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Respiration monitoring method and apparatus

  • US 3,911,899 A
  • Filed: 11/08/1973
  • Issued: 10/14/1975
  • Est. Priority Date: 11/08/1973
  • Status: Expired due to Term
First Claim
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1. In a monitor, circuitry for measuring the rate of recurrence of a physiological parameter of a patient and for providing an alarm upon variation of the parameter from preselected values;

  • sensing means responsive to said parameter for producing a sensing signal;

    first integrator means responsive to said sensing signal to produce a variable parameter signal;

    second integrator means responsive to said variable parameter signal to produce a relatively stable base signal;

    differential amplifier means responsive to the difference between said base and variable parameter signals to produce an electrical signal having a waveform the slope and amplitude of which varies in accordance with the parameter being monitored;

    reflexive means responsive to said electrical signal for detecting said rate of recurrence, said reflexive means being responsive to a recurring slope of said waveform, whereby a waveform having a slope of a first direction initiates a pulse, said reflexive means preventing the production of a second pulse until said waveform reverses to a second direction and returns to said first direction to thereby define a complete cycle of said parameter and a recurrence of the parameter being measured;

    first adjustable alarm means responsive to the rate of recurrence of said pulses to produce a first alarm signal when said rate exceeds a first preset value;

    second adjustable alarm means responsive to the rate of recurrence of said pulses to produce a second alarm signal when said rate falls below a second preset value; and

    indicator means responsive to said alarm signals.

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