If redundancy is important for safety, as it usually is in a
controlled ETM procedure, all of the above devices would generally
require the placement of two probes. This may require two probes
placed in different locations that may reflect different
temperature profiles, a very real problem for controlling ETM. It
may require that two probes be attached together, which makes the
probes large and often clumsy to use.
[0017] Very importantly, when used to control an ETM procedure, all
of the above require a device (the probe) in addition to the ETM
catheter already being inserted into the patient's body. These are
generally separately placed requiring an additional procedural
step, are often quite distal to the insertion site of the catheter
but must still be attached to the controller that is attached to
the ETM catheter. This may greatly complicate what may already be a
crowded operating room or other area and add undesirable complexity
to the procedure.
[0018] For ETM to accurately control the temperature of a target
tissue, it is important that the temperature measured by the probe
provides current and accurate measurement of the temperature of the
target tissue and responds quickly to changes in temperature of the
target temperature. This is not always the case with the probes
mentioned above. If the controller precisely and rapidly responds
to the temperature feedback to control the temperature of the
target tissue, for example if the patient's temperature is being
increased at a very precise rate of, for example, 0.2.quadrature. C
per hour, the controller must act to add heat when the temperature
is not increasing fast enough, remove heat if the body is adding
metabolic heat so fast that it would result in rewarming too fast,
or maintain the temperature of the heat exchange catheter the same
as the blood if the patient's temperature is increasing at exactly
the correct rate. The systems described in the publications
incorporated above may be capable of such precision, but rely on
temperature information from the temperature probes that is current
and accurate.
[0019] Temperature probes placed directly in the bloodstream in one
of the great vessels such as the inferior vena cava (IVC) generally
accurately reflect the core body temperature which is also
generally the temperature of the brain or heart tissue, currently
the two most common target tissues for ETM, but if the probe is
placed some distance from the heat exchange catheter such placement
usually involves an additional incision or puncture into the
vasculature, and if the probe is placed in the same general
vicinity as the heat exchange catheter, there is a likelihood that
the temperature reading will be unacceptably influenced by the heat
exchange region on the catheter or the temperature of the catheter
shaft and thus not represent the temperature of the target tissue
sufficiently to serve as a control temperature for the system.
[0020] Further, when the temperature probe is placed in the
vasculature in general, the distal tip of the probe which generally
houses the temperature sensor itself may come into contact with the
wall of the vessel. In such a case, the temperature that is sensed
will be that of the vessel wall and not of the blood. While these
two temperatures may often be the same, there will be occasions
where they may be unacceptably different. Furthermore, the distal
tip of such a probe must be designed so that it will not be
traumatic to the vessel wall. It would be best, of course, if
contact with the vessel wall could be avoided altogether.
[0021] When any device is inserted into a patient, the physician
generally would prefer to make as small an incision or puncture as
possible. Thus where a probe is inserted into the bloodstream, a
low profile is generally preferable. If the probe is attached or
otherwise associated with another device that is being inserted
into a patient, a means to keep the overall profile to the device
being inserted would be desirable.
[0022] Accordingly, it would be helpful to have a temperature probe
that was easy to place in conjunction with an ETM procedure.
[0023] It would also be helpful to have a temperature probe that
precisely and accurately measured a relevant tissue temperature for
ETM.
[0024] It would also be helpful to have a temperature probe that
rapidly responded to changes in temperature in a target tissue.
[0025] It would also be helpful to have a temperature probe that
did not create additional crowding in during treatment by ETM.
[0026] It would also be helpful to have a temperature probe that
did not require additional punctures or incisions in a patient
undergoing ETM.
[0027] It would also be helpful to have a temperature probe that
had a deployed and an undeployed configuration.
[0028] Accordingly, it would be helpful to have a temperature probe
located in the blood stream at a location close to the heat
exchange catheter to accurately measure the temperature of the
blood but not be unduly influenced by the temperature of the heat
exchange catheter.
[0029] It would be helpful to have a temperature probe that had a
plurality of temperature sensors for redundancy and safety.
[0030] It would be helpful to have a temperature probe that had an
atraumatic distal tip.
[0031] It would be helpful to have a temperature probe that could
be advantageously inserted into the vasculature of a patient
undergoing EMT without the need of a second incision or
puncture.
[0032] It would be helpful to have a temperature probe that was an
on board temperature probe.
[0033] It would be helpful to have a temperature probe that had a
deployed and an undeployed position, wherein the operator could
move the probe between the deployed and the undeployed
configuration.
[0034] Furthermore, it would be helpful to have a system and method
that ensure that the temperature reading provided at the heat
exchange catheter is accurate in order to ensure appropriate
operation of the heat exchange catheter.
