Transcutaneous Photoplethysmography

• US 20170172433A1
• Filed: 02/10/2015
• Published: 06/22/2017
• Est. Priority Date: 02/14/2014
• Status: Active Grant

• Current Assignee: Lifeq Global Limited
• Original Assignee: Lifeq Global Limited
• Inventors: Olivier, Laurence Richard
• Granted Patent: US 10,314,500 B2
• Time in Patent Office: 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 wearable device to determine at least one physiological parameter by way of close-proximity triangulation photoplethysmography to be worn against the user'"'"'s skin, comprising a plurality of measurement islands including, but not limited to;

optical sensing module(s),

electronic embodiment(s) for measuring a signal,

a given the spatial arrangement of said measurement islands.

2. The wearable device of claim 1 where said optical sensing module(s) comprises one or more light-emitting diode(s) and one or more light-sensitive component.

3. The process of claims 1 and 2 to determine at least one physiological parameter by way of close-proximity triangulation photoplethysmography comprising;

where said optical sensing module comprises one or more light-emitting diode(s) and one or more light-sensitive component(s),

where the measurement islands measure pulse wave characteristics including, but not limited to, velocity, direction and magnification of the wave phenomena (such as pulse wave, Mayer waves and motion artifacts),

including electronic embodiments for measuring a signal,

where the amplified and conditioned signal(s) is digitized by an analog to digital converter (ADC),

where a microprocessor is employed to algorithmically distinguish between the biological waveforms and is used to store to digital signal.

4. The process of claims 1 to 3 where a microprocessor is used in conjunction with at least three signal modules to algorithmically separate and determine the speed, direction and magnitude of different biological waves, given the spatial arrangement of said measurement island(s);

including an electronic component to analyze the timing of the PPG peaks and PPG characteristics between the respective measurement islands,

including an algorithm to identify common features and/or align the raw features of the signals from different measurement islands to analyze the speed of the biological waves, as the distances between the measurement islands is known,

where the motion compensated, decomposition of the waveforms including, but not limited to, the pulse wave, motion artifacts and Mayer waves, allows for robust measurement of the physiological parameters,

where close-proximity triangulation PPG involves simultaneous and/or sequential PPG measurements at the individual sensor islands.

5. Where said measurement islands of claims 1 to 4 are spatially arranged in a configuration including, but not limited to, a triangular formation.

6. The process of claims 1 to 4 for determining a number of physiological parameters including, but not limited to, heart rate, heart rate variability, respiration rate, blood oxygen saturation and pulse wave velocity.

7. The process of claims 1 to 4 whereby the distance and illumination level of the respective measurement islands prevents interference with the light detectors on a separate measurement island.

8. Including embodiments of claims 1 to 4 where the plurality of the light source(s) of a single measurement island are of different wavelengths from the two light sources and are programmed to sequentially emit light, and then the light detector subsequently detects the reflected light.

9. Including embodiments of claims 1 to 4 where the adjustment parameters are adjusted/controlled, including, but not limited to;

embodiments where the light source intensity is adjusted,

embodiments where signal amplification and/or signal conditioning parameters are adjusted,

embodiments where digitized signal values obtained by the microprocessor can be used to readjust said signal amplitude and signal conditioning parameters.

10. A process of claims 1 to 4 where the amplified and/or conditioned digital signal is stored on memory and/or communicated to peripheral electronics by a communication module.

11. A wearable device of claims 1 to 4 that transmits the motion compensated physiological signal to a mobile electronic device, such as a mobile phone or personal computer.

12. The wearable device of claims 1 to 4 with the means to transmit the physiological data 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 or a wearable electronic device.