U.S. patent application number 12/209294 was filed with the patent office on 2009-03-19 for tracking and security for adherent patient monitor.
This patent application is currently assigned to Corventis, Inc.. Invention is credited to Badri Amurthur, Mark J. Bly, Kristofer J. James, Yatheendhar D. Manicka, Scott T. Mazar, Jerry S. Wang.
Application Number | 20090076346 12/209294 |
Document ID | / |
Family ID | 40452528 |
Filed Date | 2009-03-19 |
United States Patent
Application |
20090076346 |
Kind Code |
A1 |
James; Kristofer J. ; et
al. |
March 19, 2009 |
Tracking and Security for Adherent Patient Monitor
Abstract
A heart failure patient management system includes a detecting
system. The detecting system includes an adherent device configured
to be coupled to a patient. The adherent device includes a
plurality of sensors to monitor physiological parameters of the
patient to determine heart failure status. At least one ID may be
coupled to the adherent device that is addressable and unique to
each adherent device. A wireless communication device is coupled to
the plurality of sensors and configured to transfer patient data
directly or indirectly from the plurality of sensors to a remote
monitoring system. The remote monitoring system is coupled to the
wireless communication device. An energy management device may be
coupled to the plurality of sensors
Inventors: |
James; Kristofer J.; (Eagan,
MN) ; Amurthur; Badri; (Los Gatos, CA) ; Bly;
Mark J.; (Falcon Heights, MN) ; Manicka; Yatheendhar
D.; (Woodbury, MN) ; Mazar; Scott T.;
(Woodbury, MN) ; Wang; Jerry S.; (Blaine,
MN) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Corventis, Inc.
San Jose
CA
|
Family ID: |
40452528 |
Appl. No.: |
12/209294 |
Filed: |
September 12, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60972537 |
Sep 14, 2007 |
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60972336 |
Sep 14, 2007 |
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60972340 |
Sep 14, 2007 |
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61055666 |
May 23, 2008 |
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61079746 |
Jul 10, 2008 |
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Current U.S.
Class: |
600/301 ;
235/380 |
Current CPC
Class: |
A61B 5/6846 20130101;
A61N 1/36535 20130101; A61B 5/021 20130101; A61B 5/282 20210101;
A61N 1/36542 20130101; A61B 5/02455 20130101; A61B 2560/0209
20130101; A61N 1/37282 20130101; A61B 2560/0412 20130101; A61B
5/349 20210101; A61B 5/6833 20130101; A61N 1/36592 20130101; A61B
5/4869 20130101; A61N 1/36521 20130101; A61B 5/318 20210101; A61B
5/7232 20130101; A61B 5/0006 20130101; A61B 5/1118 20130101; A61B
7/003 20130101; A61B 5/1116 20130101; A61B 2562/08 20130101; A61B
5/7275 20130101; A61B 5/0022 20130101; A61B 5/02405 20130101; G06Q
2220/00 20130101; G16H 40/67 20180101; A61B 5/0809 20130101; G16H
10/60 20180101; A61B 5/02438 20130101; A61B 5/0816 20130101; A61B
5/02055 20130101 |
Class at
Publication: |
600/301 ;
235/380 |
International
Class: |
A61B 5/02 20060101
A61B005/02; G06F 19/00 20060101 G06F019/00 |
Claims
1. A patient monitoring system, comprising: a patient detecting
system for measuring the patient including, an adherent device
configured to be coupled to a patient, the adherent device
including a plurality of sensors that monitors physiological
parameters, at least one ID coupled to the adherent device that is
addressable and unique to the adherent device; a wireless
communication device coupled to the plurality of sensors; and a
remote monitoring system coupled to the wireless communication
device, the wireless communication system configured to transfer
patient data from the plurality of sensors to the remote monitoring
system.
2. The system of claim 1, wherein the at least one ID comprises a
memory component.
3. The system of claim 1, wherein the at least one ID comprises a
sensor ID.
4. The system of claim 3, wherein the sensor ID comprises a memory
component.
5. The system of claim 1, wherein the adherent device comprises a
patch set configured to be coupled to the patient.
6. The system of claim 5, wherein the at least one ID is unique to
each adherent device.
7. The system of claim 5, wherein the at least one ID comprises a
removable memory component with a unique patient ID that is
configured to be reused when patches associated with the adherent
patch are replaced.
8. The system of claim 5, wherein the patch set is linked together
and comprises replacement patches that are linked.
9. The system of claim 8, wherein the patch set is linked by
hardware.
10. The system of claim 8, wherein the patch set is linked by
software at the remote monitoring system.
11. The system of claim 5, wherein the adherent device is
configured to register with the remote monitoring system when the
adherent device is given to the patient.
12. The system of claim 11, wherein the adherent device is
configured register via a web site and patient data is uploaded to
the adherent device.
13. The system of claim 11, wherein a modem assigned to the patient
is configured to link to the adherent device.
14. The system of claim 13, wherein the modem is configured to
determine which patch is sending information to the modem.
15. The system of claim 14, wherein the modem is configured to
communicate only with the patch set of the patient and the modem is
configured to communicate only with patches associated with the
modem.
16. The system of claim 13, wherein the modem is at the remote
monitoring system or at the patient detecting system.
17. The system of claim 13, wherein registration with the remote
monitoring system occurs automatically each time a patch of the
adherent device is put on the patient.
18. The system of claim 17, wherein on registration ID information
is sent to the remote monitoring system.
19. The system of claim 1, wherein the at least one ID is coupled
to the adherent device with an ID sensor.
20. The system of claim 19, wherein the ID sensor is configured to
transmit to the remote monitoring system.
21. The system of claim 19, wherein the ID sensor is configured to
associate data from the plurality of sensors to the remote
monitoring system.
22. The system of claim 19, wherein the ID sensor is not
incorporated in the adherent device.
23. The system of claim 19, wherein the ID sensor is configured to
associate the adherent patch with the patient with at least one of,
caller ID, an RFID tag on the patient, a body tattoo, fingerprint
ID and GPS.
24. The system of claim 19, wherein the ID sensor is configured to
produce a first output that has protected patient data with
restricted communication and a second output that has general
device and patient information for general communication.
25. The system of claim 24, wherein access to the protected patient
data requires an additional security verification.
26. The system of claim 24, wherein at least a portion of the
protected patient data is encrypted.
27. The system of claim 25, wherein the addition security
verification comprises at least one of a skin tattoo with an
adherent device reader, a modem identification, an encrypted
communication, an encrypted data storage on the adherent device, a
biometric ID or an x-ray ID tag.
28. The system of claim 1, wherein the patient parameters comprise
parameters to determine heart failure status of the patient.
29. The system of claim 1, wherein the adherent device is housed in
a tamper proof housing prior to placement on the patient.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application claims the benefit under 35 USC
119(e) of U.S. Provisional Application Nos. 60/972,340, 60/972,537,
60/972,336 all filed Sep. 14, 2007, 61/055,666 filed May 23, 2008,
and 61/079,746 filed Jul. 10, 2008; the full disclosures of which
are incorporated herein by reference in their entirety.
[0002] The subject matter of the present application is related to
the following applications: 60/972,512; 60/972,329; 60/972,354;
60/972,616; 60/972,363; 60/972,343; 60/972,581; 60/972,629;
60/972,316; 60/972,333; 60/972,359 all of which were filed on Sep.
14, 2007; 61/046,196 filed Apr. 18, 2008; 61/047,875 filed Apr. 25,
2008; and 61/055,645, 61/055,656, 61/055,662 all filed May 23,
2008.
[0003] The following applications are being filed concurrently with
the present application, on Sep. 12, 2008: Attorney Docket Nos.
026843-000110US entitled "Multi-Sensor Patient Monitor to Detect
Impending Cardiac Decompensation Prediction"; 026843-000220US
entitled "Adherent Device with Multiple Physiological Sensors";
026843-000410US entitled "Injectable Device for Physiological
Monitoring"; 026843-000510US entitled "Delivery System for
Injectable Physiological Monitoring System"; 026843-000620US
entitled "Adherent Device for Cardiac Rhythm Management";
026843-000710US entitled "Adherent Device for Respiratory
Monitoring"; 026843-000810US entitled "Adherent Athletic Monitor";
026843-000910US entitled "Adherent Emergency Monitor";
026843-001320US entitled "Adherent Device with Physiological
Sensors"; 026843-001410US entitled "Medical Device Automatic
Start-up upon Contact to Patient Tissue"; 026843-001900US entitled
"System and Methods for Wireless Body Fluid Monitoring";
026843-002010US entitled "Adherent Cardiac Monitor with Advanced
Sensing Capabilities"; 026843-002410US entitled "Adherent Device
for Sleep Disordered Breathing"; 026843-002710US entitled "Dynamic
Pairing of Patients to Data Collection Gateways"; 026843-003010US
entitled "Adherent Multi-Sensor Device with Implantable Device
Communications Capabilities"; 026843-003110US entitled "Data
Collection in a Multi-Sensor Patient Monitor"; 026843-003210US
entitled "Adherent Multi-Sensor Device with Empathic Monitoring";
and 026843-003310US entitled "Energy Management for Adherent
Patient Monitor."
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] This invention relates generally to systems and methods that
use wireless physiological monitoring, and more particularly to
systems and methods for heart failure patient monitoring.