SUMMARY OF THE INVENTION
[0035] The present invention provides a catheter that includes an
on-board temperature sensor.
[0036] In one aspect of the invention, the present invention
provides a catheter system for sensing the temperature of a
patient. The catheter system includes a catheter having a shaft, a
heat exchange region and a temperature probe lumen. The temperature
probe lumen defines an aperture that is located proximal of the
heat exchange region. A deployable temperature probe is provided
that includes a temperature sensor and a signal carrying mechanism
that extends from the sensor to a location outside of the patient.
The temperature probe has an undeployed configuration and a
deployed configuration and is movable between the undeployed and
deployed configurations. When the temperature probe is in the
deployed configuration, the temperature sensor is located further
from the shaft than when the temperature probe is in the undeployed
configuration. The temperature sensor generates a signal
representing a sensed temperature and the signal carrying mechanism
transmits the signal from the temperature sensor to the location
outside the patient.
[0037] In accordance with one aspect of the present invention, the
distal end of the movable temperature probe comprises a
thermistor.
[0038] In accordance with a further aspect of the present
invention, the distal end of the temperature control lumen includes
a ramp coupled to the opening.
[0039] In accordance with yet another aspect of the present
invention, the opening is in the form of a flat slot and a portion
of the temperature probe is flat.
[0040] In accordance with yet another aspect of the present
invention, the movable temperature probe includes an atraumatic tip
at the distal end portion.
[0041] In accordance with yet another aspect of the present
invention, the movable temperature probe comprises a shape memory
metal such as nickel-titanium alloy (nitonol) at a tip portion of
the distal end portion.
[0042] The present invention also provides a temperature probe that
includes two temperature sensors.
[0043] The present invention also provides a temperature probe
having a heat memory shaped distal portion containing a temperature
sensor wherein the distal portion of the probe assumes a shape when
warmed by blood flow that positions the temperature sensor away
from the catheter shaft;
[0044] The present invention also provides a catheter shaft having
channels for the flow of heat exchange fluid and a temperature
sensor that is positioned by the inflation of a balloon on the
catheter shaft at a location away from the heat exchange fluid
channels;
[0045] The present invention also provides a catheter system having
a temperature probe with a temperature sensor in its distal
portion, the temperature sensor is deployable to locate the
temperature sensor away from the catheter shaft;
[0046] The present invention also provides a catheter system with a
temperature sensor that has a first configuration having one
profile for insertion, and a second configuration that has a
greater profile wherein the temperature sensor is located farther
away from the catheter shaft in the second configuration than in
the first configuration;
[0047] The present invention also provides a method of monitoring
the body temperature of a patient by monitoring the temperature of
blood flowing within a blood vessel of the patient. The method
includes advancing a catheter body comprising a temperature control
lumen coupled to the catheter shaft wherein the temperature control
lumen includes an opening defined at a distal end of the catheter,
into the patient's blood vessel such that the opening is in contact
with the patient's blood. The method further includes moving a
temperature probe within the temperature control lumen such that a
distal end portion of the movable temperature probe protrudes
through the opening into the blood flowing within the blood
vessel.
[0048] The present invention thus provides catheters and methods
for inducing or treating hypothermia or hyperthermia by inserting a
catheter body into a blood vessel of the patient, moving a
temperature probe into the blood stream within the blood vessel and
selectively transferring heat either to or from the blood flowing
through the vessel while monitoring the temperature of the blood
stream. It enhances the ability to monitor the temperature of the
blood stream, thereby enhancing both the ability to induce or treat
hypothermia or hyperthermia and the ability to rapidly and
precisely control the body temperature of the patient.
[0049] Other features and advantages of the present invention will
be understood upon reading and understanding the detailed
description of preferred exemplary embodiments found herein below,
in conjunction with reference to the drawings, in which like
numerals represent like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1 is a perspective view of a catheter system in
accordance with the present invention;
[0051] FIG. 2A is a sectional view of the catheter illustrated in
FIG. 1 taken along the line 2A-2A;
[0052] FIG. 2B is a sectional view of the catheter illustrated in
FIG. 1 taken along the line 2B-2B;
[0053] FIG. 2C is a cross section of the balloon portion of the
catheter taken along the lines 2C-2C in FIG. 1;
[0054] FIG. 3A is a sectional view of the catheter illustrated in
FIG. 1 of the portion of the catheter of FIG. 1 contained in circle
3A-3A;
[0055] FIG. 3B is an elevation view of a distal end portion of a
temperature probe lumen in accordance with the present
invention;
[0056] FIG. 4 is an elevation view of a distal end portion of a
temperature probe lumen in accordance with an alternative
embodiment of the present invention; and
[0057] FIG. 5 is an elevation view of a distal end portion of a
temperature probe lumen in accordance with an alternative
embodiment of the present invention; and
[0058] FIG. 6 is an elevation view of a distal end portion of a
temperature probe lumen in accordance with an alternative
embodiment of the present invention.
