John T Canavan

US Patent:

44691076, Sep 4, 1984

Filed:

Jun 1, 1981

Appl. No.:

6/269511

Inventors:

Raymond A. Asmar - Danbury CT
John Canavan - Washington Depot CT

International Classification:

A61B 502

US Classification:

128681

Abstract:

A blood pressure measurement apparatus comprises electronic circuitry which converts an output from a pressure transducer into a digital display for both the systolic and diastolic blood pressure of an individual. The output of the pressure transducer contains an electrical DC voltage component with a superimposed AC voltage component during arterial blood flow. Sample and hold and logarithmic scaling circuits are used to properly sense the AC voltage over a wide range of values so as to eliminate improper sensing due to noise. A digital output display shows the individual's systolic blood pressure while another display shows the current transducer reading which becomes set upon reaching the diastolic pressure. Control circuitry is used to sense occurrence of the systolic and diastolic pressures. In one embodiment, the circuitry is enclosed in a wristwatch type case which also includes a constrictable band and an integral air bulb, resulting in an easily portable wrist-worn blood pressure measuring device.