[0006] Frequent monitoring of patients permits the patients'
physician to detect worsening symptoms as they begin to occur,
rather than waiting until a critical condition has been reached. As
such, home monitoring of patients with chronic conditions is
becoming increasingly popular in the health care industry for the
array of benefits it has the potential to provide. Potential
benefits of home monitoring are numerous and include: better
tracking and management of chronic disease conditions, earlier
detection of changes in the patient condition, and reduction of
overall health care expenses associated with long term disease
management. The home monitoring of a number of diverse "chronic
diseases" is of interest, where such diseases include diabetes,
dietary disorders such as anorexia and obesity, anxiety,
depression, epilepsy, respiratory diseases, AIDS and other chronic
viral conditions, conditions associated with the long term use of
immunosuppressants, e.g. in transplant patients, asthma, chronic
hypertension, chronic use of anticoagulants, and the like.
[0007] Of particular interest in the home monitoring sector of the
health care industry is the remote monitoring of patients with
heart failure (HF), also known as congestive heart failure. HF is a
syndrome in which the heart is unable to efficiently pump blood to
the vital organs. Most instances of HF occur because of a decreased
myocardial capacity to contract (systolic dysfunction). However, HF
can also result when an increased pressure-stroke-volume load is
imposed on the heart, such as when the heart is unable to expand
sufficiently during diastole to accommodate the ventricular volume,
causing an increased pressure load (diasystolic dysfunction).
[0008] In either case, HF is characterized by diminished cardiac
output and/or damming back of blood in the venous system. In HF,
there is a shift in the cardiac function curve and an increase in
blood volume caused in part by fluid retention by the kidneys.
Indeed, many of the significant morphologic changes encountered in
HF are distant from the heart and are produced by the hypoxic and
congestive effects of the failing circulation upon other organs and
tissues. One of the major symptoms of HF is edema, which has been
defined as the excessive accumulation of interstitial fluid, either
localized or generalized.
[0009] HF is the most common indication for hospitalization among
adults over 65 years of age, and the rate of admission for this
condition has increased progressively over the past two decades. It
has been estimated that HF affects more than 3 million patients in
the U.S. (J. B. O'Connell et al., J. Heart Lung Transpl. (1993)
13(4):S107-112).
[0010] In the conventional management of HF patients, where help is
sought only in crisis, a cycle occurs where patients fail to
recognize early symptoms and do not seek timely help from their
care-givers, leading to emergency department admissions (Miller, P.
Z., 1995, "Home monitoring for congestive heart failure patients,"
Caring Magazine, August 1995: 53-54). Recently, a prospective,
randomized trial of 282 patients was conducted to assess the effect
of the intervention on the rate of admission, quality of life, and
cost of medical care. In this study, a nurse-directed, multi
disciplinary intervention (which consisted of comprehensive
education of the patient and family, diet, social-service
consultation and planning, review of medications, and intensive
assessment of patient condition and follow-up) resulted in fewer
readmissions than the conventional treatment group and a
concomitant overall decrease in the cost of care (M. W. Rich et
al., New Engl. J. Med. (1995) 333:1190-95).
[0011] Similarly, comprehensive discharge planning and a home
follow-up program was shown to decrease the number of readmissions
and total hospital charges in an elderly population (M. Naylor et
al., Amer. College Physicians (1994) 120:999-1006). Therefore, home
monitoring is of particular interest in the HF management segment
of the health care industry.
[0012] Another area in which home-monitoring is of particular
interest is in the remote monitoring of a patient parameter that
provides information on the titration of a drug, particularly with
drugs that have a consequential effect following administration,
such as insulin, anticoagulants, ACE inhibitors, .beta.-blockers,
diuretics, etc.
[0013] Although a number of different home monitoring systems have
been developed, there is continued interest in the development of
new monitoring systems. Of particular interest would be the
development of a system that provides for improved patient
compliance, ease of use, etc. Of more particular interest would be
the development of such a system that is particularly suited for
use in the remote monitoring of patients suffering from HF.
[0014] There is a need for an improved home monitoring of patients
with chronic conditions. There is a further need for an improved HF
monitoring system.
[0015] 2. Description of the Background Art
[0016] The following U.S. patents and Publications may describe
relevant background art: U.S. Pat. Nos. 4,121,573; 4,955,381;
4,981,139; 5,080,099; 5,353,793; 5,511,553; 5,544,661; 5,558,638;
5,724,025; 5,772,586; 5,862,802; 5,944,659; 6,047,203; 6,117,077;
6,129,744; 6,225,901; 6,385,473; 6,416,471; 6,454,707; 6,527,711;
6,527,729; 6,551,252; 6,595,927; 6,595,929; 6,605,038; 6,645,153;
6,659,947; 6,821,249; 6,980,851; 6,988,989; 7,020,508; 7,054,679;
7,130,396; 7,153,262; 2003/0092975; 2004/0225199; 2005/0113703;
2005/0131288; 2006/0010090; 2006/0031102; 2006/0074462;
2006/0089679; 2006/0122474; 2006/0142820; 2006/0155183;
2006/0202816; 2006/0224051; 2006/0235281; 2006/0264730;
2007/0015973; 2007/0021678; 2007/0038038; and 2007/0180047.
BRIEF SUMMARY OF THE INVENTION
[0017] Accordingly, an object of the present invention is to
provide an improved remote monitoring system of patients, for
example patients with chronic conditions.
[0018] Another object of the present invention is to provide an
improved remote monitoring system for HF patients.
[0019] A further object of the present invention is to provide a
remote monitoring system for HF patients with at least one of an
energy management device or at least one ID coupled to sensors to
monitor a patient.
[0020] A further object of the present invention is to provide a
remote monitoring system for HF patients that uses outputs of a
plurality of sensors have multiple features to enhance
physiological sensing performance.
[0021] Another object of the present invention is to provide a
remote monitoring system for HF patients.
[0022] Still a further object of the present invention is to
provide a remote monitoring system for HF patients where heart
failure status is determined by a weighted combination change in
sensor outputs.
[0023] Yet another object of the present invention is to provide a
remote monitoring system for HF patients where heart failure status
is determined when a rate of change of at least two sensor outputs
is an abrupt change in the sensor outputs as compared to a change
in the sensor outputs over a longer period of time.
[0024] A further object of the present invention is to provide a
remote monitoring system for HF patients where heart failure status
is determined by a tiered combination of at least a first and a
second sensor output, with the first sensor output indicating a
problem that is then verified by at least a second sensor
output.
[0025] Another object of the present invention is to provide a
remote monitoring system for HF patients where heart failure status
is determined by a variance from a baseline value of sensor
outputs.
[0026] Yet another object of the present invention is to provide a
remote monitoring system for HF patients where baseline values are
defined by a look up table.
[0027] Still a further object of the present invention is to
provide a remote monitoring system for HF patients where heart
failure status is determined when a first sensor output is at a
high value that is greater than a baseline value, and at least one
of a second a third sensor outputs is at a high value also
sufficiently greater than a baseline value to indicate heart
failure status.
[0028] Another object of the present invention is to provide a
remote monitoring system for HF patients where heart failure status
is determined by time weighting the outputs of at least first,
second and third sensors, and the time weighting indicates a recent
event that is indicative of the heart failure status.
[0029] These and other objects of the present invention can be
achieved in many embodiments comprising a patient monitoring system
that includes a detecting system. The detecting system has, (i) an
adherent device configured to be coupled to a patient, the adherent
device including a plurality of sensors that monitors physiological
parameters of the patient, for example physiological parameters to
determine heart failure status, (ii) at least one ID coupled to the
adherent device that is addressable and unique to each adherent
device, and (iii) a wireless communication device coupled to the
plurality of sensors and configured to transfer patient data from
the plurality of sensors to a remote monitoring system. The remote
monitoring system is coupled to the wireless communication device.
An energy management device may be coupled to the plurality of
sensors so as to minimize power consumption when the patch is worn
by the patient.
[0030] In a first aspect, embodiments of the present invention
provide a patient monitoring system. The patient monitoring system
comprises a patient detecting system for measuring the patient. The
patient monitoring system includes an adherent device configured to
be coupled to a patient. The adherent device includes a plurality
of sensors that monitors physiological parameters. The patient
monitoring system also includes at least one ID coupled to the
adherent device. The at least one ID is addressable and unique to
the adherent device. The patient monitoring system also includes a
wireless communication device coupled to the plurality of sensors
and a remote monitoring system. The remote monitoring system is
coupled to the wireless communication device. The wireless
communication system is configured to transfer patient data from
the plurality of sensors to the remote monitoring system.
[0031] In many embodiments, the at least one ID comprises a memory
component. In many embodiments, the ID comprises a sensor ID, which
may comprise a memory component.
[0032] In many embodiments, the adherent device comprises a patch
set configured to be coupled to the patient. The at least one ID
may be unique to each adherent device. The at least one ID may
comprise a removable memory component with a unique patient ID that
is configured to be reused when patches associated with the
adherent patch are replaced. The patch set may be linked together
and may comprise replacement patches that are linked. In some
embodiments, the patch set is linked by hardware. In some
embodiments, the patch set is linked by software at the remote
monitoring system.
[0033] In some embodiments, the adherent device is configured to
register with the remote monitoring system when the adherent device
is given to the patient. The adherent device may be configured to
register via a web site and patient data is uploaded to the
adherent device. A modem assigned to the patient may be configured
to link to the adherent device. The modem may be configured to
determine which patch is sending information to the modem. The
modem may be configured to communicate only with the patch set of
the patient and the modem may be configured to communicate only
with patches associated with the modem. The modem may be at the
remote monitoring system or at the patient detecting system.
Registration with the remote monitoring system may occur
automatically each time a patch of the adherent device is put on
the patient. On registration, ID information may be sent to the
remote monitoring system.
[0034] In many embodiments, the at least one ID is coupled to the
adherent device with an ID sensor. In some embodiments, the ID
sensor is configured to transmit to the remote monitoring system.
