ABSTRACT
BACKGROUND: Phase-lag entropy (PLE) was recently described as a measurement of temporal pattern diversity in the phase relationship between two electroencephalographic signals from prefrontal and frontal montages. This study was performed to evaluate the performance of PLE for assessing the depth of sedation. METHODS: Thirty adult patients undergoing upper limb surgery with a brachial plexus block were administered propofol by target-controlled infusion. The depth of sedation was assessed using the Observer's Assessment of Alertness/Sedation (OAA/S) scale. The effect-site concentration (Ce) of propofol was initially started at 0.5 μg/ml and was increased in increments of 0.2 μg/ml until an OAA/S score of 1 was reached. Three minutes after the target Ce was reached, the PLE, bispectral index (BIS), and level of sedation were assessed. Correlations between the OAA/S score and PLE or BIS were determined. The prediction probabilities (P(k)) of PLE and BIS were also analyzed. RESULTS: The PLE values were closely correlated with the OAA/S scores (Spearman's Rho = 0.755; P < 0.001) to an extent comparable with the correlation between the BIS and OAA/S score (Spearman's Rho = 0.788; P < 0.001). The P(k) values of PLE and BIS were 0.731 and 0.718, respectively. CONCLUSIONS: PLE is a new and reliable consciousness monitoring system for assessing the depth of sedation induced by propofol, which is comparable with the BIS.
Subject(s)
Adult , Humans , Brachial Plexus Block , Consciousness Monitors , Electroencephalography , Entropy , Propofol , Upper ExtremityABSTRACT
BACKGROUND@#Phase-lag entropy (PLE) was recently described as a measurement of temporal pattern diversity in the phase relationship between two electroencephalographic signals from prefrontal and frontal montages. This study was performed to evaluate the performance of PLE for assessing the depth of sedation.@*METHODS@#Thirty adult patients undergoing upper limb surgery with a brachial plexus block were administered propofol by target-controlled infusion. The depth of sedation was assessed using the Observer's Assessment of Alertness/Sedation (OAA/S) scale. The effect-site concentration (Ce) of propofol was initially started at 0.5 μg/ml and was increased in increments of 0.2 μg/ml until an OAA/S score of 1 was reached. Three minutes after the target Ce was reached, the PLE, bispectral index (BIS), and level of sedation were assessed. Correlations between the OAA/S score and PLE or BIS were determined. The prediction probabilities (P(k)) of PLE and BIS were also analyzed.@*RESULTS@#The PLE values were closely correlated with the OAA/S scores (Spearman's Rho = 0.755; P < 0.001) to an extent comparable with the correlation between the BIS and OAA/S score (Spearman's Rho = 0.788; P < 0.001). The P(k) values of PLE and BIS were 0.731 and 0.718, respectively.@*CONCLUSIONS@#PLE is a new and reliable consciousness monitoring system for assessing the depth of sedation induced by propofol, which is comparable with the BIS.
ABSTRACT
OBJECTIVE: Although the reference value of cardiac index (CI) is derived by pulmonary arterial pressure, the use of pulmonary arterial catheterization is limited by low cost effectiveness and many concerns regarding complications. Therefore, relatively noninvasive indirect measurement is used widely perioperatively. The goal of this study was to determine the accuracy of the CI derived by Mobil-O-Graph NG (cCI) noninvasively in patients undergoing general anesthesia by comparing that measured by FloTrac/Vigileo (fCI), the minimal invasive method. METHODS: The Bland-Altman method was used to quantify agreement. Bias (mean difference between fCI-cCI) represents the systematic error between methods and precision (standard deviation of the bias) represents the random error or variability between techniques. The percentage error was considered clinically acceptable, and the tested method (Mobil-O-Graph NG) was regarded as interchangeable with the reference method (FloTrac/Vigileo), if it was below 30%. RESULTS: One hundred and ninety-five patients were included in this study, and CI, measured in the 121 patients. The Bland-Altman analysis revealed a bias −0.01 and the percentage error of 32.4%. And the difference is inversely increased according the mean CI. CONCLUSION: Results showed that CI measured by Mobil-O-Graph NG had a wide limit of agreement with that measured by FloTrac/Vigileo, therefore regarded as not interchangeable.