Detection of Peak Peripheral Blood Flow

Abstract: Electrical impedance measurement of a body segment is performed by applying a low-amplitude, high frequency constant current through one pair of electrodes, while the resulting voltage is recorded using a separate pair of sensing electrodes. The measured voltage varies with the volume of blood present in the measured region. The negative first derivative of the impedance waveform is a peripheral blood flow (PBF) signal. Distinct fiducial points in the PBF waveform correspond to specific phases of the cardiac cycle, utilized to derive cardiovascular parameters and assess beat- to-beat variations. This study investigates automated detection of peaks in the PBF signal using three methods based on custom logic, implemented on PBF signals from subjects with normal health, hypertension, lung cancer, and coronary artery disease. Signals were recorded from 6 subjects of each type, yielding 24 recordings of 8,996 cycles. Method M3 achieved sensitivity 99.57%, precision 99.71%, F1-score 99.64%, and detection error 0.72%, outperforming all other methods.

Keywords: Electrical impedance, Fiducial points, Peripheral blood flow (PBF), Wavelet methods.