Cardiovascular measurements by sound velocity dilution
First Claim
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1. Apparatus for measuring blood parameters, comprising:
- a blood system, having an upstream end and a downstream end and including an arterial portion and a venous portion connected to carry blood between said upstream and said downstream end;
a sound velocity sensor coupled to at least one of said arterial and venous portions of said blood system for detecting the velocity of sound in blood flowing within said at least one portion;
an injection port in said blood system upstream of said sound velocity sensor;
an indicator injectable through said injection port to produce an indicator bolus in blood flowing in said system, said indicator bolus having sound velocity characteristics different from sound velocity characteristics of blood flowing within said blood system in the absence of said indicator to thereby dilute said blood sound velocity characteristics;
means responsive to said sensor for detecting said bolus in said bloodstream and for producing and recording curves representing said diluted sound velocity characteristics; and
means for determining selected blood characteristics from said sound velocity dilution characteristics.
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Abstract
An apparatus and method for measuring hemodynamic parameters includes a sound velocity sensor coupled to at least one of an arterial or venous portion of a blood system. An indicator medium is injected into the blood system upstream of the sensor to dilute the bloodstream, and the sensor detects the dilution through changes in measured sound velocity. The changes are recorded and used to determine hemodynamic parameters.
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23 Claims
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1. Apparatus for measuring blood parameters, comprising:
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a blood system, having an upstream end and a downstream end and including an arterial portion and a venous portion connected to carry blood between said upstream and said downstream end; a sound velocity sensor coupled to at least one of said arterial and venous portions of said blood system for detecting the velocity of sound in blood flowing within said at least one portion; an injection port in said blood system upstream of said sound velocity sensor; an indicator injectable through said injection port to produce an indicator bolus in blood flowing in said system, said indicator bolus having sound velocity characteristics different from sound velocity characteristics of blood flowing within said blood system in the absence of said indicator to thereby dilute said blood sound velocity characteristics; means responsive to said sensor for detecting said bolus in said bloodstream and for producing and recording curves representing said diluted sound velocity characteristics; and means for determining selected blood characteristics from said sound velocity dilution characteristics. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification