U.S. patent application number 09/924674 was filed with the patent office on 2002-02-28 for temperature probe with dual sensors.
Invention is credited to Philips, Peter J..
Application Number | 20020026227 09/924674 |
Document ID | / |
Family ID | 23083924 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020026227 |
Kind Code |
A1 |
Philips, Peter J. |
February 28, 2002 |
Temperature probe with dual sensors
Abstract
A temperature probe having dual temperature elements is
connected to a cooling catheter controller to provide redundancy in
temperature feedback to the controller, namely, to provide both a
control temperature feedback signal and an alarm temperature
feedback signal to the controller.
Inventors: |
Philips, Peter J.; (Trabuco
Canyon, CA) |
Correspondence
Address: |
Arlyn L. Alonzo
ALSIUS CORPORATION
Suite 150
15770 Laguna Canyon Road
Irvine
CA
92618
US
|
Family ID: |
23083924 |
Appl. No.: |
09/924674 |
Filed: |
August 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09924674 |
Aug 8, 2001 |
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09282971 |
Mar 31, 1999 |
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6290717 |
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Current U.S.
Class: |
607/113 |
Current CPC
Class: |
A61F 2007/0086 20130101;
A61F 7/12 20130101 |
Class at
Publication: |
607/113 |
International
Class: |
A61F 007/12 |
Claims
What is claimed is:
1. A temperature sensing apparatus for insertion into a patient's
body, comprising: at least first and second temperature sensors
supported by a probe body configured for advancing the sensors into
the patient's body; the probe body comprising a male or female
telephone probe connector; an interconnect cable having a female or
male telephone cable connector selectively snappingly engageable
with the probe connector; at least one controller connector
engageable with a controller of a closed circuit cooling catheter
heat exchange system, the interconnect cable establishing
electrical connectivity between the cable connector and the
controller connector.
2. The probe of claim 1, wherein the probe body is configured for
advancement into the patient's esophagus.
3. The probe of claim 1, wherein the probe body is configured for
advancement into the patient's bladder.
4. The probe of claim 1, wherein the probe body is configured for
advancement into the patient's blood vessel.
5. A temperature probe for insertion into a patient's body
comprising: an elongated probe body, the probe body being
configured for advancing the probe body into a patient's body; at
least first and second temperature sensors located on the probe
body generating respective first and second temperature signals,
wherein the second signal is in electrical communication with an
alarm.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. Application Ser.
No. 09/282,971 filed Mar. 31, 1999, herein incorporated by
reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to methods and
apparatus for cooling patients for therapeutic purposes, and more
particularly to systems for measuring temperature in a patient to
provide a feedback control signal for controlling a cooling
catheter.
BACKGROUND
[0003] 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 is degraded if the patient's body
temperature rises above normal (38.degree. C.). It is further
believed that the medical outcome for many such patients might be
significantly improved if the patients were to be cooled relatively
quickly to around 32.degree. C. for a short period, e.g., 24-72
hours. Apart from the therapeutic benefits of hypothermia, the
outcomes for brain trauma or ischemia patients that develop fevers
is worse than for patients that do not develop fevers.
Consequently, temperature management for such patients is
important, even when hypothermia is not to be used to treat the
patients.
[0004] The affected organ, in any case, is the brain. Accordingly,
systems and methods have been disclosed that propose cooling blood
flowing to the brain through the carotid artery. An example of such
systems and methods is disclosed in co-pending U.S. patent
application Ser. No. 09/063,984, filed Apr. 21, 1998, owned by the
present assignee and incorporated herein by reference. In the
referenced application, various catheters are disclosed which can
be advanced into a patient's carotid artery and through which
coolant can be pumped in a closed circuit, to remove heat from the
blood in the carotid artery and thereby cool the brain. The
referenced devices have the advantage over other methods of cooling
(e.g., wrapping patients in cold blankets) of being controllable,
relatively easy to use, and of being capable of rapidly cooling and
maintaining blood temperature at a desired set point.
[0005] As recognized in co-pending U.S. patent application Ser. No.
09/133,813, filed Aug. 13, 1998, owned by the present assignee and
incorporated herein by reference, the above-mentioned advantages in
treating brain trauma/ischemic patients by cooling can also be
realized by cooling the patient's entire body, i.e., by inducing
systemic hypothermia. The advantage of systemic hypothermia is
that, as recognized by the present assignee, to induce systemic
hypothermia a cooling catheter or other cooling device need not be
advanced into the blood supply of the brain, but rather can be
easily and quickly placed into the relatively large vena cava of
the central venous system.