[0059] FIG. 7 is an elevational view of the cable and connector of
the invention;
[0060] FIG. 8A is an elevational view of a distal end portion of a
catheter system of an alternative embodiment of the present
invention with the probe shown in a deployed state;
[0061] FIG. 8B is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in a collapsed
state;
[0062] FIG. 9A is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an undeployed
state;
[0063] FIG. 9B is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in a deployed state;
[0064] FIG. 10A is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an undeployed
state;
[0065] FIG. 10B is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in a deployed state;
[0066] FIG. 11A is an elevation view of a distal portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an undeployed
state;
[0067] FIG. 11B is an elevation view of a distal portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in a deployed state;
[0068] FIG. 12A is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an undeployed
state;
[0069] FIG. 12B is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in a deployed state;
[0070] FIG. 13A is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an undeployed
state;
[0071] FIG. 13B is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in a deployed state;
[0072] FIG. 14 is a cross section of the catheter system of the
invention taken along the line 14-14 in FIG. 13B;
[0073] FIG. 15A is an elevation view of a distal end portion of a
catheter system of the present invention;
[0074] FIG. 15B is an elevation view of a distal end portion of a
catheter system in accordance with an alternative embodiment of the
present invention;
[0075] FIG. 16A is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an unadvanced
state;
[0076] FIG. 16B is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an advanced
state;
[0077] FIG. 17A is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in an undeployed
state;
[0078] FIG. 17B is an elevation view of a distal end portion of a
temperature probe in accordance with an alternative embodiment of
the present invention with the probe shown in a deployed state;
[0079] FIG. 18A is an elevational view of the proximal end of a
catheter system of FIG. 17A where the with the distal end of the
probe is undeployed; and
[0080] FIG. 18B is an elevational view of the proximal end of a
catheter system of FIG. 17B with the distal end of the probe
deployed.
DESCRIPTION OF SPECIFIC EXEMPLARY EMBODIMENTS
[0081] Referring to FIG. 1, a heat exchange catheter system that
includes a catheter body 10 is illustrated. Catheter body 10 may
comprise any type of heat exchange catheter. Numerous suitable
examples of heat exchange catheter systems which may comprise the
present catheter body 10 are found in various US Patents. It is to
be understood that the present invention may be adapted for use
with a wide variety of different temperature regulating catheter
systems. For example, in accordance with the present invention, the
catheter system used may comprise a catheter system adapted for
warming the body fluid passing thereover (for example, a system
having an electric heater disposed therein, or a catheter with a
heat exchange region thereon which is warmed by circulating warm
heat exchange fluid therethrough). In addition, the catheter system
used may comprise a catheter system adapted for cooling the body
fluid passing thereover (for example, a catheter with a heat
exchange region such as a heat exchange balloon or the like
thereon, which heat exchange region is placed in the blood stream
and cooled by pumping a cooled fluid flow therethrough).
Furthermore, those skilled in the art will understand that even
non-heat exchange catheters may be used with the present invention
if a catheter having an on-board deployable temperature probe is
desirable.
[0082] In the embodiment of the invention illustrated in FIG. 1,
catheter body or shaft 10 includes a proximal end portion 11 in the
form of a Y adaptor, a heat exchange region 16 on the distal
portion of the catheter in the form of a helically wound
multi-lobed balloon, a temperature probe exit region 17 as
illustrated in FIG. 3A, and a distal end 19 having a soft,
atraumatic tip 25.
[0083] The heat exchange region 16 is heated or cooled by the flow
of a heat exchange liquid therethrough. Referring to FIG. 2A, the
shaft 10 has four lumens therein proximal of the temperature probe
exit region 17, and three lumens therein distal of that region.
Proximal of that region, the shaft includes an inflow lumen 12, an
outflow lumen 13, a guidewire lumen 14 and a temperature probe
lumen 15. The transition between the four lumen (FIG. 2A) and three
lumen (FIG. 2B) catheter tubing may be made by merely skiving off
the top portion of the tube, or may be a joinder of the three lumen
extrusion to four lumen extrusion using extension tubes between the
three lumens to be retained and an external jacket around that
joined length of catheter shaft made of the two different
extrusions. The jacket may be heat shrunk or heat welded around the
tubing to secure the joint. Outflow lumen 13 is fluidly connected
between outflow connector 84 and outflow lumens 58, 60, 62. Inflow
lumen is fluidly connected between inflow connector 82 and balloon
inflow lumen 64. A complete description of heat transfer catheters
similar to that described here is included in U.S. Pat. No.