In some embodiments, the ID sensor is configured to associate data
from the plurality of sensors to the remote monitoring system. In
some embodiments, the ID sensor is not incorporated in the adherent
device. In some embodiments, the ID sensor is configured to
associate the adherent patch with the patient with at least one of,
caller ID, an RFID tag on the patient, a body tattoo, fingerprint
ID and GPS. In some embodiments, the ID sensor is configured to
produce a first output that has protected patient data with
restricted communication and a second output that has general
device and patient information for general communication. Access to
the protected patient data may require an additional security
verification. At least a portion of the protected patient data may
be encrypted. The addition security verification may comprise at
least one of a skin tattoo with an adherent device reader, a modem
identification, an encrypted communication, an encrypted data
storage on the adherent device, a biometric ID or an x-ray ID
tag.
[0035] In many embodiments, the patient parameters comprise
parameters to determine heart failure status of the patient.
[0036] In many embodiments, the adherent device is housed in a
tamper proof housing prior to placement on the patient.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1 is a block diagram illustrating one embodiment of a
patient monitoring system of the present invention;
[0038] FIGS. 2A and 2B illustrate exploded view and side views of
embodiments of an adherent device with sensors configured to be
coupled to the skin of a patient for monitoring purposes;
[0039] FIG. 3 illustrates one embodiment of an energy management
device that is coupled to the plurality of sensors of FIG. 1;
[0040] FIG. 4 illustrates one embodiment of present invention
illustrating logic resources configured to receive data from the
sensors and/or the processed patient for monitoring purposes,
analysis and/or prediction purposes;
[0041] FIG. 5 illustrates an embodiment of the patient monitoring
system of the present invention with a memory management
device;
[0042] FIG. 6 illustrates an embodiment of the patient monitoring
system of the present invention with an external device coupled to
the sensors;
[0043] FIG. 7 illustrates an embodiment of the patient monitoring
system of the present invention with a notification device;
[0044] FIG. 8 is a block diagram illustrating an embodiment of the
present invention with sensor leads that convey signals from the
sensors to a monitoring unit at the detecting system, or through a
wireless communication device to a remote monitoring system;
[0045] FIG. 9 is a block diagram illustrating an embodiment of the
present invention with a control unit at the detecting system
and/or the remote monitoring system;
[0046] FIG. 10 is a block diagram illustrating an embodiment of the
present invention where a control unit encodes patient data and
transmits it to a wireless network storage unit at the remote
monitoring system;
[0047] FIG. 11 is a block diagram illustrating one embodiment of an
internal structure of a main data collection station at the remote
monitoring system of the present invention; and
[0048] FIG. 12 is a flow chart illustrating an embodiment of the
present invention with operation steps performed by the system of
the present invention in transmitting information to the main data
collection station.
DETAILED DESCRIPTION OF THE INVENTION
[0049] Embodiments of the present invention comprise an adherent
multi-sensor patient monitor capable of tracking a patient's
physiological status. The monitor can be configured for and
detecting and predicting physiological events, for example negative
physiological events. The device may comprise an intelligent
combination of sensors to enhance detection and prediction
capabilities, for example to detect cardiac decompensation.
[0050] Decompensation is failure of the heart to maintain adequate
blood circulation. Although the heart can maintain at least some
pumping of blood, the quantity is inadequate to maintain healthy
tissues. Several symptoms can result from decompensation including
pulmonary congestion, breathlessness, faintness, cardiac
palpitation, edema of the extremities, and enlargement of the
liver. Cardiac decompensation can result in slow or sudden death.
Sudden Cardiac Arrest (hereinafter "SCA"), also referred to as
sudden cardiac death, is an abrupt loss of cardiac pumping function
that can be caused by a ventricular arrhythmia, for example
ventricular tachycardia and/or ventricular fibrillation. Although
decompensation and SCA can be related in that patients with
decompensation are also at an increased risk for SCA,
decompensation is primarily a mechanical dysfunction caused by
inadequate blood flow, and SCA is primarily an electrical
dysfunction caused by inadequate and/or inappropriate electrical
signals of the heart.
[0051] The combination of sensors can be used to detect cardiac
decompensation, which can be difficult to diagnose in the early
stages.
[0052] The adherent patch device may comprise an energy management
device configured with a variety of energy management features. The
energy management device comprises circuitry configured for energy
management, for example at least one of timer circuitry, processor
circuitry, or programmable array logic (PAL) circuitry. The energy
management device may be configured with at least one of the
following:
1. Patch Activation
[0053] a. Patch can be activated [0054] b. Mechanism for removing
from storage mode [0055] i. Automatic impedance/physiological
variable trigger [0056] ii. Tab pull (e.g. integrated into package)
[0057] iii. Battery insertion [0058] iv. Hall/reed switch [0059] v.
Breakable glass capsule [0060] vi. Dome switch [0061] vii. Light
activated (storage in opaque package) [0062] viii. Pressure
activated (storage in vacuum sealed package) [0063] ix. Temperature
(body temperature activated) [0064] x. Temp/activity/physiological
variable within range [0065] xi. Connection between electronics and
patch [0066] xii. Exposure to air (zinc-air battery, etc.) [0067]
xiii. Capacitive skin sensor
2. Intermittent Sampling
3. Data Management
[0067] [0068] a. Data compression [0069] b. Prioritizing sensor
data--all sensors monitored in real time--subset of sensors stored
for report [0070] c. Noise blanking [0071] d. Low-power caching
[0072] e. Decimate old data [0073] f. EOC dropoff to transfer data
[0074] g. ERI: call center notification
4. Power/Energy Generation/Storage
[0074] [0075] a. Thermo-electric unit [0076] b. Kinetic [0077] c.
Fuel cell [0078] d. Solar powered [0079] e. Zinc-air [0080] f.
Faraday generator [0081] g. Internal combustion [0082] h. Nuclear
powered [0083] i. Micro-battery [0084] j. Acoustic [0085] k.
Inductive [0086] l. Rechargeable
5. Energy Management
[0086] [0087] a. Modulate clock speed to optimize energy [0088] b.
Physiological (e.g. sleep) control of sensors--duty cycle, sample
rate control (based on always-on sensor)
6. Energy Monitoring
[0088] [0089] a. Monitor cell voltage drop--unload cell [0090] b.
Monitor coulomb-meter or other battery monitor
[0091] In one embodiment, illustrated in FIG. 1, the present
invention is a patient management system, generally denoted as 10,
that tracks the patient's physiological status, detects and
predicts negative physiological events. In one embodiment, a
plurality of sensors are used in combination to enhance detection
and prediction capabilities as more fully explained below.
[0092] Embodiments may comprise a patient management system
comprising an adherent patch that is applied to the patient, for
example for monitoring heart failure patients. The patch can be
configured to monitor physiological patient parameters,
communicates wirelessly with a remote center, and provides alerts
when necessary. The patient management system may comprise a
variety of tracking and security devices.
[0093] The heart failure patient management system can monitor
physiological parameters and uses algorithms to determine heart
failure status and an predict impending cardiac decompensation. The
system comprises an adherent patch device with wireless
communication capabilities. The patch device is configured to
communicate with a remote center, for example via an intermediate
device in the patient's home.
[0094] The adherent patch device may be tagged with a sensor ID,
which is addressable and unique to each patch. This ID may be
transmitted to the remote sensor with the data stream, and can be
used to associate the data with the particular patch system. If
multiple disposable patches are used by the same patient, the
multiple patches may be linked as a set, and replacement patches
linked to the original set. At the hospital, when the patch set is
given to the patient, the nurse may register via a web site and
upload patient info onto patch, for example using a hospital unit
with scanner and wireless connection to patch.
[0095] The modem may be assigned to the patient, which then links
to the patch set. A particular modem can be configured to only
communicate with a specific patch set, which is associated with a
specific patient. Registration with the remote center may occur
automatically.
[0096] The patch may be associated with a patient using caller ID
(to determine the source of the modem communication, using an RFID
tag on the patient, for example an implant or second patch, a body
tattoo, a fingerprint ID, or GPS. A removable memory component, for
example containing a unique tag, may be reused as the patches are
replaced.
[0097] To enhance security, a tamper-proof electronics housing may
be used with the adherent patch device.
[0098] The adherent patch device may also produce two different
outputs, protected patient data with restricted communication and
general device and/or patient information for general
communication. The restricted communication may require additional
security verification. The restricted communication may be
encrypted, while general communication is not.
[0099] Additional security mechanism may include: skin tattoo with
patch reader, modem identification, encrypted communication,
encrypted data storage on the device, biometric ID, and x-ray ID
tags.
[0100] In the embodiments illustrated in FIG. 1, a patient
management system, generally denoted as 10, tracks the patient's
physiological status, detects and predicts negative physiological
events. In one embodiment, a plurality of sensors are used in
combination to enhance detection and prediction capabilities as
more fully explained below.
[0101] In one specific embodiment, the system 10 is used for
decompensation prediction of a heart failure patient. For example
system 10 may comprise a heart failure patient management system
used for decompensation prediction of a heart failure patient.
System 10 comprises a detecting system, for example a patient
measuring system, denoted as 12, and a remote monitoring system 18.
The detecting system comprises an adherent device configured to
couple to the patient, for example configured to adhere to the
patient's skin.
[0102] The adherent device comprises a plurality of sensors 14. The
plurality of sensors can measure physiological parameters of the
patient to monitor the patient and determine the status of the
patient, for example to determine heart failure status. The
physiological parameters can provide an indication of at least one
physiological event, for example a cardiac decompensation or an
impending cardiac decompensation. The plurality of sensors may be
coupled to the patient, for example adhered to the patient's
thorax. The adherent device may be housed in a tamper proof housing
prior to placement on the patient.
