Apparatus for measuring relative changes in blood volume in a portion of an animal body to detect a venous occlusion
First Claim
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1. Apparatus for measuring relative changes in blood volume in a portion of an animal body, comprising:
- A. means for measuring the impedance through said body portion;
B. means for registering a first value of said impedance when the animal body is in a first reference condition in which a temporary, forced blockage of the venous return to the heart is applied,c. means for registering a second value of said impedance when the animal body is in a second reference condition free of said temporary forced blockage,D. means for forming an index relating the difference between said first and second impedance values to a selected reference value, andE. means for providing an output indicative of the magnitude of said index.
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Abstract
An apparatus is provided which can assist in determining the presence or absence of a venous obstruction such as occurs in hemorrhage or inflammatory conditions affecting the veins by measuring the precentage change in electrical impedance of the veins caused by their temporary forced blockage. This measured change in impedance, normalized with respect to a baseline impedance measured during normal respiration, provides a sensitive index which is indicative of the presence or absence of a clot or constriction.
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5 Claims
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1. Apparatus for measuring relative changes in blood volume in a portion of an animal body, comprising:
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A. means for measuring the impedance through said body portion; B. means for registering a first value of said impedance when the animal body is in a first reference condition in which a temporary, forced blockage of the venous return to the heart is applied, c. means for registering a second value of said impedance when the animal body is in a second reference condition free of said temporary forced blockage, D. means for forming an index relating the difference between said first and second impedance values to a selected reference value, and E. means for providing an output indicative of the magnitude of said index. - View Dependent Claims (2, 3, 4, 5)
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Specification