METHOD FOR SPECTROPHOTOMETRIC BLOOD OXYGENATION MONITORING

• US 20150025344A1
• Filed: 07/18/2014
• Published: 01/22/2015
• Est. Priority Date: 07/18/2013
• Status: Active Grant

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Cas Medical Systems Incorporated (Edwards Lifesciences Corporation)
• Inventors: Benni, Paul
• Granted Patent: US 9,848,808 B2
• Time in Patent Office: Days
• US Class Current: 600/328
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424

Abstract

An apparatus and method for non-invasively determining a blood oxygen parameter value of a subject'"'"'s tissue is provided. An embodiment of the method includes the steps of: a) providing a spectrophotometric sensor that includes a processing portion and a transducer, b) detecting at least a portion of transmitted light after passage through the subject'"'"'s tissue and producing initial signal data from the detected light; and c) using the processing portion to: (i) determine a value representative of an attenuation of at least one wavelength of light detected; (ii) determine whether the representative attenuation value is outside a predefined range of attenuation values; and (iii) determine the blood oxygen parameter value using a first interrogation or an alternate interrogation setting.

Claims

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

providing a spectrophotometric sensor that includes a processing portion and at least one transducer, which transducer is operable to transmit light at predetermined wavelengths into the subject'"'"'s tissue, and to sense the transmitted light;

detecting at least a portion of the transmitted light after passage through the subject'"'"'s tissue using the transducer, and producing initial signal data from the light sensed;

using the processing portion to;

determine a value representative of an attenuation of at least one of the predetermined wavelengths of light detected using the initial signal data; and

determine whether the representative attenuation value is outside a predefined range of attenuation values; and

determine the blood oxygen parameter value using a first interrogation setting if the representative attenuation value is outside the predefined range of attenuation values, or using an alternate interrogation setting if the representative attenuation value is within the predefined range of attenuation values.

2. The method of claim 1, wherein the step of using the processing portion to determine the blood oxygen parameter value includes using the first interrogation setting if the representative attenuation value is greater than the predefined range of attenuation values, or using an alternate interrogation setting if the representative attenuation value is within the predefined range of attenuation values.

3. The method of claim 1, wherein the first interrogation setting includes a first predefined range of wavelengths of light, and the alternate interrogation setting includes another predefined range of wavelengths of light, and wherein the alternate predefined range of wavelengths includes a wavelength of light not present in the first predefined range of wavelengths.

4. The method of claim 3, wherein the alternate predefined range of wavelengths of light includes at least one wavelength of light below the predefined range of wavelengths of light within the first predefined range of wavelengths of light.

5. The method of claim 4, wherein the alternate predefined range of wavelengths of light includes at least one wavelength of light below 720 nm.

6. The method of claim 3 wherein the first predefined range of wavelengths of light includes a lowest wavelength of light, and the alternate predefined range of wavelengths of light includes a lowest wavelength of light, and the lowest wavelength of light in the first predefined range is higher than the lowest wavelength of light in the alternate predefined range.

7. The method of claim 1, wherein the method is performed over a period of time, and wherein the initial signal data is produced once during the period of time.

8. The method of claim 1, wherein the method is performed over a period of time, and wherein the initial signal data is produced more than once during the period of time.

9. The method of claim 1, wherein the initial signal data is produced periodically during the period of time.

10. The method of claim 1, wherein the transducer includes a light source and a plurality of light detectors.

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

providing a spectrophotometric sensor that includes a processing portion and at least one transducer, which transducer is operable to transmit light at predetermined wavelengths into the subject'"'"'s tissue, and to sense the transmitted light;

detecting at least a portion of the transmitted light after passage through the subject'"'"'s tissue using the transducer, and producing initial signal data from the light sensed;

using the processing portion to;

determine a value representative of an attenuation of at least one of the predetermined wavelengths of light detected using the initial signal data; and

determine a value representative of a hemoglobin concentration within the tissue;

determine whether the representative attenuation value is outside a predefined range of attenuation values associated with the determined hemoglobin concentration; and

determine the blood oxygen parameter value using a first interrogation setting if the representative attenuation value is outside the predefined range of attenuation values associated with the determined hemoglobin concentration, or using an alternate interrogation setting if the representative attenuation value is within the predefined range of attenuation values associated with the determined hemoglobin concentration.

