P76 PERIPHERAL BLOOD PRESSURE AND STIFFNESS INDEX ESTIMATION USING THE PPG SIGNAL MEASURED WITH THE pOpmètre DEVICE: CALIBRATION WITH THE CUFF BLOOD PRESSURE

Arterial stiffness may influence the contour of the peripheral pulse, suggesting that contour analysis of the digital volume pulse (DVP) might be used to estimate peripheral blood pressure and a stiffness index (SI). The objective is to establish a transfer function that estimates the peripheral blood pressure using the PPG pulse, calibrated with a brachial pressure cuff, and then to deduce a stiffness index using the established parameters. We positioned the photodiode sensor on the finger. Brachial blood pressure measurement was performed with a cuff adapted to the arm circumference and an oscillometric device (Omron M10 -IT). Pulse wave velocity (PWV) measurements were performed with the pOpmètre® system. DVP waveforms were recorded over a 10 s period and ensemble-averaged to obtain a single waveform from which DT (DVP) was determined as the time between the first systolic peak and the early diastolic peak/inflection point in the waveform. The SI is the ratio of the subject’s height to the DT (DVP). 69 subjects were included: 24 healthy subjects and 45 patients with essential hypertension. The correlation between the estimated peripheral diastolic pressure and the brachial one was good and significant (r2 = 0.51; p < 0.001). A better correlation was found in terms of peripheral systolic pressure (r2 = 0.56; p < 0.001). The correlation between the SI and the ft-PWV was significant (r = 0.5; p < 0.001) classifying the estimation as good agreement. The estimation of the peripheral blood pressure and a stiffness index with the PPG signal qualifies as good agreement with the reference technique.