Patent ID: 11969236
Assignee: ACCURATE MEDITECH INC
Field: Medical technology (Instruments)
Classification: CPC A  G | IPC A

Claim 0:
1. A device for measuring blood pressure, comprising:
a housing;
a processing unit disposed in the housing;
a display disposed on the housing and in communication with the processing unit;
a plurality of sensors in communication with the processing unit and configured to sense an artery of a user and transmit at least one physiological signal corresponding to the artery to the processing unit, the plurality of sensors comprises a piezoelectric sensor, an accelerometer and a gyroscope; and
a signal controller and a signal detector in communication with the piezoelectric sensor,
wherein the processing unit is configured to:
process the at least one physiological signal to obtain a plurality of hemodynamic parameters and a pulse transit time (PTT), the plurality of hemodynamic parameters comprising a blood vessel wall thickness, a blood vessel diameter, and a blood density,
determine a pulse wave velocity (PWV) as being equal to a distance between two of the plurality of sensors divided by the PTT,
determine a posture according to an axial change detected by the accelerometer and the gyroscope,
calibrate the PWV according to the posture by referencing a posture-to-PWV look up table stored in the processing unit, the posture-to-PWV look up table created by obtaining correction coefficients corresponding to different angles and angular acceleration received from the accelerometer and the gyroscope,
determine an intra-arterial pressure from the plurality of hemodynamic parameters and the calibrated PWV via a Moens-Korteweg (MK) function, and considering the intra-arterial pressure as a mean arterial pressure,
determine a set of arterial stiffness values using a set of PTT values,
obtain a photoplethysmogram intensity ratio (PIR) and normalizing the PIR by the set of arterial stiffness values,
determine a pulse pressure according to the normalized PIR via a look-up table of arterial stiffness normalized PIR versus pulse pressure (PP) stored in the processing unit, the PP being a difference between a systolic arterial pressure and a diastolic arterial pressure,
determine the systolic arterial pressure and the diastolic arterial pressure from the mean arterial pressure, and the PP and a coefficient k ranging from 0 to 1, and
control the display to display the systolic arterial pressure and the diastolic arterial pressure,
wherein the signal detector is configured to detect a first signal direction of at least one first physiological signal sent from the piezoelectric sensor, and when a polarization direction of the piezoelectric sensor is opposite to an expected polarization direction, the signal controller is configured to change a second signal direction of at least one second physiological signal subsequent to the at least one first physiological signal.