Differential conductivity hemodynamic monitor
First Claim
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1. A method for quantitatively determining a flow rate in a tube of a first fluid having a first electrical conductivity and a corresponding first concentration of conductivity producing ions, comprising:
- altering the electrical conductivity of the first fluid;
measuring the electrical conductivity at a measuring location of the first fluid after the conductivity is altered;
determining the period of time over which the altered conductivity fluid passes the measuring location;
integrating the measured conductivity over the period of time; and
interpreting the time integrated value of conductivity to determine flow rate;
wherein the step of measuring the conductivity of the first fluid further comprises;
flowing the first fluid through a first conduit, said first conduit comprising a first conductivity cell through which the first fluid flows with a continuous path configuration;
inducing by electromagnetic induction a first electrical current in the first fluid in the first conductivity cell; and
sensing by electromagnetic induction the first electrical current in the first fluid in the first conductivity cell.
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Abstract
A flow rate of a fluid flowing in a tube is quantitatively determined by altering the electrical conductivity of the fluid by injection of a bolus of saline. The electrical conductivity of the altered conductivity is measured over the time it takes the altered conductivity fluid to pass a conductivity measuring location. The measured conductivity is integrated over the time it take to pass the conductivity measuring location. The integral is interpreted to determine the flow rate.
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Citations
23 Claims
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1. A method for quantitatively determining a flow rate in a tube of a first fluid having a first electrical conductivity and a corresponding first concentration of conductivity producing ions, comprising:
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altering the electrical conductivity of the first fluid; measuring the electrical conductivity at a measuring location of the first fluid after the conductivity is altered; determining the period of time over which the altered conductivity fluid passes the measuring location; integrating the measured conductivity over the period of time; and interpreting the time integrated value of conductivity to determine flow rate; wherein the step of measuring the conductivity of the first fluid further comprises; flowing the first fluid through a first conduit, said first conduit comprising a first conductivity cell through which the first fluid flows with a continuous path configuration; inducing by electromagnetic induction a first electrical current in the first fluid in the first conductivity cell; and sensing by electromagnetic induction the first electrical current in the first fluid in the first conductivity cell. - View Dependent Claims (2, 3, 4)
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5. A method for quantitatively determining a flow rate in a tube of a first fluid having a first electrical conductivity and a corresponding first concentration of conductivity producing ions, comprising:
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altering the electrical conductivity of the first fluid; measuring the electrical conductivity at a measuring location of the first fluid after the conductivity is altered; determining the period of time over which the altered conductivity fluid passes the measuring location; integrating the measured conductivity over the period of time; and interpreting the time integrated value of conductivity to determine flow rate; wherein a second fluid flows in another tube the second fluid having a second electrical conductivity and a corresponding second concentration of conductivity producing ions, wherein the measuring step further comprises; measuring the electrical conductivity of the second fluid; and comparing the conductivity of the first fluid with the conductivity of the second fluid. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. An apparatus for determining a rate of flow of a first fluid in a tube, said first fluid having a first electrical conductivity and a first concentration of conductivity producing ions, comprising:
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means for altering the electrical conductivity of the first fluid; means for measuring the electrical conductivity of the first fluid after the conductivity is altered; means for determining the period of time over which the altered conductivity fluid passes the measuring location; means for integrating the measured conductivity over the period of time; and means for interpreting the time integrated value of conductivity to determine flow rate; wherein the means for measuring the conductivity of the first fluid further comprises; a first conduit through which the first fluid flows, said first conduit comprising a first conductivity cell through which the first fluid flows with a first conductivity cell upstream connection, a first conductivity cell downstream connection, and two branches connecting the upstream connection to the downstream connection with a continuous path configuration from the upstream connection to the downstream connection through one of the two branches and returning to the upstream connection through the other one of the two branches; means for inducing by electromagnetic induction a first electrical current in the first fluid in the first conductivity cell; means for sensing by electromagnetic induction the first electrical current in the first fluid in the first conductivity cell. - View Dependent Claims (13, 14, 15, 16)
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17. An apparatus for determining a rate of flow of a first fluid in a tube, said first fluid having a first electrical conductivity and a first concentration of conductivity producing ions, comprising:
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means for altering the electrical conductivity of the first fluid; means for measuring the electrical conductivity of the first fluid after the conductivity is altered; means for determining the period of time over which the altered conductivity fluid passes the measuring location; means for integrating the measured conductivity over the period of time; and means for interpreting the time integrated value of conductivity to determine flow rate; wherein a second fluid having a second conductivity and a second concentration of conductivity producing ions is flowing in another tube, further comprising; means for measuring the electrical conductivity of the second fluid, and for comparing the conductivity of the first fluid with the conductivity of the second fluid. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification