Duration and Depth of Anesthesia Induced by a Bolus of Etomidate

Induction of general anesthesia requires to be safe and to ensure a proper level of anesthesia. A proper anesthesia is sufficient to guarantee loss of consciousness and amnesia and without being too depth leading to a electroencephalogram (EEG) with burst suppression. The depth of anesthesia is monitored by the bispectral index analyse of the EEG, this allows to detect any under- or over-dose of anesthesia. The monitoring works with an unknown algorithm (patent), which evaluate the state of consciousness in the patient. Etomidate and propofol are commonly use to ensure general anesthesia. Actually, really few litterature has objective informations about the monitoring of Etomidate. The few existant are the old ones and has just a clinical evaluation of the depth of anesthesia (loss of consciousness, loss of breathing, loss of palpebral reflex). Except the fact that these clinical evaluations come from the brain stem, and in fact are not reliable to assess the cortical activity which is reduced by etomidate. Therefore, some anesthetists are fearful that etomidate is not sufficient to ensure a proper anesthesia to intubate the patient. This interventionnal study has two purpose. Firstly, a survey will be conduct about the habits and beliefs when use of etomidate. Secondly, a prospective study will be conduct to monitore with the bispectral index the depth and duration of anesthesia with etomidate.