[0103] The logic circuitry, or resources, can be configured in many
ways to detect the at least one physiological event, such as heart
failure. For example, the remote monitoring system may comprise the
logic circuitry, and the remote monitoring system may determine HF
status when a rate of change of at least two sensor outputs
comprises an abrupt change in the sensor outputs, such as an abrupt
change as compared to a change in the sensor outputs over a longer
period of time. The remote monitoring system may determine HF
status by a tiered combination of at least a first and a second
sensor output, with the first sensor output indicating a problem
that is then verified by at least a second sensor output. The
remote monitoring system may determine HF status in response a
variance from a baseline value of sensor outputs. In some
embodiments, the baseline values may be defined by a look up table.
The HF status may be determined when a first sensor output is at a
high value that is greater than a baseline value, and at least one
of a second or a third sensor outputs is at a high value also
sufficiently greater than a baseline value to indicate heart
failure status. Heart failure status may be determined by time
weighting the outputs of at least first, second and third sensors,
and the time weighting indicates a recent event that is indicative
of the heart failure status. When the patient measuring system
comprises the logic circuitry, the patient measuring system may
similarly detect the at least one physiological event.
[0104] The detecting system 12 also includes a wireless
communication device 16, coupled to the plurality of sensors 14.
The wireless communication device transfers patient data directly
or indirectly from the plurality of sensors 14 to a remote
monitoring system 18. The remote monitoring system 18 uses data
from the sensors to determine heart failure status and predict
impending decompensation of the patient. The detecting system 12
can continuously, or non-continuously, monitor the patient, alerts
are provided as necessary and medical intervention is provided when
required. The wireless communication device 16 may comprise at
least one of a gateway or a wireless local area network for
receiving data from the plurality of sensors.
[0105] The plurality of sensors 14 may comprise at least one ID
sensor. The at least one ID sensor may be coupled to the adherent
device, addressable, and unique to each adherent device. The
adherent device may comprise the ID sensor of the plurality of
sensors 14.
[0106] FIGS. 2A and 2B show embodiments of the plurality of sensors
14 supported with an adherent device 200 configured to adhere to
the skin. Adherent device 200 is described in U.S. App. No.
60/972,537, the full disclosure of which has been previously
incorporated herein by reference. As illustrated in an exploded
view of the adherent device, a cover 262, batteries 250,
electronics 230, including but not limited to flex circuits and the
like, an adherent tape 210T, the plurality of sensors may comprise
electrodes and sensor circuitry, and hydrogels which interface the
plurality of sensors 14 with the skin, are provided.
[0107] Adherent device 200 comprises a support, for example
adherent patch 210, configured to adhere the device to the patient.
Adherent patch 210 comprises a first side, or a lower side 210A,
that is oriented toward the skin of the patient when placed on the
patient and a second side, or upper side 210B, opposite of the
first side. In many embodiments, adherent patch 210 comprises a
tape 210T which is a material, preferably breathable, with an
adhesive 216A. Patient side 210A comprises adhesive 216A to adhere
the patch 210 and adherent device 200 to patient P. Electrodes
212A, 212B, 212C and 212D are affixed to adherent patch 210. In
many embodiments, at least four electrodes are attached to the
patch, for example six electrodes. In some embodiments the patch
comprises two electrodes, for example two electrodes to measure the
electrocardiogram (ECG) of the patient. Gel 214A, gel 214B, gel
214C and gel 214D can each be positioned over electrodes 212A,
212B, 212C and 212D, respectively, to provide electrical
conductivity between the electrodes and the skin of the patient. In
many embodiments, the electrodes can be affixed to the patch 210,
for example with known methods and structures such as rivets,
adhesive, stitches, etc. In many embodiments, patch 210 comprises a
breathable material to permit air and/or vapor to flow to and from
the surface of the skin. In some embodiments, a printed circuit
board (PCB), for example flex PCB 220, may be connected to upper
side 210B of patch 210 with connectors. In some embodiments,
additional PCB's, for example rigid PCB's 220A, 220B, 220C and
220D, can be connected to flex PCB 220. Electronic components 230
can be connected to flex PCB 220 and/or mounted thereon. In some
embodiments, electronic components 230 can be mounted on the
additional PCB's.
[0108] Electronic circuitry and components 230 comprise circuitry
and components to take physiologic measurements, transmit data to
remote center and receive commands from remote center. In many
embodiments, electronics components 230 may comprise known low
power circuitry, for example complementary metal oxide
semiconductor (CMOS) circuitry components. Electronics components
230 comprise an activity sensor and activity circuitry, impedance
circuitry and electrocardiogram circuitry, for example ECG
circuitry. In some embodiments, electronics circuitry may comprise
a microphone and microphone circuitry to detect an audio signal
from within the patient, and the audio signal may comprise a heart
sound and/or a respiratory sound, for example an S3 heart sound and
a respiratory sound with rales and/or crackles. Electronics
circuitry and components 230 may comprise a temperature sensor, for
example a thermistor, and temperature sensor circuitry to measure a
temperature of the patient, for example a temperature of a skin of
the patient.
[0109] A cover 262 can extend over the batteries, electronic
components and flex printed circuit board. In many embodiments, an
electronics housing 260 may be disposed under cover 262 to protect
the electronic components, and in some embodiments electronics
housing 260 may comprise an encapsulant over the electronic
components and PCB. In some embodiments, cover 262 can be adhered
to the adhesive patch with an adhesive. In many embodiments,
electronics housing 260 may comprise a water proof material, for
example a sealant adhesive such as epoxy or silicone coated over
the electronics components and/or PCB. In some embodiments,
electronics housing 260 may comprise metal and/or plastic. Metal or
plastic may be potted with a material such as epoxy or
silicone.
[0110] Cover 262 may comprise many known biocompatible cover,
casing and/or housing materials, such as elastomers, for example
silicone. The elastomer may be fenestrated to improve
breathability. In some embodiments, cover 262 may comprise many
known breathable materials, for example polyester, polyamide,
and/or elastane (Spandex). The breathable fabric may be coated to
make it water resistant, waterproof, and/or to aid in wicking
moisture away from the patch.
[0111] Adherent device 200 comprises several layers. Gel 214A, or
gel layer, is positioned on electrode 212A to provide electrical
conductivity between the electrode and the skin. Electrode 212A may
comprise an electrode layer. Adhesive patch 210 may comprise a
layer of breathable tape 210T, for example a known breathable tape,
such as tricot-knit polyester fabric. In many embodiments, a gap
269 extends from adhesive patch 210 to the electronics circuitry
and components 230, such that breathable tape 210T can breath to
provide patient comfort. An adhesive 216A, for example a layer of
acrylate pressure sensitive adhesive, can be disposed on underside
210A of patch 210. A gel cover 280, or gel cover layer, for example
a polyurethane non-woven tape, can be positioned over patch 210
comprising the breathable tape. A PCB layer, for example flex PCB
220, or flex PCB layer, can be positioned over gel cover 280 with
electronic components 230 connected and/or mounted to flex PCB 220,
for example mounted on flex PCB so as to comprise an electronics
layer disposed on the flex PCB. In many embodiments, the adherent
device may comprise a segmented inner component, for example the
PCB, for limited flexibility. In many embodiments, the electronics
layer may be encapsulated in electronics housing 260 which may
comprise a waterproof material, for example silicone or epoxy. In
many embodiments, the electrodes are connected to the PCB with a
flex connection, for example trace 223A of flex PCB 220, so as to
provide strain relive between the electrodes 212A, 212B, 212C and
212D and the PCB. Gel cover 280 can inhibit flow of gel 214A and
liquid. In many embodiments, gel cover 280 can inhibit gel 214A
from seeping through breathable tape 210T to maintain gel integrity
over time. Gel cover 280 can also keep external moisture from
penetrating into gel 214A. Gel cover 280 may comprise at least one
aperture 280A sized to receive one of the electrodes. In many
embodiments, cover 262 can encase the flex PCB and/or electronics
and can be adhered to at least one of the electronics, the flex PCB
or the adherent patch, so as to protect the device. In some
embodiments, cover 262 attaches to adhesive patch 210 with adhesive
216B. Cover 262 can comprise many known biocompatible cover,
housing and/or casing materials, for example silicone. In many
embodiments, cover 262 comprises an outer polymer cover to provide
smooth contour without limiting flexibility. In some embodiments,
cover 262 may comprise a breathable fabric. Cover 262 may comprise
many known breathable fabrics, for example breathable fabrics as
described above. In some embodiments, the breathable fabric may
comprise polyester, polyamide, and/or elastane (Spandex.TM.) to
allow the breathable fabric to stretch with body movement. In some
embodiments, the breathable tape may contain and elute a
pharmaceutical agent, such as an antibiotic, anti-inflammatory or
antifungal agent, when the adherent device is placed on the
patient.
[0112] In one embodiment, the wireless communication device 16 is
configured to receive instructional data from the remote monitoring
system.
[0113] Referring to FIG. 3, an energy management device 19 can be
coupled to the plurality of sensors. In one embodiment, the energy
management device 19 is part of the detecting system. In various
embodiments, the energy management device 19 performs one or more
of modulate a clock speed to optimize energy, monitor cell voltage
drop--unload cell, monitor coulomb-meter or other battery monitor,
battery end of life dropoff to transfer data, elective replacement
indicator, call center notification, sensing windows by the sensors
14 based on a monitored physiological parameter and sensing rate
control.
[0114] In one embodiment, energy management is achieved by using
time as a variable. This can be achieved by intermittent sampling.
Variable time courses can be used for measuring signals from the
beginning and the duty cycle rates can be adjusted, for example
adjusted at the remote monitoring system 18.
