Method and system for non-invasive determination of the main cardiorespiratory parameters of the human body
First Claim
1. A method for determining at least one main cardiorespiratory parameter of an individual, the method comprising the steps of:
- attaching at least two electrodes to the body of an individual and providing a low impedance contact between the electrodes and a skin of the individual, and positioning the electrodes on at least one arm or at least one leg and at least another arm or at least another leg of the individual to enable current to pass between said at least two electrodes on said at least one arm or at least one leg to at least another arm or at least another leg of the individual;
passing an alternating current with a stable and constant amplitude through said at least two electrodes;
measuring, while passing said alternating current, a potential change as the result of a current flow to obtain a measurement of an electrical integral bioimpedance of the body of the individual from a measured potential between said at least two electrodes;
simultaneously separating an active component of the integral bioimpedance from measured integral bioimpedance;
calculating at least one of a cardio parameter and a respiratory parameter of the individual from the active component of said integral bioimpedance, using a semi-empiric formula applicable to integral bioimpedance measurements to obtain a number of values of said at least one parameter for a number of cardiac cycles during a respiratory cycle, and calculating an average of said at least one parameter during a single respiratory cycle; and
displaying said average of said at least one parameter thus obtained.
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Abstract
A method and a system for non-invasively determining at least one main cardiorespiratory parameter of an individual, such as the Stroke Volume, at least one parameter characterizing balance of the extracellular fluid in the body (such as the Index Balance), and for diagnostics of blood circulatory problems and/or failures of cardiac functions. The method for determining the main cardiorespiratory parameter comprises the steps of attaching at least two electrodes to the individual'"'"'s body in a manner enabling to obtain electrical bioimpedance measurements of the whole individual'"'"'s body, passing an alternating current with a stable and constant amplitude through the electrodes, measuring the integral bioimpedance as the result of the current flow; simultaneously separating an active component from the integral bioimpedance; calculating the cardiorespiratory parameter of the individual from the obtained active component, using an empiric formula applicable to integral bioimpedance measurements. The calculation is based on obtaining a number of values of the parameter for a number of cardia cycles during a respiratory cycle, and computing an average of the cardiorespiratory parameter during a single respiratory cycle.
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Citations
17 Claims
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1. A method for determining at least one main cardiorespiratory parameter of an individual, the method comprising the steps of:
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attaching at least two electrodes to the body of an individual and providing a low impedance contact between the electrodes and a skin of the individual, and positioning the electrodes on at least one arm or at least one leg and at least another arm or at least another leg of the individual to enable current to pass between said at least two electrodes on said at least one arm or at least one leg to at least another arm or at least another leg of the individual; passing an alternating current with a stable and constant amplitude through said at least two electrodes; measuring, while passing said alternating current, a potential change as the result of a current flow to obtain a measurement of an electrical integral bioimpedance of the body of the individual from a measured potential between said at least two electrodes; simultaneously separating an active component of the integral bioimpedance from measured integral bioimpedance; calculating at least one of a cardio parameter and a respiratory parameter of the individual from the active component of said integral bioimpedance, using a semi-empiric formula applicable to integral bioimpedance measurements to obtain a number of values of said at least one parameter for a number of cardiac cycles during a respiratory cycle, and calculating an average of said at least one parameter during a single respiratory cycle; and displaying said average of said at least one parameter thus obtained. - View Dependent Claims (2, 4, 6, 8, 10, 11, 12, 13, 14, 15, 17)
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3. 3-(3.1*(Actual Age-20)), for men younger than 20 years old;
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527.3, for men from 20 to 40 years old; 527.3+(3.1*(Actual Age-40)), for men older than 40 years old; 587.6-(2.9*(Actual Age-18)), for women younger than 18 years old; 587.6, for women from 18 to 50 years old; 587.6+(2.9*(Actual Age-50)), for women older than 50 years old; δ
r is the amplitude value of the change of the individual'"'"'s basic body resistance R at the anacrotic (systolic) portion of a cardiac cycle;R is the individual average basic body resistance during one cardiac cycle; Hcorr. is a corrected height of the individual, given by;
##EQU16## α
+β
is duration of a cardiac cycle, being a sum of its anacrotic and catacrotic portion;β
is duration of the catacrotic portion of a cardiac cycle;Kel is a coefficient dependent on ion concentration in the individual'"'"'s blood plasma, calculated based on the blood analysis and being given by; a) for an individual exposed to a hemodialysis Kel=sum of the blood concentrations at ##EQU17## b) for other individuals Kel=blood concentration of Na+ /142; Kw is a weight coefficient, being a ratio Actual weight,/Ideal weight where Ideal weight being obtained from International Tables of ideal weights; IB is an Index Balance, reflecting ratio between the measured volume of extracellular fluids and the individual'"'"'s proper volume of extracellular fluids. - View Dependent Claims (5, 7, 9)
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16. A non-invasive medical system for accurately determining at least one cardiorespiratory parameter of the human body, the system comprising:
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at last two electrodes, an electrical integral bioimpedance measuring unit for measuring integral bioimpedance of a human body, coupled to the electrodes and including a high stability amplitude alternating current source and an electronic circuit for automatic derivation of an active component of the integral bioimpedance; and a computer coupled to the electrical integral bioimpedance measuring unit for calculating an average value measured cardio parameter or a respiratory parameter of the individual, the average value being of a number of values of said parameter for a number of cardiac cycles during a respiratory cycle, each parameter being calculated from said active component using a semi-empiric formula applicable to integral bioimpedance measurements, the computer being further coupled to a display for displaying said average value.
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Specification