Fig. 3From: Heart rate variability-derived features based on deep neural network for distinguishing different anaesthesia statesCorrelations between the four features and EACL. a_d Correlations of HF, LF, ratio of HF/LF, and RR interval SampEn with the EACL, respectively. I, II, and III represent anaesthesia induction, anaesthesia maintenance, and anaesthesia recovery, respectively. EACL: expert assessment of consciousness level; HF: high-frequency; LF: low-frequency; HF/LF: high-to-low-frequency ratioBack to article page