[0115] In one embodiment, the energy management device 19 is
configured to generate energy by at least one of, a thermo-electric
unit, kinetics, fuel cell, through solar power, a zinc air
interface, Faraday generator, internal combustion, nuclear power, a
micro-battery and with a rechargeable device.
[0116] Referring again to FIG. 1, the adherent device may include a
patch set configured to be coupled to the patient. Patches in the
patch set, as well as replacement patches can be linked together
and coupled to hardware at the detecting system 12 or at the remote
monitoring system 18. Patches of the patch set can also be linked
at software at a back end at the remote monitoring system 18.
Registration with the remote monitoring system 18 can occur each
time a new patch is put on the patient.
[0117] When an adherent device is provided to a patient, a medical
provider registers that adherent device, associated with that
patient, with the remote monitoring system 18. Registration can
take place a variety of different ways, including but not limited
to, via a web site, and the like. Upon registration, patient data
is uploaded to the adherent device. An association of the adherent
patch with the patient occurs by at least one of, caller ID, an
RFID tag on the patient, a body tattoo, fingerprint ID and GPS.
[0118] In one embodiment, a modem is assigned to the patient and
links to the adherent device. The modem can be configured to
determine which patch is sending information to the modem. The
modem communicates only with the patch set of the patient, and the
modem only communicates with those patches with which it is
associated. The modem can be at the detecting system 12 or at the
remote monitoring system 18.
[0119] In one embodiment, the ID sensor 14 has a removable memory
component with a unique patient ID that is reused as patches of the
patch set are replaced. In one embodiment, the ID sensor 14
produces a first output that has protected patient data with
restricted communication, and a second output that has general
device and patient information for general communication. Access to
the protected patient data can require an additional security
verification. At least a portion of the protected patient data can
be encrypted. A variety of additional security verifications
including but not limited to, a skin tattoo with an adherent device
reader, a modem identification, an encrypted communication, an
encrypted data storage on the adherent device, a biometric ID, an
x-ray ID tag and the like.
[0120] The system 10 is configured to automatically detect events.
The system 10 automatically detects events by at least one of, high
noise states, physiological quietness, sensor continuity and
compliance. In response to a detected physiological event, patient
states are identified when data collection is inappropriate. In
response to a detected physiological event, patient states are
identified when data collection is desirable. Patient states
include, physiological quietness, rest, relaxation, agitation,
movement, lack of movement and a patient's higher level of patient
activity.
[0121] The system can use an intelligent combination of sensors to
enhance detection and prediction capabilities, as more fully
discloses in U.S. patent application Ser. No. 60/972,537,
identified as Attorney Docket No. 026843-000200US, filed Sep. 14,
2007, the full disclosure of which has been previously incorporated
herein by reference, and as more fully explained below. The
intelligent combination of sensors may comprise a sensor to measure
at least two of an electrocardiogram signal, a hydration signal, an
accelerometer signal or a respiration signal of the patient.
[0122] In one embodiment, the detecting system 12 communicates with
the remote monitoring system 18 periodically or in response to a
trigger event. The trigger event can include but is not limited to
at least one of, time of day, if a memory is full, if an action is
patient initiated, if an action is initiated from the remote
monitoring system, a diagnostic event of the monitoring system, an
alarm trigger, a mechanical trigger, and the like.
[0123] The adherent device be activated by a variety of different
means including but not limited to, a physiological trigger,
automatic impedance, a tab pull, battery insertion, a hall or reed
switch, a breakable glass capsule, a dome switch, by light
activation, pressure activation, body temperature activation, a
connection between electronics associated with the sensors and the
adherent device, exposure to air, by a capacitive skin sensor and
the like.
[0124] The detecting system 12 can continuously, or
non-continuously, monitor the patient, alerts are provided as
necessary and medical intervention is provided when required. In
one embodiment, the wireless communication device 16 is a wireless
local area network for receiving data from the plurality of
sensors.
[0125] A processor 20 is coupled to the plurality of sensors 14 and
can also be a part of the wireless communication device 16. The
processor 20 comprises at least one tangible medium and may
comprise a processor system. The processor 20 receives data from
the plurality of sensors 14 and creates processed patient data.
[0126] In many embodiments, the processor 20 comprises at least one
of a processor of detecting system 12 comprising a tangible medium,
a processor of remote monitoring system 18 comprising a tangible
medium, a processor of wireless communication device 16 comprising
a tangible medium or a processor of monitoring unit 22 comprising a
tangible medium. In one embodiment, the processor 20 is located at
the remote monitoring system. In another embodiment, the processor
20 is located at the detecting system 12.
[0127] The processor 20 can be integral with a monitoring unit 22
that is part of the detecting system 12 or part of the remote
monitoring system, or both. The monitoring unit can be located at
the remote monitoring system 18.
[0128] The processor 20 has program instructions for evaluating
values received from the sensors 14 with respect to acceptable
physiological ranges for each value received by the processor 20
and determine variances. The processor 20 can receive and store a
sensed measured parameter from the sensors 14, compare the sensed
measured value with a predetermined target value, determine a
variance, accept and store a new predetermined target value and
also store a series of questions from the remote monitoring system
18.
[0129] As shown in FIG. 4, logic resources 24 are provided that
take the data from the sensors 14, and/or the processed patient
data from the processor 20, to predict an impending decompensation.
The logic resources 24 can be at the remote monitoring system 18 or
at the detecting system 12, such as in the monitoring unit 22.
[0130] In one embodiment, illustrated in FIG. 5, a memory
management device 25 is provided. In various embodiments, the
memory management device 25 performs one or more of data
compression, prioritizing of sensing by a sensor 14, monitoring all
or some of sensor data by all or a portion of sensors 14, sensing
by the sensors 14 in real time, noise blanking to provide that
sensor data is not stored if a selected noise level is determined,
low-power of battery caching and decimation of old sensor data.
[0131] The sensors 14 can have associated circuitry, e.g. processor
20, which can provide a variety of different functions, including
but not limited to, initiation, programming, measuring, storing,
analyzing, communicating, predicting, and displaying of a
physiological event of the patient. Each of sensors 14 is
preferably sealed, such as housed in a hermetically sealed package.
In one embodiment, at least a portion of the sealed packages
include a power source, a memory, logic resources and a wireless
communication device. In one embodiment, the sensors 14 can
include, flex circuits, thin film resistors, organic transistors
and the like. The sensors 14 can include ceramics to enclose the
electronics. Additionally, the sensors 14 can include drug eluting
coatings, including but not limited to, an antibiotic,
anti-inflammatory agent and the like.
[0132] A wide variety of different sensors 14 can be utilized,
including but not limited to, bioimpedance, heart rate, heart
rhythm, HRV, HRT, heart sounds, respiration rate, respiration rate
variability, respiratory sounds, SpO2, blood pressure, activity,
posture, wake/sleep, orthopnea, temperature, heat flux and an
accelerometer. A variety of activity sensors can be utilized,
including but not limited to a, ball switch, accelerometer, minute
ventilation, HR, bioimpedance noise, skin temperature/heat flux,
BP, muscle noise, posture and the like.
[0133] The outputs of the sensors 14 can have multiple features to
enhance physiological sensing performance. These multiple features
have multiple sensing vectors that can include redundant vectors.
The sensors can include current delivery electrodes and sensing
electrodes. Size and shape of current delivery electrodes, and the
sensing electrodes, can be optimized to maximize sensing
performance. The system 10 can be configured to determine an
optimal sensing configuration and electronically reposition at
least a portion of a sensing vector of a sensing electrode. The
multiple features enhance the ability of system 10 to determine an
optimal sensing configuration and electronically reposition sensing
vectors. In one embodiment, the sensors 14 can be partially masked
to minimize contamination of parameters sensed by the sensors
14.
[0134] The size and shape of current delivery electrodes, for
bioimpedance, and sensing electrodes can be optimized to maximize
sensing performance. Additionally, the outputs of the sensors 14
can be used to calculate and monitor blended indices. Examples of
the blended indices include but are not limited to, heart rate (HR)
or respiratory rate (RR) response to activity, HR/RR response to
posture change, HR+RR, HR/RR+bioimpedance, and/or minute
ventilation/accelerometer and the like.
[0135] The sensors 14 can be cycled in order to manage energy, and
different sensors 14 can sample at different times. By way of
illustration, and without limitation, instead of each sensor 14
being sampled at a physiologically relevant interval, e.g. every 30
seconds, one sensor 14 can be sampled at each interval, and
sampling cycles between available sensors.
[0136] By way of illustration, and without limitation, the sensors
14 can sample no more than 30 seconds for every minute for ECG, no
more than once a second for an accelerometer sensor, and no more
than 60 seconds for every 15 minutes for bio-impedance.
[0137] In one embodiment, a first of sensors 14 comprises a core
sensor that continuously monitors and detects, and a second of
sensors 14 verifies a physiological status in response to the core
sensor 14 raising a flag. Additionally, at least some of sensors 14
can be used for short term tracking, and other sensors of sensor 14
used for long term tracking.
[0138] Referring to FIG. 6, in one embodiment, an external device
38, which may comprise a medical treatment device, is coupled to
the sensors 14. The external device 38 can be coupled to a
monitoring unit 22 that is part of the detecting system 12, or in
direct communication with the sensors 14. A variety of different
external devices 38 can be used to monitor and/or treat the
patient, the external devices 38 including but not limited to, a
weight scale, blood pressure cuff, cardiac rhythm management
device, a medical treatment device, medicament dispenser and the
like. Suitable cardiac rhythm management devices include but are
not limited to, Boston Scientific's Latitude system, Medtronic's C
are Link system, St. Jude Medical's HouseCall system and the like.
Such communication may occur directly, or via an external
translator unit.
