Cardiovascular measurements by sound velocity dilution
First Claim
Patent Images
1. Apparatus for measuring selected parameters of blood, comprising:
- a blood circulating system having an arterial portion leading from an upstream blood flow and a venous portion leading to a downstream blood flow, said arterial and venous portions being connected in said circulating system to allow blood to travel from said upstream flow through the circulating system to said downstream flow;
a sound velocity sensor coupled to at least one of said arterial and venous portions for detecting the velocity of blood traveling therein;
an injection port in at least one of said arterial and venous portions;
an indicator injectable through said injection port to produce a bolus in blood flowing in said blood circulating system, said bolus having sound velocity characteristics different from sound velocity characteristics of blood flowing within said system in the absence of said indicator;
a sound velocity detector connected to each said sound velocity sensor for producing an output signal corresponding to sensed sound velocity in blood flowing in said stream to thereby produce sound velocity dilution signals representing changes in blood characteristics due to said bolus; and
an evaluating device for determining from said dilution signals selected blood characteristics.
0 Assignments
0 Petitions
Accused Products
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.
89 Citations
49 Claims
-
1. Apparatus for measuring selected parameters of blood, comprising:
-
a blood circulating system having an arterial portion leading from an upstream blood flow and a venous portion leading to a downstream blood flow, said arterial and venous portions being connected in said circulating system to allow blood to travel from said upstream flow through the circulating system to said downstream flow; a sound velocity sensor coupled to at least one of said arterial and venous portions for detecting the velocity of blood traveling therein; an injection port in at least one of said arterial and venous portions; an indicator injectable through said injection port to produce a bolus in blood flowing in said blood circulating system, said bolus having sound velocity characteristics different from sound velocity characteristics of blood flowing within said system in the absence of said indicator; a sound velocity detector connected to each said sound velocity sensor for producing an output signal corresponding to sensed sound velocity in blood flowing in said stream to thereby produce sound velocity dilution signals representing changes in blood characteristics due to said bolus; and an evaluating device for determining from said dilution signals selected blood characteristics.
-
-
2. A method of measuring hemodynamic parameters by indicator dilution, comprising:
-
coupling a sound velocity sensor to at least one of an arterial or venous portion of a blood circulating system; producing a bolus of indicator material in the blood circulating system, said bolus having a sound velocity characteristic which differs from sound velocity characteristics of blood flowing in the blood circulating system to thereby dilute said blood; detecting, by said sound velocity sensor, changes in sound velocity within said blood caused by dilution of the blood due to said bolus and producing output signals representing changes in blood sound velocity parameters over time caused by said bolus; and evaluating said output signals to determine selected blood characteristics. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of measuring a volume of a selected portion of a vascular system, comprising:
-
injecting into an inlet blood stream flowing into a selected portion of a vascular system a first-quantity of an isotonic solution having a characteristic substantially equal to the same characteristic of said vascular system; measuring in an outlet blood stream flowing out of said selected portion changes in said blood parameter as said first quantity of said isotonic solution flows through said outlet blood stream to obtain a blood characteristic curve; injecting into said inlet blood stream a second quantity of said isotonic solution having a characteristic substantially different than that of said blood system; measuring in said outlet blood stream changes in said blood parameter as said second quantity of said isotonic solution flows through said outlet blood stream; determining differences in said blood parameter changes to obtain a difference curve; and comparing said difference curve with said blood characteristic curve to yield a measurement of said volume of said blood system. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
-
-
23. A method of measuring the extravascular volume of an organ in a patient, comprising injecting a first isotonic solution having a first osmolality into an organ vascular system prior to the organ to dilute blood flowing in said system and passing through said organ;
-
measuring in said vascular system following said organ changes in the velocity of sound in said blood due to said first solution; injecting a second isotonic solution having a second osmolality into said system prior to said organ; measuring in said vascular system following said organ changes in the velocity of sound in said blood due to said second solution; and comparing said measurements to obtain the extravascular volume of said organ. - View Dependent Claims (24, 25, 26)
-
-
27. A method of measuring blood flow in a patient, comprising:
-
injecting, from a catheter placed in the vascular system leading to a selected organ of a patient, a first saline solution at a temperature substantially equal to the patient'"'"'s body temperature; measuring, in the vascular system leading from the selected organ of the patient, changes in the velocity of ultrasound in blood flowing in the vascular system caused by said first solution; establishing a curve representing said changes in velocity; and determining from an area under said curve the flow of blood from the selected organ. - View Dependent Claims (28, 29)
-
-
30. A method of measuring total organ blood flow in a patient, comprising:
-
injecting a first quantity of an indicator solution in a vascular system downstream of a patient'"'"'s organ; measuring by a first sensor a first selected parameter of said blood flow downstream of said injection and measuring by a second sensor blood flow rate downstream of said injection to measure changes produced by said first indicator solution to calibrate said first sensor; injecting a second quantity of said indicator solution upstream of said organ; measuring changes in said first selected parameter and changes in blood flow rate produced downstream of said organ by said second quantity of indicator solution; and comparing changes produced by said first and second quantities of indicator solution to obtain a measure of total organ blood flow. - View Dependent Claims (31, 32, 33, 34)
-
-
35. 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 ends; a first sound velocity sensor coupled to said venous portion of said blood system; a second sound velocity sensor closely matched to said first sound velocity sensor and coupled to said arterial portion of said blood system; 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; and means responsive to said first and second sound velocity sensors for detecting said bolus in said bloodstream and for producing and recording curves representing said diluted sound velocity characteristics. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
-
Specification