Method for spectrophotometrically determining a blood oxygen parameter

• US 10,261,010 B2
• Filed: 12/10/2013
• Issued: 04/16/2019
• Est. Priority Date: 12/10/2012
• Status: Active Grant

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Cas Medical Systems Incorporated (Edwards Lifesciences Corporation)
• Inventors: Duffy, Karen, Dalene, Matthew, Gamelin, John, Benni, Paul
• Primary Examiner(s): Winakur, Eric F
• Assistant Examiner(s): Fardanesh, Marjan
• Application Number:
  US14/651,160
• Publication Number:
  US 20150308946A1
• Time in Patent Office: 1,953 Days
• Field of Search: None
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 2562/146 for optical coupling
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• 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: G01N 21/35 using infrared light G01N21/39 takes precedence
• CPC Class Codes: G01N 33/4925 measuring blood gas content, e.g. O2, CO2 , HCO3

Abstract

According to an aspect of the present invention, a near infrared spectroscopy (NIRS) sensor assembly, system, and method for measuring a characteristic of a biological tissue is provided. The NIRS sensor assembly includes a light source, at least one light detector, and a subject contact layer. The light source is operable to emit light at one or more predetermined wavelengths. The light detector has an active area for detecting light emitted by the light source and passed through the biological tissue. The detector is operable to produce signals representative of the detected light. The subject contact layer is disposed to cover one or both of the light detector and the light source. The subject contact layer has at least one optically transmissive portion.

Claims

1. A near-infrared spectroscopy (NIRS) system for measuring a characteristic of a biological tissue, comprising:

at least one sensor assembly including a light source operable to emit light at one or more predetermined wavelengths, at least one light detector having an active area for detecting light emitted by the light source and passed through the biological tissue, and which detector is operable to produce signals representative of the detected light, and a subject contact layer disposed to cover at least one of the light source or the at least one light detector, which subject contact layer has an optically transmissive portion, the optically transmissive portion of the subject contact layer having at least one of known uniform optical attenuation characteristics or known uniform light scattering characteristics; and

a processor adapted to use the signals produced by the detector to determine the characteristic of the tissue, and which processor is adapted to account for at least one of the known uniform optical attenuation characteristics or the known uniform light scattering characteristics in making such determination.

2. The NIRS system of claim 1, wherein the at least one sensor assembly further comprises a pad having at least one light detector aperture aligned with the light detector, and at least one light source aperture aligned with the at least one light detector;

and

wherein the subject contact layer is disposed to cover both the light source and the at least one detector, and wherein the at least one optically transmissive portion of the subject contact layer includes portions aligned with the light source and the at least one detector.

3. The NIRS system of claim 1, wherein the processor is adapted with empirically collected data that is representative of at least one of the known uniform optical attenuation characteristics or the known uniform light scattering characteristics.

7. The NIRS system of claim 1, wherein the subject contact layer is made from one or more materials selected from the group consisting of:

a silicone foam, a polyethylene foam, a polyurethane foam, or a polyvinyl chloride foam.

8. The NIRS system of claim 1, wherein the subject contact layer is made from one or more materials selected from the group consisting of:

a tricot fabric;

a knit fabric, a loose weave fabric, a spunlace fabric, a microporous fabric, or an elastic fabric.

9. The NIRS system of claim 1, wherein the subject contact layer is made from one or more materials selected from the group consisting of:

a hydrogel adhesive, a hydrocolloid adhesive, or an encapsulated gel.

4. A method for determining a blood oxygen parameter of a subject tissue, comprising the steps of:

providing a near-infrared spectroscopy (NIRS) system, which system includes at least one sensor assembly and a processor, wherein the at least one sensor assembly includes;

a light source operable to emit light at one or more predetermined wavelengths;

at least one light detector having an active area for detecting light emitted by the light source and passed through the biological tissue, the detector configured to selectively produce signals representative of the detected light; and

a subject contact layer having at least one optically transmissive portion, the optically transmissive portion having at least one of known uniform optical attenuation characteristics or known uniform light scattering characteristics, the at least one optically transmissive portion disposed to cover at least one of the light source or the at least one light detector;

interrogating the subject tissue with light emitted from the sensor assembly;

detecting light emitted by the light source, which light has passed through the biological tissue and has passed through the at least one optically transmissive portion, and producing signals representative of the detected light; and

determining the blood oxygen parameter of the subject tissue using the processor, the signals representative of the detected light, and calibration stored within the processor that is representative of at least one of the known uniform optical attenuation characteristics or the known uniform light scattering characteristics.

5. The method of claim 4, wherein the stored calibration is based on empirically collected data that is representative of at least one of the known uniform optical attenuation characteristics or the known uniform light scattering characteristics.

6. The method of claim 4, wherein the sensor assembly further comprises a pad having at least one light detector aperture aligned with the light detector, and at least one light source aperture aligned with the at least one light detector;

and

wherein the subject contact layer is disposed to cover both the light source and the at least one detector, and wherein the at least one optically transmissive portion of the subject contact layer includes portions aligned with the light source and the at least one detector.

10. A near-infrared spectroscopy (NIRS) system for measuring a characteristic of a biological tissue, comprising:

at least one sensor assembly including a light source operable to emit light at one or more predetermined wavelengths, at least one light detector having an active area for detecting light emitted by the light source and passed through the biological tissue, and which detector is operable to produce signals representative of the detected light, and a subject contact layer disposed to cover at least one of the light detector or the light source, which subject contact layer has an optically transmissive portion, the optically transmissive portion of the subject contact layer having at least one of known uniform optical attenuation characteristics or known uniform light scattering characteristics; and

a processor in communication with the at least one sensor assembly and a non-transitory memory storing instructions, which instructions include calibration that accounts for at least one of the known uniform optical attenuation characteristics or the known uniform light scattering characteristics, and which instructions when executed cause the processor to determine the characteristic of the tissue using the calibration.