Flexible Piezoresistive Yarn Pressure Sensor for Arterial Blood Pressure Waveform Measurement

The arterial blood pressure (ABP) waveform contains essential information concerning the hemodynamic status and its relation to the diagnosis of cardiovascular conditions. Therefore, the continuous monitoring of the ABP waveform has become important. The arterial cannula, considered the gold standard for this monitoring, carries a risk of vascular trauma due to its invasive nature. Consequently, a measurement system that offers a non-invasive approach and maintains high accuracy in detecting morphological details of the ABP waveform is needed. In this study, we introduce a flexible piezoresistive yarn (FPY) pressure sensor for continuous non-invasive ABP waveform measurement. The sensor was experimentally validated using two scenarios: measurements on a hardware simulator and at a radial artery site. The simulator measurement aimed to assess the sensor's performance in detecting consistent waveforms, while the radial artery site measurements evaluated the sensor's performance in measuring ABP waveforms corresponding to the cardiovascular cycle. The simulator measurement results showed high repeatability, reproducibility, and accuracy relative to the reference signal at the upper limit of realistic force magnitude, as measured by the Pearson correlation coefficients: 0.9999 ± 0.0002 (10 measurements), 0.9994 ± 0.0002 (3 measurements), and 0.9731 ± 0.0027 (10 measurements), respectively. The correlation value derived from measurements at the radial artery site compared with measurements using a 3D force sensor as a reference sensor was 0.9880 ± 0.0035 (10 measurements from a single subject). Based on our results, the FPY pressure sensor can be used as an innovative solution for monitoring ABP waveforms and has further potential to be developed as a diagnostic device for evaluating cardiovascular conditions.