Systems and methods for monitoring the circulatory system

• US 9,011,346 B2
• Filed: 01/26/2012
• Issued: 04/21/2015
• Est. Priority Date: 01/27/2011
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Wiard, Richard M., Giovangrandi, Laurent B., Kovacs, Gregory T.
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): CAREY, MICHAEL JAMES
• Application Number:
  US13/982,185
• Publication Number:
  US 20130310700A1
• Time in Patent Office: 1,181 Days
• Field of Search: 600/526, 600/527, 600/508
• US Class Current: 600/526
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0265 using electromagnetic means, e.g. electromagnetic flowmeter
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/1102 Ballistocardiography
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/6887 mounted on external non-worn devices, e.g. non-medical devices
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: G01G 19/50 having additional measuring devices, e.g. for height

Abstract

In accordance with embodiments of the present disclosure, a ballistocardiogram (BCG) sensor is used to detect heart and vascular characteristics of a user, and provide a BCG output indicative of the detected cardiovascular characteristics. The BCG output can be used for various purposes, such as detecting arterial aging. Secondary sensors can be used in conjunction with the BCG and can be used to determine the central arterial blood pressure, when used in conjunction with a peripheral blood pressure measurement.

Claims

1. A system for determining biological or physiological aspects relating to stiffness of at least one artery, the system comprising:

a body scale including and integrating a first sensor;

the first sensor configured and arranged to capture, from a user in an upright position while on the body scale, a heart-related signal indicative of at least one of physical movement and mechanical output of the user'"'"'s heart and of the mechanical movement of blood through an aorta of the user; and

a second sensor configured and arranged to detect characteristics of the user at a distal artery location while the user is on the body scale, the characteristics including a measurement of the volumetric change of an artery or organ of the user; and

a logic circuit that is configured and arranged to process information provided from the first sensor and from the second sensor,

the logic circuit being configured and arranged to generate arterial pulse wave velocity based on portions of the heart-related signal that are indicative of a pressure pulse of an ascending portion of the aorta, the characteristics of the user at a distal artery location and a distance between the aorta and the distal artery location, wherein the arterial pulse wave velocity is indicative of the biological or physiological aspects relating to or corresponding to the arterial stiffness of the user.

2. The system of claim 1, wherein the scale is a body weighing scale that includes

a display configured to output a weight of the user while the user is standing on the scale, and

another sensor that includes a set of force sensors configured to provide indications of weight distribution across the weighing scale to the logic circuit.

3. The system of claim 1, wherein the second sensor is configured in the scale to capture the photoplethysmography characteristics of the distal artery location that is at or below the user'"'"'s femoral artery.

4. The system of claim 1, further including another sensor configured and arranged to detect an indication of at least one of noise present in the heart-related signal and wherein the logic circuit is configured to process the heart-related signal by removing the noise present in the heart-related signal.

5. The system of claim 3, wherein the body scale further includes an electrocardiogram (ECG) sensor configured and arranged to detect an ECG signal from the user and to provide an output characterizing the detected ECG signal, and

the logic circuit is configured to use the output from the ECG sensor to process the captured heart-related signal by processing the heart-related signal by filtering and averaging the heart-related signal to generate a BCG (ballistocardiogram) signal.

6. The system of claim 1, wherein a plurality of photoplethysmography sensors are used in conjunction with a T1 signal to derive a central aortic stiffness and a peripheral arterial stiffness from pulse timings.

7. The system of claim 1, wherein a plurality of pressure sensors are used in conjunction with a T1 signal to derive a central aortic stiffness and a peripheral arterial stiffness from pulse timings.

8. The system of claim 1, wherein the logic circuit is configured to generate a BCG signal by generating an ensemble-average, or triggered moving average, of the detected heart-related signal using a detected photoplethysmography signal.

9. The system of claim 2, wherein the body scale further includes a noise sensor configured to detect noise in a user'"'"'s environment and a heart characteristic sensor configured to detect a physiologic characteristic of the user'"'"'s heart, and

the logic circuit is configured to generate a BCG signal by using the detected noise to mitigate noise in the heart-related signal and using the detected heart characteristic to modify the heart-related signal.

10. The system of claim 3, wherein

the first and second sensors are integrated with a bodyweight sensing scale, and further including hand-grip electrodes coupled to the scale, the electrodes and second sensor being configured to detect at least one of an electrocardiogram (ECG) or photoplethysmography characteristic of the user.

11. The system of claim 1, wherein the system further includes a peripheral blood pressure sensor;

and

the logic circuit is configured to use an output of the peripheral blood pressure sensor system to determine the central pressures;

to generate BCG signals over time; and

to provide an indication of at least one of arterial stiffness and central/peripheral pressure difference.

