Method and device for determining the segmental volume and electrical parallel conductance of a cardiac chamber or blood vessel
First Claim
1. A method for determining the segmental volume and the electrical parallel conductance of a cardiac chamber or a blood vessel of a patient, the method comprising:
- injecting a conductance indicator, which influences electrical conductance of blood, into a bloodstream of a patient, wherein an injected quantity of the conductance indicator is determined;
measuring the electrical conductance in said cardiac chamber or blood vessel;
calculating a sum of segmental volume of said cardiac chamber or blood vessel and electrical parallel conductance from said measured electrical conductance;
measuring development of concentration of a concentration indicator in the bloodstream;
calculating the cardiac output from the injected quantity of concentration indicator and the development of the concentration thereof; and
calculating the segmental volume and the electrical parallel conductance of the cardiac chamber or the blood vessel from the calculated cardiac output, the injected quantity of conductance indicator and the measured electrical conductance.
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Accused Products
Abstract
The segment volume of a cardiac chamber or blood vessel of a patient is determined by injecting a first indicator in the blood stream of a patient, which influences the conductance of the blood. The electrical conductance in the cardiac chamber or blood vessel is measured. An injected quantity of indicator is determined and the development of the concentration of this indicator in the blood is measured wherein the cardiac output is calculated from the injected quantity of indicator and the development of the concentration in the blood. Subsequently, the segment volume and electrical parallel conductance of a cardiac chamber or blood vessel are calculated from the calculated cardiac output, the injected quantity of conductance indicator and the measured conductance.
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Citations
16 Claims
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1. A method for determining the segmental volume and the electrical parallel conductance of a cardiac chamber or a blood vessel of a patient, the method comprising:
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injecting a conductance indicator, which influences electrical conductance of blood, into a bloodstream of a patient, wherein an injected quantity of the conductance indicator is determined; measuring the electrical conductance in said cardiac chamber or blood vessel; calculating a sum of segmental volume of said cardiac chamber or blood vessel and electrical parallel conductance from said measured electrical conductance; measuring development of concentration of a concentration indicator in the bloodstream; calculating the cardiac output from the injected quantity of concentration indicator and the development of the concentration thereof; and calculating the segmental volume and the electrical parallel conductance of the cardiac chamber or the blood vessel from the calculated cardiac output, the injected quantity of conductance indicator and the measured electrical conductance. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for determining a segmental volume of a cardiac chamber or a blood vessel of a patient, the apparatus comprising:
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a processing unit having a control output for initiating injection of a conductance indicator into a bloodstream of the patient, which influences electrical conductance of blood; a first detector configured to be placed in the cardiac chamber or blood vessel for measuring a conductance signal, which depends on the electrical conductance at the location of the first detector, wherein said processing unit is arranged for calculating the segmental volume of the cardiac chamber or the blood vessel from said conductance signal; a second detector configured to be placed in the bloodstream for measuring an indicator signal depending on a concentration of a concentration indicator in the blood, wherein said processing unit is arranged for calculating the cardiac output from an injected quantity of the conductance indicator and the indicator signal, and calculating the segmental volume and electrical parallel conductance of the cardiac chamber or blood vessel from the calculated cardiac output, the injected quantity of conductance indicator and the conductance signal. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A catheter for determining segmental volume and electrical parallel conductance of a cardiac chamber or a blood vessel of a patient, the catheter comprising:
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a first detector configured for measuring a conductance signal depending on electrical conductance of blood; a second detector configured for measuring an indicator signal depending on a concentration of a concentration indicator in the blood, wherein said first detector is positioned closer to a distal end than said second detector; and a third detector corresponding to said first detector, which third detector is spaced from said distal end by such a distance so that the third detector is adapted to be positioned in an aorta when said first detector is positioned in a heart. - View Dependent Claims (14, 15, 16)
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Specification