Non-invasive determination of the concentration of a blood substance
First Claim
1. A method for determining concentration of a substance in blood of a subject, the method comprising:
- creating an a priori relationship indicative of the effect of tissue on in-vivo measurement signals at at least three wavelengths, wherein the in-vivo measurement signals are indicative of absorption caused by blood of a subject;
acquiring the in-vivo measurement signals from in-vivo tissue at the at least three wavelengths;
determining, based on the a priori relationship, a specific value of a tissue parameter for which the effect of the in-vivo tissue on the in-vivo measurement signals is consistent for the at least three wavelengths, the specific value representing concentration of the substance in the blood of the subject; and
presenting the specific value as the determined concentration of the substance in blood of the subject.
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Accused Products
Abstract
In order to provide a non-invasive and continuous concentration measurement with the technology of standard pulse oximeters, an a priori relationship is created, through an in-vivo tissue model including a nominal estimate of a tissue parameter indicative of the concentration of a blood substance. The a priori relationship is indicative of the effect of tissue on in-vivo measurement signals at a plurality of wavelengths, the in-vivo measurement signals being indicative of absorption caused by pulsed arterial blood. In-vivo measurement signals are acquired from in-vivo tissue at the plurality of wavelengths and a specific value of the tissue parameter is determined based on the a priori relationship, the specific value being such that it yields the effect of the in-vivo tissue on the in-vivo measurement signals consistent for the plurality of wavelengths. The specific value then represents the concentration of the substance in the blood.
15 Citations
18 Claims
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1. A method for determining concentration of a substance in blood of a subject, the method comprising:
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creating an a priori relationship indicative of the effect of tissue on in-vivo measurement signals at at least three wavelengths, wherein the in-vivo measurement signals are indicative of absorption caused by blood of a subject; acquiring the in-vivo measurement signals from in-vivo tissue at the at least three wavelengths; determining, based on the a priori relationship, a specific value of a tissue parameter for which the effect of the in-vivo tissue on the in-vivo measurement signals is consistent for the at least three wavelengths, the specific value representing concentration of the substance in the blood of the subject; and presenting the specific value as the determined concentration of the substance in blood of the subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An arrangement for determining concentration of a substance in blood of a subject, the arrangement comprising:
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a first determination unit configured to store an a priori relationship indicative of the effect of tissue on in-vivo measurement signals at at least three wavelengths, wherein the in-vivo measurement signals are indicative of absorption caused by blood of a subject; a measurement unit configured to acquire the in-vivo measurement signals from in-vivo tissue at the at least three wavelengths; a second determination unit configured to determine, based on the a priori relationship, a specific value of a tissue parameter for which the effect of the in-vivo tissue on the in-vivo measurement signals is consistent for the at least three wavelengths, the specific value representing concentration of a substance in the blood of the subject; and a display unit for presenting the specific value as the determined concentration of the substance in blood of the subject. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for determining concentration of a substance in blood of a subject, the apparatus comprising:
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an interface unit configured to download an a priori relationship indicative of the effect of tissue on in-vivo measurement signals at at least three wavelengths, wherein the in-vivo measurement signals are indicative of absorption caused by blood of a subject; a signal reception unit configured to receive in-vivo measurement signals acquired from in-vivo tissue at the at least three wavelengths; and a determination unit configured to determine, based on the a priori relationship, a specific value of a tissue parameter for which the effect of the in-vivo tissue on the in-vivo measurement signals is consistent for the at least three wavelengths, the specific value representing concentration of a substance in the blood of the subject.
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18. A non-transitory computer program product embodied on a tangible medium of expression for determining concentration of a substance in blood of a subject, the computer program product comprising:
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a first program product portion configured to receive an a priori relationship indicative of the effect of tissue on in-vivo measurement signals at at least three wavelengths, wherein the in-vivo measurement signals are indicative of absorption caused by blood of a subject; a second program product portion configured to receive in-vivo measurement signals acquired from in-vivo tissue at the at least three wavelengths; and a third program product portion configured to determine, based on the a priori relationship, a specific value of a tissue parameter for which the effect of the in-vivo tissue on in-vivo measurement signals is consistent for the at least three wavelengths, the specific value representing concentration of a substance in the blood of the subject.
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Specification