12. The method of claim 11, wherein the step of determining a value representative of the hemoglobin concentration within the tissue includes determining an oxyhemoglobin (HbO2) value, or a deoxyhemoglobin (Hb) value, or both.

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

providing a spectrophotometric sensor that includes a processing portion and at least one transducer, which transducer is operable to transmit light at predetermined wavelengths into the subject'"'"'s tissue, and to sense the transmitted light;

detecting at least a portion of the transmitted light after passage through the subject'"'"'s tissue using the transducer, and producing initial signal data from the light sensed;

using the processing portion to;

determine a value representative of an attenuation of at least one of the predetermined wavelengths of light detected using the initial signal data; and

determine a value representative of the oxygen saturation value of the tissue; and

determine whether the representative attenuation value is outside a predetermined range of attenuation values associated with the determined oxygen saturation value; and

determine the blood oxygen parameter value using a first interrogation setting if the representative attenuation value is outside the predefined range of attenuation values associated with the determined oxygen saturation value, or using an alternate interrogation setting if the representative attenuation value is within the predefined range of attenuation values associated with the determined oxygen saturation value.

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

providing a spectrophotometric sensor that includes a processing portion and at least one transducer, which transducer is operable to transmit light at predetermined wavelengths into the subject'"'"'s tissue, and to sense the transmitted light;

detecting at least a portion of the transmitted light after passage through the subject'"'"'s tissue using the transducer, and producing initial signal data from the light sensed; and

using the processing portion to;

determine a value representative of an attenuation for one or more predetermined wavelengths of light detected using the initial signal data; and

compare at least one representative attenuation value relative to one or more of the other representative attenuation values to determine whether the representative attenuation value for any wavelength is disproportionate to the representative attenuation value of one or more of the other wavelengths; and

determine the blood oxygen parameter value using a first interrogation setting if the representative attenuation value of one or more of the wavelengths is disproportionate to the representative attenuation value of another of the predetermined wavelengths, or using an alternate interrogation setting if the representative attenuation value of one or more of the wavelengths is not disproportionate to the representative attenuation value of another of the predetermined wavelengths.

15. An apparatus for non-invasively determining a blood oxygen parameter value of a subject'"'"'s tissue, comprising:

a spectrophotometric sensor that includes a processing portion and at least one transducer, which transducer is operable to transmit light at predetermined wavelengths into the subject'"'"'s tissue, and is operable to detect at least a portion of the transmitted light after passage through the subject'"'"'s tissue using the transducer, and to produce initial signal data from the light sensed;

wherein the processing portion is adapted to determine a value representative of an attenuation of at least one of the predetermined wavelengths of light detected using the initial signal data, and to determine whether the representative attenuation value is outside a predefined range of attenuation values, and to determine the blood oxygen parameter value using a first interrogation setting if the representative attenuation value is outside the predefined range of attenuation values, or using an alternate interrogation setting if the representative attenuation value is within the predefined range of attenuation values.

16. The apparatus of claim 15, wherein the first interrogation setting includes a first predefined range of wavelengths of light, and the alternate interrogation setting includes another predefined range of wavelengths of light, and wherein the alternate predefined range of wavelengths includes a wavelength of light not present in the first predefined range of wavelengths.

17. The apparatus of claim 16, wherein the alternate predefined range of wavelengths of light includes at least one wavelength of light below the predefined range of wavelengths of light within the first predefined range of wavelengths of light.

18. The apparatus of claim 17, wherein the alternate predefined range of wavelengths of light includes at least one wavelength of light below 720 nm.