System for calculating compliance and cardiac hemodynamic parameters
First Claim
1. A system for determining compliance of a vessel, the system comprising:
- a displacement balloon insertable into the vessel;
a tube having at least first and second openings, the first opening being connected to the displacement balloon;
an adjustable pressure source connected to the second opening of the tube that selectively changes volume of the displacement balloon by an amount, thereby changing volume of the vessel by essentially the amount;
pressure detecting means for measuring blood pressure in the vessel at a position near the displacement balloon and generating a pressure signal indicative of the measured blood pressure; and
processing means for receiving the pressure signal, determining change in blood pressure caused by the change in volume of the displacement balloon, and determining the compliance based on the change in volume and the change in blood pressure.
1 Assignment
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Accused Products
Abstract
A catheter set (10) is used in connection with a blood flow monitor and calibration system (80) to determine the compliance C of a vessel according to the equation C=dV2/ (PE-PA), where dV2 is the change in volume of the vessel created by the change in volume (e.g., deflation) of a displacement balloon (30) adjacent to a catheter (14), PE is an estimate of what the pressure measured by a pressure transducer (56) or a strain gage (78) would have been but for the change in volume of the displacement balloon at a particular time, and PA is the actual pressure measured by the transducer at the particular time. The determined compliance is more accurate than that obtained through thermal dilution procedures. The determined value of compliance C may then be used in calculation of blood flow. In addition, pulmonary vascular resistance and systemic vascular resistance may calculated through procedures and in equations using the determined compliance without directly measuring the pulmonary capillary wedge pressure.
117 Citations
26 Claims
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1. A system for determining compliance of a vessel, the system comprising:
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a displacement balloon insertable into the vessel; a tube having at least first and second openings, the first opening being connected to the displacement balloon; an adjustable pressure source connected to the second opening of the tube that selectively changes volume of the displacement balloon by an amount, thereby changing volume of the vessel by essentially the amount; pressure detecting means for measuring blood pressure in the vessel at a position near the displacement balloon and generating a pressure signal indicative of the measured blood pressure; and processing means for receiving the pressure signal, determining change in blood pressure caused by the change in volume of the displacement balloon, and determining the compliance based on the change in volume and the change in blood pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for determining compliance of a vessel, the system comprising:
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a catheter that is insertable into the vessel; a tube having at least first and second openings, the first opening being positioned in the vessel; an adjustable pressure source that holds fluid and that is connected to the second opening of the tube, the adjustable pressure source selectively changes volume of fluid in the adjustable pressure source by a predetermined amount, thereby changing volume of the vessel by essentially the predetermined amount; pressure detecting means for measuring blood pressure in the vessel and generating a pressure signal indicative of the measured blood pressure; and processing means for receiving the pressure signal, determining change in blood pressure caused by the change in volume of the fluid, and determining the compliance through an equation that includes the change in volume and the change in blood pressure. - View Dependent Claims (17, 18)
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19. A method for determining compliance of a vessel, the method comprising the steps of:
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inserting a displacement balloon into the vessel, the displacement balloon being connected to a first opening of a tube having at least first and second openings, the second end being connected to an adjustable pressure source; changing the pressure of the adjustable pressure source so as to change volume of the displacement balloon by a predetermined amount; sensing blood pressure in the vessel at a position near the displacement balloon; determining change in blood pressure caused by the change in volume of the displacement balloon, and determining the compliance through an equation that includes the change in volume and the change in blood pressure.
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20. A method for calculating blood flow in a vessel, the method comprising:
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determining the compliance of the vessel by determining a change in pressure caused by a change in volume in the vessel; and calculating the blood flow according to an equation in which the compliance is a parameter.
