Classification of Three Anesthesia Stages Based on Near-Infrared Spectroscopy Signals

Proper monitoring of anesthesia stages can guarantee the safe performance of clinical surgeries. In this study, different anesthesia stages were classified using near-infrared spectroscopy (NIRS) signals with machine learning. The cerebral hemodynamic variables of right proximal oxyhemoglobin (HbO₂) in maintenance (MNT), emergence (EM) and the consciousness (CON) stage were collected and then the differences between the three stages were compared by phase-amplitude coupling (PAC). Then combined with time-domain including linear (mean, standard deviation, max, min and range), nonlinear (sample entropy) and power in frequency-domain signal features, feature selection was performed and finally classification was performed by support vector machine (SVM) classifier. The results show that the PAC of the NIRS signal was gradually enhanced with the deepening of anesthesia level. A good three-classification accuracy of 69.27% was obtained, which exceeded the result of classification of any single category feature. These results indicate the feasibility of NIRS signals in performing three or even more anesthesia stage classifications, providing insight into the development of new anesthesia monitoring modalities.

I. Introduction

General anesthesia a state induced by anesthetics that encompasses sedation, analgesia, immobility, and amnesia, and is an important part of the surgical procedure [1]. Each year, tens of millions of patients undergo surgery, and accidental intraoperative awareness may affect up to 1% of patients worldwide [2]. Intraoperative awareness may cause serious impacts on the patient's physiology and psychology. Also, too deep anesthesia can lead to several physiological injuries, such as increased postoperative recovery time, liver damage, stroke, and even increased mortality [1], [3]. Therefore, monitoring the patient's anesthesia stages and guiding the anesthesiologist to administer medication in reasonable doses is an important guarantee for the safe implementation of clinical surgeries.