U.S. patent application number 12/489156 was filed with the patent office on 2010-12-23 for icg/ecg monitoring apparatus.
This patent application is currently assigned to Analogic Corporation. Invention is credited to Anthony Ralph Diciaccio, Lewis Norman Harrold.
Application Number | 20100324404 12/489156 |
Document ID | / |
Family ID | 43354913 |
Filed Date | 2010-12-23 |
United States Patent
Application |
20100324404 |
Kind Code |
A1 |
Harrold; Lewis Norman ; et
al. |
December 23, 2010 |
ICG/ECG MONITORING APPARATUS
Abstract
An ICG/ECG electrode includes a first electrode and a second
electrode, wherein at least one of the first or second electrode
senses both an ICG signal and an ECG voltage signal. A physiologic
parameter monitoring apparatus includes a set of electrodes,
including an electrode for sensing both an ICG voltage signal and
an ECG voltage signal corresponding to a patient. The apparatus
further includes an ICG monitor for processing the ICG voltage
signal sensed by the electrode and an ECG monitor for processing
the ECG voltage signal sensed by the same electrode.
Inventors: |
Harrold; Lewis Norman;
(Georgetown, MA) ; Diciaccio; Anthony Ralph;
(Peabody, MA) |
Correspondence
Address: |
DRIGGS, HOGG, DAUGHERTY & DEL ZOPPO CO., L.P.A.
38500 CHARDON ROAD, DEPT. DLBH
WILLOUGBY HILLS
OH
44094
US
|
Assignee: |
Analogic Corporation
Peabody
MA
|
Family ID: |
43354913 |
Appl. No.: |
12/489156 |
Filed: |
June 22, 2009 |
Current U.S.
Class: |
600/391 ;
600/506; 600/509 |
Current CPC
Class: |
A61B 5/0295 20130101;
A61B 5/282 20210101; A61B 5/053 20130101; A61B 5/026 20130101 |
Class at
Publication: |
600/391 ;
600/509; 600/506 |
International
Class: |
A61B 5/0408 20060101
A61B005/0408; A61B 5/02 20060101 A61B005/02 |
Claims
1. An ICG/ECG electrode, comprising: a first electrode contact; and
a second electrode contact; wherein one of the first or the second
electrode contacts senses both an ICG voltage signal and an ECG
voltage signal.
2. The ICG/ECG electrode of claim 1, further comprising: a
substrate, wherein the first and second electrode contacts are
affixed to the substrate; and a barrier disposed on the substrate
between the first and second electrode contacts.
3. The ICG/ECG electrode of claim 2, wherein the barrier includes
an adhesive material for affixing the electrode contacts to a
patient.
4. The ICG/ECG electrode of claim 2, wherein the barrier mitigates
cross-coupling of an ICG electrical current signal applied to one
of the first or second electrode contacts and the other of the
first or second electrode contacts sensing the ECG voltage
signal.
5. The ICG/ECG electrode of claim 2, wherein the first and second
electrode contacts are affixed to wells of the substrate.
6. The ICG/ECG electrode (128) of claim 1, further comprising:
first and second barriers, wherein the first and second electrode
contacts are surrounded by the first barrier and second barriers
(212, 214).
7. The ICG/ECG electrode of claim 6, wherein the first barrier is a
non-adhesive barrier and the second barrier is an adhesive
barrier.
8. The ICG/ECG electrode of claim 7, wherein the first and second
barriers mitigate cross-coupling of an electrical current signal
applied to one of the first or second electrode contacts and the
other of the first or second electrode contacts sensing the ECG
voltage signal.
9. The ICG/ECG electrode of claim 1, wherein no more than three
ICG/ECG electrodes are used for ICG/ECG monitoring.
10. The ICG/ECG electrode of claim 1, wherein the ICG/ECG electrode
is part of a carrier that includes no more than three ICG/ECG
shared electrodes.
11. A physiologic parameter monitoring apparatus, comprising: a set
of electrodes, including an electrode for sensing both an ICG
voltage signal and an ECG voltage signal corresponding to a
patient; an ICG monitor for processing the ICG voltage signal
sensed by the electrode; and an ECG monitor for processing the ECG
voltage signal sensed by the same electrode.
12. The physiologic parameter monitoring apparatus of claim 11,
further comprising: a synchronizer that time-synchronizes the
sensed ICG and ECG voltage signals.
13. The physiologic parameter monitoring apparatus of claim 12,
wherein the ICG and ECG voltage signals are acquired based on a
common acquisition clock.
