2P1-B06 Log-linearized Peripheral Arterial Viscoelastic Indices Using a Photoplethysmogram(Medical Robotics and Mechatronics)

Abstract

This paper proposes a new model for estimating dynamic viscoelasticity of peripheral arterial wall using arterial pressure and photoplethysmogram. The proposed model is able to suppress the well-known pressure dependency of arterial stiffness using a log-linearization technique and estimate the changes of viscosity as well as stiffness of peripheral arterial wall induced by autonomic nervous activity. The validity of the proposal model is discussed by estimating the change of stiffness values during arm position tests and during endoscopic thoracic sympathectomies (ETSs). As results of the arm position tests, the position-dependent change of the stiffness was very little between arm positions during at rest and during loading (Up: 3.8 [%], Down: 5.6 [%]). Then, as results of the ETSs, the variation of the stiffness was significantly changed between before and during the ETS procedure (p<0.005), and between during and after the ETS procedure (p<0.025). Thus we concluded that the proposed method enabled to assess changes in the autonomic nervous activity.