12. The system of claim 10, wherein

the scale includes a memory that stores baseline data including at least one of rms BCG data and ensemble average BCG amplitude data, and

the logic circuit is configured to generate output BCG signals based upon the stored baseline data.

13. The system of claim 12, wherein

the logic circuit is configured to use recorded changes in the user'"'"'s cardiovascular characteristics and/or bodyweight over a period of time for determining a treatment for the user.

14. The system of claim 1, wherein

the first and second sensor are integrated with a bodyweight sensing scale,

another sensor is integrated with a detachable component connected to the scale and is configured to detect a photoplethysmograph characteristic of the user, and

the logic circuit is configured to generate heart-related signals over time and thereby provide an indication of at least one of arterial stiffness and central/peripheral pressure difference.

15. The system of claim 1, wherein the body scale is further configured to generate an ECG signal using characteristics detected from the user, and wherein the logic circuit is configured to modify coefficients of a transform function used to generate a BCG signal, based upon the ECG signal.

16. The system of claim 3, wherein the second sensor includes a foot-to-foot impedance cardiogram or ICG sensor to obtain a T2 timing of the descending aorta.

17. The system of claim 3, further including a hand-to-hand impedance cardiogram sensor to obtain a T1 time point.

18. The system of claim 1, wherein the heart-related signal is indicative of forces near the arch of the aorta and wherein the logic circuit is configured to correlate the arterial pulse wave velocity to arterial aging.

19. The system of claim 1, wherein the logic circuit is further configured and arranged to process information provided from the first sensor and from the second sensor by assessing the standing measurements or estimates indicative of arterial stiffness with information regarding the user including at least one of age and gender.

20. The system of claim 1, wherein the logic circuit is further configured and arranged to process information provided from the first sensor and from the second sensor by assessing the standing measurements or estimates indicative of arterial stiffness, including at least one of central systolic and central pulse pressures, with the user'"'"'s age and gender, to indicate hypertension.

21. The system of claim 1, wherein the logic circuit is further configured and arranged to process information provided from the first sensor and from the second sensor by assessing the standing measurements or estimates including ballistocardiogram and photoplethysmography characteristics indicative of arterial stiffness, wherein the logic circuit and the body scale are further configured and arranged to obtain the standing measurements or estimates concurrently and from the feet of the user while the user is standing on the body scale.

22. The system of claim 1, wherein the second sensor is configured with and communicatively coupled to a detachable photoplethysmograph sensor to capture photoplethysmography characteristics at the distal artery location that is at or below the user'"'"'s femoral artery.

23. A system for determining biological or physiological aspects relating to stiffness of at least one artery, the system comprising:

a body scale including and integrating first sensing means;

the first sensing means for capturing, from a user in an upright position while on the body scale, a heart-related signal indicative of at least one of physical movement and

mechanical output of the user'"'"'s heart and of the mechanical movement of blood through an aorta of the user; and

second sensing means for detecting characteristics of the user at a distal artery location while the user is on the body scale, the characteristics including a measurement of the volumetric change of an artery or organ of the user; and

logic circuitry that is configured and arranged to process information provided from the first sensor means and from the second sensor means,

the logic circuitry configured and arranged to generate arterial pulse wave velocity based on portions of the heart-related signal that are indicative of a pressure pulse of an ascending portion of the aorta, the characteristics of the user at a distal artery location and a distance between the aorta and the distal artery location, wherein the arterial pulse wave velocity is indicative of the biological or physiological aspects relating to or corresponding to the arterial stiffness of the user.

24. A method for determining biological or physiological aspects relating to stiffness of at least one artery, the method comprising:

in a body scale including and integrating a first sensor, using the first sensor to capture, from a user in an upright position while the user is on the body scale, a heart-related signal indicative of at least one of physical movement and mechanical output of the user'"'"'s heart and of the mechanical movement of blood through an aorta of the user; and

also while the user is on the body scale, using a second sensor to detect characteristics of the user at a distal artery location, the characteristics including a measurement of the volumetric change of an artery or organ of the user; and

using logic circuitry to process information provided from the first sensor and from the second sensor, and

generating, from the logic circuitry, arterial pulse wave velocity based on portions of the heart-related signal that are indicative of a pressure pulse of an ascending portion of the aorta, the characteristics of the user at a distal artery location and a distance between the aorta and the distal artery location, wherein the arterial pulse wave velocity is indicative of the biological or physiological aspects relating to or corresponding to the arterial stiffness of the user.