[0139] Referring again to FIG. 6, the external device 38 can be
coupled to an auxiliary input of the monitoring unit 22 at the
detecting system 12 or to the monitoring system 22 at the remote
monitoring system 18. Additionally, an automated reader can be
coupled to an auxiliary input in order to allow a single monitoring
unit 22 to be used by multiple patients. As previously mentioned
above, the monitoring unit 22 can be at the remote monitoring
system 18 and each patient can have a patient identifier (ID)
including a distinct patient identifier. In addition, the ID
identifier can also contain patient specific configuration
parameters. The automated reader can scan the patient identifier ID
and transmit the patient ID number with a patient data packet such
that the main data collection station can identify the patient.
[0140] It will be appreciated that other medical treatment devices
can also be used. The sensors 14 can communicate wirelessly with
the external devices 38 in a variety of ways including but not
limited to, a public or proprietary communication standard and the
like. The detecting system 12 comprising sensors 14 can be
configured to serve as a communication hub for multiple medical
devices, coordinating sensor data and therapy delivery while
transmitting and receiving data from the remote monitoring system
18.
[0141] In one embodiment, the detecting system 12 comprising
sensors 14 is configured to coordinate data sharing between the
external systems 38 allowing for sensor integration across devices.
The coordination of the sensors 14 provides for new pacing,
sensing, defibrillation vectors and the like.
[0142] In one embodiment, the processor 20 is included in the
monitoring unit 22 and the external device 38 is in direct
communication with the monitoring unit 22.
[0143] In another embodiment, illustrated in FIG. 7, a notification
device 42 is coupled to the detecting system 12 and the remote
monitoring system 18. The notification device 42 is configured to
provide notification when values received from the sensors 14 are
not within acceptable physiological ranges. The notification device
42 can be at the remote monitoring system 18 or at the monitoring
unit 22 that is part of the detecting system 12. A variety of
notification devices 42 can be utilized, including but not limited
to, a visible patient indicator, an audible alarm, an emergency
medical service notification, a call center alert, direct medical
provider notification and the like. The notification device 42
provides notification to a variety of different entities, including
but not limited to, the patient, a caregiver, the remote monitoring
system, a spouse, a family member, a medical provider, from one
device to another device such as the external device 38, and the
like.
[0144] Notification can be according to a preset hierarchy. By way
of illustration, and without limitation, the preset hierarchy can
be, patient notification first and medical provider second, patient
notification second and medical provider first, and the like. Upon
receipt of a notification, a medical provider, the remote
monitoring system 18, or a medical treatment device can trigger a
high-rate sampling of physiological parameters for alert
verification.
[0145] The system 10 can also include an alarm 46, that can be
coupled to the notification device 42, for generating a human
perceptible signal when values received from the sensors 14 are not
within acceptable physiological ranges. The alarm 46 can trigger an
event to render medical assistance to the patient, provide
notification as set forth above, continue to monitor, wait and see,
and the like.
[0146] When the values received from the sensors 14 are not within
acceptable physiological ranges the notification is with the at
least one of, the patient, a spouse, a family member, a caregiver,
a medical provider and from one device to another device, to allow
for therapeutic intervention to prevent decompensation, and the
like.
[0147] In another embodiment, the sensors 14 can switch between
different modes, wherein the modes are selected from at least one
of, a stand alone mode with communication directly with the remote
monitoring system 18, communication with an implanted device,
communication with a single implanted device, coordination between
different devices (external systems) coupled to the plurality of
sensors and different device communication protocols.
[0148] By way of illustration, and without limitation, the patient
can be a congestive heart failure patient. Heart failure status is
determined by a weighted combination change in sensor outputs and
be determined by a number of different means, including but not
limited to, (i) when a rate of change of at least two sensor
outputs is an abrupt change in the sensor outputs as compared to a
change in the sensor outputs over a longer period of time, (ii) by
a tiered combination of at least a first and a second sensor
output, with the first sensor output indicating a problem that is
then verified by at least a second sensor output, (iii) by a
variance from a baseline value of sensor outputs, and the like. The
baseline values can be defined in a look up table.
[0149] In another embodiment, heart failure status is determined
using three or more sensors by at least one of, (i) when the first
sensor output is at a value that is sufficiently different from a
baseline value, and at least one of the second and third sensor
outputs is at a value also sufficiently different from a baseline
value to indicate heart failure status, (ii) by time weighting the
outputs of the first, second and third sensors, and the time
weighting indicates a recent event that is indicative of the heart
failure status and the like.
[0150] In one embodiment, the wireless communication device 16 can
include a, modem, a controller to control data supplied by the
sensors 14, serial interface, LAN or equivalent network connection
and a wireless transmitter. Additionally, the wireless
communication device 16 can include a receiver and a transmitter
for receiving data indicating the values of the physiological event
detected by the plurality of sensors, and for communicating the
data to the remote monitoring system 18. Further, the wireless
communication device 16 can have data storage for recording the
data received from the sensors 14 and an access device for enabling
access to information recording in the data storage from the remote
monitoring system 18.
[0151] In various embodiments, the remote monitoring system 18 can
include a receiver, a transmitter and a display for displaying data
representative of values of the one physiological event detected by
the sensors 14. The remote monitoring system can also include a,
data storage mechanism that has acceptable ranges for physiological
values stored therein, a comparator for comparing the data received
from the monitoring system 12 with the acceptable ranges stored in
the data storage device and a portable computer. The remote
monitoring system 18 can be a portable unit with a display screen
and a data entry device for communicating with the wireless
communication device 16.
[0152] Referring now to FIG. 8, for each of sensors 14, a sensor
lead 112 and 114 conveys signals from the sensor 14 to the
monitoring unit 22 at the detecting system 12, or through the
wireless communication device 16 to the remote monitoring system
18, or both. In one embodiment, each signal from a sensor 14 is
first passed through a filter 116, such a low-pass filter, at the
detecting system 12 or at the remote monitoring system 18, to
smooth the signal and reduce noise. The signal is then transmitted
to an analog-to-digital converter 118A, which transforms the
signals into a stream of digital data values that can be stored in
a digital memory 118B. From the digital memory 118B, data values
are transmitted to a data bus 120, along which they are transmitted
to other components of the circuitry to be processed and archived.
From the data bus 120, the digital data can be stored in a
non-volatile data archive memory. The digital data can be
transferred via the data bus 120 to the at least one processor 20,
which processes the data based in part on algorithms and other data
stored in a non-volatile program memory.
[0153] The detecting system 12 can also include a power management
module 122 configured to power down certain components of the
system, including but not limited to, the analog-to-digital
converters 118A, digital memories 118B and the non-volatile data
archive memory and the like, between times when these components
are in use. This helps to conserve battery power and thereby extend
the battery life. Other circuitry and signaling modes may be
devised by one skilled in the art.
[0154] As can be seen in FIG. 9, a control unit 126 is included at
the detecting system 12, the remote monitoring system 18 or at both
locations.
[0155] In one embodiment, the control unit 126 can be a known 486
microprocessor, available from Intel, Inc. of Santa Clara, Calif.
The control unit 126 can be coupled to the sensors 14 directly at
the detecting system 12, indirectly at the detecting system 12 or
indirectly at the remote monitoring system 18. Additionally the
control unit 126 can be coupled to a blood pressure monitor, a
cardiac rhythm management device, a scale or a device that
dispenses medication that can indicate the medication has been
dispensed.
[0156] The control unit 126 can be powered by AC inputs which are
coupled to internal AC/DC converters 134 that generate multiple DC
voltage levels. After the control unit 126 has collected the
patient data from the sensors 14, the control unit 126 encodes the
recorded patient data and transmits the patient data through the
wireless communication device 16 to transmit the encoded patient
data to a wireless network storage unit 128 at the remote
monitoring system 18 as shown in FIG. 10. In another embodiment,
wireless communication device 16 transmits the patient data from
the sensors 14 to the control unit 126 when it is at the remote
monitoring system 18.
[0157] Each time the control unit 126 plans to transmit patient
data to a main data collection station 130, located at the remote
monitoring system 18, the control unit 126 attempts to establish a
communication link. The communication link can be wireless, wired,
or a combination of wireless and wired for redundancy, e.g., the
wired link checks to see if a wireless communication can be
established. If the wireless communication link 16 is available,
the control unit 126 transmits the encoded patient data through the
wireless communication device 16. However, if the wireless
communication device 16 is not available for any reason, the
control unit 126 waits and tries again until a link is
established.
[0158] Referring now to FIG. 10 and FIG. 11, one embodiment of an
internal structure of a main data collection station 130, at the
remote monitoring system 18, is illustrated. The patient data can
be transmitted to the remote monitoring system 18 by either the
wireless communication device 16 or conventional modem to the
wireless network storage unit 128. After receiving the patient
data, the wireless network storage unit 128 can be accessed by the
main data collection station 130. The main data collection station
130 allows the remote monitoring system 18 to monitor the patient
data of numerous patients from a centralized location without
requiring the patient or a medical provider to physically interact
with each other.
[0159] The main data collection station 130 can include a
communications server 136 that communicates with the wireless
network storage unit 128. The wireless network storage unit 128 can
be a centralized computer server that includes a unique, password
protected mailbox assigned to and accessible by the main data
collection station 130. The main data collection station 130
communicates with the wireless network storage unit 128 and
downloads the patient data stored in a mailbox assigned to the main
data collection station 130.
[0160] Once the communications server 136 has formed a link with
the wireless network storage unit 128, and has downloaded the
patient data, the patient data can be transferred to a database
server 138. The database server 138 includes a patient database 140
that records and stores the patient data of the patients based upon
identification included in the data packets sent by each of the
monitoring units 22. For example, each data packet can include an
identifier.
