Apparatus for the ph determination of blood and method therefor

• US 20060129036A1
• Filed: 05/27/2004
• Published: 06/15/2006
• Est. Priority Date: 06/06/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Puppels, Gerwin Jan, Lucassen, Gerhardus Wilhelmus
• Granted Patent: US 7,544,503 B2
• Time in Patent Office: Days
• US Class Current: 600/315
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 21/65 Raman scattering

Abstract

The present invention relates to a spectroscopic apparatus for non-invasive in vivo analysis of blood and to a corresponding analysis method, in particular for direct determination of the pH value of the blood. From a Raman signal detected from an excited target region containing blood at least one predetermined pH sensitive signal portion is determined, from which the pH value of the blood in the target region by use of a relationship between pH value and one or more band parameters of pH sensitive vibrations of at least one molecule or part of a molecule present in blood, in particular heme vibrations of hemoglobin, is determined.

Claims

1. A spectroscopic analysis apparatus for non-invasive in vivo analysis of blood comprising:

an excitation system for emitting an excitation beam to excite a target region containing blood,

a detection system for detecting scattered radiation from the target region generated by the excitation beam to obtain a Raman signal,

a signal processing system for extracting at least one predetermined pH sensitive signal portion from said Raman signal and for determining the pH value of the blood in the target region from said at least one pH sensitive signal portion by use of a relationship between pH value and one or more band parameters of pH sensitive vibrations of at least one molecule or part of a molecule present in blood.

2. An analysis apparatus as claimed in claim 1, wherein said signal processing system is adapted for determining the pH value by use of a given relationship between pH value and band position, band intensity, band polarization ratio, band width and/or band shape.

3. An analysis apparatus as claimed in claim 1, wherein said signal processing system is adapted for determining the pH value by use of a relationship between pH value and one or more band parameters of pH sensitive heme vibrations of hemoglobin.

4. An analysis apparatus as claimed in claim 3, wherein said detection system is adapted to detect only one or more Raman signal portions of heme vibrations of hemoglobin.

5. An analysis apparatus as claimed in claim 1, wherein said detection system is adapted to detect scattered radiation from a target region containing essentially whole blood or red blood cells.

6. An analysis apparatus as claimed in claim 1, further comprising a monitoring system for imaging the target region and a focussing system for focussing the excitation system, the detection system and the monitoring system on the target region, in particular on a blood vessel.

7. An analysis apparatus as claimed in claim 1, wherein said signal processing system is further adapted for checking if the at least one pH sensitive signal portion includes interferences from other analytes and for removing such interferences from the at least one pH sensitive signal portion.

8. An analysis apparatus as claimed in claim 1, wherein said excitation system adapted for emitting an excitation beam at a wavelength which is optimized such that the at least one pH sensitive signal portion shows an optimum pH sensitivity.

9. An analysis apparatus as claimed in claim 1, wherein said signal processing system is adapted for extracting at least one predetermined pH sensitive signal portion from said Raman signal at a band position of substantially 1378 cm⁻

1, 1506 cm<sup>−

1</sup> or 1638 cm<sup>−

1</sup>.

10. An analysis apparatus as claimed in claim 1, wherein said excitation system is adapted for emitting an excitation beam having a predetermined polarization orientation and wherein said signal processing system is adapted for determining the depolarization ratio from said at least one pH sensitive signal portion of said Raman signal and for determining the pH value of the blood in the target region from said depolarization ratio by use of a relationship between pH value and depolarization ratio of vibrations of one or more molecules at excitation wavelengths included in said at least one pH sensitive signal portions.

11. A spectroscopic analysis method for non-invasive in vivo analysis of blood comprising the steps of:

emitting an excitation beam to excite a target region containing blood,

detecting scattered radiation from the target region generated by the excitation beam to obtain a Raman signal,

extracting at least one predetermined pH sensitive signal portion from said Raman signal and

determining the pH value of the blood in the target region from said at least one pH sensitive signal portion by use of a relationship between pH value and one or more band parameters of pH sensitive vibrations of at least one molecule or part of a molecule present in blood.