14. The physiologic parameter monitoring apparatus of claim 12,
wherein the ICG and ECG voltage signals are acquired based on
different acquisition clocks, and the synchronizer
time-synchronizes the clocks, thereby time-synchronizing the sensed
ICG and ECG voltage signals.
15. The physiologic parameter monitoring apparatus of claim 11,
wherein the ICG and ECG voltage signals are concurrently
sensed.
16. The physiologic parameter monitoring apparatus of claim 11,
wherein the ICG and ECG voltage signals are individually
sensed.
17. The physiologic parameter monitoring apparatus of claim 11,
further comprising: a substrate, wherein the set of electrodes are
affixed to the substrate.
18. The physiologic parameter monitoring apparatus of claim 17,
further comprising: at least one barrier disposed on the substrate,
separating the electrodes.
19. The physiologic parameter monitoring apparatus of claim 18,
wherein the at least one barrier electrically isolates the
electrodes from each other.
20. The physiologic parameter monitoring apparatus of claim 11,
wherein at least a second one of the electrodes is configured for
applying an ICG electrical current signal to the patient.
21. The physiologic parameter monitoring apparatus of claim 20,
further comprising a signal generator, wherein the signal generator
generates a biphasic ICG electrical current signal, which is
supplied to the at least the second one of the electrodes.
22. The physiologic parameter monitoring apparatus of claim 21,
wherein the biphasic ICG electrical current signal has a zero
time-average value.
23. The physiologic parameter monitoring apparatus of claim 21,
wherein the biphasic ICG electrical current signal has a
polarization value equal to about a polarization of the
electrodes.
24. A method, comprising: supplying an ICG electrical current
signal to one electrode of a pair of electrodes of at least one of
no more than three sets of pairs of electrodes affixed to a patient
about the heart of the patient; sensing an ICG voltage signal by
the other electrode of the pair of electrodes; and generating at
least one cardiac parameter based on the sensed ICG voltage signal
and the supplied ICG electrical current signal.
25. The method of claim 24, further comprising computing a
bio-impedance based on the ICG current signal and the ICG voltage
signal, identifying a variation in the bio-impedance over time, and
determining a cardiac parameter based on the identified
variation.
26. The method of claim 24, further comprising: sensing an ECG
voltage signal by the other of the pair of electrodes.
27. The method of claim 26, further comprising: time-synchronizing
the ICG voltage signal and the ECG voltage signal.
28. The method of claim 24, further comprising computing a
bio-impedance based on the ICG current signal and the ICG voltage
signal, wherein the bio-impedance is indicative of an impedance of
blood flow from the heart during a heart cycle.
29. A method, comprising: supplying a first ICG signal to one
electrode of a pair of electrodes affixed to a patient about the
heart of the patient; sensing a second ICG signal by the other
electrode of the pair of electrodes; generating a cardiac parameter
based on the second ICG signal; sensing a signal indicative of
electrical activity of the heart of the patient by the same
electrode that senses the second ICG signal; generating an ECG
signal based on the sensed signal indicative of the electrical
activity of the heart; and presenting the cardiac parameter and the
ECG signal.
30. The method of claim 29, wherein the pair of electrodes is one
of no more than three pairs of electrodes affixed to the patient.
Description
TECHNICAL FIELD
[0001] The following generally relates to a physiologic parameter
monitoring apparatus and is described with particular application
to impedance cardiography (ICG)/electrocardiography (ECG)
monitoring utilizing at least one shared ICG/ECG electrode.
BACKGROUND
[0002] Impedance cardiography (ICG) is used to derive various
cardiac parameters based on the impedance of blood flowing through
the heart. With ICG, historically four pairs of electrodes are
attached to the patient, two pairs at opposing regions about the
neck and two pairs at opposing regions about the front lower chest.
One electrode of each pair is used to inject a pre-determined
electrical current, which travels through a low resistance path in
the body such as blood flowing from the heart. The other electrode
of each pair detects a signal indicative of a change in impedance
(thoracic electric bio-impedance) of the blood flowing from the
heart during each heart cycle based on the change in impedance from
the change in voltage induced by the injected electrical
current.
