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

Abstract

Background: 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.Methods: 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.Results: PLE values were inversely correlated to changes in propofol Ce (propofol Ce from 0 to 6.0 μg/ml, r 2 = − 0.83; propofol Ce from 6.0 to 2.0 μg/ml, r 2 = − 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 2 = 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 < 0.05). Conclusions: The PLE value is a useful anesthetic depth indicator, similar to the BIS value, during propofol anesthesia. Spectral analysis of EEG acquired from the PLE monitor demonstrated the typical patterns seen in propofol anesthesia. Trial registration: This clinical trial was retrospectively registered at ClinicalTrials.gov at October 2017 (NCT03299621).

Comparison of the effect of electromyogram activity during emergence on anesthetic depth monitoring between phase lag entropy and bispectral index: a prospective observational study

“…Therefore, theoretically, the PLE score could be less affected by EEG than the BIS; however, there have been few studies on the relationship between the PLE score and PLE-EMG. Although several studies showed PLE score has correlation with BIS for evaluating consciousness and depth of anesthesia during general anesthesia (11,12,24), the present study is meaningful since it is the first to investigate the PLE-EMG effect on the PLE score.…”

“…A previous study reported no changes in the BIS score even after 10 min of sugammadex reversal (22); however, the EMG activity was a single entity rather than dividing it into low and high groups, which may differ from other studies. The PLE monitor has been recently approved for clinical use, with several studies assessing its usefulness and comparison with the BIS; moreover, it has been shown as useful for LOC evaluation in general anesthesia (11,12,23,24). PLE employs EEG signals with ranges of 0.1-1 and 32-45 Hz while PLE-EMG uses signals >45 Hz.…”

Monitoring of Anesthesia by Bispectral Analysis of EEG Signals

“…This algorithm is similar to PLE (phase lag entropy) that uses four-channel EEG to measure the temporal pattern diversity in the phase relationship of frequency brain signals [ 16 , 17 ].…”

Analysis : Electroencephalography Acquisition System: Analog Design

“…Electroencephalography (EEG) is a biosignal that is widely used in research and clinical practices, including pain quantification, 1 brain-computer interface applications (e.g. wheelchair control), 2,3 sleep studies, 4 anesthetic depth monitoring, 5 and diagnosis of conditions (e.g., epilepsy, head injuries, dizziness, brain tumors, psychiatric conditions). [5][6][7] This signal starts at a frequency of 0.1 to 0.7 Hz and ends at 30 to 100 Hz.…”

“…wheelchair control), 2,3 sleep studies, 4 anesthetic depth monitoring, 5 and diagnosis of conditions (e.g., epilepsy, head injuries, dizziness, brain tumors, psychiatric conditions). [5][6][7] This signal starts at a frequency of 0.1 to 0.7 Hz and ends at 30 to 100 Hz. It has an amplitude range from 10 to 100 µV.…”