System and method for health monitoring using a non-invasive, multi-band biosensor

• US 9,980,676 B2
• Filed: 04/18/2017
• Issued: 05/29/2018
• Est. Priority Date: 07/19/2015
• Status: Active Grant

• Current Assignee: Trilinear Bioventures LLC
• Original Assignee: Sanmina-SCI Corporation
• Inventors: Newberry, Robert Steven
• Primary Examiner(s): Winakur, Eric
• Assistant Examiner(s): Fardanesh, Marjan
• Application Number:
  US15/490,813
• Publication Number:
  US 20170215793A1
• Time in Patent Office: 406 Days
• Field of Search: None
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• 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 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/4845 Toxicology, e.g. by detection of alcohol, drug or toxic products A61B5/4848 takes precedence
• CPC Class Codes: A61B 5/6817 Ear canal
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• 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
• 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 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A biosensor includes a PPG circuit that emits light directed at skin tissue at a plurality of wavelengths. A first and second spectral response of light reflected from the tissue is obtained around a first wavelength and a second wavelength. Using absorption coefficients for substances at the plurality of wavelengths, concentration levels of a plurality of substances may then be determined from the spectral responses. The biosensor may thus be used to determine concentrations of a plurality of substances in arterial blood flow using the spectral response.

Claims

1. A biosensor, comprising:

a PPG circuit configured to;

emit light having at least a first wavelength and a second wavelength directed at skin tissue of a patient;

generate a first spectral response using light around the first wavelength reflected from the skin tissue of the patient;

generate a second spectral response using light around the second wavelength reflected from the skin tissue of the patient;

a processing circuit configured to;

isolate a systolic point and a diastolic point in the first spectral response and obtain a value L<sub>λ

1</sub> using a ratio of the systolic point and the diastolic point in the first spectral response;

isolate a systolic point and a diastolic point in the second spectral response and obtain a value L<sub>λ

2</sub> using a ratio of the systolic point and diastolic point in the second spectral response;

obtain a value R<sub>λ

1, λ

2</sub> from a ratio of the value L<sub>λ

1</sub> and the value L<sub>λ

2</sub>, wherein the value R<sub>λ

1, λ

2</sub> is an indicator of one or more liver enzymes;

obtain a blood alcohol level using a calibration table and the value R<sub>λ

1, λ

2</sub>; and

transmit the blood alcohol level for display.

2. The biosensor of claim 1, wherein the first spectral response generated for light detected around the first wavelength is responsive to a liver enzyme cytochrome oxidase (P450) released in response to alcohol in pulsating arterial blood flow.

3. The biosensor of claim 2, wherein the value R_λ

1, λ

2 obtained from the ratio of the value L<sub>λ

1</sub> and the value L<sub>λ

2</sub> correlates to an indicator of the P450 liver enzyme.

4. The biosensor of claim 3, wherein the processing circuit is further configured to output the indicator of the P450 liver enzyme.

5. The biosensor of claim 4, wherein the first frequency has a high absorption coefficient for the P450 liver enzyme.

6. The biosensor of claim 5, wherein the first frequency is at approximately 468 nm.

7. The biosensor of claim 5, wherein the second frequency has a low absorption coefficient for the P450 liver enzyme.

8. The biosensor of claim 5, wherein the PPG circuit is configured to generate the first spectral response for light detected at the wavelength of 468 nm and for wavelengths in a range of 1 nm to 50 nm around 468 nm.

9. The biosensor of claim 8, wherein the calibration table includes a range of R_λ

1, λ

2 values and correlated blood alcohol levels, wherein the calibration table is generated using blood alcohol level measurements obtained from a sample population during a same measurement period as the range of R<sub>λ

1, λ

2</sub> values is obtained by the biosensor for the sample population.

10. A biosensor, comprising:

a PPG circuit configured to;

generate at least a first spectral response for light reflected around a first wavelength from skin tissue of the patient;

generate at least a second spectral response for light reflected around a second wavelength from the skin tissue of the patient;

a processing circuit configured to;

obtain a value L<sub>λ

1</sub> using the first spectral response, wherein the value L<sub>λ

1</sub> isolates the first spectral response due to pulsating arterial blood flow;

obtain a value L<sub>λ

2</sub> using the second spectral response, wherein the value L<sub>λ

2</sub> isolates the second spectral response due to pulsating arterial blood flow;

obtain a value R<sub>λ

1, λ

2</sub> from a ratio of the value L<sub>λ

1</sub> and the value L<sub>λ

2</sub>;

obtain a liver enzyme indicator based on the value R<sub>λ

1, λ

2</sub> that indicates a liver enzyme concentration level in the pulsating arterial blood flow; and

obtain a blood alcohol level using a calibration table and the value R<sub>λ

1, λ

2</sub>.

11. The biosensor of claim 10, further comprising:

a wireless transceiver configured to transmit the blood alcohol level to a remote device.

12. The biosensor of claim 10, wherein the first spectral response generated for light detected around the first wavelength is responsive to a liver enzyme, wherein a concentration level of the liver enzyme increases in the pulsating arterial blood flow in response to alcohol intake by the patient.

13. The biosensor of claim 12, wherein the liver enzyme includes cytochrome oxidase (P450).

14. The biosensor of claim 13, wherein the first frequency has a high absorption coefficient for P450 and the second frequency has a low absorption coefficient for P450.

15. The biosensor of claim 14, wherein the first frequency is approximately 468 nm and the second frequency is approximately 940 nm.

16. The biosensor of claim 13, wherein the PPG circuit is configured to generate the first spectral response for light detected at the wavelength of 468 nm and for wavelengths in a range of 1 nm to 50 nm around 468 nm.

17. The biosensor of claim 16, wherein the calibration table includes a range of R_λ

1, λ

2 values and correlated blood alcohol levels, wherein the calibration table is generated using blood alcohol level measurements obtained from a sample population during a same measurement period as the range of R<sub>λ

1, λ

2</sub> values is obtained by the biosensor of the sample population.

18. A method for measuring blood alcohol levels, comprising:

generating at least a first spectral response for light reflected around a first wavelength from skin tissue of the patient;

generating at least a second spectral response for light detected around a second wavelength reflected from the skin tissue of the patient;

obtaining a value L<sub>λ

1</sub> using the first spectral response, wherein the value L<sub>λ

1</sub> isolates the first spectral response due to pulsating arterial blood flow;

obtaining a value L<sub>λ

2</sub> using the second spectral response, wherein the value L<sub>λ

2</sub> isolates the second spectral response due to pulsating arterial blood flow;

obtaining a value R<sub>λ

1, λ

2</sub> from a ratio of the value L<sub>λ

1</sub> and the value L<sub>λ

2</sub>, wherein the value R<sub>λ

1, λ

2</sub> is the indicator of a concentration level of a liver enzyme of the patient;

obtaining a blood alcohol concentration level of the patient from a calibration table and the value R<sub>λ

1, λ

2</sub>, wherein the calibration table includes a range of R<sub>λ

1, λ

2</sub> values and correlated blood alcohol concentration levels; and

transmitting the blood alcohol concentration level of the patient for display.

19. The method of claim 18, wherein the first spectral response for light reflected around a first wavelength from skin tissue of the patient is responsive to a liver enzyme cytochrome oxidase (P450) released in response to alcohol in pulsating arterial blood flow.

20. The biosensor of claim 19, wherein the calibration table includes a range of R_λ

1, λ

2 values and correlated blood alcohol levels, wherein the calibration table is generated using blood alcohol level measurements obtained from a sample population during a same measurement period as the range of R<sub>λ

1, λ

2</sub> values is obtained by the biosensor of the sample population.