[0161] Each data packet transferred from the remote monitoring
system 18 to the main data collection station 130 does not have to
include any patient identifiable information. Instead, the data
packet can include the serial number assigned to the specific
detecting system 12. The serial number associated with the
detecting system 12 can then be correlated to a specific patient by
using information stored on the patient database 138. In this
manner, the data packets transferred through the wireless network
storage unit 128 do not include any patient-specific
identification. Therefore, if the data packets are intercepted or
improperly routed, patient confidentiality can not be breached.
[0162] The database server 138 can be accessible by an application
server 142. The application server 142 can include a data adapter
144 that formats the patient data information into a form that can
be viewed over a conventional web-based connection. The transformed
data from the data adapter 144 can be accessible by propriety
application software through a web server-146 such that the data
can be viewed by a workstation 148. The workstation 148 can be a
conventional personal computer that can access the patient data
using proprietary software applications through, for example, HTTP
protocol, and the like.
[0163] The main data collection station further can include an
escalation server 150 that communicates with the database server
138. The escalation server 150 monitors the patient data packets
that are received by the database server 138 from the monitoring
unit 22. Specifically, the escalation server 150 can periodically
poll the database server 138 for unacknowledged patient data
packets. The patient data packets are sent to the remote monitoring
system 18 where the processing of patient data occurs. The remote
monitoring system 18 communicates with a medical provider if the
event that an alert is required. If data packets are not
acknowledged by the remote monitoring system 18. The escalation
server 150 can be programmed to automatically deliver alerts to a
specific medical provider if an alarm message has not been
acknowledged within a selected time period after receipt of the
data packet.
[0164] The escalation server 150 can be configured to generate the
notification message to different people by different modes of
communication after different delay periods and during different
time periods.
[0165] The main data collection station 130 can include a batch
server 152 connected to the database server 138. The batch server
152 allows an administration server 154 to have access to the
patient data stored in the patient database 140. The administration
server allows for centralized management of patient information and
patient classifications.
[0166] The administration server 154 can include a batch server 156
that communicates with the batch server 152 and provides the
downloaded data to a data warehouse server 158. The data warehouse
server 158 can include a large database 160 that records and stores
the patient data.
[0167] The administration server 154 can further include an
application server 162 and a maintenance workstation 148 that allow
personnel from an administrator to access and monitor the data
stored in the database 160.
[0168] The data packet utilized in the transmission of the patient
data can be a variable length ASCII character packet, or any
generic data formats, in which the various patient data
measurements are placed in a specific sequence with the specific
readings separated by commas. The control unit 126 can convert the
readings from each sensor 14 into a standardized sequence that
forms part of the patient data packet. In this manner, the control
unit 126 can be programmed to convert the patient data readings
from the sensors 14 into a standardized data packet that can be
interpreted and displayed by the main data collection station 130
at the remote monitoring system 18.
[0169] Referring now to the flow chart and method of operation
shown in FIG. 12, if an external device 38 fails to generate a
valid reading, as illustrated in step A, the control unit 126 fills
the portion of the patient data packet associated with the external
device 38 with a null indicator. The null indicator can be the lack
of any characters between commas in the patient data packet. The
lack of characters in the patient data packet can indicate that the
patient was not available for the patient data recording. The null
indicator in the patient data packet can be interpreted by the main
data collection station 130 at the remote monitoring system 18 as a
failed attempt to record the patient data due to the unavailability
of the patient, a malfunction in one or more of the sensors 14, or
a malfunction in one of the external devices 38. The null indicator
received by the main data collection station 130 can indicate that
the transmission from the detecting system 12 to the remote
monitoring system 18 was successful. In one embodiment, the
integrity of the data packet received by the main data collection
station 130 can be determined using a cyclic redundancy code,
CRC-16, check sum algorithm. The check sum algorithm can be applied
to the data when the message can be sent and then again to the
received message.
[0170] After the patient data measurements are complete, the
control unit 126 displays the sensor data, including but not
limited to blood pressure cuff data and the like, as illustrated by
step B. In addition to displaying this data, the patient data can
be placed in the patient data packet, as illustrated in step C.
[0171] As previously described, the system 10 can take additional
measurements utilizing one or more auxiliary or external devices 38
such as those mentioned previously. Since the patient data packet
has a variable length, the auxiliary device patient information can
be added to the patient data packet being compiled by the remote
monitoring unit 22 during patient data acquisition period being
described. Data from the external devices 38 is transmitted by the
wireless communication device 16 to the remote monitoring system 18
and can be included in the patient data packet.
[0172] If the remote monitoring system 18 can be set in either the
auto mode or the wireless only mode, the remote monitoring unit 22
can first determine if there can be an internal communication
error, as illustrated in step D.
[0173] A no communication error can be noted as illustrated in step
E. If a communication error is noted the control unit 126 can
proceed to wireless communication device 16 or to a conventional
modem transmission sequence, as will be described below. However,
if the communication device is working the control unit 126 can
transmit the patient data information over the wireless network 16,
as illustrated in step F. After the communication device has
transmitted the data packet, the control unit 126 determines
whether the transmission was successful, as illustrated in step G.
If the transmission has been unsuccessful only once, the control
unit 126 retries the transmission. However, if the communication
device has failed twice, as illustrated in step H, the control unit
126 proceeds to the conventional modem process if the remote
monitoring unit 22 was configured in an auto mode.
[0174] When the control unit 126 is at the detecting system 12, and
the control unit 126 transmits the patient data over the wireless
communication device 16, as illustrated in step I, if the
transmission has been successful, the display of the remote
monitoring unit 22 can display a successful message, as illustrated
in step J. However, if the control unit 126 determines in step K
that the communication of patient data has failed, the control unit
126 repeats the transmission until the control unit 126 either
successfully completes the transmission or determines that the
transmission has failed a selected number of times, as illustrated
in step L. The control unit 126 can time out the and a failure
message can be displayed, as illustrated in steps M and N. Once the
transmission sequence has either failed or successfully transmitted
the data to the main data collection station, the control unit 126
returns to a start program step, for example step A.
[0175] The processor system, as described above, can be configured
to perform the method shown in FIG. 12, including many of the steps
described above. It should be appreciated that the specific steps
illustrated in FIG. 12 provide a particular method, according to
one embodiment of the present invention. Other sequences of steps
may also be performed according to alternative embodiments. For
example, alternative embodiments of the present invention may
perform the steps outlined above in a different order. Moreover,
the individual steps illustrated in FIG. 12 may include multiple
sub-steps that may be performed in various sequences as appropriate
to the individual step. Furthermore, additional steps may be added
or removed depending on the particular applications. One of
ordinary skill in the art would recognize many variations,
modifications, and alternatives.
[0176] Referring again to FIG. 11, the patient data packets are
first sent and stored in the wireless network storage unit 128.
From there, the patient data packets are downloaded into the main
data collection station 130. The main data collection station 130
decodes the encoded patient data packets and records the patient
data in the patient database 140. The patient database 140 can be
divided into individual storage locations for each patient such
that the main data collection station 130 can store and compile
patient data information from a plurality of individual
patients.
[0177] A report on the patient's status can be accessed by a
medical provider through a medical provider workstation that is
coupled to the remote monitoring system 18. Unauthorized access to
the patient database can be prevented by individual medical
provider usernames and passwords to provide additional security for
the patient's recorded patient data.
[0178] The main data collection station 130 and the series of work
stations 148 allow the remote monitoring system 18 to monitor the
daily patient data measurements taken by a plurality of patients
reporting patient data to the single main data collection station
130. The main data collection station 130 can be configured to
display multiple patients on the display of the workstations 148.
The internal programming for the main data collection station 130
can operate such that the patients are placed in a sequential
top-to-bottom order based upon whether or not the patient can be
generating an alarm signal for one of the patient data being
monitored. For example, if one of the patients monitored by
monitoring system 130 has a blood pressure exceeding a
predetermined maximum amount, this patient can be moved toward the
top of the list of patients and the patient's name and/or patient
data can be highlighted such that the medical personnel can quickly
identify those patients who may be in need of medical assistance.
By way of illustration, and without limitation, the following
paragraphs are a representative order ranking method for
determining the order which the monitored patients are
displayed:
[0179] Alarm Display Order Patient Status Patients are then sorted:
1 Medical Alarm Most alarms violated to least alarms violated, then
oldest to newest 2 Missing Data Alarm Oldest to newest 3 Late
Oldest to newest 4 Reviewed Medical Alarms Oldest to newest 5
Reviewed Missing Data Oldest to newest Alarms 6 Reviewed Null
Oldest to newest 7 NDR Oldest to newest 8 Reviewed NDR Oldest to
newest.
[0180] Alarm Display Order Patient Status Patients can then be
sorted: 1 Medical Alarm Most alarms violated to least alarms
violated, then oldest to newest 2 Missing Data Alarm Oldest to
newest 3 Late Oldest to newest 4 Reviewed Medical Alarms Oldest to
newest 5 Reviewed Missing Data Oldest to newest Alarms 6 Reviewed
Null Oldest to newest 7 NDR Oldest to newest 8 Reviewed NDR Oldest
to newest.
[0181] As listed in the above, the order of patients listed on the
display can be ranked based upon the seriousness and number of
alarms that are registered based upon the latest patient data
information. For example, if the blood pressure of a single patient
exceeds the tolerance level and the patient's heart rate also
exceeds the maximum level, this patient will be placed above a
patient who only has one alarm condition. In this manner, the
medical provider can quickly determine which patient most urgently
needs medical attention by simply identifying the patient's name at
the top of the patient list. The order which the patients are
displayed can be configurable by the remote monitoring system 18
depending on various preferences.
