U.S. patent application number 15/484816 was filed with the patent office on 2017-08-03 for system and method for leak detection in external cooling pad.
The applicant listed for this patent is Zoll Circulation, Inc.. Invention is credited to Kenneth A. Collins, David Searl Kimball, Lynn Miyeko Shimada, Stelica Stelea.
Application Number | 20170216089 15/484816 |
Document ID | / |
Family ID | 37662645 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170216089 |
Kind Code |
A1 |
Stelea; Stelica ; et
al. |
August 3, 2017 |
SYSTEM AND METHOD FOR LEAK DETECTION IN EXTERNAL COOLING PAD
Abstract
An externally-applied heat exchange pad has three layers
laminated together, an inner and outer non-conductive layer and a
middle conductive layer. A leak in the inner layer causes coolant
to contact the middle layer and change impedance, which can be
sensed and used as an indication of an impending total leak of the
pad.
Inventors: |
Stelea; Stelica; (Yorba
Linda, CA) ; Kimball; David Searl; (Irvine, CA)
; Shimada; Lynn Miyeko; (Orange, CA) ; Collins;
Kenneth A.; (Mission Viejo, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zoll Circulation, Inc. |
San Jose |
CA |
US |
|
|
Family ID: |
37662645 |
Appl. No.: |
15/484816 |
Filed: |
April 11, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13653800 |
Oct 17, 2012 |
9615966 |
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15484816 |
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13283036 |
Oct 27, 2011 |
8308788 |
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13653800 |
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13031462 |
Feb 21, 2011 |
8097030 |
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13283036 |
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11181122 |
Jul 14, 2005 |
7951182 |
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13031462 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2007/0054 20130101;
A61F 7/02 20130101; A61F 7/0085 20130101; A61F 2007/0001 20130101;
A61B 2017/00119 20130101; A61F 7/10 20130101; A61F 2007/0056
20130101; A61B 2017/00026 20130101 |
International
Class: |
A61F 7/10 20060101
A61F007/10; A61F 7/00 20060101 A61F007/00 |
Claims
1. A system, comprising: an impedance detector; and a pad
positionable against the skin of a patient to exchange heat
therewith, the impedance detector communicating with an interior
space formed by the pad and a location on the pad outside the
interior space to receive signals representing an electrical
impedance between the interior space and the location on the pad
outside the interior space, wherein the pad includes an outer
non-conducting layer, an inner non-conducting layer, and a middle
conducting layer sandwiched therebetween, the middle conducting
layer being electrically connected to the impedance detector to
provide signals thereto, the impedance detector being connectable
to a control system to send a signal thereto.
2. The system of claim 1, wherein the control signal is for
activating an alarm indicating a leak in the pad.
3. The system of claim 1, wherein a rupture in the outer layer
causes a substance from outside the pad to contact the middle layer
to establish a change in impedance that is sensed by the impedance
detector.
4. The system of claim 3, wherein the control system is configured
to use an impedance between the middle layer and the substance as
an indication as to whether a leak exists.
5. The system of claim 1, wherein the control system is configured
to correlate a drop in impedance to a leak in the outer layer.
6. The system of claim 1, wherein the inner layer is made of the
same material as the outer layer.
7. The system of claim 1, wherein the middle layer is made of
foil.
8. The system of claim 1, wherein the middle layer is made of
plastic impregnated with conductive material.
9. The system of claim 1, wherein the system is configured to cause
an alert to be activated indicating a rupture has occurred
responsive to a change in impedance sensed by the impedance
detector.
10. The system of claim 1, wherein the system is configured to
cause an alert on the impedance detector to be activated indicating
a rupture has occurred responsive to a correlation by the impedance
detector.
11. The system of claim 9, wherein the alert is an audible
alarm.
12. The system of claim 9, wherein the alert is a visual alert.
13. The system of claim 9, wherein the alert includes both an
audible alarm and a visual alert.
14. The system of claim 1, wherein the layers are laminated
together.
15. The system of claim 1, wherein the system is included on a
patient temperature control system engaged with the pad to
circulate coolant therethrough to establish a desired
temperature.
16. The system of claim 3, wherein the substance is a gel and/or
liquid.
