A new blood pressure prediction method using wrist pulse examination

Abstract

Wrist pulse examination plays an imperative role in clinical practice including contemporary medicine systems like Ayurveda. Wrist pulse measurement system can also be used for blood pressure (BP) monitoring. This article proposes an extension of wrist pulse analysis system for BP monitoring. Wrist pulse signals are captured using three piezoelectric thin film sensors at the radial artery of the wrist as per Ayurvedic pulse diagnosis method. The wave features such as Spatial Pulse Transit Time (SPTT) and Spatial Pulse Wave Velocity (SPWV) are extracted from the captured wrist pulses. Pearson’s correlation coefficient is computed to find the correlation between SPTT and BP measured using standard measuring instrument (Omron HEM-6131). A moderate correlation is found between SPTT and Systolic Blood Pressure (SBP) with correlation coefficient of 0.72. SPWV values computed from SPTT are used to develop an empirical model for BP in terms of SPWV. Limitations of the empirical model lead to a theoretical model using Poiseuilli law. The Mean Artery Pressure (MAP) using theoretical model is recorded for 41 participants. The deviation of MAP thus computed as compared to the readings taken from clinically validated BP monitoring device is found to be varying in the range of 4.5 ± 2.3 mmHg.