6,231,594 B1 owned by applicant's assignee and incorporated herein
in full, and U.S. application Ser. No. 09/777,612.
[0084] The proximal end of the catheter of the invention terminates
in a Y adaptor 78 which is attached to an outflow connector 84, an
inflow connector 82, a guide wire lumen terminus 83, a temperature
probe lumen terminus 86, and an aspiration valve 88. A short length
of strain relief tubing 90 may be placed over the catheter at the
location where it attaches to the Y adaptor. The outflow connector
may fluidly connect the outflow lumen 13 to an outflow line 92
carrying heat exchange fluid between the outflow lumen and the
controller 25. The inflow connector fluidly connects the inflow
lumen of the catheter 12 to an inflow line 94 that carries heat
exchange fluid from the controller to the inflow lumen. The inflow
connector 84 may be closed, and the heat exchange fluid in the
balloon withdrawn through the aspiration valve 88 when it is
desired to collapse the balloon, for example when the catheter is
to be withdrawn from within the vasculature of a patient. The guide
wire lumen terminus provides access from the Y adaptor to the guide
wire lumen 14 that extends entirely through the catheter for
insertion of a guide wire 27 therethrough. The guidewire lumen also
functions as a working lumen for the injection of drugs,
thrombolytics, or other substances from outside the body to a
location distal to the catheter, or for sensing the pressure of the
blood stream distal of the catheter. It is also possible to insert
other devices through the lumen, for example a temperature sensor
for sensing the temperature distal of the heat exchange balloon, an
angioplasty catheter for treating the patient at a location distal
of the balloon, an angiojet type device or any similar type device
for treatment distal of the balloon. In fact, it is possible if a
temperature is sensed proximal of the balloon, and another
temperature is sensed distal of the balloon, and the amount of
energy emitted or absorbed by the balloon is determined, to
determine blood flow.
[0085] The proximal portion of the temperature probe 20 exits the
catheter from the temperature probe lumen terminus 86. The proximal
end terminates in an appropriate plug, for example a plastic clip
type plug 96. That plug, in turn attaches to a clip type jack 98
reminiscent of the type of plastic clip attachments common in
telephones and similar devices. This plug to jack attachment
connects the temperature probe electrically to the temperature
probe cable 100 which in turn is connected to the controller. This
provides for temperature signals generated by the temperature probe
as will be described below to be transmitted to the controller so
that the controller may control the heating and cooling effected by
the catheter based on temperature feed back from the patient as
described in U.S. Pat. Nos. 6,149,673 and 6,149,676 incorporated
herein in full. A controller suitable for receiving temperature
signals generated by the present invention and using said signals
to control the transfer of heat from a patient is described in U.S.
patent application Ser. No. 09/707,257 incorporated herein in
full.
[0086] A temperature probe 20 is included and is movable within
temperature probe lumen 15. As can be seen in FIGS. 3b, 4, 5 and 6,
the temperature probe preferably includes temperature sensor such
as a thermistor 21 at its distal end portion 22. Other temperature
sensors may be employed, for example a thermocouple, light probes
capable of sensing temperature, infra red sensors, or similar
device, as long as the sensor is able to sense the temperature of a
specified tissue and generate a signal representing that
temperature that may subsequently be transmitted to a controller
for controlling the heat exchange of a heat exchange catheter or
for some other desired purpose. In the example as shown in this
embodiment, the temperature sensor is a thermistor, the sensed is
that of the blood surrounding the thermistor, and the signal
generated is an electrical signal representing that
temperature.
[0087] At least a portion 23 of the temperature probe adjacent its
distal end portion generally comprises insulating materials. A
coating of plastic 106, as in encasing the signal wires 102, 104
within a plastic tube, may be sufficient. It is important that the
wires that carry the electric signal from the thermistor be
sufficiently insulated that they do not conduct the temperature of
the heat exchange catheter to the thermistor and thereby
significantly influence the temperature sensed by the
thermistor.
[0088] For safety reasons, it is generally preferable that there be
redundancy in the temperature sensors. For example, the distal
portion of the temperature probe may contain two thermistors each
of which has independent connector wires that extend down the probe
to the connection 96/98 and thus to the controller. The controller
is generally programmed so that if the two signals do not
correspond to each other within some predetermined range, the
controller responds appropriately. For example, it may sound an
alarm; it may flash a warning on a user interface if it has one; it
may cease to provide hot or cold heat exchange fluid to the
catheter, or any combination including all of the above. While this
redundancy will generally not be repeated as to each embodiment
described below, it is to be understood that such redundancy may be
a feature incorporated into each embodiment. Furthermore, the
redundancy may be accomplished by incorporating two or more sensors
in each probe, or by incorporating more than one embodiment of the
probe in a particular catheter.
