Health monitoring systems and methods
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.
1. A method for determining a health parameter including one or more of detecting heart beats or determining pulse oxygenation; the method comprising one or more of:
a) detecting heart beats;
using ECG,
using green or another wavelength, or
using a weighted combination of wavelengths;
b) determining pulse oxygenation through generating one or more of a first pulse shape template or a dataset representing a first pulse shape, including using:
green wavelengths,
an ensemble average of green over approximately the same amount of time as for either red or IR,
an ensemble average of multiple wavelengths over approximately the same amount of time as for either red or IR, or
an ensemble average of multiple wavelengths over significantly longer than the amount of time as for either red or IR; or
a long time average of a single wavelength of any color;
c) obtaining a red pulse shape template or dataset representing same and an IR pulse shape template or dataset representing same, and comparing these or one or the other or each of these to the first pulse shape template; and,
d) correlating via linear regression between a red ensemble average with a first pulse shape template or dataset to an IR ensemble average with the first pulse shape template or dataset, where the ratio of these correlations is then used as the AC ratio for oxygen saturation.
2. A method according to any of claim 1 wherein colors other than green or red or IR are used.
3. A method according to claim 2 wherein color selection is limited only by minimal effectiveness in one or both of signal to noise ratio or reflectiveness related to oxygenation.
4. A method according to any of claim 1 further comprising:
recording the first photoplethymogram PPG or ECG data in time-concordance with one or two or more additional photoplethysmographs of different light wavelengths;
detecting the heart beats in the first photoplethymogram PPG or ECG signal, these heart beats providing 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 PPG signal is reinforced by this averaging because the photoplethysmogram PPG signals are 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 including one or more of hemoglobin, carbon dioxide or others.
5. A method according to any of claim 1 wherein the operations are repeated for additional light wavelengths to estimate from the gain value one or more of the blood oxygen saturation or other components present in the blood including one or more of hemoglobin, carbon dioxide or others.
6. A method for health monitoring comprising:
sensing ECG signals by one or more ECG sensors and photoplethysmograph PPG signals by one or more optical sensors disposed on a single health monitoring device disposed on a body;
using a processor for:
determining from one or more or a combination of a user's ECG or a first photoplethysmogram PPG signal or a weighted combination of wavelengths when heart beats occur, the weighted combination being of any number of different wavelengths of light as sensed by the optical sensors;
time averaging the first photoplethysmogram PPG signal to generate a first pulse shape template or dataset;
time averaging each of two additional photoplethysmogram PPG signals correlated to the beat locations; one of the additional signals being a red signal, the other additional signal being an IR signal;
generating ensemble averages for each of the red and IR signals to obtain red and IR ensemble averages;
comparing each of the red and IR ensemble averages to the first pulse shape template or dataset to obtain red and IR ensemble average comparisons;
using a linear regression of each of the red and IR ensemble average comparisons to the first pulse shape template or dataset to determine the linear gain factor between the two signals;
determining from the linear gain factor the patient oxygen saturation.
7. A method according to claim 6 wherein the first photoplethymogram PPG signal is one or more of: green, non-red; non-infrared or a weighted combination of wavelengths.
8. A method according to claim 6 wherein the two photoplethysmogram PPG signals include one or more or all of green, red and infrared signals.
9. 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;
whereby the gain between red frame signals and infrared (IR) frame signals are found by:
generating one or more of green or other color PPG signals or a long time average of red and IR signals;
including the one or more of green or other color PPG signals or the long time average of red and IR signals with the red frame signals and infrared (IR) frame signals to create two frames;
averaging the two frames together first to provide a signal with reduced noise;
performing linear regression of the red versus combined with green or long time average of red and IR signals and infrared (IR) versus combined with green or long time average of red and IR signals; or linear regression of red versus green or long time average of red and IR signals and infrared (IR) versus green or long time average of red and IR signals; or linear regression by combining green or long time average of red and IR signals with each of the red frame signals and infrared (IR) frame signals and using the ratio of these results; and
then finding the ratio of the two corresponding results.
10. A method according to claim 9 for determining one or both of depth and rate of respiration.
11. A method according to claim 10 including
measuring IR or red or green reflection by the photodiode to estimate depth or rate of respiration.
12. A method according to claim 10 where one or both of:
maximum values and minimum values of a curve or waveform of the IR or red or green data represent the difference between the maximum and minimum values related to the depth of breath in an individual being monitored, and
over time, the rate of respiration is evaluated from the curve of maximum and minimum values over time.
13. A method according to claim 10 using PPG signals.
14. A method according to claim 13 including one or both:
obtaining the PPG signals when the chest expands and contracts during breathing, the motion hereof presenting as a wandering baseline artifact on PPG signals; and,
isolating the respiration signal by filtering out the PPG data to focus on the breathing/respiration signal.
15. A method according to claim 13 wherein the PPG is chest-mounted.
16. A method according to claim 10 wherein any one or more of PPG and accelerometer methods are used discretely or in combination with each other or with the ECG-based respiration estimation techniques.
17. A method according to claim 10 wherein using multiple methods improves accuracy when compared to estimates based on a single method.
18. A method according to claim 10 wherein one or both:
one or more of ECG data, PPG data, pulse oximeter data and accelerometer data is used to determine respiration rate or depth of respiration; and,
where one or more of red or IR or green values over time are used.
19. A method according to claim 18 including
generating, using the one or more of ECG data, PPG data, pulse oximeter data and accelerometer data, a respiration waveform.
20. A device using the method according to claim 9 wherein one or more of the signals are obtained from one or more of:
a wearable health monitoring device having:
a substrate;
a conductive sensor connected to the substrate, and
a double-sided composite adhesive having:
at least one conductive adhesive portion, and
at least one non-conductive adhesive portion;
the double-sided composite adhesive being attached to the substrate and the conductive sensor;
the at least one conductive adhesive portion being disposed in conductive communicative contact with the conductive sensor, and
being configured to be conductively adhered to the skin of the subject for conductive signal communication from the subject to the conductive sensor.