Cardiac output measurement system and method
First Claim
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1. A cardiac output measurement apparatus, comprising:
- cardiac output obtaining means for obtaining cardiac output by a thermal attenuation method;
blood flow velocity means for obtaining blood flow velocity by a thermal-type flowrate measurement;
means for obtaining a constituent value functionally related to the cardiac output and blood flow velocity obtained by said cardiac output obtaining means and said blood flow velocity means;
storing means for holding the constituent value obtained;
means for starting said blood flow velocity means during continuous measurement instants;
means for updating said constituent value including means for initiating said cardiac output obtaining means to measure a new cardiac output; and
calculating means for calculating cardiac output from the constituent value held in said storing means and as updated by said updating means, and a newly obtained blood flow velocity each time said blood flow velocity means is started.
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Abstract
An apparatus for measuring cardiac output includes a first system for obtaining cardiac output based on a thermal attenuation method and a second system for obtaining blood flow velocity based on a thermal-type flowrate measurement. A constituent value is obtained from the cardiac output and blood flow velocity, and the constituent value is held. The apparatus also includes a computing unit for computing cardiac output from the already obtained constituent value and a blood flow velocity obtained at the time of measurement. The constituent value can be updated by re-starting the first system.
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10 Claims
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1. A cardiac output measurement apparatus, comprising:
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cardiac output obtaining means for obtaining cardiac output by a thermal attenuation method; blood flow velocity means for obtaining blood flow velocity by a thermal-type flowrate measurement; means for obtaining a constituent value functionally related to the cardiac output and blood flow velocity obtained by said cardiac output obtaining means and said blood flow velocity means; storing means for holding the constituent value obtained; means for starting said blood flow velocity means during continuous measurement instants; means for updating said constituent value including means for initiating said cardiac output obtaining means to measure a new cardiac output; and calculating means for calculating cardiac output from the constituent value held in said storing means and as updated by said updating means, and a newly obtained blood flow velocity each time said blood flow velocity means is started. - View Dependent Claims (2)
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3. A cardiac output measurement apparatus comprising:
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a catheter-type sensor having a liquid charging section and internally accommodating a first temperature-sensitive element for sensing blood temperature attenuated by a liquid and a heated second temperature-sensitive element; first temperature detecting means for detecting a signal indicative of blood temperature sensed by said first temperature-sensitive element; thermal attenuation-type cardiac output calculating means for calculating cardiac output based on a thermal attenuation method using an output signal from said first temperature detecting means; second temperature detecting means for detecting a temperature of the heated second temperature-sensitive element; blood flow velocity calculating means for calculating blood flow velocity based on an output signal from said second temperature detecting means and an output signal from said first temperature detecting means; holding means for calculating, and for holding as a calibration value, a blood vessel cross-sectional area based on the cardiac output calculated by said thermal attenuation-type cardiac output calculating means and the blood flow velocity calculated by said blood flow velocity calculating means; and cardiac output calculating means for calculating cardiac output based on the calibration value from said holding means and the blood flow velocity. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A cardiac output measurement method, comprising:
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a first step of obtaining cardiac output by a thermal attenuation method; a second step of obtaining blood flow velocity by a thermal-type flowrate measurement; a third step of obtaining a constituent value functionally related to the obtained cardiac output and blood flow velocity; a fourth step of obtaining blood flow velocity at continuous measurement instants; a fifth step of updating the constituent value by initiating said first step thereby obtaining a new cardiac output; and a sixth step of obtaining cardiac output from the blood flow velocity obtained and the already obtained constituent value as updated in said fifth step. - View Dependent Claims (10)
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Specification