[0006] Moreover, since many patients already are intubated with
central venous catheters for other clinically approved purposes
anyway, providing a central venous catheter that can also cool the
blood, if only to manage temperature and thereby ameliorate fever
spikes, requires no additional surgical procedures for those
patients. A cooling central venous catheter is disclosed in the
present assignee's co-pending U.S. patent application Ser. No.
09/______, filed Feb. 19, 1999 and incorporated herein by
reference.
[0007] To supply coolant such as saline to the above-disclosed
catheters, a cooling system such as the present assignee's system
disclosed in co-pending U.S. patent application Ser. No.
09/220,897, filed Dec. 24, 1998 and incorporated herein by
reference, can be used to remove heat from the coolant and return
the coolant to the catheter in a closed loop heat exchange system.
An alternate system is the thermoelectric cooler (TEC)-based system
owned by the present assignee and disclosed in co-pending U.S.
patent application Ser. No. 09/260,950, filed Mar. 2, 1999, also
incorporated herein by reference. In any case, a cooling system
controller preferably maintains temperature at a desired setpoint,
be it normothermic or hypothermic. As recognized herein, to
facilitate such temperature maintenance, it is necessary to measure
patient temperature.
[0008] As understood by the present invention, esophageal
temperature is a preferred parameter to use because it is more
sensitive to body core temperature changes than, e.g., rectal
temperature. As also understood by the present invention, for ease
of use and to avoid burdensome sterilization procedures, the
portion of an esophageal temperature sensor that is advanced into a
patient should be disposable. Portions not in contact with the
patient, however, need not be disposable. The present invention is
provided with these considerations in mind.
SUMMARY OF THE INVENTION
[0009] A temperature probe for a therapeutic cooling catheter
system includes an elongated probe body that has a distal end and a
proximal end, and that is configured for being advanced into a
patient with the distal end located in the patient's body and the
proximal end located outside the patient's body. First and second
temperature sensors, preferably thermistors, are located at or near
the distal end of the probe body for generating respective first
and second temperature signals. Also, a probe connector is located
at or near the proximal end of the probe body, and a reusable
interconnect cable has a cable connector configured for engaging
the probe connector and at least one controller connector
electrically connected to the cable connector and engageable with a
controller.
[0010] In a preferred embodiment, the probe body is configured for
advancement into a patient's esophagus. Also in the preferred
embodiment, the probe connector snappingly engages the cable
connector. One of the connectors preferably is a male telephone
connector and the other connector is a female telephone connector.
More specifically, the preferred probe connector includes an
outwardly biased pivot arm and the cable connector includes a
socket including at least one retainer rail, and the arm snappingly
engages the rail when the probe connector is advanced into the
cable connector. The arm of the probe connector extends beyond the
cable connector when the probe connector is fully engaged with the
cable connector, with the arm being manipulable to cause the arm to
clear the rail and thereby permit disengagement of the probe
connector from the cable connector.
[0011] As disclosed in greater detail below, the cable includes
first and second controller segments terminating in respective
first and second controller connectors. Each controller connector
is engageable with the controller. The controller connectors can be
phone plugs.
[0012] With further regard to the controller, the first temperature
sensor generates a control feedback signal that is useful by the
controller for controlling a heat exchanger. Also, the second
temperature sensor generates an alarm feedback signal useful by the
controller for generating an alarm signal. The system is disclosed
in combination with a heat exchange catheter in closed loop fluid
communication with the heat exchanger.
[0013] In another aspect, a controller includes a program of
instructions for undertaking method acts for controlling a heat
exchanger. These acts includes receiving, from first and second
temperature sensors, respective first and second patient esophageal
temperature signals. Also, the method acts includes controlling a
heat exchanger for a cooling catheter in response to at least the
first signal, and generating an alarm signal when the second signal
reaches a predetermined setpoint.
[0014] In still another aspect, an esophageal temperature sensing
apparatus includes first and second temperature sensors supported
by a disposable probe body. The probe body is configured for
advancing the sensors into a patient's esophagus, with the proximal
end of the probe body remaining outside the patient's body at all
times. A male or female telephone probe connector is at the
proximal end, and an interconnect cable having a female or male
telephone cable connector is selectively snappingly engageable with
the probe connector. Moreover, a controller connector is engageable
with a controller of a closed circuit cooling catheter heat
exchange system. As set forth below, the interconnect cable
establishes electrical connectivity between the cable connector and
the controller connector.