17. The system of claim 3, wherein the substance is interposed
between the pad and the skin of the patient.
18. The system of claim 1, wherein the pad is electrically
connected to the impedance detector through plural leads.
19. A system, comprising: an electrical signal detector; and a pad,
the electrical signal detector communicating with an interior space
formed by the pad and a location on the pad outside the interior
space to receive signals representing an electrical parameter
between the interior space and the location on the pad outside the
interior space, wherein the pad includes an outer layer, an inner
layer, and a middle conducting layer sandwiched therebetween, the
middle conducting layer being electrically connected to the
electrical signal detector to provide signals thereto.
20. The system of claim 19, wherein the electrical signal detector
is connectable to a control system to send a signal thereto, and
wherein the control signal is for activating an alarm indicating a
leak in the pad.
Description
FIELD
[0001] The present invention relates generally to patient
temperature control using externally-applied devices.
BACKGROUND
[0002] Patient temperature control systems have been introduced to
prevent fever in patients in the neuro ICU due to suffering from
sub-arachnoid hemorrhage or other neurologic malady such as stroke.
Also, such systems have been used to induce mild or moderate
hypothermia to improve the outcomes of patients suffering from such
maladies as stroke, cardiac arrest, myocardial infarction,
traumatic brain injury, and high intracranial pressure. The present
assignee has covered one or more of the above treatments using an
intravascular heat exchange catheter in U.S. Pat. Nos. 6,149,670,
6,290,717, 6,432,124, 6,454,793, 6,682,551, and 6,726,710
(collectively, "the Alsius treatment patents"), all of which are
incorporated herein by reference.
[0003] Less optimally, external patient temperature control systems
may be used. Such systems are disclosed in U.S. Pat. Nos.
6,827,728, 6,818,012, 6,802,855, 6,799,063, 6,764,391, 6,692,518,
6,669,715, 6,660,027, 6,648,905, 6,645,232, 6,620,187, 6,461,379,
6,375,674, 6,197,045, and 6,188,930 (collectively, "the external
pad patents"), all of which are incorporated herein by reference.
Because such systems are used, the present invention recognizes the
need to detect impending coolant leaks in the applied pads to avoid
such leaks, so that patient discomfort and system malfunction are
avoided before they occur.
SUMMARY OF THE INVENTION
[0004] A heat exchange pad configured for placement against the
skin of a patient to exchange heat with the patient includes an
outer envelope. The outer envelope includes an outer layer made of
a high dielectric material such that any electrical discharge in
the pad is effectively blocked from passing through the outer layer
to the patient. Also, the envelope has an inner layer. A middle
layer is sandwiched between the inner and outer layers and is made
of a relatively electrically conductive material. The middle layer
is electrically connected to a control system associated with the
pad.
[0005] If desired, the layers can be laminated together. In some
embodiments, in the event of a rupture in the inner layer, coolant
in the pad contacts the middle layer to establish a change in
impedance that may be sensed by the control system. In specific
embodiments an impedance between the middle layer and the coolant
can be used as an indication as to whether a leak exists. More
particularly, in some implementations a drop in impedance can
indicate that a leak is in the inner layer. The inner layer may be
made of the same material as the outer layer, and the middle layer
may be foil or plastic impregnated with conductive material.
[0006] In another aspect, a patient temperature control system
includes at least one pad positionable against the skin of a
patient to exchange heat therewith, and a control system engaged
with the pad to circulate coolant therethrough to establish a
desired temperature. Means are provided on the pad for providing
early warning of a complete loss of integrity of the pad before it
occurs.
[0007] In still another aspect, a method for providing an alarm
that indicates an impending loss of fluid integrity of a heat
exchange pad engageable with the exterior of a patient before fluid
in the pad leaks out of the pad onto the patient includes receiving
a signal from the pad representing an impedance. If the signal
satisfies a leakage threshold, an alarm is activated.
