الفهرس 
Depth of anesthesiaOnly 14 pages are availabe for public view
 |  | from | 162 |  |  |
| | | from | 162 | | |
Abstract
Anesthesia is a balance between anesthetic drug requirement and the
state of arousal of the patient.Inadequate doses lead to increase incidence of awareness, while generous administration of drugs leads to hemodynamic instability, delayed recovery, and increase in other complications. In the absence of central nervous system monitoring, hypnotic agents are traditionally administered on the basis of fixed dose regimen adjusted to the response of patient judged by clinical parameters including loss of verbal response. The fixed dosing regimen however does not consider the pharmacokinetic or pharmacodynamic variability between patients and may be a cause of frequent over or under dosing of induction agent in patients.Spectral entropy is a processed EEG variable that has been introduced recently in clinical practice for monitoring depth of anaesthesia. The entropy module (M-Entropy; Datex-Ohmeda, Helsinki, Finland) provides two different entropy values: The State Entropy(SE)and the Response Entropy(RE). SE is computed over the EEG dominant frequency band of the EEG(0.8–32 Hz) and ranges between 0 and 91. It is thought to reflect the hypnotic component of anaesthesia. RE is computed over a larger frequency domain(0.8–47 Hz) including both the EEG activity and the EMG activity of facial muscles, and ranges between 0 and 100. RE and the RE–SE gradient increase in response to nociceptive stimulations and are thought to reflect the nociceptive– anti-nociceptive balance during general anesthesia.