Method for spectrophotometric blood oxygenation monitoring

• US 9,456,773 B2
• Filed: 11/20/2014
• Issued: 10/04/2016
• Est. Priority Date: 05/12/2005
• Status: Active Grant

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Cas Medical Systems Incorporated (Edwards Lifesciences Corporation)
• Inventors: Benni, Paul B.
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US14/549,135
• Publication Number:
  US 20150201872A1
• Time in Patent Office: 684 Days
• US Class Current: 1/1
• 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 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• 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 5/14553 specially adapted for cerebral tissue
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: G01N 2021/3144 for oxymetry
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/49 within a body or fluid

Abstract

According to the present invention, a method and apparatus for non-invasively determining the blood oxygen saturation level within a subject'"'"'s tissue is provided. The method comprises the steps of: a) providing a spectrophotometric sensor operable to transmit light into the subject'"'"'s tissue, and to sense the light; b) detecting light after passage through the subject'"'"'s tissue using the sensor, and producing initial signal data from the light sensed; c) calibrating the sensor to that particular subject using the initial signal data, thereby accounting for the specific physical characteristics of the particular subject'"'"'s tissue being sensed; and d) using the calibrated sensor to determine the blood oxygen parameter value within the subject'"'"'s tissue.

Claims

1. A method for non-invasively determining a blood oxygen parameter value of a subject'"'"'s tissue, comprising:

providing a spectrophotometric sensor having one or more transducers, each operable to transmit light into the subject'"'"'s tissue and to sense the light after passage through the subject'"'"'s tissue, and a processor portion adapted to selectively control transmission of light by each transducer and to receive and process signals from each transducer, which signals are representative of the sensed light;

transmitting light into the subject'"'"'s tissue using the sensor;

detecting light after passage through the subject'"'"'s tissue using the sensor, and producing initial signal data from the light sensed;

calibrating the sensor, using the processing portion, to that particular subject using the initial signal data, thereby accounting for the specific physical characteristics of the particular subject'"'"'s tissue being sensed; and

determining the blood oxygen parameter value within the subject'"'"'s tissue using the calibrated sensor.

2. The method of claim 1, wherein the processor portion is adapted to utilize an algorithm to process the signals from each transducer, including producing the initial signal data, calibrating the sensor to that particular subject using the initial signal data, and determining the blood oxygen parameter value within the subject'"'"'s tissue using the calibrated sensor.

3. The method of claim 2, wherein the blood oxygen parameter is oxyhemoglobin.

4. The method of claim 2, wherein the blood oxygen parameter is deoxyhemoglobin.

5. The method of claim 2, wherein the calibrating includes processing the initial signal data to account for pigmentation of the subject'"'"'s tissue.

6. The method of claim 5, wherein the processing of the initial signal data includes the use of absorption coefficients for pigmentation in the subject'"'"'s tissue.

7. The method of claim 2, wherein the determining the blood oxygen parameter value within the subject'"'"'s tissue comprises using signal data acquired subsequent to the acquisition of the initial signal data.

8. The method of claim 2, wherein the initial signal data is attributable to non-pulsatile blood flow within the subject'"'"'s tissue.

9. An apparatus for non-invasively determining a blood oxygen saturation level within a subject'"'"'s tissue present during a monitoring period of time, the apparatus comprising:

a spectrophotometric sensor having at least one light emitting transducer operable to transmit light into the subject'"'"'s tissue, and at least one light detecting transducer operable to detect the light after passage through the subject'"'"'s tissue and produce signals representative of the sensed light; and

a processor adapted to utilize an algorithm to process the signals from each light detecting transducer, including producing a signal data set initially produced during the monitoring period of time, calibrating the apparatus to that particular subject using the initial signal data set, thereby accounting for the specific physical characteristics of the particular subject'"'"'s tissue being sensed, and determining the blood oxygen parameter value within the subject'"'"'s tissue using the calibrated apparatus.

10. The apparatus of claim 9, wherein each light emitting transducer is operable to transmit light along a plurality of wavelengths into the subject'"'"'s tissue.

11. The apparatus of claim 9, wherein the blood oxygen parameter is oxyhemoglobin.

12. The apparatus of claim 9, wherein the blood oxygen parameter is deoxyhemoglobin.

13. The apparatus of claim 9, wherein the processor is adapted to process the initial signal data set to account for pigmentation of the subject'"'"'s tissue.

14. The apparatus of claim 13, wherein the processor is adapted to process the initial signal data set to account for pigmentation of the subject'"'"'s tissue using one or more absorption coefficients for pigmentation in the subject'"'"'s tissue.

15. The apparatus of claim 9, wherein the processor is adapted to determine the blood oxygen parameter value within the subject'"'"'s tissue using signal data acquired subsequent to the acquisition of the initial signal data set.

16. A method for non-invasively determining a blood oxygen parameter value of a subject'"'"'s tissue, comprising:

providing a spectrophotometric sensor having one or more transducers, each operable to transmit light into the subject'"'"'s tissue and to sense the light after passage through the subject'"'"'s tissue and produce signals representative of the sensed light, and a processor portion adapted to selectively control transmission of light by each transducer and to receive and process the signals from each transducer, and which processor portion utilizes an algorithm to selectively process the signals from each transducer;

detecting light after passage through the subject'"'"'s tissue using the sensor, and producing first signal data from the light sensed;

altering the algorithm using the first signal data to account for the specific physical characteristics of the particular subject'"'"'s tissue being sensed; and

determining the blood oxygen parameter value within the subject'"'"'s tissue using the altered algorithm.

17. The method of claim 16, wherein altering the algorithm includes processing the initial signal data set to account for pigmentation of the subject'"'"'s tissue.

18. The method of claim 17, wherein the processing of the initial signal data set includes the use of absorption coefficients for pigmentation in the subject'"'"'s tissue.

19. The method of claim 16, wherein the determining the blood oxygen parameter value within the subject'"'"'s tissue comprises using one or more second signal data sets acquired subsequent to the acquisition of the first signal data set.

20. The method of claim 16, wherein the first signal data set is attributable to non-pulsatile blood flow within the subject'"'"'s tissue.