Transcutaneous photoplethysmography

• US 10,314,500 B2
• Filed: 02/10/2015
• Issued: 06/11/2019
• Est. Priority Date: 02/14/2014
• Status: Active Grant

• Current Assignee: Lifeq Global Limited
• Original Assignee: Lifeq Global Limited
• Inventors: Olivier, Laurence Richard
• Primary Examiner(s): Manuel, George
• Application Number:
  US15/118,183
• Publication Number:
  US 20170172433A1
• Time in Patent Office: 1,582 Days
• 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 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 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 5/02427 Details of sensor
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• 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 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6813 Specially adapted to be attached to a specific body part A61B5/6802 takes precedence
• CPC Class Codes: A61B 5/7235 Details of waveform analysis A61B5/349 takes precedence

Abstract

The present invention discloses a reflectance type PPG-based physiological sensing system with a close proximity triangulation approach toward robustly measuring several physiological parameters including, but is not limited to, heart rate, breathing rate, blood oxygen saturation and pulse wave velocity.

Claims

1. A method for the determination of at least one physiological parameter by way of close proximety triangulation photoplethysmography (PPG) comprising;

(a) measuring a PPG signal at different sensor measurement islands within a single point on a subject, wherein the different sensor measurement islands comprise at least three sensor measurement islands located from one another at known distances;

(b) measuring pulse wave characteristics of the PPG signal, wherein the pulse wave characteristics comprise velocity, direction and magnification of wave phenomena;

(c) measuring the timing of PPG peaks and PPG characteristics of the PPG signal between sensor measurement islands;

(d) amplifying and conditioning the PPG signal;

(e) converting amplified and conditioned signal(s) to a digital signal;

(f) employing an algorithm to distinguish between biological waveforms derived from the PPG signal and to store the digital signal; and

(g) transmitting the digitial signal and/or physiological parameters derived from said digital signal.

2. The method of claim 1, further comprising identifying common features and/or aligning raw features of the PPG signals from different sensor measurement islands to analyze the speed of the biological waveforms.

3. The method of claim 1, further comprising performing motion compensation and decomposition of the wave phenomena.

4. The method of claim 1, wherein the wave phenomena comprise pulse waves, Mayer waves, and motion artifacts.

5. The method of claim 1, further configured to determine a number of physiological parameters comprising heart rate, heart rate variability, respiration rate, blood oxygen saturation and/or pulse wave velocity.

6. The method of claim 1, wherein the measuring of the PPG signals at the different sensor measurement islands involves simultaneous and/or sequential PPG measurements.

7. The method of claim 1, wherein the distances between and illumination level of the different measurement islands prevents interference with light detectors of the different individual measurement islands.

8. The method of claim 1, further comprising adjusting and/or controlling adjustment parameters, wherein the adjusting and/or controlling comprises at least one of:

adjusting light source intensity of at least one of the different individual sensor measurement islands;

adjusting signal amplification and/or signal conditioning parameters; and

readjusting said signal amplitude and signal conditioning parameters using obtained digitized signal values.

9. The method of claim 1, wherein the amplified and/or conditioned digital signal and/or physiological parameters derived from said digital signal is stored on memory and/or communicated to a mobile electronics device by a communication module.

10. The method of claim 1, wherein the transmitting the digitial signal and/or physiological parameters further comprises transmitting the digital signal and/or physiological parameters derived from said digital signal wirelessly to a platform where said data can be stored or processed on a server, analyzed and viewed on client computing platforms, including, but not limited to, mobile computing devices, home computers and/or a wearable device.

11. A wearable device configured to be worn against a user'"'"'s skin and to determine at least one physiological parameter by way of close proximety triangulation photoplethysmography (PPG) of the user, the wearable device comprising;

(a) at least three individual sensor measurement islands at a given spatial arrangement which are comprised of a plurality of optical sensing modules and electronic embodiment(s), wherein the at least three individual sensor measurement islands are configured for measuring a PPG signal, including measuring pulse wave characteristics of the PPG signal through the optical sensing modules, wherein the pulse wave characteristics comprise at least one of a velocity, direction, and magnification of wave phenomena;

(b) a signal module configured to amplify and condition the PPG signal;

(c) an analog to digital converter (ADC) to convert amplified and conditioned signal(s) to a digital signal;

(d) a processor configured to measure the timing of PPG peaks and PPG characteristics between individual sensor measurement islands, distinguish between biological waveforms derived from the PPG signal, and store the digital signal; and

(e) a transmitter to transmit the digitial signal and/or physiological parameters derived from said digital signal.

12. The wearable device of claim 11, wherein the at least three individual sensor measurement islands are spatially arrange in a configuration including, but not limited to, a triangular formation.

13. The wearable device of claim 11, wherein said optical sensing module(s) comprise one or more light-emitting diodes(s) and one or more light-sensitive components.

14. The wearable device of claim 11, where at least one of the at least three individual sensor measurement islands comprises:

a plurality of the light source of different wavelengths programmed to sequentially emit light; and

at least one light detector to subsequently detect the reflected light from the plurality of light sources.

15. The wearable device of claim 11, wherein at least one of the at least three individual sensor measurement islands comprises:

a plurality of the light source(s) of the same wavelength programmed to simultaneously emit light; and

at least one light detector to subsequently detect the reflected light from the plurality of light sources.

16. The wearable device of claim 11, wherein the processor is used in conjunction with at least three optical sensing modules to algorithmically separate and determine the speed, direction and magnitude of different biological waves, given the spatial arrangement of the at least three individual sensor measurement islands.

17. The wearable device of claim 11, wherein the wearable device is further configured to perform motion compensation and decomposition of the waveforms for measurement of physiological parameters, wherein the waveforms include pulse waves, Mayer waves, and motion artifacts.

18. The wearable device of claim 11 is further configured to determine a number of physiological parameters including, but not limited to, heart rate, heart rate variability, respiration rate, blood oxygen saturation and pulse wave velocity.

19. The wearable device of claim 11, wherein close-proximity triangulation PPG involves simultaneous and/or sequential PPG measurements at the at least three individual sensor measurement islands.

20. The wearable device of claim 11, wherein the individual distance and individual illumination level of each of the individual sensor measurement islands prevents interference with light detectors of the other plurality of individual sensor measurement islands.

21. The wearable device of claim 11, wherein the wearable device is further configured to:

adjust light source intensity of at least one of the at least three individual sensor measurement islands;

adjust signal amplification and/or signal conditioning parameters; and

readjust said signal amplitude and signal conditioning parameters using obtained digitized signal values.

22. The wearable device of claim 11, further comprising memory and a communication module, wherein the amplified and/or conditioned digital signal and/or physiological parameters derived from said digital signal is stored on the memory and/or communicated to a mobile electronics device, such as a mobile phone or personal computer, by the communication module.

23. The wearable device of claim 11, wherein the transmitter is configured to transmit conditioned digital signal and/or physiological parameters derived from said digital signal wirelessly to a platform where said data can be stored or processed on a server, analyzed and viewed on client computing platforms, including, but not limited to, mobile computing devices, home computers and/or a wearable device.