[0003] Electrocardiography (ECG) is used to sense and record
electrical activity of the heart. For a commonly used Wilson
three-lead ECG, two electrodes are attached to opposing shoulder
regions and a third electrode is attached to the front lower chest
area. The different electrodes sense electrical activity of the
heart during each heart cycle. Historically, difference signals,
corresponding to differences between voltage measurements for pairs
of electrodes, are generated and graphically presented as waves
(e.g., on a display or paper) and provide information about the
heart. This information can be used to identify electrical rhythms
of the heart, including abnormal electrical rhythms, heart muscle
damage, and/or other information.
[0004] When the above noted ICG and three-lead ECG configurations
are used in conjunction, a relatively large number of electrodes
(e.g., seven, or four electrode pairs for ICG and three separate
and distinct electrodes for ECG) are affixed to the patient. With
five and twelve lead ECG configurations, even more electrodes are
attached to the patient. Moreover, cables are run from each
electrode to the ICG and ECG monitoring apparatuses.
SUMMARY
[0005] Aspects of the application address the above matters, and
others.
[0006] In one aspect, an ICG/ECG electrode includes a first
electrode contact and a second electrode contact. At least one of
the first or second electrode contacts senses both an ICG voltage
signal and an ECG voltage signal.
[0007] In another aspect, a physiologic parameter monitoring
apparatus includes a set of electrodes, including an electrode for
sensing both an ICG voltage signal and an ECG voltage signal
corresponding to a patient. The apparatus further includes an ICG
monitor for processing the ICG voltage signal sensed by the
electrode and an ECG monitor for processing the ECG voltage signal
sensed by the electrode.
[0008] In another aspect, a method includes supplying a ICG current
signal to one electrode of a pair of electrodes of at least one of
no more than three sets of pairs of electrodes affixed to a patient
about the heart of the patient, sensing an ICG voltage signal by
the other electrode of the pair of electrodes, and generating a
cardiac parameter based on the ICG current signal and the ICG
voltage signal.
[0009] In another aspect, a method includes supplying a first ICG
signal to one electrode of a pair of electrodes affixed to a
patient about the heart of the patient. The method further includes
sensing a second ICG signal by the other electrode of the pair of
electrodes and generating a cardiac parameter based on the second
ICG signal. The method further includes sensing a signal indicative
of an electrical activity of the heart of the patient by the same
electrode that senses the second ICG signal and generating an ECG
signal based on the sensed signal indicative of an electrical
activity of the heart. The method further includes presenting the
cardiac parameter and the ECG signal indicative of heart electrical
activity.
[0010] Those skilled in the art will recognize still other aspects
of the present application upon reading and understanding the
attached description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The application is illustrated by way of example and not
limitation in the figures of the accompanying drawings, in which
like references indicate similar elements and in which:
[0012] FIG. 1 illustrates an example physiologic monitoring
apparatus;
[0013] FIG. 2 illustrates an example shared ICG/ECG electrode;
[0014] FIG. 3 illustrates an example electrode carrier;
[0015] FIG. 4 illustrates another example electrode carrier;
[0016] FIG. 5 illustrates another example electrode carrier;
[0017] FIG. 6 illustrates an example method; and
[0018] FIG. 7 illustrates another example method.
DETAILED DESCRIPTION
[0019] FIG. 1 illustrates a physiologic monitoring apparatus 100 in
connection with a patient 102. The illustrated physiologic
monitoring apparatus 100 includes a physiologic parameter monitor
104, with an impedance cardiography (ICG) monitor 106 and an
(electrocardiography) ECG monitor 108, and is configured for
concurrent and individual ICG/ECG monitoring.
[0020] The ICG monitor 106 includes a current transmitter 110 and a
voltage receiver 112. The current transmitter 110 is configured to
supply a predetermined ICG electrical current signal to be applied
to the patient 102. The voltage receiver 112 is configured to
receive a sensed voltage signal. The voltage signal is used to
determine a bio-impedance of blood flowing from the heart of the
patient 102 due to the applied current signal from the ICG
transmitter 110.
[0021] A signal generator 114 generates the ICG current signal. In
the illustrated embodiment, the signal generator 114 generates a
biphasic electrical current signal in a range of about one (1) to
four (4) milliamps (mA). The biphasic nature of the current signal
provides for a current with a substantially zero time average (or
essentially no DC component), which can mitigate electrode
polarization, which may affect ECG voltage signal reception and/or
processing. The frequency of the generated current signal is in a
range of about seventy thousand Hertz (70 k Hz) to about one
hundred and fifty thousand Hz (150 k Hz), which allows for passing
the current signal through the skin.
