Method and Device for Determining Blood Components Using Ratiometric Absolute Pulse Spectroscopy
First Claim
1. Noninvasive method for measuring blood components, wherein, with the use of spectrophotometry, light from at least one light source is generated and passed through a tissue located at an application site to at least one photoelectric transducer, and wherein at least one measuring signal of the photoelectric transducer is conducted to an evaluation unit, wherein light signals of a first wavelength are generated at two successive times T1 and T2, that light signals of a second wavelength are generated at two successive times T3 and T4, that light signals of a third wavelength are generated at two successive times T5 and T6, and that this procedure is continued for n pairs of times Tn and Tn+1 at n wavelengths. The times Tn . . . Tn+1 have a well-defined relationship with respect to time. Time differences between individual times can be small. The evaluation unit considers the incoming signals from the photoelectric transducer for all n wavelengths according to a predetermined computational model to determine the concentration of a blood component.
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Abstract
The method and the device according to the invention are used for the non-invasive measurement of concentrations of blood components. At least one light source generates light using spectrophotometry and the light is guided to at least one photodetector through a tissue present at the location of application and supplied with pulsating blood. At least the measuring signal of the photodetector is guided to an evaluation unit. The light signals of a first, second, third to (n+1)st wavelength are generated at subsequent pairwise times T1 and T2, T3 and T4 and T5 and T6 to Tn and Tn+1. The evaluation unit takes into consideration the received signals of the photodetector for all wavelengths according to a defined arithmetic pattern and determines a concentration of the blood component. The inventive device comprises at least three light sources that generate light of different wavelength in relation to each other. The evaluation unit is provided with an arithmetic unit for carrying out logarithms, divisions, multiplications, additions and subtractions. The inventive method is especially used for determining the total hemoglobin concentration CHb and for determining physiological substances that are iatrogenically applied to the area that is supplied with pulsating blood.
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19 Claims
- 1. Noninvasive method for measuring blood components, wherein, with the use of spectrophotometry, light from at least one light source is generated and passed through a tissue located at an application site to at least one photoelectric transducer, and wherein at least one measuring signal of the photoelectric transducer is conducted to an evaluation unit, wherein light signals of a first wavelength are generated at two successive times T1 and T2, that light signals of a second wavelength are generated at two successive times T3 and T4, that light signals of a third wavelength are generated at two successive times T5 and T6, and that this procedure is continued for n pairs of times Tn and Tn+1 at n wavelengths. The times Tn . . . Tn+1 have a well-defined relationship with respect to time. Time differences between individual times can be small. The evaluation unit considers the incoming signals from the photoelectric transducer for all n wavelengths according to a predetermined computational model to determine the concentration of a blood component.
- 13. Device for measuring blood components, which has at least one light source, at least one photoelectric transducer, and at least one evaluation unit connected with the photoelectric transducer, wherein at least three light sources (1, 2, 3) are used, which generate wavelengths that are different from one another, and that the evaluation unit (6) has an arithmetic unit (7) both for taking logarithms and for performing divisions, multiplications, additions, and subtractions.
Specification