[0089] FIGS. 2A, 2B illustrate cross sections of the catheter
depicting the portion of the catheter shaft containing the
temperature probe lumen. The innerdiameter of temperature probe
lumen 15 is generally in a range of 0.020'' to 0.035-0''.
Preferably, the inner-diameter of the temperature probe lumen is
about 0.030 and may not be round, depending on the extrusion. The
temperature probe along its length is configured to move through
the lumen, for example, the probe may comprise a tube with
thermistors in it near the distal end and wires for transmitting a
signal from the thermistors contained within the tube. The tube may
have, for example an outer diameter of about 0.025 or less. As
described below, the diameter of the probe along its length may
vary. For example, a portion may be flat for alignment with a flat
exit ramp; a portion may have a slightly larger diameter so that it
cannot be entirely withdrawn, or the like. If the probe is of the
type that is moved within the temperature probe lumen, the probe,
the lumen, or both may be constructed of material that slides
easily against the other such as PTFE (Teflon.TM.) or FEP.
[0090] FIG. 4 illustrates a slot 30 at the distal end portion of
the temperature control lumen. The slot is provided to allow
thermistor 21 of temperature probe 20 to protrude from the catheter
in order that the thermistor may be advanced away from the catheter
shaft and into the blood stream when the catheter is inserted into
a subject's blood vessel. As can be seen in FIG. 4, the thermistor
preferably curls into a substantially J-shape so that it moves away
from the catheter and the effects of the temperature generated by
the heat exchange catheter, thus allowing the thermistor to obtain
a more accurate measurement of the temperature of blood flow of the
subject. Preferably, the tip of the temperature probe containing
the thermistor moves at least 1.8-2.2 mm away from the catheter.
The temperature control catheter generally contains a flow of heat
exchange fluid at a temperature different than the blood
temperature of the patient, and it has been found that if a
temperature is sensed by the thermistor at a distance greater then
1.8 mm from the shaft of the catheter, it generally accurately
represents the temperature of the blood flowing within the vessel
and is not unduly influenced by the temperature of the catheter
shaft. It may be possible to advance the probe too far, however.
For example, if the catheter is in a vessel and the sensor is too
far away from the shaft, the sensor in may impact on the vessel
wall. Likewise, if the sensor portion of the temperature probe is
extended too far out of the temperature probe lumen, it may
prolapse back onto the catheter shaft and the temperature sensed
may be significantly influenced by the temperature of the catheter
shaft.
[0091] The location of the distal exit opening in the temperature
probe lumen along the length of the catheter is also important.
When the catheter is used for whole body cooling in the inferior
vena (IVC) the catheter is generally inserted through an introducer
sheath into the femoral vein and advanced so that the balloon is
located entirely in the IVC. So that the cooling may be maximized,
it is desirable that the balloon occupy as much as possible of the
IVC. That means that the shaft of the catheter is located to a
large extent in the femoral vein, a much smaller vein than the IVC.
In fact the shaft extends all the way back through the introducer
sheath. The blood in the introducer sheath tends to flow very
little if at all, and therefore to be greatly influenced by the
temperature of the catheter shaft. Thus it is desirable that the
temperature sensed be that of the blood in the IVC and not in the
femoral vein or in the introducer sheath. Yet if the sensor is too
close to the balloon, the effect heat exchange region, it is likely
to be greatly influenced by the temperature of the heat exchange
fluid. Therefore the exit of the temperature probe lumen is
desirably as close to the balloon as possible to ensure that it is
measuring the temperature of the blood in the IVC and not the
femoral vein, or the introducer sheath, and yet far enough away
from the balloon to accurately sense the temperature of the blood
and not be unduly influenced by the temperature of the heat
exchange fluid in the balloon. It has been found that if the probe
lumen exit slot 30 is located about 0.5 cm or more proximal of the
heat exchange region, that this is generally acceptable. (The
closeness of the probe tip to the expanded balloon also has the
important advantage of allowing the balloon to somewhat act as a
bumper to shield the tip of the probe from contacting the wall of
the vessel.)
[0092] Likewise, the length that the probe extends from the exit
opening in the lumen is important. Besides not prolapsing on the
catheter shaft, it is important that the probe not extend far
enough to lay against the balloon. Again, in this embodiment, it
has been found that generally a gentle J shaped extension resulting
in the thermistors being extended 1.8-1.0 mm from the shaft is
desirable.
[0093] As can be seen in FIG. 4, the end of the temperature probe
lumen preferably includes a ramp 31 leading up to the opening.
