Pulse and active pulse spectraphotometry

• US 6,961,598 B2
• Filed: 02/21/2003
• Issued: 11/01/2005
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Corporation
• Inventors: Diab, Mohamed K.
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US10/371,968
• Publication Number:
  US 20030220576A1
• Time in Patent Office: 984 Days
• Field of Search: 600/310, 600/316, 600/322, 600/323, 600/330, 600/335
• US Class Current: 600/310
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

A pulse and active pulse spectraphotometry system comprises a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band and a secondary band. The tissue site has a modulated blood volume resulting from the pulsatile nature of arterial blood or from an induced pulse. A detector is configured to receive the optical radiation attenuated by the tissue site and to generate a detector output responsive to absorption of the optical radiation within the tissue site. A normalizer operating on the detector output generates a plurality of normalized plethysmographs corresponding to the plurality of wavelengths. Further, a processor is configured to calculate a ratio of fractional volumes of analytes in the blood volume based upon the normalized plethysmographs.

Claims

1. A pulse spectraphotometry system comprising:

a light source adapted to illuminate a tissue site with optical radiation having a plurality of wavelengths selected from at least one of a primary band and a secondary band, said tissue site having a modulated blood volume;

a detector configured to receive said optical radiation attenuated by said tissue site and to generate a detector output responsive to absorption of said optical radiation within said tissue site;

a normalizer operating on said detector output to generate a plurality of normalized plethysmographs corresponding to said plurality of wavelengths; and

a processor configured to calculate a ratio of fractional volumes of analytes in said blood volume based upon said normalized plethysmographs,

wherein said secondary band is in a range of about 1000 nm to about 1380 nm.

2. The pulse spectraphotometry system according to claim 1 wherein said primary band is in a range of about 1620 nm to about 1730 nm.

3. The pulse spectraphotometry system according to claim 2 wherein said primary band is in a range of about 1620 nm to about 1670 nm.

4. The pulse spectraphotometry system according to claim 3 wherein at least one of said wavelengths is selected in a range of about 1650 nm ±

5 nm.

5. The pulse spectraphotometry system according to claim 1 wherein at least one of said wavelengths is selected in a range of about 1032 nm±

5 nm.

6. The pulse spectraphotometry system according to claim 1 wherein at least one of said wavelengths is selected in a range of about 1097 nm±

5 nm.

7. The pulse spectraphotometry system according to claim 1 wherein at least one of said wavelengths is selected in a range of about 1375 nm±

5 nm.

8. A pulse spectraphotometry system comprising:

a light source adapted to illuminate a tissue site with optical radiation having, a plurality of wavelengths the selected from at least one of a primary band and a secondary band, said tissue site having a modulated blood volume;

a detector configured to receive said optical radiation attenuated by said tissue site and to generate detector output responsive to absorption of said optical radiation within said tissue site;

a normalizer operating on said detector output to generate a plurality of normalized plethysmographs corresponding to said plurality of wavelengths; and

a processor configured to calculate a ratio of fractional volumes of analytes in said blood volume based upon said normalized plethysmographs;

wherein said detector is configured to receive said optical radiation after reflection from said tissue site and said wavelengths are further selected from a tertiary band of said wavelengths in a range of about 2000 nm to about 2500 nm.

9. A pulse spectraphotometry method comprising the steps of:

illuminating a tissue site having a pulsatile blood flow with a narrowband optical radiation;

time division multiplexing said optical radiation over a plurality of wavelengths;

selecting at least a portion of said wavelengths within a range of about 1620 nm to about 1730 nm;

selecting a second portion of said wavelengths within a range of about 1000 nm to about 1380 nm;

detecting an attenuated optical radiation from said tissue site as the result of said illuminating step; and

calculating a ratio of analytes in said blood flow based upon said attenuated optical radiation.

10. The pulse spectraphotometry method according to claim 9 wherein said selecting step comprises the substep of selecting at least one wavelength in a range of about 1620 nm to about 1670 nm.

11. The pulse spectraphotometry method according to claim 9 wherein said selecting step comprises a substep of selecting at least one wavelength in a range of about 1650 nm±

5 nm.

12. The pulse spectraphotometry method according to claim 9 wherein said selecting a second portion step comprises a substep of selecting at least one wavelength in a range of about 1032 nm±

5 nm.

13. The pulse spectraphotometry method according to claim 9 wherein said selecting a second portion step comprises a substep of selecting at least one wavelength in a range of about 1097 nm±

5 nm.

14. The pulse spectraphotometry method according to claim 9 wherein said selecting a second portion step comprises a substep of selecting at least one wavelength in a range of about 1375 nm±

5 nm.

15. A pulse spectraphotometry system comprising:

an optical radiation means for illuminating a tissue site;

a filter means for determining a nominal and secondary wavelength of said optical radiation, said nominal wavelength selected from a range of about 1620 nm to about 1730 nm or from a range of about 2000 nm to about 2500 nm, said secondary wavelength selected from a range of about 1000 nm to about 1380 nm;

a detector means for receiving said optical radiation after transmission through or reflection from said tissue site and generating a corresponding plethysmograph signal; and

a processor means for calculating a ratio of analyte portions of pulsatile blood flow within said tissue site based upon said plethysmograph signal.

16. The pulse spectraphotometry system according to claim 15 wherein said nominal wavelength is selected from a range of about 1620 nm to about 1670 nm.

17. The pulse spectraphotometry system according to claim 16 wherein said nominal wavelength is selected from a range of about 1650 nm±

5 nm.

18. The pulse spectraphotometry system according to claim 15 wherein said secondary wavelength is selected from a range of about 1032 nm±

5 nm.

19. The pulse spectraphotometry system according to claim 15 wherein said secondary wavelength is selected from a range of about 1097 nm±

5 nm.

20. The pulse spectraphotometry system according to claim 15 wherein said secondary wavelength is selected from a range of about 1375 nm±

5 nm.

21. The pulse spectraphotometry system according to claim 15 wherein said nominal wavelength is selected from a range of about 2000 nm to about 2500 nm.