Clinical Trial: Relationship Between Bispectral Index (BIS) and Spectral Entropy (SpEn) During Desflurane Anaesthesia

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Relationship Between Bispectral Index (BIS) and Spectral Entropy (SpEn) During Desflurane Anaesthesia

Brief Summary: The aim of this study was to estimate the relationship between BIS and Spectral Entropy values and any explicit or implicit memory or dreams recall during desflurane anaesthesia.

Detailed Summary:

During the last decade, an increasing number of monitor systems were developed designed to assess the depth of anesthesia.

Awareness is a rare occurrence of explicit recalls during anaesthesia with an incidence of 0,18% and the use of cerebral monitoring prevents about 50% of these events.

Different stages of awareness should be defined and implicit memorization is subconscious awareness without explicit recall and possible implicit recall with an incidence greater than awareness.

To assess implicit recalls, a large number of test can be used, for example the "word stem completation test" and the "free recall association test". These result easy to use and reliable in detect implicit memory.

Bispectral Index (BIS) and Spectral Entropy (SpEn) has been proposed, in recent years, as electroencephalographic monitors of anaesthesia depth.

The bispectral index is a monitor of anaesthetic depth approved by the Food and Drug Administration in the USA. The BIS monitor reports a dimensionless number between 0 (complete EEG inactivity) and 100 (awake state); BIS values from 40 to 60 are thought to be suitable for general anaesthesia. Spectral Entropy acquires the electroencephalograph (EEG) and frontal electromyography (FEMG) signals which are processed into three parameters: State Entropy (SE), Response Entropy (RE) and Burst Suppression Ratio (BSR).

SE is computed over the EEG dominant part of the spectrum (0.8-32 Hz), and therefore primarily should reflect the cortical state of the patient and results useful to assess hypnotic effects of drugs .

RE is computed over
Sponsor: Catholic University of the Sacred Heart

Current Primary Outcome: BIS index [ Time Frame: change from baseline at 15 min ]

Original Primary Outcome: Same as current

Current Secondary Outcome: entropy values [ Time Frame: 24 h after emergency from anaesthesia ]

Original Secondary Outcome: Same as current

Information By: Catholic University of the Sacred Heart

Dates:
Date Received: November 12, 2012
Date Started: September 2008
Date Completion:
Last Updated: May 30, 2013
Last Verified: May 2013