Impedance-based measuring method for hemodynamic parameters
First Claim
1. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface,wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, andwherein the impedance is sensed at the thorax close to the inferior and superior thoracic apertures for at least two different measuring lengths (L, L2, L3, L4, L5) of essentially the same body segment.
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Abstract
A method is provided for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters. According to the method, an alternating measuring current of at least one frequency is introduced into the body, and the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body.
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Citations
31 Claims
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1. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the impedance is sensed at the thorax close to the inferior and superior thoracic apertures for at least two different measuring lengths (L, L2, L3, L4, L5) of essentially the same body segment.
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2. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the electrical current is introduced at or close to the upper body end, such as at the neck, head, arms, and the lower body end, such as at a leg or legs, and that the impedance is measured at the thorax and/or trunk for at least two different measuring lengths (L, L2, L3, L4, L5).
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3. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the impedance of at least one lower extremity is sensed for at least two different measuring lengths (L, L2, L3, L4, L5) of essentially the same body segment.
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4. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein additionally whole-body impedance between the lower and upper body end is measured.
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5. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the length difference (d, d1, a, a1) between the two different measuring lengths is small compared to the length of the examined body part.
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8. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths ((L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein from the impedance values determined for different measuring lengths (L, L2, L3, L4, L5) between electrodes, an operational electrode measuring length (L0), which corresponds to the electrically operational length of the body segment, and optionally an operational electrode distance (d0) are calculated.
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10. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, wherein the impedance is sensed at the thorax close to the inferior and superior thoracic apertures for at least two different measuring lengths (L, L2, L3, L4, L5) of essentially the same body segment, and wherein voltage electrodes at the inferior thoracic aperture are provided as double electrodes on the left and right side, respectively, of the thorax, wherein electrodes positioned at the same distance in the longitudinal direction are electrically connected to each other.
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12. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, wherein the electrical current is introduced at or close to the upper body end, such as at the neck, head, arms, and the lower body end, such as at a leg or legs, and that the impedance is measured at the thorax and/or trunk for at least two different measuring lengths (L, L2, L3, L4, L5), and wherein measuring electrodes at the lower end of the trunk are provided as double electrodes on the left and right side, respectively, of the lower end of the trunk, wherein electrodes positioned at the same distance in the longitudinal direction are electrically connected to each other.
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14. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein impedance variations with respect to time are measured at at least two frequencies.
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17. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein a maximum temporal variation of the measured impedance values (dZ/dt) is determined at at least two different measuring frequencies, and that the resistivity of the blood present in the body is determined therefrom.
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21. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, wherein the impedance variations with respect to time are measured at at least two frequencies, and wherein the frequency of the alternating measuring current is continuously varied from a lower measuring frequency to a higher measuring frequency.
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23. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, wherein the impedance variations with respect to time are measured at at least two frequencies, and wherein the measuring current is impressed for at least another current electrode distance and at several different measuring frequencies, and that the impedance is measured for the different voltage measuring lengths and at the different frequencies.
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24. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the phase angle between measuring current and measuring voltage is determined.
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25. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein amplitudes, areas, and ascending or descending tangents of the impedance waves are used independently or together for calculating hemodynamic parameters.
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26. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein empirical equations that have been determined by means of a gold standard including one of the Fick principle for stroke volume and e.g. echocardiography or isotope methods for other parameters, including as ejection fraction, pulmonal wedge pressure, diastolic function and the like, are used for measuring hemodynamic parameters.
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27. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the sodium content in serum is determined and used in the calculation of relevant parameters.
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28. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the sodium concentration in serum is mathematically estimated by the method and obtained as a result.
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29. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein hormones, including one of ADH and natriuretic peptide, especially brain natriuretic peptide, and precursors thereof regulating body fluids, fractions and the composition thereof, are estimated by means of empirical equations and obtained as a result.
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30. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein results of the measurements are sent to a central station in digital form by one of telephone and e-mail where the results are further processed and assessed, whereafter all necessary measures and therapy changes are transmitted to the patient from a remote place.
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31. A non-invasive method for measuring the volume, the composition and the movement of electroconductive body fluids, based on the electrical impedance of the body or a body segment, especially for performing electromechanocardiography (ELMEC) or impedance cardiography (IKG) measurements for determining hemodynamic parameters,
wherein an alternating measuring current of at least one frequency is introduced into the body by means of measuring electrodes attached to the body surface, wherein the impedance and temporal variations thereof of essentially the same body segment through which the alternating measuring current flows are measured for at least two different measuring lengths (L, L2, L3, L4, L5), essentially in the longitudinal direction of the body, and wherein the body fluid is determined with its fractions, including extracellular space and intracellular space, and read out.
Specification