Spectral entropy and bispectral index as measures of the electroencephalographic effects of XXXX .

@entity1 @entity3290 @entity1875 @entity1009
Recently, Datex-Ohmeda introduced the Entropy Moduletrade mark for measuring depth of anesthesia. Based on the Shannon entropy of the electroencephalogram, @entity3290 ( @entity3290 ) and response entropy (RE) are computed. We investigated the dose-response relationship of @entity3290 and RE during @entity1875 anesthesia in comparison with the Bispectral Indextrade mark (BIS). Twenty @entity1 were studied without surgical stimulus. Anesthesia was induced by a constant @entity1875 infusion of 2000 mg/h (451 +/- 77 microg x @entity1009 ) x kg(-1)) via a large forearm vein. @entity1875 was infused until substantial burst suppression occurred (more than 50%) or mean arterial blood pressure decreased to <60 mm Hg. Hereafter, infusions were stopped until recovery of BIS values up to 60 was reached. Subsequently, the constant @entity1875 infusion of 2000 mg/h was restarted to increase depth of anesthesia and again decreased (infusion was stopped) within the BIS value range of 40-60. The coefficient of determination (R2) and the prediction probability (P(K)) were calculated to evaluate the performance of @entity3290 , RE, and BIS to predict changing @entity1875 effect-site concentrations. R2 values for @entity3290 , RE, and BIS of 0.88 +/- 0.08, 0.89 +/- 0.07, and 0.92 +/- 0.06, respectively, were similar. The calculated P(K) values, however, revealed a significant difference between @entity3290 and RE compared with BIS, with P(K) = 0.77 +/- 0.09, 0.76 +/- 0.10, and 0.84 +/- 0.06, respectively. BIS seems to show slight advantages in predicting @entity1875 effect-site concentrations compared with @entity3290 and RE, as measured by P(K) but not as measured by R2.
