Hypothermia and etomidate. Electroencephalographic aspects

Etomidate 0.3 mg/kg was injected in 30 seconds to patients submitted to coronary surgery under ECC (output = 2.4 l/min/m2) and moderate hypothermia (29 degrees). The effect of this injection on the EEG was investigated in 3 patients by the traditional EEG monitoring (bipolar fronto-parietal derivation) as well as in 12 patients by the Berg-Fourier spectral analysis. At 29 degrees C etomidate induces an EEG depression in the form of burst suppression periods of 3 to 10 seconds lasting for about 4 minutes. After etomidate injection, the electric activity measured between 0.5 Hz and 32 Hz in 7 patients remained for 4.5 minutes (+/- 1.5 min.) lower than 20% of the value noted prior to the injection. The significance of this important EEG decrease as well as the possible protective effect of etomidate against cerebral anoxia are discussed.