CPC A61B 5/02427 (2013.01) [A61B 5/02116 (2013.01); A61B 5/02125 (2013.01); A61B 5/6826 (2013.01); A61B 5/7221 (2013.01); A61B 5/7239 (2013.01); A61B 5/7264 (2013.01)] | 7 Claims |
1. A system for real-time evaluation and screening of hypertension of a subject, the system comprising a processor and storage storing data and software for performing a method comprising the steps of:
a) obtaining an original infrared PPG signal of the subject using a fingertip photoplethysmograph (PPG);
b) obtaining a processed PPG signal by performing a signal conditioning of the original infrared PPG signal using an amplifying circuit, a bandpass filter circuit and a baseline drift suppression circuit;
c) obtaining derivative waveforms of the processed PPG signal including a velocity of plethysmograph (VPG) and an acceleration of plethysmograph (APG) from the processed PPG signal;
d) defining and extracting waveforms, from the processed PPG signal and its derivative waveforms, the extracted waveforms comprising at least a time interval, an amplitude, an area, a ratio, a slope, and an energy parameter;
e) analyzing a physiological significance of the extracted waveforms to obtain at least one physiologically significant feature;
f) selecting the at least one physiologically significant feature from the extracted waveforms, the at least one physiologically significant feature selected from a group including:
i. a slope from a first point of the processed PPG signal corresponding in time to a minimum of the APG waveform immediately preceding a systolic maximum of the processed PPG signal and a second point of the processed PPG signal corresponding in time to a maximum of the APG waveform immediately following the systolic maximum of the processed PPG signal,
ii. a time interval from the systolic maximum of the processed PPG signal to the second point of the processed PPG signal, and
iii. a time interval from the first point of the processed PPG signal to a third point of the processed PPG signal, the third point have an amplitude equal to the amplitude of the first point of the processed PPG signal;
g) based on the selected at least one physiologically significant feature, establishing a cubic Support Vector Machine (SVM) classification model of hypertension; and
(h) using the cubic Support Vector Machine (SVM) classification model of hypertension to generate classification of patients into different stages of hypertension.
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