Method and apparatus for measuring blood pressure

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG.
1, there is illustrated a functional block diagram of an automatic blood pressure measuring system incorporating objects and features of the present invention.
A conventional sphygmomanometer cuff C is wrapped about, for example, a patient's arm.
The pressure applied to cuff C is determined by operating a conventional pump/vent mechanism 10, by means of a pump control 12, which applies either a pump signal (P) or a vent signal (V) to pump/mechanism 10.
The operation of pump control 12 is, in turn, controlled by model acquisition logic 14, which is programmed to produce a predetermined sequence of nominal pressures within cuff C.
The actual instantaneous pressure in cuff C is sensed by a conventional pressure transducer 16, which produces an electrical signal representative of the sensed pressure, which signal is applied to pressure analyzer 18.
This pressure analyzer extracts signals representing the pulsatile pressure perturbations due to the patient's heart beat and provides two fundamental signals to model acquisition logic 14: (i) information relating to the pulsatile perturbation; and (ii) the accompanying cuff pressure.
Various information about the pulsatile perturbations has been utilized to generate blood pressure characteristics.
This includes various derivatives of wave forms representing the actual pulses and the amplitude of the pulses.
However, the pulse amplitude is the most commonly used characteristic.
In model acquisition logic 14, the pulsatile information and cuff pressure are converted to a processable form (e.
g.
digital information) and are then stored in a conventional memory 20.
Model acquisition logic also operates a conventional display 22 which may indicate such parameters as systolic pressure, diastolic pressure, mean pressure, and pulse rate (derived in model acquisition logic 14).
Thus far, the block diagram of FIG.
1 illustrates the operation of a conventional blood pressure measuring apparatus of the oscillometric type, of which there exists many varieties