Method for noninvasive (in-vivo) total hemoglobin, oxyhemogolobin, deoxyhemoglobin, carboxyhemoglobin and methemoglobin concentration determination

• US 5,692,503 A
• Filed: 03/10/1995
• Issued: 12/02/1997
• Est. Priority Date: 03/10/1995
• Status: Expired due to Term

• Current Assignee: Kuenstner J. Todd
• Original Assignee: Kuenstner J. Todd
• Inventors: Kuenstner, J. Todd
• Primary Examiner(s): Bahr, Jennifer
• Assistant Examiner(s): YARNELL, BRYAN KEITH
• Application Number:
  US08/402,245
• Time in Patent Office: 998 Days
• Field of Search: 128/633, 128/664-7, 356/39-41
• US Class Current: 600/322
• CPC Class Codes: A61B 5/14551 for measuring blood gases

Abstract

Non-invasive in-vivo and in-vitro methods for determining a person'"'"'s total hemoglobin concentration as well as the concentration of the hemoglobin species which contribute to this total concentration, i.e., oxy-, deoxy-, carboxy-, and methemoglobin are described. The measurement comprises a ratio formed by dividing absorbance data at analyte wavelengths by absorbance data at reference wavelengths. In a first embodiment the analyte wavelengths occur at a local maximum of each of the hemoglobin species in the visible region. The reference wavelengths include those in the short wavelength near-infrared region from 800 to 1300 nm. In order to determine the concentration of each hemoglobin species a dA/A treatment is utilized comprising a difference term of absorbance data in the region from 800 to 1300 nm divided by the absorbance at a local maximum for each species. These measurements at local maxima are then combined in a series of simultaneous equations which are then solved for the concentration of each species and the total concentration. In a second embodiment, analyte wavelengths are selected in the range of 480 nm to 630 nm, with separate analyte wavelengths for each hemoglobin species. The measurements are then combined in a series of simultaneous equations which are then solved for the concentration of each species and the total concentration of hemoglobin. In addition, a measurement for total hemoglobin concentration which uses a ratio of absorbance at a triple isosbestic point and the above described difference term is described.

Claims

1. A method for the in-vivo determination of the concentration of one or more hemoglobin species comprising:

generating an absorbance data measurement by

measuring the absorbance of light at a plurality of wavelengths in capillary bed tissue, said plurality of wavelengths including;

at least one analyte wavelength for a hemoglobin species;

a first reference wavelength; and

a second reference wavelength;

comparing the difference in absorbance at the first and second reference wavelengths to the absorbance at the analyte wavelength to generate the absorbance data measurement;

and comparing the absorbance data measurement to a reference curve generated by a correlation study to determine the concentration of the hemoglobin species in the tissue.

2. The method of claim 1 further comprising:

isolating the absorbance data measurement due to arterial blood by;

generating a peak absorbance data measurement by measuring the absorbance of light at said plurality of wavelengths in capillary bed tissue during the peak of a blood pulsation through the tissue,

generating a trough absorbance data measurement by measuring the absorbance of the light at said plurality of wavelengths in capillary bed tissue during the trough of a blood pulsation through the tissue,

subtracting the trough absorbance data measurement from the peak absorbance data measurement to isolate the absorbance data measurement due to arterial blood; and

comparing the absorbance data measurement due to arterial blood to said reference data.

3. The method of claim 2 wherein said analyte wavelength corresponds to a local substantially maximum absorbance of a hemoglobin species.

4. The method of claim 3 wherein an absorbance data measurement is generated at a plurality of analyte wavelengths, and each analyte wavelength corresponds to a local substantially maximum absorbance of a hemoglobin species.

5. The method of claim 3 wherein the hemoglobin species is selected from the group consisting of:

oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin, and sulfhemoglobin.

6. The method of claim 4 wherein the plurality of analyte wavelengths comprises an analyte wavelength for each of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin, and sulfhemoglobin.

7. The method of claim 6 further comprising:

determining total hemoglobin concentration by totaling the concentration of each hemoglobin species.

8. The method of claim 2 wherein an absorbance data measurement is generated at a plurality, n, of analyte wavelengths corresponding to a plurality, n, of hemoglobin species to be measured and said comparison includes a multivariate analysis including the solution of n equations having n variables.

9. The method of claim 8 wherein the plurality of analyte wavelengths comprises an analyte wavelength for each of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin, and sulfhemoglobin.

10. A method for the in-vivo determination of the concentration of one or more hemoglobin species, the method comprising the steps of:

a. generating an absorbance data measurement by;

(1) measuring the absorbance of light at a plurality of wavelengths in capillary bed tissue, said plurality of wavelengths including;

i. at least one analyte wavelength for a hemoglobin species;

ii. a first reference wavelength; and

iii. a second reference wavelength;

(2) calculating the difference in the absorbance at the first reference wavelength and the second reference wavelength to define a difference term;

(3) utilizing ratios of the difference term and absorbance measured at said analyte wavelength to generate the absorbance data measurement; and

b. comparing the absorbance data measurement to a reference curve generated by a correlation study to determine the concentration of the hemoglobin species in the tissue.

11. The method of claim 10, wherein the step of utilizing the ratios to generate the absorbance data measurement comprises dividing the difference term by the absorbance measured at said analyte wavelength.

12. The method of claim 10, wherein the step of utilizing the ratios to generate the absorbance data measurement comprises dividing the absorbance measured at said analyte wavelength by the difference term.

13. The method of claim 10, wherein said first and second reference wavelengths are selected from wavelengths in the near infrared region ranging from approximately 800 nm to 1300 nm.

14. The method of claim 13, wherein said first and second reference wavelengths are separated by at least 300 nm.

15. The method of claim 10, further comprising the steps of:

isolating the absorbance data measurement due to arterial blood by;

generating a peak absorbance data measurement by measuring the absorbance of light at said plurality of wavelengths in capillary bed tissue during the peak of a blood pulsation through the tissue;

generating a trough absorbance data measurement by measuring the absorbance of the light at said plurality of wavelengths in capillary bed tissue during the trough of a blood pulsation through the tissue;

subtracting the trough absorbance data measurement from the peak absorbance data measurement to isolate the absorbance data measurement due to arterial blood; and

comparing the absorbance data measurement due to arterial blood to said reference data.

16. The method of claim 15, wherein said analyte wavelength corresponds to a local substantially maximum absorbance of a hemoglobin species.

17. The method of claim 16, wherein an absorbance data measurement is generated at a plurality of analyte wavelengths, and each analyte wavelength corresponds to a local substantially maximum absorbance of a hemoglobin species.

18. The method of claim 17, wherein the plurality of analyte wavelengths comprises an analyte wavelength for each of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin and sulfhemoglobin.

19. The method of claim 18, further comprising the step of:

determining total hemoglobin concentration by totaling the concentration of each hemoglobin species.

20. The method of claim 16, wherein the hemoglobin species is selected from the group consisting of:

oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin and sulfhemoglobin.

21. The method of claim 15, wherein an absorbance data measurement is generated at a plurality, n, of analyte wavelengths corresponding to a plurality, n, of hemoglobin species to be measured and said comparison includes a multivariate analysis including the solution of n equations having n variables.

22. The method of claim 21, wherein the plurality of analyte wavelengths comprises an analyte wavelength for each of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin and sulfhemoglobin.