Thus, when the thermistor portion of the temperature control probe
encounters the ramp, the ramp directs the thermistor up and through
slot 30 into the blood stream. The end of the probe is generally
shaped in a gentle J shape in a manner well know to those in the
art of guide wires and like probes, and is constrained in a
relatively straight shape within the temperature probe lumen. Once
extended out of the lumen through the ramp, it assumes its
substantially J-shape.
[0094] It will be appreciated that a J-shaped wire that is round
may be rotated, and the distal tip of the probe may not be directed
out away from the catheter. In order to assure proper orientation
of the J tip away from the catheter, slot 30 is preferably in the
form of a flat slot. The portion of temperature probe 20 that mates
against this flat surface when the probe is extended is preferably
in the form of a substantially flat probe. Thus, when the flat
portion of the temperature probe encounters the flat ramp, the
shape of the ramp orients the probe to ensure that the
substantially J-shape extends outward away from the catheter
shaft.
[0095] Accordingly, the catheter is inserted into a subject's blood
vessel with the temperature probe retracted and the thermistors on
the end of the probe within the temperature lumen in an undeployed
state. By extending the temperature probe forward, the thermistor
tip is moved through the slot and the temperature is thus deployed
into the subject's blood stream.
[0096] Since the catheter is within a blood vessel, tip 40 of the
thermistor preferably comprises an atraumatic tip. This helps
prevent puncturing of the blood vessel or irritating the
endothelium of the vessel if the temperature control probe
encounters the wall of the blood vessel.
[0097] Other embodiments of an on-board temperature probe are
clearly within the contemplation of this invention. With reference
to FIG. 3A, it can be seen that instead of having a lumen within
the catheter for a movable temperature probe as shown in FIG. 2A, a
tube with a channel 50 may extend along the exterior of the
catheter shaft. With the embodiment illustrated in FIG. 3A, the
deployable temperature probe may be deployed into its substantially
J-shape through a slot as illustrated in FIG. 3B.
[0098] FIG. 5 illustrates alternative embodiment of the catheter
system and the on-board temperature probe. The temperature probe
150 is fixedly contained within a temperature probe channel 152 and
held in place by plug 154. The distal portion 156 of the
temperature probe is upwardly biased so that if unrestrained it
assumes a curved shape 156' with the tip extending outward away
from the catheter body. A biodegradable band such as a suture 60
that may be rapidly dissolvable in blood restrains the distal
portion against the shaft of the catheter. When the catheter is
placed into the blood stream, the restraining band is dissolved and
the distal portion of the probe assumes its curved configuration
156 with the temperature sensors in the tip 158' extending outward
from the catheter shaft. Preferably this assumes a gentle J shape
as described above to adequately locate the temperature sensor away
from the catheter shaft but to have an atraumatic configuration.
The distal portion of the probe may have a mechanical bias such as
a fixed shape with spring-like bias, or it may have a temperature
sensitive bias. That is, it may have a straight shape when at room
temperature, but be made of a shape memory material such as nitonol
or various temperature memory plastics, so it is straight at room
temperature but assumes a curved shape when it is warmed to body
temperature by the blood. If this type of shape memory material is
used, a restraining band need not be used, although it might also
be used as an additional restraint. It should be noted that
whenever a probe tip is described herein as biased in a particular
configuration, that bias may be a permanent mechanical bias or it
may be a bias that is temperature dependent as described herein,
and both are within the contemplation of this invention.
[0099] FIG. 6 illustrates another embodiment wherein the
temperature probe is fixed in its axial orientation, and uses a
"pull wire" mechanism to deploy the distal portion of the
temperature probe away from the catheter shaft. In this embodiment,
two wires 70, 71 are used to deploy the temperature probe into the
bloodstream. The distal portion is configured, either as a spring
(not illustrated) or a solid portion with cut-out sections. The
wires are attached to the tip at a location slightly off-center. By
pulling on one wire or the other, the top of the distal portion is
compressed, and the lower portion expands to deploy the temperature
probe into the bloodstream, preferably in a gentle, substantially
J-shape. Reversing the process may return the probe to its
generally straight configuration and thus minimize its profile for
insertion and withdrawal. Various mechanism for activating the pull
wire or pull wires are well known in the art and are not
illustrated here.
[0100] Another embodiment of an on-board, deployable probe is
illustrated in FIGS. 8A and 8B. An outwardly biased member
comprised of two legs 162, 164 which may be a unitary member is
provided at an appropriate location proximal of the heat exchange
region. The temperature sensor, such as a thermistor 166 is located
in the central portion between the two legs, so that when they
assume their outward configuration (FIG. 8A) the temperature sensor
is held outward away from the catheter shaft. In this embodiment,
the legs may be rigid, for example a flat piece of plastic, and may
be provided with a slot 168 in which to retract when compressed. In
this Figure the slot is shown as provided for the forward leg, but
it is equally acceptable for the forward leg to be fixed and the
rear leg to retract when compressed. The upwardly biased member
162/164 may in fact be a curved member and not two distinct legs,
as will be readily appreciated by those in the art. Alternatively,
the upwardly biased member 162/164 may simply be compressible into
a flat configuration and not a slidable configuration as
illustrated.
