Sensor fusion for the accurate non-invasive measurement of blood pressure

Abstract

The paper demonstrates that ECG and photoplethysmographic (PPG) signals recorded in parallel with cuff pressure help improve the accuracy of non-invasive blood pressure (BP) measurement. The proposed method eliminates erroneous results of automatic BP monitors caused by increased arterial stiffness and/or arrhythmia. In addition, it provides a feasible estimate on stress level of the test subject. 138 recordings of 54 subjects were taken both at rest and after a short physical exercise on patients with cardiovascular disease, as well as healthy control subjects. Further five hundred previously taken measurements were re-evaluated for algorithm development. The proposed method is able to determine systolic blood pressure (SBP) both during inflation and deflation. The deviation from the gold standard was −0.7 ± 1.5 mmHg for SBPinfl and −0.3 ± 1.8 mmHg for SBPdefl. The extra information of ECG and PPG reveals that even after short physical exercise 10-min rest is required before BP measurement. The extra information makes SBP estimation of patients with left ventricular assist device (LVAD) possible, which oscillometric monitors are unable to do. The method reported in this paper is expected to be introduced for BP measurement both in hospital and at home for patients with arrhythmia and living with LVAD.