[0015] 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
[0016] FIG. 1 is a schematic view of the present invention in its
intended environment;
[0017] FIG. 2 is a top view of the probe body in an exploded
relationship with the interconnect cable;
[0018] FIG. 3 is a cross-sectional view of the cable connector as
seen along the line 3-3 in FIG. 2;
[0019] FIG. 4 is a cross-sectional view of the cable connector as
seen along the line 4-4 in FIG. 2; and
[0020] FIG. 5 is a flow chart of the logic of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring initially to FIG. 1, a therapeutic system,
generally designated 10, is shown for establishing and maintaining
hypothermia in a patient 12, or for attenuating a fever spike in a
patient and then maintaining normal body temperature in the
patient. As shown, the system 10 includes a cooling system 14 that
can be a water-bath system or a TEC-based system such as either of
the systems disclosed in the last two of the above-referenced
applications. In any case, the cooling system 14 can be considered
a source of coolant, preferably sterile saline, for the catheters
of the present invention.
[0022] As set forth in the last two of the above-referenced
applications, the cooling system 14 can include a heat exchange
system 16 including a pump. The pump and/or heat exchange elements
in the heat exchange system 16 are controlled by a controller 18.
The controller 18 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 pump and/or heat exchanger in
response to a temperature signal derived from one or more sensors
in the patient 12.
[0023] As shown in FIG. 1, a catheter 20 can communicate with the
cooling system 14 via coolant supply and return lines 22, 23. The
coolant lines 22, 23 can be IV lines or tubes or other suitable
fluid conduits, such as metal (steel) tubes. When the coolant lines
22, 23 are plastic tubes, they can be connected to the catheter 20
and the cooling system 14 by suitable connecting structure, such as
Luer fittings, interference fits, solvent bonding, heat staking,
ultrasonic welding, and the like. The catheter 20 can be any of the
catheters disclosed in the first two of the above-referenced
applications in which coolant is circulated in a closed fluid
communication loop to remove heat from the patient 12. The catheter
20 is advanced (preferably through an introducer sheath) into the
patient 12 through a neck entry point or femoral entry point to
establish hypothermia in the patient 12, or to attenuate a fever
back to normal body temperature. Preferably, the catheter 20 is
advanced into the central venous system, and more preferably into
the vena cava, either through the subclavian vein or jugular vein
or femoral vein.
[0024] To enable the controller 18 to control the heat exchanger
16, patient temperature feedback is required. As understood by the
present invention, patient safety standards can dictate that the
feedback be redundant, such that if one temperature sensor fails,
the second sensor can still monitor temperature. As further
understood by the present invention, while two sensors are
desirable, it is also desirable to minimize the number of probes
that are advanced into a patient.
[0025] Accordingly, a temperature feedback apparatus 24 including a
probe body 26 and an interconnect cable 28 is provided herein to
interconnect at least first and second temperature sensors (not
shown in FIG. 1) that are positioned in the patient 12 to the
controller 18. Although the sensors can be positioned in, e.g., the
rectum, bladder, or near the tympanic membrane of the patient 12,
they are preferably positioned in the esophagus.
[0026] FIGS. 2-4 show the details of the temperature feedback
apparatus 24. As can be appreciated in reference to FIG. 2, the
probe body 26 is a disposable elongated probe body having a distal
end 30 and a proximal end 32. In the preferred embodiment, the
probe body 26 is configured for advancing the probe body into a
patient's esophagus with the distal end 30 located in the patient's
body and the proximal end 32 located outside the patient's
body.
[0027] At least first and second temperature sensors 34, 36 are
located at or near the distal end 30 of the probe body 26. The
sensors are preferably YSI400 series thermistors that generate
respective first and second temperature signals. Each thermistor is
electrically connected to two electrical leads in accordance with
means known in the art, and the leads extend through the probe body
26 to the proximal end 32 of the body 26. Surrounding the leads and
the sensors 34, 36 is a plastic biocompatible sheath 38 that can be
coated with antimicrobial coatings and/or antithrombogenic
coatings. Also, the sensors 34, 36 are isolated from each other by
placing the first sensor 34 inside a first insulative sheath and
then placing the first sheath and second sensor 36 inside a second
sheath. Sensors other than thermistors, such as thermocouples,
resistance temperature detectors (RTDs), and the like can be
used.
[0028] A probe connector 40 is located at or near the proximal end
32 of the probe body 26. The interconnect cable 28, which
preferably is reusable, has a cable connector 42 that is configured
for easily and quickly engaging and disengaging the probe connector
40, preferably in a snapping or interference fit. In one preferred
embodiment, the probe connector 40 is a male telephone connector
and cable connector is a female telephone connector, although these
structures can be reversed.
