Time‐frequency balanced spectral entropy as a measure of anesthetic drug effect in central nervous system during sevoflurane, propofol, and thiopental anesthesia

Abstract

All indices, RE, SE, and BIS, distinguished excellently between conscious and unconscious states during propofol, sevoflurane, and thiopental anesthesia. During burst suppression, Entropy parameters RE and SE, but not BIS, behave monotonously. During regaining of consciousness after a thiopental or propofol bolus, RE and SE values recovered significantly closer to their baseline values than did BIS. Response entropy indicates emergence from anesthesia earlier than SE or BIS.

Comparison of Spectral Entropy and Bispectral Index Electroencephalography in Coronary Artery Bypass Graft Surgery

“…Hence, reliable and more robust electroencephalographic devices are needed to secure continuous cerebral monitoring. One such method may be the spectral entropy of EEG realized in the M-entropy module (GE Healthcare, Brussels, Belgium) that was introduced in 2004 [7]. With this device, the digitized raw EEG signal is first transformed into the frequency domain by fast Fourier transformation to identify sinusoidal components and calculate its power spectrum.…”

To Compare the Dose of Propofol for Induction of Anaesthesia by Entropy Monitoring against Standard Induction dose in Elderly Patients

“…Sensitivity and specificity of the entropy were demonstrated in previous reports which showed that entropy is as efficient as Bispectral index in predicting changes in the hypnotic component of anaesthesia, and the changes in SE and RE values followed a similar pattern to the Bispectral index values during propofol induction in adults . (13,14) Also, Anderson and Jakobsson demonstrated good correlation between propofol sedation and entropy indices in young and elderly patients (15). Valjus and colleagues showed low entropy recording during the first 5 min of the anaesthesia .…”

Electroencephalography (EEG) and Unconsciousness

“…Approximate entropy can quantify the irregularity of data time series, i.e., the predictability of subsequent amplitude values based upon the knowledge of the previous amplitude values. Entropy of the EEG measures the regularity of the signal: high levels of entropy during anesthesia demonstrate that the subject is awake, whereas low levels of entropy correlate with deeper unconsciousness (Anderson et al , 2004, Bruhn et al , 2003, Hans et al , 2005, Vakkuri et al , 2004.…”

“…Researchers have demonstrated that LZC and ApEn can distinguish between awake and anaesthetized state of human subjects (Anderson, Barr, 2004, Bruhn, Bouillon, 2003, Ferenets et al , 2006, Ferenets et al , 2007, Hans, Dewandre, 2005, Kumar et al , 2007, Noh et al , 2006, Vakkuri, Yli-Hankala, 2004, Voss et al , 2006, Zhang, Roy, 2001). In sleep research ApEn was statistically significantly lower during Stage IV and higher during wake and REM sleep (Burioka et al , 2005, Papadelis et al , 2007.…”