US 11,653,847 B2
Method and apparatus for hypertension classification
Newton Howard, Providence, RI (US); Mohamed Elgendi, Vancouver (CA); Yongbo Liang, Guangxi (CN); Zhencheng Chen, Guangxi (CN); and Rabab Ward, Vancouver (CA)
Filed by Newton Howard, Providence, RI (US); Mohamed Elgendi, Vancouver (CA); Yongbo Liang, Guangxi (CN); Zhencheng Chen, Guangxi (CN); and Rabab Ward, Vancouver (CA)
Filed on Oct. 1, 2019, as Appl. No. 16/589,612.
Claims priority of provisional application 62/740,578, filed on Oct. 3, 2018.
Prior Publication US 2020/0107737 A1, Apr. 9, 2020
Int. Cl. A61B 5/024 (2006.01); A61B 5/021 (2006.01); A61B 5/00 (2006.01)
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
OG exemplary drawing
 
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.