Evaluation of Pulse Transit Time for Different Sensing Methodologies of Arterial Waveforms

Abstract

We perform a novel comparative analysis between optically and mechanically derived pulse transit time (PTT) that is universally employed technique for cuffless blood pressure (BP) estimation. Two inline photoplethysmogram (PPG) sensors were placed at the distal and proximal phalanxes of the index finger and two finger ballistocardiogram (BPP) sensors were wrapped on top of the PPG sensors fixture around the phalanxes of the index finger. The stacking of the BPP sensor over the PPG sensor provided vertical spatial alignment for same location acquisition of the blood flow waveform through the radial artery. The analysis of variance (ANOVA) between PTT derived from the PPG and BPP sensors resulted in a statistically significant difference at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> < 0.05. The PTT derived from the BPP sensors showed higher values,17.8 milliseconds on average, than the PTT derived from the PPG sensors. Higher accuracy PTT values will improve the estimation of cuffless BP and thus has the potential to revolutionize the technology.