Fluid viscoelastic test apparatus and method
AssigneeSienco, Inc.
InventorJon H. Henderson
Life of this patent
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Abstract
An instrument for testing the viscoelastic characteristics of fluids, such as blood, exhibits improved temperature regulation of the blood sample under test, includes probe drive circuitry to simplify calibration and signal conditioning, incorporates resonant frequency monitoring to detect mechanical noise disturbances, and provides automated analysis of a graphical signature, over time, of the viscoelastic characteristics of the blood sample, including a visual indication to the user of the activated clotting time period (ACT) and the rate of clot formation (RATE) of the blood sample under test, thereby improving the accuracy of the test results and simplifying operation of the instrument to permit its use by surgical personnel.
Claims22
An instrument for measuring one or more viscoelastic properties of a fluid sample, the instrument comprising:
- probe means disposed in contact with the fluid sample;
- electromechanical transducer means coupled to the probe means for providing mechanical displacement of the probe means relative to the fluid sample;
- first circuit means, connected to the electromechanical transducer means, said first circuit means comprising drive circuitry providing a drive signal for generating oscillatory mechanical displacement of the probe means relative to the fluid sample, said first circuit means further comprising response circuitry for monitoring a response signal generated by the electromechanical transducer means, the response signal being representative of the one or more viscoelastic properties of the fluid sample, said drive circuitry and response circuitry forming a feedback loop wherein the drive signal is developed from the response signal and vice versa;
- second circuit means for regulating an amplitude of a first signal within said feedback loop, while allowing said feedback loop to operate at resonant oscillatory frequency determined by said probe means, said electromechanical transducer means, and said first circuit means;
- and
- microcontroller means for receiving and analyzing said response signal to determine the one or more viscoelastic properties of the fluid sample represented by said response signal, said microcontroller means being responsive to said response signal for computing a time period thereof between a measurement start time and the occurrence of a viscoelastic change in the fluid sample represented by said response signal.
An instrument for measuring a plurality of viscoelastic properties of a fluid sample, the instrument comprising:
- probe means disposed in contact with the fluid sample;
- electromechanical transducer means coupled to the probe means for providing mechanical displacement of the probe means relative to the fluid sample;
- first circuit means, connected to the electromechanical transducer means, said first circuit means comprising drive circuitry providing a drive signal for generating oscillatory mechanical displacement of the probe means relative to the fluid sample, said first circuit means further comprising response circuitry for monitoring a response signal generated by the electromechanical transducer means, the response signal being representative of the plurality of viscoelastic properties of the fluid sample, said drive circuitry and response circuitry forming a feedback loop wherein the drive signal is developed from the response signal and vice versa;
- second circuit means for regulating an amplitude of a first signal within said feedback loop;
- and
- microcontroller means for receiving and analyzing said response signal to determine said plurality of viscoelastic properties of the fluid sample represented by said response signal, said microcontroller means being responsive to said response signal for computing a time period thereof between a measurement start time and the occurrence of a viscoelastic change in the fluid sample represented by said response signal.
Dependencies are inferred from the claim text.