HEALTH MONITORING SYSTEMS AND METHODS

• US 20150148622A1
• Filed: 12/09/2014
• Published: 05/28/2015
• Est. Priority Date: 10/07/2012
• Status: Active Grant

• Current Assignee: RDS
• Original Assignee: Rhythm Diagnostic Systems, Inc.
• Inventors: Moyer, Daniel Van Zandt, Golda, George Stefan, Marriott, Mark P., Eletr, Sam, O'Neil, Bruce
• Granted Patent: US 10,993,671 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 2560/0295 adapted for recording user messages or annotations
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• 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 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• 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 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02141 Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits A61B5/02233, A61B5/0235 take precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/335 using integrated circuit memory devices
• CPC Class Codes: A61B 5/352 : Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/6828 : Leg
• CPC Class Codes: A61B 5/6833 : Adhesive patches
• CPC Class Codes: A61B 5/72 : Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/7207 : of noise induced by motion artifacts
• 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 5/7214 : using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/7275 : Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor

Abstract

Systems, methods and devices for reducing noise in health monitoring including monitoring systems, methods and/or devices receiving a health signal and/or having at least one electrode or sensor for health monitoring.

Claims

1. A method for health monitoring comprising:

determining from a user'"'"'s ECG signal when heart beats occur;

time averaging each of two photoplethysmogram signals correlated to the beat locations;

generating ensemble averages;

using a linear regression of the ensemble averages to determine the linear gain factor between the two signals;

determining from the gain factor the patient oxygen saturation.

2. A method according to claim 1 further comprising:

recording ECG data in time-concordance with two or more photoplethysmographs of different light wavelengths;

detecting the heart beats in the ECG signal, these heart beats allowing for definition of a frame of photoplethysmogram data for the time between two adjacent heart beats;

averaging two or more of these frames together at each point in time to create an average frame for the time interval;

wherein the photoplethysmograph signal is reinforced by this averaging because the photoplethysmogram is correlated with the heartbeat, and any motion artifact or other noise source that is uncorrelated in time with the heartbeat is diminished;

interpreting the signal-to-noise ratio of the average frame as typically higher than that of the individual frames;

using linear regression to estimate the gain between the two average frame signals;

estimating from this gain value one or more of the blood oxygen saturation or other components present in the blood such as hemoglobin, carbon dioxide or others.

3. A method according to claim 2 wherein the operations are repeated for additional light wavelengths in order to estimate from the gain value one or more of the blood oxygen saturation or other components present in the blood such as hemoglobin, carbon dioxide or others.

4. A method comprising:

selecting a possible gain value,

multiplying the average frame signal by it, and

determining the residual error with respect to an average frame of a different wavelength; and

,

optionally, repeating the selecting, multiplying and determining operations for a number of potential gain values.

6. A method according to claim 4 wherein this method includes finding local minima;

wherein if it is likely that the global minimum represents correlation caused by motion artifact, venous blood movement or another noise source, it may be ignored, and a local minimum may be selected instead.

7. A method according to claim 4 whereby the gain between red and infrared (IR) frame signals are found by:

averaging the two frames together first to provide a signal with reduced noise;

performing linear regression of the red versus combined and IR versus combined and then finding the ratio of these two results

8. A method according to claim 4 for determining depth and/or rate of respiration.

9. A method according to claim 8 wherein one or more of ECG data, PPG data, pulse oximeter data and/or accelerometer data is used to determine respiration rate and/or depth.

10. A method according to claim 9 including

generating, using the one or more of ECG data, PPG data, pulse oximeter data and/or accelerometer data, a respiration waveform.

11. A method according to claim 8 where Red or IR values over time are used.

12. A method according to claim 8 including

measuring IR or red reflection by the photodiode to estimate depth and/or rate of respiration.

13. A method according to claim 8 where one or both of maximum values and minimum values of a curve or waveform of the IR or red data represent the difference between the maximum and minimum values related to the depth of breath in an individual being monitored, and/or over time, the rate of respiration can be evaluated from the curve of maximum and minimum values over time.

14. A method according to claim 8 using PPG signals.

15. A method according to claim 14 including generating the PPG signals when the chest expands and contracts during breathing, the motion hereof presenting as a wandering baseline artifact on PPG signals.

16. A method according to claim 14 including

isolating the respiration signal by filtering out the PPG data to focus on the breathing/respiration signal.

17. A method according to claim 14 wherein the PPG is chest-mounted.

18. A method according to claim 8 using accelerometer signals.

19. A method according to claim 18 including

generating the accelerometer signals when one or both the chest expands and contracts, or the chest accelerates up and down, as measured by the accelerometer.

20. A method according to claim 18 including isolating the respiration signal may by filtering out the accelerometer data to focus on the breathing/respiration signal.

21. A method according to claim 18 wherein one or both the accelerometer is chest-mounted and the user is lying on his/her back.

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