[0101] The temperature sensor, such as thermistor 166, is attached
to two signal carrying wires 170, 172 that carry the temperature
sensing signal to the exterior plug 96. As stated previously, it is
important that the wires be thermally insulated so that the
temperature sensed by the thermistor 166 is that of the blood
flowing over it and is not a temperature of the catheter shaft
conducted up the wires 170, 172.
[0102] The deployed sensor of this embodiment has the advantage
that nothing need be done to deploy the on-board sensor. That is,
it is essentially always deployed, but will compress down against
the shaft upon insertion through an introducer sheath so that it
assumes a small profile for insertion, but will immediately spring
back out when unconstrained in the bloodstream.
[0103] Yet another embodiment is depicted in FIGS. 9A and 9B. In
this embodiment, a movable temperature probe 178 with an upwardly
biased distal portion 180 is placed in a temperature probe lumen
with an open window 174 and a closed distal end 176. Prior to being
deployed the distal end of the probe is retained within the distal
end 176 of the lumen. When the probe is withdrawn a short distance
(shown in FIG. 9B) the upwardly biased portion exits through the
window and assumes the curved configuration that orients the
temperature sensor 182 away from the catheter shaft. When the
catheter is subsequently withdrawn, the temperature probe will
naturally fold down against the catheter shaft as it is being drawn
through the introducer sheath.
[0104] When ever the deployment of a temperature probe is
accomplished by the axial movement of the probe, the amount of
axial movement may be important in order to orient the temperature
sensor the proper distance away from the catheter shaft. One method
of doing so is shown in FIGS. 18A and 18B. An indicia, such as a
marker band 184, may be located on the distal end of the
temperature probe, and when that marker is at the proper location
that would indicated the amount of axial movement of the
temperature probe. In the example illustrated, the probe is
deployed by withdrawing the temperature probe, and the amount of
withdrawal necessary is indicated when the marker band just clears
the exit port 86. Of course, the same effect may be had if the
marker band is used to indicate the advancement of the temperature
probe as in FIG. 1; the marker would be placed farther up on the
distal end of the probe and the correct amount of advancement
indicated when the marker band is at the correct location relative
to the exit port 86. The probe may then be locked in place in any
of various means; for example affixing a keyed or barbed channel
with a mating shape on the probe surface.
[0105] Other means of ensuring the correct amount of axial movement
may be seen in FIGS. 10A and 10B and 17A and 17B. In 10A a
temperature probe with a large distal portion is located in a
temperature probe channel as in FIG. 9A. The proximal end of the
large distal portion of the temperature probe is too large a
diameter to fit within the proximal temperature probe channel 188
and therefore when the temperature probe is withdrawn, it will only
withdraw until the probe is withdrawn a certain distance. The probe
distal portion then assumes its J shape, either because of its
permanent bias or temperature based memory shape.
[0106] In this embodiment, the distal portion of the channel 188
must be large enough to accept the distal portion of the probe, yet
the proximal portion of the channel 186 must be small enough not to
accept the proximal end of that portion of the temperature probe.
If the proximal portion of the probe tip is tapered or otherwise of
increased diameter, a channel of the same diameter could be used
for both sections which has obvious manufacturing advantages.
Another way in which this could be accomplished as shown in FIGS.
17A and 17B. In this example, a section of enlarged diameter 190 is
contained on the temperature probe in the section located in the
window 174. When the probe is withdrawn, it can only be withdrawn
until the enlarged section contacts the proximal edge of the
window. In this way the exact amount of axial movement of the probe
can be predetermined, and the exact shape of the distal portion
determined for placement of the temperature sensor the appropriate
distance from the catheter shaft.
[0107] Another embodiment for accomplishing this precise amount of
axial movement is shown in FIGS. 16A and 16B. In this embodiment,
the probe has a location of sharp increase in diameter 192, and the
distal end of the temperature probe lumen has a flap 194 that is
biased down against the catheter shaft. When the temperature probe
is advanced it can exit under the flap 194, but when it is
withdrawn, it cannot be withdrawn past the location of increased
diameter. In this way the probe may be deployed forward, and then
pulled back to the correct, predetermined position and no
farther.
[0108] These methods of determining position of the probe after
deployment may, of course, be used alone or in combination with
each other.
