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Automatic, continuous and indirect blood pressure measurement apparatus

  • US 4,524,777 A
  • Filed: 05/05/1983
  • Issued: 06/25/1985
  • Est. Priority Date: 02/25/1983
  • Status: Expired due to Term
First Claim
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1. In an automatic, continuous and indirect blood pressure measurement apparatus comprising:

  • (a) a cuff which is adapted to be attached to a segment to be measured;

    (b) external force applying means for applying an external force to fluid contained in said cuff to thereby generate a cuff pressure;

    (c) a pressure sensor means for measuring said cuff pressure; and

    (d) a volume sensor means for detecting a volume per unit length of an artery of said segment, said volume varying in accordance with said cuff pressure and a pulsating intravascular pressure, said volume sensor means generating a volume signal corresponding to said volume, said volume signal comprising a DC component and a volumetric pulse signal, wherein said external force applying means is energized in accordance with said volumetric pulse signal shifted in phase and controlled in amplitude in order to control and maintain said volume per unit length constant and to obtain an instantaneous blood pressure of said artery as a function of said cuff pressure;

    the improvement which comprises;

    DC level adjustment and first gain control means which is supplied with an output from said volume sensor means, said output being subjected to DC level adjustment and amplitude control, said DC level adjustment and first gain control means generating a DC level adjusted and amplitude controlled volume signal;

    phase compensator and second gain control means which controls the phase and amplitude of said volume signal from said DC level adjustment and first gain control means to generate said phase shifted and amplitude controlled volumetric pulse signal; and

    driver means responsive to said volumetric pulse signal shifted in phase and controlled in amplitude for driving said external force applying means.

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