Wavelet Entropy as a measure of Depth of Anaesthesia

Depth of Anaesthesia(DoA) is one of the advanced anaesthesia monitoring which helps to optimize the quantity of anaethestic drug delivered to a patient during surgery. This reduces the costs and improves patient outcomes. Present study aims to measure Depth of Anaesthesia(DoA) using Wavelet Analysis. Wavelet Entropy(WE) of the EEG signal is extracted as a measure of DoA from the EEG signals collected during the four phases of general anaesthesia called awake, induction, maintenance and recovery. In order to find out the wavelet entropy, EEG signals during anaesthesia were decomposed into its constituent frequency bands, then WE was calculated from the approximation and detail coefficients. Finally extracted WE is compared with BIS index, which is a commercially available DoA monitor.