Evaluation of Autonomic Nervous Activity Based on Arterial Wall Impedance and Heart Rate Variability

This paper proposes a new method for evaluating the autonomic nervous activities by using the mechanical impedance of the arterial wall and heart rate variability. The cardiovascular system is indispensable to life maintenance functions, and homeostasis is maintained by the autonomic nervous system. It is very important to give a diagnosis based on the autonomic nervous activities of the whole body. The proposed method is evaluated in surgical operations, where the mechanical impedance of the arterial wall is estimated from the arterial blood pressure and a pulseoximetric photoplethysmogram, and heart rate variability is estimated by electrocardiogram RR interval spectral analysis. From the experimental results, we concluded that the proposed method is able to estimate autonomic nerve activities corresponding to events during operations.