| 摘要 |
A process and a device are provided for determining the proportion of a component of the air exhaled by a breathing living being that is characteristic of the metabolic function of such living being. The invention relates to a process for determination of a first component A<SUB>a,1 </SUB>in the air exhaled by a patient that is characteristic of the metabolic function of the patient such as carbon dioxide (CO<SUB>2</SUB>) or oxygen (O<SUB>2</SUB>), where the exhaled air having at least two components (i=1, 2, . . . ) each having a proportion A<SUB>a,i</SUB>. The molecular weights M; and the adiabatic coefficients k<SUB>i </SUB>of the components are known. The process measures the velocity of sound v<SUB>S </SUB>in the exhaled air, and the portion A<SUB>i,1 </SUB>of the first component in the exhaled air is calculated by use of the measured velocity, at a temperature T of the exhaled air. The proportion of the component is determined by the equation M<SUB>G</SUB>/k<SUB>G</SUB>=RxT/(v<SUB>s</SUB><SUP>2</SUP>), where M<SUB>G</SUB>=sum(A<SUB>a,i</SUB>xM<SUB>i</SUB>), i=1, 2, . . . , and where M<SUB>G </SUB>is the molecular weight of the exhaled air, and 1/(1-k<SUB>G</SUB>)=sum(A<SUB>a,i</SUB>/(1-k<SUB>i</SUB>)), i=1, 2, . . . , where k<SUB>G </SUB>is the adiabatic coefficient, and R is the universal gas constant.
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