[0029] Accordingly, in the preferred embodiment shown in FIGS. 2-4,
the probe connector 40 includes an outwardly biased pivot arm 44
that is formed with transverse ears 44a and a narrow extension 44b.
The cable connector 42, on the other hand, includes a socket 46
that in turn includes at least one retainer rail 48. The arm 44 of
the probe connector 40 rides against the rail 48 when the probe
connector 40 is advanced into the cable connector 42 to overcome
the outward bias of the arm 44. When the probe connector 40 has
been advanced a sufficient distance into the cable connector 42,
the ears 44a clear the rail 48, causing the pivot arm 44 to snap
outwardly under the influence of its material bias, thereby
engaging the connectors 40, 42. Electrical contact between the
connectors 40, 42 is established between a connector ramp 50 in the
cable connector 42 and complementarily-formed structure (not shown)
on the probe connector 40.
[0030] When the connectors 40, 42 are fully engaged, the extension
44b of the probe connector 40 extends beyond the cable connector
42. The extension 44b can be manipulated to cause the arm 44 to
clear the rail 48 and thereby permit the connectors 40, 42 to be
disengaged by pulling the probe connector 40 out of the cable
connector 42.
[0031] In the embodiment shown in FIG. 2, the cable 28 includes
first and second controller segments 52, 54 that terminate in
respective first and second controller connectors 56, 58. It is to
be understood that the first controller connector 56 is
electrically connected to the first sensor 34 via the first segment
52 and probe body 26 when the connectors 40, 42 are engaged, and
the second controller connector 58 is electrically connected to the
second sensor 36 via the second segment 54 and probe body 26 under
these circumstances. In accordance with the present invention, each
controller connector 56, 58 is engageable with the controller 18
(FIG. 1) to thereby establish an electrical path between the
sensors 34, 36 and the controller 18. Preferably, the controller
connectors 56, 58 are phone plugs.
[0032] Per the present invention the first temperature sensor 34
generates a control feedback signal that is useful by the
controller 18 for controlling the heat exchanger 16. Also, the
second temperature sensor 36 generates an alarm feedback signal
that is useful by the controller 18 for generating an alarm
signal.
[0033] FIG. 5 shows the logic of the present controller 18 in
treating the signals from the sensors 34, 36. Commencing at
decision diamond 60, it is determined whether two valid signals
have been received. If not, indicating an undesirable loss of
redundancy, the process moves to block 62 to return an error signal
or alarm. Otherwise, the logic moves to block 64.
[0034] At block 64, the controller 18 uses the control signal from
the first sensor 34 to control the heat exchanger 16 as set forth
in the latter two of the above-disclosed patent applications.
Proceeding to decision diamond 66, it is determined whether the
second signal, i.e., the signal from the second sensor 36, has
reached a high temperature or low temperature setpoint. If not, the
process ends at state 68, but if a setpoint has been reached an
alarm is generated at block 70. The process, although shown in flow
chart format for ease of disclosure, can be a continuous state
process.
[0035] While the particular TEMPERATURE PROBE AND INTERCONNECT
CABLE FOR HYPOTHERMIA CATHETER TEMPERATURE FEEDBACK as herein shown
and described in detail is fully capable of attaining the
above-described objects of the invention, it is to be understood
that it is the presently preferred embodiment of the present
invention and is thus representative of the subject matter which is
broadly contemplated by the present invention, that the scope of
the present invention fully encompasses other embodiments which may
become obvious to those skilled in the art, and that the scope of
the present invention is accordingly to be limited by nothing other
than the appended claims, in which reference to an element in the
singular is not intended to mean "one and only one" unless
explicitly so stated, but rather "one or more". All structural and
functional equivalents to the elements of the above-described
preferred embodiment that are known or later come to be known to
those of ordinary skill in the art are expressly incorporated
herein by reference and are intended to be encompassed by the
present claims. Moreover, it is not necessary for a device or
method to address each and every problem sought to be solved by the
present invention, for it to be encompassed by the present claims.
Furthermore, no element, component, or method step in the present
disclosure is intended to be dedicated to the public regardless of
whether the element, component, or method step is explicitly
recited in the claims. No claim element herein is to be construed
under the provisions of 35 U.S.C. .sctn.112, sixth paragraph,
unless the element is expressly recited using the phrase "means
for".
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