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21. A system for calculating blood flow of blood in a vessel of a subject, comprising:
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a displacement balloon that is insertable into the vessel; a tube having at least first and second openings, the first opening being connected to the displacement balloon; an adjustable pressure source connected to the second opening of the tube that selectively changes volume of the displacement balloon by an amount, thereby changing the volume of the vessel by essentially the amount; pressure detecting means for measuring blood pressure in the vessel at a position near the displacement balloon and generating a pressure signal indicative of the measured blood pressure; processing means for receiving the pressure signal, determining change in blood pressure caused by the change in volume of the displacement balloons and determining the compliance based on an equation that includes the change in volume and the change in blood pressure; the processing means using the pressure signal for measuring heart rate (F) of the subject, for measuring an average pressure (Pcd) in the arterial tree of the subject at end of systole, measuring an average pressure (Pab) in the arterial tree of the subject at end of diastole, generating an arterial pressure curve of the subject during systolic drainage and an arterial pressure curve of the subject during diastolic drainage, measuring area (Sa) under the arterial pressure curve during systolic drainage, measuring area (Da) under the arterial pressure curve during diastolic drainage, and calculating BF according to an equation BF=C×
F (Pcd-Pab) (1+Sa/Da).
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22. A method for calculating pulmonary vascular resistance (PVR) of a subject, without directly measuring pulmonary capillary wedge pressure, the method comprising the steps of:
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determining the compliance C of pulmonary artery of the subject through a procedure that includes measuring blood pressure; measuring pulmonary artery pressure (PAP1) of the subject at time t1; measuring pulmonary artery pressure (PAP2) of the subject at time t2; and calculating PVR according to an equation PVR=(t2-t1)/(C×
ln(PAP1/PAP2)). - View Dependent Claims (23)
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24. A method for calculating systemic vascular resistance (SVR) of a subject, without directly measuring pulmonary capillary wedge pressure, the method comprising the steps of:
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calculating pulmonary vascular resistance (PVR) of the subject; determining mean pulmonary artery pressure (PAP) of the subject; calculating cardiac output (CO) of the subject; determining mean arterial pressure (AOP) of the subject; calculating the pulmonary capillary wedge pressure (PCW) according to an equation PCW=(PVR×
CO)/PAP; andcalculating the systemic vascular resistance of the subject according to an equation SVR=(AOP×
PCW)/CO; andin which the PVR is calculated according to a method including the determining compliance of the subject through a procedure that includes measuring blood pressure; measuring pulmonary artery pressure (PAP1) of the subject at time t1; measuring pulmonary artery pressure (PAP2) of the subject at time t2; and calculating PVR according to an equation PVR=(t2-t1)/(C×
ln(PAP1/PAP2)).
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25. A method for calculating systemic vascular resistance (SVR) of a subject, the method comprising the steps of:
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calculating pulmonary vascular resistance (PVR) of the subject; determining mean arterial pressure (AOP) of the subject; determining mean pulmonary artery pressure (PAP) of the subject; calculating the SVR of the subject according to an equation SVR=AOP×
PVR/PAP; andin which the PVR is calculated according to a method including the steps of; determining compliance of the subject through a procedure that includes measuring blood pressure; measuring pulmonary artery pressure (PAP1) of the subject at time t1; measuring pulmonary artery pressure (PAP2) of the subject at time t2; and calculating PVR according to an equation PVR=(t2-t1)/(C×
ln(PAP1/PAP2)).
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26. A system for determining compliance of a vessel, the system comprising:
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a catheter that is insertable into the vessel; a displacement balloon positioned adjacent to the catheter; a tube having at least first and second openings, the first opening being connected to the displacement balloon; an adjustable pressure source connected to the second opening of the tube that selectively changes volume of the displacement balloon by a predetermined amount, thereby changing volume of the vessel by essentially the predetermined amount; pressure detecting means for measuring blood pressure in the vessel at a position near the displacement balloon and generating a pressure signal indicative of the measured blood pressure; and processing means for receiving the pressure signal, determining change in blood pressure caused by the change in volume of the displacement balloon, and determining the compliance based on the change in volume and the change in blood pressure.
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Specification