A wavelet transform based method to determine depth of anesthesia to prevent awareness during general anesthesia

Awareness during general anesthesia for its serious psychological effects on patients and some juristically problems for anesthetists
has been an important challenge during past decades. Monitoring depth of anesthesia is a fundamental solution to this problem.
The induction of anesthesia alters frequency and mean of amplitudes of the electroencephalogram (EEG), and its phase couplings.
We analyzed EEG changes for phase coupling between delta and alpha subbands using a new algorithm for depth of general
anesthesia measurement based on complex wavelet transform(CWT) in patients anesthetized by Propofol. Entropy and histogram
of modulated signals were calculated by taking bispectral index (BIS) values as reference. Entropies corresponding to different BIS
intervals usingMann-Whitney