[0182] As discussed previously, the escalation server 150
automatically generates a notification message to a specified
medical provider for unacknowledged data packets based on user
specified parameters.
[0183] Referring again to FIG. 9, in addition to displaying the
current patient data for the numerous patients being monitored, the
software of the main data collection station 130 allows the medical
provider to trend the patient data over a number of prior
measurements in order to monitor the progress of a particular
patient. In addition, the software allows the medical provider to
determine whether or not a patient has been successful in recording
their patient data as well as monitor the questions being asked by
the remote monitoring unit 22.
[0184] As previously mentioned, the system 10 uses an intelligent
combination of sensors to enhance detection and prediction
capabilities. Electrocardiogram circuitry can be coupled to the
sensors 14, or electrodes, to measure an electrocardiogram signal
of the patient. An accelerometer can be mechanically coupled, for
example adhered or affixed, to the sensors 14, adherent patch and
the like, to generate an accelerometer signal in response to at
least one of an activity or a position of the patient. The
accelerometer signals improve patient diagnosis, and can be
especially useful when used with other signals, such as
electrocardiogram signals and impedance signals, including but not
limited to, hydration, respiration, and the like. Mechanically
coupling the accelerometer to the sensors 14, electrodes, for
measuring impedance, hydration and the like can improve the quality
and/or usefulness of the impedance and/or electrocardiogram
signals. By way of illustration, and without limitation, mechanical
coupling of the accelerometer to the sensors 14, electrodes, and to
the skin of the patient can improve the reliability, quality and/or
accuracy of the accelerometer measurements, as the sensor 14,
electrode, signals can indicate the quality of mechanical coupling
of the patch to the patient so as to indicate that the device is
connected to the patient and that the accelerometer signals are
valid. Other examples of sensor interaction include but are not
limited to, (i) orthopnea measurement where the breathing rate is
correlated with posture during sleep, and detection of orthopnea,
(ii) a blended activity sensor using the respiratory rate to
exclude high activity levels caused by vibration (e.g. driving on a
bumpy road) rather than exercise or extreme physical activity,
(iii) sharing common power, logic and memory for sensors,
electrodes, and the like.
[0185] The signals from the plurality of sensors can be combined in
many ways. In some embodiments, the signals can be used
simultaneously to determine an impending cardiac
decompensation.
[0186] In some embodiments, the signals can be combined by using
the at least two of the electrocardiogram signal, the respiration
signal or the activity signal to look up a value in a previously
existing array.
TABLE-US-00001 TABLE 1 Lookup Table for ECG and Respiration
Signals. Respiration Heart Rate A-B bpm C-D bpm E-F bpm U-V per min
N N Y W-X per min N Y Y Y-Z per min Y Y Y
[0187] Table 1 shows combination of the electrocardiogram signal
with the respiration signal to look up a value in a pre-existing
array. For example, at a heart rate in the range from A to B bpm
and a respiration rate in the range from U to V per minute triggers
a response of N. In some embodiments, the values in the table may
comprise a tier or level of the response, for example four tiers.
In specific embodiments, the values of the look up table can be
determined in response to empirical data measured for a patient
population of at least about 100 patients, for example measurements
on about 1000 to 10,000 patients. The look up table shown in Table
1 illustrates the use of a look up table according to one
embodiment, and one will recognize that many variables can be
combined with a look up table.
[0188] In some embodiments, the table may comprise a three or more
dimensional look up table, and the look up table may comprises a
tier, or level, of the response, for example an alarm.
[0189] In some embodiments, the signals may be combined with at
least one of adding, subtracting, multiplying, scaling or dividing
the at least two of the electrocardiogram signal, the respiration
signal or the activity signal. In specific embodiments, the
measurement signals can be combined with positive and or negative
coefficients determined in response to empirical data measured for
a patient population of at least about 100 patients, for example
data on about 1000 to 10,000 patients.
[0190] In some embodiments, a weighted combination may combine at
least two measurement signals to generate an output value according
to a formula of the general form
OUTPUT=aX+bY
[0191] where a and b comprise positive or negative coefficients
determined from empirical data and X, and Z comprise measured
signals for the patient, for example at least two of the
electrocardiogram signal, the respiration signal or the activity
signal. While two coefficients and two variables are shown, the
data may be combined with multiplication and/or division. One or
more of the variables may be the inverse of a measured
variable.
[0192] In some embodiments, the ECG signal comprises a heart rate
signal that can be divided by the activity signal. Work in relation
to embodiments of the present invention suggest that an increase in
heart rate with a decrease in activity can indicate an impending
decompensation. The signals can be combined to generate an output
value with an equation of the general form
OUTPUT=aX/Y+bZ
[0193] where X comprise a heart rate signal, Y comprises an
activity signal and Z comprises a respiration signal, with each of
the coefficients determined in response to empirical data as
described above.
[0194] In some embodiments, the data may be combined with a tiered
combination. While many tiered combinations can be used a tiered
combination with three measurement signals can be expressed as
OUTPUT=(.DELTA.X)+(.DELTA.Y)+(.DELTA.Z)
[0195] where (.DELTA.X), (.DELTA.Y), (.DELTA.Z) may comprise change
in heart rate signal from baseline, change in respiration signal
from baseline and change in activity signal from baseline, and each
may have a value of zero or one, based on the values of the
signals. For example if the heart rate increases by 10%, (.DELTA.X)
can be assigned a value of 1. If respiration increases by 5%,
(.DELTA.Y) can be assigned a value of 1. If activity decreases
below 10% of a baseline value (.DELTA.Z) can be assigned a value of
1. When the output signal is three, a flag may be set to trigger an
alarm.
[0196] In some embodiments, the data may be combined with a logic
gated combination. While many logic gated combinations can be used,
a logic gated combination with three measurement signals can be
expressed as
OUTPUT=(.DELTA.X) AND (.DELTA.Y) AND (.DELTA.Z)
[0197] where (.DELTA.X), (.DELTA.Y), (.DELTA.Z) may comprise change
in heart rate signal from baseline, change in respiration signal
from baseline and change in activity signal from baseline, and each
may have a value of zero or one, based on the values of the
signals. For example if the heart rate increases by 10%, (.DELTA.X)
can be assigned a value of 1. If respiration increases by 5%,
(.DELTA.Y) can be assigned a value of 1. If activity decreases
below 10% of a baseline value (.DELTA.Z) can be assigned a value of
1. When each of (.DELTA.X), (.DELTA.Y), (.DELTA.Z) is one, the
output signal is one, and a flag may be set to trigger an alarm. If
any one of (.DELTA.X), (.DELTA.Y) or (.DELTA.Z) is zero, the output
signal is zero and a flag may be set so as not to trigger an alarm.
While a specific example with AND gates has been shown the data can
be combined in may ways with known gates for example NAND, NOR, OR,
NOT, XOR, XNOR gates. In some embodiments, the gated logic may be
embodied in a truth table.
[0198] The adherent patch device, as described above, can be
configured for continuous placement on the patient for and extended
period, for example at least one week. The plurality of sensors,
the wireless communication circuitry on the patch and the processor
on the patch can be configured with duty cycles, such that the
patient is monitored for at least one week and battery of the
adherent patch will last for at least one week. Table II shows a
configuration of the plurality of sensors, the wireless
communication circuitry and duty cycles configured to monitor the
patient for at least one week. The circuitry components shown in
Table II may comprise known circuitry components, for example known
ECG and HR circuitry, known Bioimpedance and Respiration Circuitry,
known Accelerometer Circuitry, known Temperature Sensor Circuitry,
Known Flash Memory Circuitry, known Processor Circuitry and known
Wireless Circuitry. The power consumption of these known circuitry
components can be used to analyze the performance of the patch.
TABLE-US-00002 TABLE II Duty cycle of patch device components for a
one week patch. Current Consumed Patch Device Sampling Time and
Duty (mAseconds Component Interval Cycle % per Day) ECG Circuitry
20 s per minute 36.8 18,670 Bioimpedance 30 s per 15 minutes 4.4
30,639 Circuitry Accelerometer 1 ms per 2-4 s 0.0006 0.21 Circuitry
Temperature Sensor 1 ms per 1 minute 1.3E-05 0.018 Circuitry Flash
Memory As needed 0.0034 23 Processor 500 ms per second 52 541,843
Wireless (BlueTooth) 2-3 minutes per 4 0.56 31,333 Circuitry
hours
[0199] As shown in Table II, most of the measurement circuitry
comprises a duty cycle of no more than 50%, and the processor
circuitry comprises a duty cycle of about 50% and the wireless
communication circuitry comprises a duty cycle of no more than
about 1%. The duty cycle of the wireless communication circuitry
can be increased from 0.5% to at least about 1%, for example to
about 3%, without significantly effecting the total current
consumed. The total energy consumed per day for the configuration
shown in Table II is about 170 mA Hours. A commercially available
battery having a capacity of 1500 mA Hours will last about 8 days.
This cycling of the measurement circuitry can allow the adherent
device to monitor a patient, for example a heart failure patient,
for at least about 1 week with the patch continuously adhered to
the patient. In some embodiments, the duty cycle of the wireless
communication circuitry can be increased, for example to about 5%
and slightly larger battery used to provide a useful life of one
week with the adherent patch continuously adhered to the patient.
The data in Table II show that a heart failure patient can be
continuously monitored with sensor cycling for an extended period
of at least about one week and with wireless transmission of no
more than about 5% when the adherent patch is adhered to the skin
of the patient.
[0200] While the exemplary embodiments have been described in some
detail, by way of example and for clarity of understanding, those
of skill in the art will recognize that a variety of modifications,
adaptations, and changes may be employed. Hence, the scope of the
present invention should be limited solely by the appended
claims.
* * * * *