[0022] An ICG voltage signal processor 116 processes the received
sensed voltage signal. The ICG voltage signal processor 116
determines various information based on the sensed voltage signal
from the sensing electrodes. Example of such information includes,
but is not limited to, cardiac output, heart rate, and/or other
cardiac information.
[0023] The ECG monitor 108 includes a receiver 118 configured to
receive a sensed voltage signal indicative of the electrical
activity of the heart. An ECG signal processor 120 processes the
received sensed electrical signal.
[0024] A data synchronizer 122 synchronizes data acquisition of the
bio-impedance and heart electrical activity signals.
Synchronization can be time synchronized through a crystal
controlled or other timing device. In one instance, the signals are
synchronized through a common clock. In another instance, the
signals are sampled based on separate clocks, and the data
synchronizer 122 synchronizes the data by synchronizing on the two
clocks. The timing of the signals can also be used to facilitate
discriminating between the signals and noise.
[0025] An output device 124 allows for presenting the ICG and/or
ECG signals on a display, paper and/or other human readable
medium.
[0026] An interface 126 is configured to route the transmitted ICG
electrical current from the physiologic parameter monitor 104 to
the patient 102 and/or the sensed signals from the patient 102
respectively to the ICG and ECG monitors 106 and 108.
[0027] A plurality of sets of electrodes 128.sub.1, 128.sub.2 and
128.sub.N (collectively referred to as sets of electrodes 128) are
affixed to the patient 102. In the illustrated embodiment, N=3 and
the sets of electrodes 128 are positioned on the patient 102 to
facilitate applying the ICG electrical current signal in connection
with predetermined anatomy (e.g., the pulmonary artery and aorta)
and sensing signals with respect to such anatomy. Note that the
illustrated positioning of the electrode pairs 128 is similar to
three-lead ECG electrode positioning. As described in greater
detail below, at least one electrode of at least one of the sets of
electrodes 128 is shared for both ICG and ECG monitoring. In one
instance, sharing an electrode contact as such allows for reducing
the overall number of electrodes affixed to the patient 102
relative to a configuration in which separate electrodes are used
for ICG and ECG monitoring.
[0028] A communications channel 130 such as a cable or the like
includes respective sets of connectors 132.sub.1, 132.sub.2 and
132.sub.N (collectively referred to as connectors 132) that connect
to and couple the plurality of sets of pairs of electrodes
128.sub.1, 128.sub.2 and 128.sub.N and the physiologic parameter
monitor 104.
[0029] FIG. 2 illustrates an example set of electrodes 128.sub.K.
The set of electrodes 128.sub.K includes a pair of electrodes,
including first and second electrodes or electrode contacts 202 and
204, affixed to a substrate 206 such as a patch or the like.
[0030] The illustrated electrodes 202 and 204 are circular in
shape. In other embodiment, the electrodes 202 and 204 are
otherwise shaped, such as polygonally shaped, elliptically shaped,
or otherwise shaped. The electrodes 202 and 204 include a
conductive material such as silver-chloride material and/or other
conductive material.
[0031] The first and second electrodes 202 or 204 are disposed in
respective separate wells 208 and 210. The first and second
electrodes 202 or 204 are successively surrounded by first and
second barriers 212 and 214. The illustrated barriers 212 and 214
are "O" or donut shaped and form concentric rings around the
electrodes 202 or 204.
[0032] The first barrier 212 includes a non-adhesive material and
the second barrier 214 includes an adhesive material. In the
illustrated embodiment, the adhesive material is a gel and
mitigates cross-coupling between the supplied ICG current and the
sensed heart electrical activity signal, which may facilitate
mitigating corruption of the sensed heart electrical activity by
the ICG signal. In other embodiments, the adhesive material
includes another electrically insulating material.
[0033] A third barrier 216 is linearly or line shaped and disposed
along the substrate 206 between the first and second electrodes 202
or 204. In another embodiment, the third barrier 216 is irregular
or otherwise shaped. Similar to the second barrier 214, the third
216 includes an adhesive material, and the adhesive material can be
in the form of a gel and also mitigate cross-coupling between the
supplied ICG current signal and the sensed signals.
[0034] One of the first or second electrodes 202 or 204 is used for
supplying the ICG electrical current signal. The other of the
electrodes 202 or 204 is used to concurrently or individually sense
(by the ICG monitor 106 and the ECG monitor 108) the bio-impedance
and the heart electrical activity voltage signals.
[0035] FIGS. 3, 4 and 5 illustrate various non-limiting embodiments
in which the sets of electrodes 128 are carried by a carrier.