[0008] 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
[0009] FIG. 1 is a schematic view of a non-limiting system in
accordance with the present invention; and
[0010] FIG. 2 is a cross-section of the present external heat
exchange pad, omitting internal coolant circulation structure for
clarity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Referring initially to FIG. 1, a system is shown, generally
designated 10, that includes one or more pads 12 that are
positioned against the external skin of a patient 14 (only one pad
12 shown for clarity). The pad 12 may be any one of the pads
disclosed in the external pad patents or it may be any other type
of external heat exchange pads, as modified as disclosed herein in
reference to FIG. 2. A substrate 16 such as a label that is affixed
to the pad or an instruction manual that accompanies the pad can
also be provided that bears instructions for use. In any case, the
temperature of the pad 12 can be controlled by a controller 18
receiving a patient temperature signal from one or more temperature
sensors "S" in accordance with principles set forth in the external
pad patents to exchange heat with the patient 14, including to
establish normothermia in a febrile patient and to induce
therapeutic mild or moderate hypothermia in the patient in response
to the patient presenting with, e.g., cardiac arrest, myocardial
infarction, stroke, high intracranial pressure, traumatic brain
injury, or other malady the effects of which can be ameliorated by
hypothermia. Patient warming can also be effected using the pad 12
for, e.g., re-warming after surgery.
[0012] Heat exchange fluid, referred to herein as "coolant"
regardless of its temperature, is circulated from the control
system 18, through a supply line 20 to the pad 12, through various
internal coolant circulation structure within the pad 12, e.g., the
structures disclosed in the pad patents, and back through a return
line 22 to the control system 18 for heating or cooling as needed
for the particular application. Electrical leads 24, e.g., two, can
be provided with one lead 24 extending between the external
three-ply case of the pad 12 and the control system 18 and the
other lead 24 extending between the interior coolant space of the
pad 24 and the control system 18, for purposes to be shortly
disclosed in relation to FIG. 2. A pump in or associated with the
control system 18 may be engaged with the coolant supply line 20 to
push coolant through the pad 12, or the pump may be engaged with
the coolant return line 22 to suck coolant through the pad 12.
[0013] FIG. 2 shows details of the invention. The pad 12 includes
an outer envelope 26 that holds internal coolant circulation
structure, which is omitted in FIG. 2 for clarity of disclosure.
The outer envelope 26 is three-ply at least. Specifically, the
envelope 26 includes an outer layer 28 made of a high dielectric
material so that any electrical discharge in the pad 12 is
effectively blocked from passing through the outer layer 28 to the
patient, it being understood that the outer layer 28 is disposed
against the skin of the patient perhaps with a gel or liquid
interposed between it and the skin. The envelope 26 also has an
inner layer 30 that may be made of the same material as the outer
layer 28. A middle layer 32 is sandwiched between the inner and
outer layers 30, 28. The middle layer 32 may be made of a
relatively electrically conductive material, e.g., foil, or plastic
impregnated with sufficient conductive material, or other
appropriate material, and it is electrically connected to one of
the electrical leads 24 and, hence, to the control system 18. The
other lead extends between the control system 18 and interior
coolant space of the pad 12 as shown. The layers 28, 30, 32
preferably are laminated together or otherwise held together
against each adjacent layer.
[0014] The point is that the middle layer 32 is sufficiently
conductive such that in the event of a rupture in the inner layer
30, coolant contacts the middle layer 32 to establish a change in
impedance that is sensed by the control system 18 through the leads
24. For instance, the impedance between the middle layer 32 and the
coolant may be measured through the leads 24 as an indication as to
whether a leak exists. As an example, a significant drop in
impedance can indicate a leak in the inner layer 30, making a leak
through all three layers more likely than otherwise and, hence,
providing early warning of such a complete loss of integrity of the
pad 12 before it occurs. Accordingly, the control system 18 may
activate an audible and/or visual alarm 34 (FIG. 1) to alert
personnel of an impending leak. The same principles can be applied
to determining whether the liquid or gel, if used, that is between
the patient and pad is leaking through a hole in the outer layer to
the middle layer.
[0015] While the particular SYSTEM AND METHOD FOR LEAK DETECTION IN
EXTERNAL COOLING PAD 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". 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. Absent express definitions
herein, claim terms are to be given all ordinary and accustomed
meanings that are not irreconcilable with the present specification
and file history.
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