General anesthesia (GA) is a state of loss of consciousness induced by anesthetic products. In a GA, two classes of products are usually used: on the one hand, hypnotics that are responsible for the sleep component (hypnosis) and memory loss (amnesia), and on the other hand opioids that have an analgesic role. The doses of hypnotic and morphine necessary to achieve this state of loss of consciousness and lack of response to painful stimulation vary from subject to subject, and during surgery depending on the intensity of the stimulus, requiring permanent adaptation to avoid overdose or underdosing, responsible for morbidity. Several monitors of the hypnotic component have been developed in recent years, which can now be used routinely, such as the Bispectral Index (BIS) or Spectral Entropy. However, there is currently no clinically validated technique for monitoring pain or the effect of opioids in the operating room. Spectral analysis of the electroencephalogram (EEG) revealed a significant decrease (-30%) in alpha spectral power, observed specifically in painful experimental conditions in healthy awake subjects. On the other hand, a painful experience is accompanied by transient changes in various parameters under vegetative control, whether cardiovascular, cutaneous or pupillary, essentially underpinned by the activation of the sympathetic system. The investigators hypothesize that a real-time dynamic analysis of the spectral power of EEG combined with that of cardiovascular vegetative parameters, cutaneous conductance and pupillary diameter is likely to be a marker of nociception under GA.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
EEG acquisition system BioSemi (Amsterdam, the Netherlands), enabling real-time measurement and continuous recording of EEG on up to 128 leads.
Chu Saint-Etienne
Saint-Etienne, France
ElectroEncephaloGram (EEG) Alpha spectral power
variations of the EEG parameters (spectral power of the alpha rhythms), during nociceptive stimuli performed under AG at constant hypnosis depth (BIS between 50 and 60), without and after injection of a standardized dose of morphine (0.2 μg / kg of sufentanil based on the theoretical weight) of the patient).
Time frame: 1 day
Beta spectral power
variations of the EEG parameters (spectral power of the beta rhythms), during nociceptive stimuli performed under AG at constant hypnosis depth (BIS between 50 and 60), without and after injection of a standardized dose of morphine (0.2 μg / kg of sufentanil based on the theoretical weight) of the patient).
Time frame: 1 day
gamma spectral power
variations of the EEG parameters (spectral power of the gamma rhythms), during nociceptive stimuli performed under AG at constant hypnosis depth (BIS between 50 and 60), without and after injection of a standardized dose of morphine (0.2 μg / kg of sufentanil based on the theoretical weight) of the patient).
Time frame: 1 day
delta spectral power
variations of the EEG parameters (spectral power of the delta rhythms), during nociceptive stimuli performed under AG at constant hypnosis depth (BIS between 50 and 60), without and after injection of a standardized dose of morphine (0.2 μg / kg of sufentanil based on the theoretical weight) of the patient).
Time frame: 1 day
theta spectral power
variations of the EEG parameters (spectral power of the tetha rhythms), during nociceptive stimuli performed under AG at constant hypnosis depth (BIS between 50 and 60), without and after injection of a standardized dose of morphine (0.2 μg / kg of sufentanil based on the theoretical weight) of the patient).
Time frame: 1 day
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