Temporal linear mode complexity as a surrogate measure of the anesthetic drug effects during sevoflurane anesthesia

Abstract

BackgroundThe aims of this study were to compare the stability, correlation with end-tidal sevoflurane, and area below the effect (AUCeffect) vs. time curves of temporal linear mode complexity (TLMC) and approximate entropy (ApEn) during sevoflurane anesthesia. Another study goal was to characterize the time course of the effects of sevoflurane.MethodsElectroencephalogram (EEG) parame1ter stability was evaluated using the coefficients of variation (CV) of the median baseline (E0), maximal (Emax), and individual median E0 - Emax values. Correlations between sevoflurane concentration and EEG parameters were tested. AUCeffect vs. time curves of TLMC and ApEn were calculated to quantitate any decrease in central nervous system activities. A sigmoid Emax model was used for pharmacodynamic modeling.ResultsTLMC and ApEn demonstrated CVs of 8.36 and 7.35 (for E0) and 19.61 and 13.45 (Emax), respectively. The CVs of the individual median E0 - Emax values were 65.16 for TLMC and 59.97 for ApEn. The Spearman correlation coefficient was -0.3103 for TLMC and -0.3410 for ApEn (P < 0.001 for both parameters). The median AUCeffect value was 338.9 for TLMC and 246.5 for ApEn (P = 0.457). The final pharmacodynamic parameters estimated by sigmoid Emax models were described as follows; E0: 0.614, 0.617, Emax: 0.334, 0.287, Ce50: 5.48, 5.07 vol%, γ: 1.88, 2.01, ke0: 0.306, 0.236 min (TLMC, ApEn).ConclusionsTLMC is comparable to ApEn according to the univariate EEG descriptors of the effects of sevoflurane. A sigmoid Emax model well described the pharmacodynamics of sevoflurane for TLMC and ApEn.

A semi-compartmental model describing the pharmacokinetic-pharmacodynamic relationship

“…This approach may demonstrate an advantage over the full parametric approach when model misspecification is observed in the PK model [ 15 ]. Moreover, this semi-compartmental model could be employed in studies where the measured concentration data are difficult to apply to the compartmental PK model, including the PD analysis of inhalational anesthetics using the end-tidal inhalational anesthetics concentration data (PK data) and PD data obtained by electroencephalogram based sedation depth measurements [ 16 , 17 ].…”

Response surface modelling of the pharmacodynamic interaction between propofol and remifentanil in patients undergoing anaesthesia

“…Temporal linear mode complexity (TLMC) measures the complexity of the temporal linear mode in a single‐channel electroencephalogram (EEG) irrespective of the length of the recording . The appropriateness of TLMC as a surrogate measure of the effects of remifentanil and sevoflurane on the central nervous system was evaluated in our preliminary studies . However, little is known about the usefulness of TLMC for quantifying the effect of propofol and remifentanil on the central nervous system.…”

“…17 The appropriateness of TLMC as a surrogate measure of the effects of remifentanil and sevoflurane on the central nervous system was evaluated in our preliminary studies. 17,18 However, little is known about the usefulness of TLMC for quantifying the effect of propofol and remifentanil on the central nervous system. This study constructed response surfaces for the probability of occurrence for muscle rigidity, apnoea and loss of consciousness (LOC) and compared the response surface parameters for ApEn and TLMC across clinically relevant concentrations of propofol and remifentanil administered to surgical patients.…”