[0036] In FIG. 3, three sets of electrodes 128 are carried by an
"L" shaped carrier 300. The "L" shaped carrier 300 removeably
affixes to the patient via an adhesive such as the adhesives 214
and 216 of the electrodes 128 described in connection with FIG. 2.
In another embodiment, the carrier 300 additionally includes one or
more elements for securing the carrier 300 to the patient 102.
[0037] Turning to FIG. 4, a carrier 400 is substantially similar to
the carrier 300 except that the carrier 400 is triangular
shaped.
[0038] Likewise, in FIG. 5, a carrier 500 is substantially similar
to the carrier 300 except for its shape. As shown in FIG. 5, the
carrier 500 is "O" shaped.
[0039] Other shapes are also contemplated herein. For example, in
another instance, the carrier is configured to conform to the
contour of the body.
[0040] In one instance, the carriers 300, 400 and 500 are
positioned on the patient 102 so that the electrodes 128 are
located about the heart of the patient 102 as described herein.
[0041] Variations are contemplated.
[0042] In another embodiment, the ICG and the ECG monitors 106 and
108 are part of separate physiologic parameter monitoring
devices.
[0043] In another embodiment, one or both of the ICG and the ECG
monitors 106 and 108 are portable units. In such an embodiment, one
or both of the ICG and the ECG monitors 106 and 108 are configured
to attach to the carriers 300, 400, and/or 500.
[0044] In another embodiment, the sets of electrodes 128 include
wireless transceivers and communicate with the monitor 104 via the
wireless transceivers.
[0045] In another embodiment, the individual sets of connectors
132.sub.1, 132.sub.2 and 132.sub.N are included in separate
cables.
[0046] In another embodiment, the signal generator 114 generates a
signal with an average value that produces a polarization voltage
that opposes the polarization voltage of the contacts 202 and 204.
Where the electrodes 202 and 204 include a silver-chloride
material, such a polarization voltage is in a range from about two
hundred and fifty (250) milliVolts (mV) to about three hundred and
fifty (350) mV.
[0047] Example methods are described.
[0048] FIG. 6 illustrates a method for acquiring an ICG electrical
voltage signal.
[0049] At 602, three sets of pairs of electrodes 128 are affixed to
the patient 102 about the heart of the patient 102. As described
herein, the sets of electrodes 128 may be individually affixed to
the patient 102 or part of the carrier 300, 400, or 500.
[0050] At 604, an ICG electrical current signal is supplied to one
electrode 202 or 204 of a pairs of electrodes 128. The ICG current
signal generally is an electrical alternating current signal that
traverses a path of lower resistance such as the blood flowing from
the heart such as from the pulmonary artery and/or aorta.
[0051] At 606, an ICG voltage signal is sensed by the other
electrode 202 or 204 of the pair of electrodes 128.
[0052] At 608, a bio-impedance of the blood flowing from the heart
is computed based on the sensed ICG voltage signal and the applied
ICG current signal. The bio-impedance and hence the sensed signal
varies as the heart expands and contracts and blood flow velocity
varies.
[0053] At 608, the sensed signal is processed to determine at least
one cardiac parameter.
[0054] FIG. 7 illustrates a method for acquiring an ICG and an ECG
signal. It is to be appreciated that the ordering of the following
acts is provided for explanatory purposes and other ordering is
contemplated herein.
[0055] At 702, a pair of electrodes 128 is affixed to the patient
102 about the heart of the patient 102 as described herein.
[0056] At 704, an ICG electrical current signal is supplied to one
electrode 202 or 204 of the pair of electrodes 128.
[0057] At 706, an ICG voltage signal is sensed by the other
electrode 202 or 204 of the pair of electrodes 128.
[0058] At 708, an ECG voltage signal is sensed by the electrode
sensing the ICG voltage signal.
[0059] At 710, the sensed ICG and ECG voltage signals are
time-synchronized.
[0060] At 712, a cardiac parameter is determined based on the
sensed ICG voltage signal and the applied ICG current signal.
[0061] The above may be implemented by way of computer readable
instructions, which when executed by a computer processor(s), cause
the processor(s) to carry out the acts. The instructions can be
stored in a computer readable storage medium associated with or
otherwise accessible to the relevant computer.
[0062] The application has been described with reference to various
embodiments. Modifications and alterations will occur to others
upon reading the application. It is intended that the invention be
construed as including all such modifications and alterations,
including insofar as they come within the scope of the appended
claims and the equivalents thereof.
* * * * *