System and method for detecting a sepsis condition

• US 9,968,289 B2
• Filed: 08/18/2017
• Issued: 05/15/2018
• Est. Priority Date: 09/25/2015
• 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:
  US15/680,991
• Publication Number:
  US 20180020964A1
• Time in Patent Office: 270 Days
• Field of Search: None
• CPC Class Codes: A61B 2560/0214 of power generation or supply
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2560/0228 using calibration standards
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• 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 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• 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 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6816 Ear lobe
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• 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 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: A61B 5/746 : Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: G16H 40/63 : for local operation
• CPC Class Codes: G16H 50/30 : for calculating health indices; for individual health risk assessment
• CPC Class Codes: Y02A 90/10 : Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A biosensor includes an optical sensor circuit that emits light directed at skin tissue of a patient at a plurality of wavelengths. A first and second spectral response of light reflected from the tissue is obtained around a first wavelength in a UV range and a second wavelength in an IR range. A measurement of nitric oxide (NO) is then determined from the spectral responses. A risk of septic condition is obtained using the measurement of NO.

Claims

1. A biosensor for detecting a sepsis condition, comprising:

a photoplethysmography (PPG) circuit configured to;

obtain at least a first spectral response of light reflected from skin tissue of a patient, wherein the light includes a first wavelength in an ultraviolet (UV) range;

obtain at least a second spectral response of light reflected from the skin tissue of the patient; and

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 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 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>, wherein the value R<sub>λ

1, λ

2</sub> is a measurement of nitric oxide (NO); and

compare the value R<sub>λ

1, λ

2</sub> to one or more predetermined thresholds; and

generate an indication of a risk of sepsis based on the comparison.

2. The biosensor of claim 1, wherein the biosensor is implemented on a disposable patch.

3. The biosensor of claim 2, wherein the disposable patch comprises at least one of:

a visible indicator of the risk of sepsis;

or

an audible indicator for providing an audible indication of the risk of sepsis.

4. The biosensor of claim 1, wherein the PPG circuit is further configured to:

obtain the second spectral response of light reflected from the skin tissue of the patient, wherein the light includes a second wavelength of 660 nm or greater.

5. The biosensor of claim 1, further comprising:

a memory configured with the one or more predetermined thresholds, wherein at least one of the predetermined thresholds is an R value indicative of a risk of sepsis.

6. The biosensor of claim 5, wherein the one or more predetermined thresholds include different values depending on a pre-existing condition of the patient.

7. The biosensor of claim 5, wherein the one or more predetermined thresholds include different values depending on a position of the biosensor or underlying skin tissue characteristics.

8. The biosensor of claim 1, the processing circuit is further configured to:

obtain a concentration level of NO using the value R<sub>λ

1, λ

2</sub>and a calibration database, wherein the calibration database is used to correlate the value R<sub>λ

1, λ

2</sub> and the concentration level of NO.

9. The biosensor of claim 1, wherein the first wavelength has a high absorption coefficient for nitric oxide in blood flow and is in a UV range of approximately 380 nm to 410 nm.

10. The biosensor of claim 1, wherein the processing circuit is further configured to:

obtain a concentration level of a plurality of hemoglobin species; and

compensate for the concentration level of the plurality of hemoglobin species to determine the value R<sub>λ

1, λ

2</sub>.

11. The biosensor of claim 10, wherein the concentration level of the one or more hemoglobin species is determined by:

analyzing spectral responses of a plurality of wavelengths to determine differential absorption signals for each hemoglobin species; and

using a Beer-Lambert matrix equation for determining the concentration levels of the one or more hemoglobin species.

12. The biosensor of claim 1, further comprising:

a transceiver configured for communicating data to a remote device, wherein the data includes the measurement of NO and the indication of the risk of sepsis.

13. The biosensor of claim 1, wherein the processing circuit is further configured to:

obtain a measurement of heart rate and respiration rate using the first spectral response.

14. The biosensor of claim 1, further comprising:

a temperature sensor configured to measure a skin temperature; and

wherein the processing circuit is further configured to;

compare the skin temperature to one or more predetermined thresholds; and

activate a health alert indicator when the skin temperature exceeds the one or more predetermined thresholds.

15. A biosensor configured to monitor one or more health conditions, comprising:

a sensor circuit configured to;

generate at least a first spectral response for light with a first wavelength in an ultraviolet (UV) range reflected from skin tissue of a patient; and

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

a processing circuit configured to;

determine a first mode of operation for monitoring a risk of sepsis;

obtain a measurement of nitric oxide (NO) in pulsating blood flow using the first spectral response and the second spectral response, wherein the measurement of NO is determined by;

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 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 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 measurement of NO;

compare the measurement of NO to one or more predetermined thresholds based on the first mode of operation; and

generate an indication of the risk of sepsis based on the comparison.

16. The biosensor of claim 15, wherein the processing circuit is further configured to:

determine a second mode of operation for determining a diabetic risk indicator;

compare the measurement of NO to one or more predetermined thresholds based on the second mode of operation; and

obtain a base insulin resistance factor that indicates a diabetic risk indicator.

17. The biosensor of claim 15, wherein the processing circuit is further configured to:

determine a third mode of operation for monitoring a blood glucose concentration level detected from an insulin response; and

obtain the blood glucose concentration level detected from the insulin response using the measurement of NO and a calibration table.

18. The biosensor of claim 15, further comprising:

a user interface circuit configured to select one or more modes of operation of the biosensor.

19. The biosensor of claim 15, wherein the processing circuit is further configured to obtain a measurement of heart rate using a spectral response from a wavelength in the UV range;

and

wherein the biosensor further comprises a heart rate indicator.

20. The biosensor of claim 19, wherein the wavelength in the UV range is 400 nm or less.

21. The biosensor of claim 19, wherein the processing circuit is further configured to:

compare the measurement of heart rate to one or more predetermined thresholds for heart rate; and

activate the heart alert indicator when the measurement of heart rate exceeds the one or more predetermined thresholds for heart rate.

22. The biosensor of claim 15, wherein the processing circuit is further configured to:

obtain a measurement of respiration rate using at least one of;

the first spectral response or the second spectral response; and

compare the respiration rate obtained to one or more predetermined thresholds; and

activate a health alert indicator then the respiration rate exceeds the one or more predetermined thresholds.

23. A method for detecting a sepsis condition, comprising:

obtaining a first spectral response of light reflected from skin tissue of a patient, wherein the light includes a first wavelength in an ultraviolet (UV) range;

obtaining a second spectral response of light reflected from skin tissue of a patient, wherein the light includes a second wavelength of 530 nm or greater;

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 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 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 a measurement of nitric oxide (NO);

comparing the value R<sub>λ

1, λ

2</sub> to one or more predetermined thresholds; and

generating an indication of a risk of sepsis based on the comparison.

24. The method of claim 23, wherein the one or more predetermined thresholds includes an R value indicative of a risk of sepsis.