PP.09.31] CALCULATION OF CENTRAL BLOOD PRESSURE BY ANALYZING THE CONTOUR OF THE PHOTOPLETHYSMOGRAPHIC PULSE MEASURED AT THE FINGER WITH THE POPMÈTRE® DEVICE

Abstract

Objective: Analysis of the contour of the peripheral pulse to assess arterial properties was first described in the nineteenth century. The reference technique to estimate central blood pressure (CBP), non-invasively, is by analyzing the radial pressure pulse acquired using a tonometer and then to establish a transfer function relating the radial pressure to the CBP. An alternative technique utilizes a volume pulse. This may conveniently be acquired optically from a finger (digital volume pulse obtained with the photodiode of the pOpmètre® device- Axelife SAS- France). The objective is to establish a transfer function estimating the central blood pressure (CBP), calibrated with a brachial pressure cuff and using the parameters obtained with the contour analysis of the photoplethysmographic pulse measured at the finger with the pOpmètre® system. Design and method: We positioned the photodiode sensor on the finger, insuring that the sensor's lens is in contact with the pulp. Brachial blood pressure measurement was performed with a cuff adapted to the arm circumference and an oscillometric device (Omron M10 -IT). The central blood pressure values measured with Sphygmocor used as the reference values, with similar calibrating pressures. Multiple regression analysis was done to establish the transfer functions. Pearson's correlation and Bland Altman graph were performed for agreement. Results: 69 subjects were included: 24 healthy subjects and 45 patients with essential hypertension aged 33 ± 8 years and 59 ± 17 years respectively. The correlation between the estimated central systolic pressure (CSP) and the reference one, was good and significant (r2 = 0.94; p < 0.0001). A better correlation was found in terms of central diastolic pressure (CDP) (r2 = 0.95; p < 0.0001). The Bland and Altman analysis, mean difference was 4 mmHg p < 0.0001 (CSP) versus 3 mmHg p < 0.0001 (CDP), the standard deviation of the difference was 5 mmHg (CSP) versus 4 mmHg (CDP), classifying the estimation as good agreement. Conclusions: The estimation of the central blood pressure with the finger pulse qualifies as good agreement with the reference technique for the central systolic and diastolic pressure estimation.