[0109] Another embodiment of an on-board temperature sensor that
has one diameter, for insertion for example, and another diameter
where the temperature sensor is held away from the catheter shaft
is depicted in FIGS. 13A, 13B and 14. In this embodiment, the
temperature sensor 196, such as a thermistor is located on a
balloon 202. Insulated wires 198, 199 conduct temperature signals
from the thermistor outside the patient's body to a controller. An
inflation channel 200 permits the introduction of inflation medium
for example saline or CO.sub.2 to inflate the balloon. The balloon
may be, for example, a non-compliant PET balloon that has a
predetermined shape and size. When fully inflated, this holds the
temperature sensor a predetermined distance out into the
bloodstream. This has the advantage of permitting some insulation,
for example the use of an insulating inflation medium such as
CO.sub.2 and providing a very atraumatic means of locating the
temperature sensor away from the catheter. The presence of the
balloon just upstream of the heat exchange region may have an
additional benefit of causing mixing eddies in the fluid stream
(blood stream) that may further enhance heat exchange between the
heat exchange region and the blood.
[0110] Two balloons may be provided as shown in FIGS. 15A and 15B.
In FIG. 15A each balloon 204, 206 is provided with a temperature
sensor 208, 210. This may provide safety through redundancy or may
provide for temperature measures at different locations. The two
balloons may be located a different locations along a common lumen
212 and therefore the probe connecting wires 214, 216 for carrying
the temperature signal may be located in the common lumen, and
likewise the same lumen may serve as the inflation lumen for both
balloons.
[0111] In 15B, a temperature probe may be located on a wire,
string, or other member 218 suspended between two balloons. This
has the advantage of allowing the access to the temperature sensor
from outside the catheter. In this situation it might be desirable
to have the wires from the sensor travel outside the body through
an external channel or not encased in a channel at all rather than
locate them in the inflation channel.
[0112] Another embodiment is shown in FIGS. 12A and 12B. In this
embodiment, a temperature probe 300 is in the form of a polymide
tube. The polyimide tube is contained in a temperature probe lumen
302. The lumen has a window 304 located at a location along the
catheter for example about 3 cm proximal to a heat exchange
balloon. The probe is fixed in the probe lumen proximal of the
window by, for example, adhesive 303.
[0113] At the location of the window the polyimide tube is crimped
306. Near the location just proximal of the crimp, a thermister 308
is located in or on the tube. A second thermister 309 may be
located just distal if the crimp to provide redundancy. Connector
wires 314, 316 run from the thermisters to the plug the proximal
end of the tube outside the patient's body.
[0114] The probe tube has two openings 318,320 one on each side of
the crimp. A pull wire 310 is affixed at the distal end 312 of the
tube, and runs from that point of attachment inside the probe tube,
out of the first opening 318, along the side of the probe tube,
back into the tube through the second opening 320, and from there
runs the length of the tube and is accessible to the operator at
the proximal end (not shown).
[0115] This embodiment, when undeployed, the temperature probe lies
flat with sensors 308, 309 within the outer profile of the catheter
and thus is insertable within the same size introducer sheath. Once
located in the desired location in the vasculature, the operator
pulls the pull wire 310 which slides the distal portion of the
probe tube backwards and causes the tube to bend at the crimp 306
and depoly the sensor through the window up and away from the
catheter.
[0116] When the catheter is to be withdrawn, the pull wire may be
pushed forward to once again cause the probe to lie flat in the
probe lumen 302. In addition, the force of pulling the catheter
back through the sheath can push in the deployed portion of the
probe back down through the window and essentially return it to the
undeployed position. Alternatively, or in addition, a biasing
member such as a spring or elastomeric string may attach the distal
end of the tube 300 to a distal location in the probe lumen 302 so
that the probe tube is pulled straight with the crimped portion
within the window section of the tube unless the pull wire is
withdrawn.
[0117] In this configuration, at the proximal end, a method of
affixing the pull wire in the "pulled" configuration in a manner
commonly known in the art, will allow the wire to be retracted,
affixed in the retracted position which will fix the sensor in the
deployed position. As discussed previously, methods of affixing the
pull wire at a specific axial location will assure the proper
amount of bending at the crimped location for proper deployment of
the probe.
[0118] When the catheter is to be withdrawn, various devices for
releasing the pull wire allow the catheter to be withdrawn with the
probe in the undeployed configuration.
[0119] Similarly in FIGS. 12A and 12B an arm 222 hinged at an
attachment to the catheter 224 may be raised away from the catheter
body with a push wire, or relaxing of a restraining wire if the
hinge has an upward bias.
[0120] Those skilled in the art will understand that other
mechanisms and/or arrangements may be used to deploy the
temperature probe into the bloodstream.
[0121] Although the present invention has been described with
reference to specific exemplary embodiments, it will be appreciated
that it is intended to cover all modifications and equivalents
within the scope of the appended claims.
* * * * *