Monitoring of anesthetic depth and EEG band power using phase lag entropy during propofol anesthesia

• Published in: BMC anesthesiology 2020-02, Vol.20 (1), p.49-49, Article 49
• Main Authors: Shin, Hye Won, Kim, Hyun Jung, Jang, Yoo Kyung, You, Hae Sun, Huh, Hyub, Choi, Yoon Ji, Choi, Seung Uk, Hong, Ji Su
• Format: Article
• Language: English
• Subjects: Adult; Analysis; Anesthesia; Anesthetic depth monitoring; Anesthetics, Intravenous - pharmacology; Bispectral index; Blood pressure; Brain - drug effects; Communication; Consciousness; Consciousness Monitors; EEG; Electrodes; Electroencephalography; Electroencephalography - instrumentation; Electroencephalography - methods; Entropy; Female; Humans; Intubation; Male; Medical personnel; Noise; Novels; Patients; Phase lag entropy; Phenols (Class of compounds); Power (Philosophy); Propofol; Propofol - pharmacology; Prospective Studies; Republic of Korea; Sensors; Signal processing; Surgery
• ISSN: 1471-2253; 1471-2253
• DOI: 10.1186/s12871-020-00964-5

Phase lag entropy (PLE) is a novel anesthetic depth indicator that uses four-channel electroencephalography (EEG) to measure the temporal pattern diversity in the phase relationship of frequency signals in the brain. The purpose of the study was to evaluate the anesthetic depth monitoring using PLE and to evaluate the correlation between PLE and bispectral index (BIS) values during propofol anesthesia. In thirty-five adult patients undergoing elective surgery, anesthesia was induced with propofol using target-controlled infusion (the Schneider model). We recorded the PLE value, raw EEG, BIS value, and hemodynamic data when the target effect-site concentration (Ce) of propofol reached 2, 3, 4, 5, and 6 μg/ml before intubation and 6, 5, 4, 3, 2 μg/ml after intubation and injection of muscle relaxant. We analyzed whether PLE and raw EEG data from the PLE monitor reflected the anesthetic depth as the Ce of propofol changed, and whether PLE values were comparable to BIS values. PLE values were inversely correlated to changes in propofol Ce (propofol Ce from 0 to 6.0 μg/ml, r  = - 0.83; propofol Ce from 6.0 to 2.0 μg/ml, r  = - 0.46). In the spectral analysis of EEG acquired from the PLE monitor, the persistence spectrogram revealed a wide distribution of power at loss of consciousness (LOC) and recovery of consciousness (ROC), with a narrow distribution during unconsciousness. The power spectrogram showed the typical pattern seen in propofol anesthesia with slow alpha frequency band oscillation. The PLE value demonstrated a strong correlation with the BIS value during the change in propofol Ce from 0 to 6.0 μg/ml (r  = 0.84). PLE and BIS values were similar at LOC (62.3 vs. 61.8) (P > 0.05), but PLE values were smaller than BIS values at ROC (64.4 vs 75.7) (P